Nutrition tube system disposed within the body of a subject

Abstract

To provide an apparatus for accessing and monitoring the gastrointestinal tract.SOLUTION: A feeding tube system may generally comprise a gastric access device having a longitudinal portion, a controller in communication with the gastric access device, and one or more impedance or conductivity sensors positioned along the longitudinal portion, and one or more temperature sensors positioned along the longitudinal portion. The controller may be configured to receive a first signal associated with the impedance or conductivity sensors and a second signal associated with respiration, and determine whether placement of the gastric access device is within the stomach of a subject.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to the installation / monitoring of a nutrition tube, as well as the measurement of gastric volume, gastric cavity formation, detection and management of gastric juice reflux. Incorporation by reference All publications and patent applications cited herein are hereby incorporated by reference in the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

Background Art

[0002] Enteral nutrition is performed using a nutrition tube when a patient is unable to ingest nutrients orally, is unable to safely swallow, or needs to supplement nutrients additionally.

[0003] There are also problems with inserting a gastric tube (nasoenteric tube, here referred to as an NG tube, or also called a nutrition tube). If the NG tube accidentally enters the trachea instead of the esophagus, it can lead to complications or death. Also, a solution is needed to accurately place the NG tube in the digestive tract (i.e., the esophagus, stomach, or intestine) rather than in the trachea or lungs.

[0004] It is also important to monitor the nutritional status of a patient to prevent undernutrition or overnutrition. The term "GRV" as used in this specification refers to Gastric Residual Volume, gastric cavity formation, gastric residual food, gastric motility, or gastric state.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In enteral nutrition, it is also important to prevent, identify, and manage gastric juice reflux because the reflux of gastric juice can enter the lungs and cause serious complications.

Means for Solving the Problems

[0006] This specification discloses embodiments of a gastric access device that improves the ability to access the GI tract with confidence and avoids inadvertent entry into the patient's trachea / lungs. The embodiments include one or more sensor types to determine whether the device is in the GI tract or in the trachea / lungs. There are also sensor types that actively identify the GI (gastrointestinal) tract, such as impedance / conductivity sensors, pH sensors, ECG (electrocardiogram) sensors, pressure sensors, etc. There are also sensor types that actively identify the trachea / lungs, such as temperature sensors, humidity sensors, O2 sensors, CO2 sensors, flow sensors, acoustic sensors, pressure sensors, etc. Some of these sensors can identify both. To properly position the device in the GI tract (or trachea / lungs), a sensor that is at least one sensor type that actively identifies the GI tract and a sensor that is at least one sensor type that actively identifies the trachea / lungs can be used in combination. Alternatively, two different sensor types that actively identify the GI tract can be used to properly position the device. Alternatively, two different sensor types that actively identify the trachea or lungs can be used to properly position the device.

[0007] In some embodiments, only one sensor type is required to properly position the device. In some embodiments, two sensor types are available for properly positioning the device. In some embodiments, three sensor types are available for properly positioning the device. Not all sensor types available are available to all patients in all environments.

[0008] One or more of any sensor type can be used along the longitudinal portion of the gastric access device. In some embodiments, two or more sensors are arranged on or along the gastric access device such that at least one sensor is in a functional position. For example, at least one temperature sensor is in a position to measure the surrounding fluid, and two or more temperature sensors can be arranged along the gastric access device so that the device does not hit the tissue when it advances. For example, two or more temperature sensors may be arranged at multiple locations in the circumferential direction of the device. Alternatively, or in addition, two or more temperature sensors may be arranged at two or more locations along the length direction of the device.

[0009] The monitor / control unit of the device may analyze the signals of one or more types of sensors to determine the position of the device. Depending on the type of signal, it may be more reliable than other signals and may be given priority over other signals. Depending on the type of signal, some signals may take more time to analyze, some may confirm previous signals, and some may not. The monitor can receive signals from the sensors continuously, intermittently, or as needed. Depending on the type of signal, some can be received and analyzed basically in real time, while some take time to receive and analyze.

[0010] Some embodiments of the gastric access device include the function of monitoring gastric residual volume or gastric cavitation. In some embodiments, the function of controlling the supply rate and / or supply amount based on the gastric residual volume or gastric cavitation is included.

[0011] Some embodiments of the gastric access device include preventing, identifying, and / or managing gastric reflux.

[0012] In some embodiments, the sensor type can also be used for patient monitoring. For example, a temperature sensor can be used both to determine the position of the device and to monitor the patient's temperature once the device is installed. Impedance / conductivity sensors can be used for at least one of determining the position of the device, confirming reflux, and monitoring gastric residual volume and gastric emptying over time after device attachment. An ECG sensor is used not only when installing the device but also to monitor the patient's ECG after the device is installed. The ECG sensor, impedance / conductivity sensor, and / or other sensors can use the same or different electrodes.

[0013] In one embodiment, a nutrition tube system generally includes a gastric access device having a longitudinal portion, a control unit in communication with the gastric access device, and one or more impedance or conductivity sensors disposed along the longitudinal portion, wherein at least one impedance or conductivity sensor is disposed at or proximate to the distal end of the longitudinal portion. Each of the one or more impedance or conductivity sensors communicates with the control unit, and the control unit is configured to receive a first signal and to confirm that the first signal indicates an impedance level or conductivity level of a fluid in contact with the one or more impedance or conductivity sensors within the subject's body. Additionally, one or more temperature sensors may be disposed along the longitudinal portion and communicate with the control unit, and the control unit is further configured to receive a second signal and to confirm that the second signal is associated with respiration and indicates a temperature level of the environment within the subject's body in contact with the one or more temperature sensors. Further, the control unit may be configured to receive the first signal and the second signal and to determine whether the gastric access device is positioned within the subject's stomach.

[0014] In the method of use according to one embodiment, the method of placing the device in the subject's stomach generally includes the step of detecting the impedance level or conductivity level of the fluid in the subject's body when one or more impedance or conductivity sensors arranged along the longitudinal portion of the gastric access device come into contact with the fluid as the gastric access device advances in the subject's body. Additionally, the method includes the step of detecting the temperature level of the environment in the subject's body associated with breathing using one or more temperature sensors arranged along the longitudinal portion, the step of receiving a first signal from the one or more impedance or conductivity sensors and a second signal from the one or more temperature sensors at a control unit that communicates with the gastric access device, and the step of determining by the control unit when the first signal indicates fluid in the stomach and the second signal indicates that there is no temperature signal of the environment in the subject's body associated with breathing.

[0015] In a nutritional tube system according to another embodiment, the system generally includes a gastric access device having a longitudinal portion, a control unit that communicates with the gastric access device, and one or more impedance or conductivity sensors disposed along the longitudinal portion, wherein at least one impedance or conductivity sensor is disposed at or proximate to the distal end of the longitudinal portion. Each of the one or more impedance or conductivity sensors communicates with the control unit, and the control unit is configured to receive a first signal and to confirm that the first signal indicates an impedance level or conductivity level of the environment within the subject's body in contact with the one or more impedance or conductivity sensors. Additionally, one or more temperature sensors are disposed along the longitudinal portion and communicate with the control unit, and the control unit is further configured to receive a second signal and to confirm that the second signal indicates a temperature level of a region within the subject's body associated with respiration in contact with the one or more temperature sensors. Further, the control unit may be configured to indicate a temporary stop of the advancement of the gastric access device into the subject's body until the second signal indicates that there is no temperature level of the region associated with respiration.

[0016] In another embodiment of the method of placing a device in a subject's stomach, the method generally includes one or more impedance or conductivity sensors disposed along the longitudinal portion of the stomach access device sensing the impedance or conductivity level of the environment within the subject's body when the stomach access device comes into contact with fluid as it advances within the subject's body, and using one or more temperature sensors disposed along the longitudinal portion to sense the temperature level of the area associated with respiration within the subject's body. Additionally, the method can include receiving at a control unit in communication with the stomach access device a first signal from one or more impedance sensors or conductivity sensors and a second signal from one or more temperature sensors, and temporarily stopping the advancement of the stomach access device into the subject until the second signal indicates that the temperature level of the area associated with respiration is absent.

Brief Description of the Drawings

[0017]

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[0018] Various exemplary embodiments are described in detail with reference to the following figures.

[0019] For the sake of convenience in explanation, the exemplary embodiments will be described below with reference to the figures in the context of the installation of a nutrition tube, the evaluation of gastric residual volume / gastric emptying, the prevention / detection / management / monitoring of gastric juice reflux in patients.

[0020] Figure 1 is a diagram showing a gastric access device according to an embodiment at a predetermined location of a human body tissue. The anatomical tissues include the esophagus 102, the stomach 104, the trachea 106, the lungs 108, and the heart 110. The gastric access device 112 is shown in a state of advancing into the stomach through the esophagus. The gastric access device includes one, two, three, or more types of sensors, and not only assists in accessing the stomach or other regions of the gastric pathway, but also evaluates gastric residual volume or gastric cavitation during nutrition supply, and prevents, identifies, and / or manages reflux. The gastric access device can include a lumen for introducing nutrition into the patient's stomach. Alternatively, the gastric access device may be used in combination with (inside or alongside) a nutrition tube.

[0021] In Figure 1, two types of sensors, type 1 shown at 114 and type 2 shown at 116, are shown. In some embodiments, sensor type 1 is a pair of electrodes, or a plurality of electrodes, for detecting impedance or conductivity. The type 2 sensor is a temperature sensor. Other types of sensors include humidity sensors, pressure sensors, chemical sensors, ECG sensors, EGG (Electrogastrogram) sensors, pH sensors, optical sensors, and the like. For example, pressure sensors and humidity sensors can be used to detect pressure and humidity fluctuations associated with breathing, and as a result, determine when the device is in the trachea / lungs.

[0022] The sensor may be used to assist in the placement of the device, or may be used for the evaluation of gastric cavity formation and contents, prevention of reflux, identification, and / or management, or may be used for any two or more of these purposes. For example, some embodiments of the gastric access device include at least one impedance sensor that measures the impedance of the environment surrounding the sensor and at least one temperature sensor. One or more impedance sensors are used for device placement, monitoring of gastric cavity formation, reflux, etc., and one or more temperature sensors may be used for device placement and, in some cases, continuous monitoring of the patient's body temperature.

[0023] One or more temperature sensors can be used for device placement by detecting relatively small temperature fluctuations caused by the sensor sucking in ambient air at a temperature different from body temperature. For example, ambient air at room temperature is usually at a lower temperature than body temperature. If the gastric access device is inadvertently advanced into the trachea instead of the esophagus, one or more temperature sensors of the gastric access device will detect temperature changes associated with breathing. These temperature fluctuations do not occur when the gastric access device is placed in the gastrointestinal system, i.e., the esophagus, stomach, or intestine.

[0024] The temperature sensor on the gastric access device transmits the temperature signal from the sensor to the control unit via a lead wire within the gastric access device. This temperature signal will indicate fluctuations associated with breathing if the gastric access device is inadvertently placed in the trachea or lung. This is a dangerous error and is important because if nutrition is later inadvertently introduced into the lung, it can cause complications and even death.

[0025] The embodiment of FIG. 1 may include, for example, two or more impedance sensors 114 and two or more temperature sensors 116. The impedance sensors can be used for device placement, measurement of gastric residual volume (GRV) / gastric emptying, and measurement of reflux. Details of embodiments including GRV / gastric cavity formation using impedance sensors or other sensors are described in U.S. Patent Application Publication No. 2017-0071502, filed Nov. 23, 2016, U.S. Patent Application Publication No. 2016-0331298, filed Jul. 28, 2016, and U.S. Patent Application Publication No. 2018-0078195, filed Nov. 13, 2017, each of which is hereby incorporated by reference in its entirety. The temperature sensors can also be used to confirm device placement and, depending on the situation, can be used as a primary indicator of placement.

[0026] FIG. 2 is a diagram showing the relative conductivity detected by an impedance sensor or a conductive sensor incorporated in a gastric access device in different regions of anatomical tissue. The stomach is characterized by having a higher conductivity than the lungs. When the gastric access device advances from the nose or mouth into the esophagus and perhaps into the stomach, one or more conductivity / impedance sensors can generally identify that the distal tip of the device has entered the stomach by an increase in conductivity (or a decrease in impedance) due to contact with the fluid contents of the stomach, which have a higher conductivity (lower impedance) than the esophageal environment or fluid. This detection is also in real time, i.e., quite rapidly on the order of less than 1 second or a few seconds (1 to 4 seconds). However, there may be situations where such changes in impedance / conductivity are not clear, or where the impedance / conductivity sensors on the gastric access device detect highly conductive regions in the trachea or lungs, for example, when the sensors are buried in mucus or pressed against tissue.

[0027] A secondary detection system can be utilized to confirm that the gastric access device is positioned in the stomach rather than the lungs or trachea. For example, one or more temperature sensors can be used on the gastric access device to detect temperature variations or the absence of temperature variations caused by respiration. If temperature changes associated with respiration are detected, the device likely has entered the trachea or lungs and thus needs to be retracted. If no temperature changes associated with respiration are detected and one or more impedance sensors indicate high conductivity / low impedance, the device is likely in the stomach. Temperature variations associated with respiration may, for example, likely have a frequency associated with respiration.

[0028] 6 weeks from birth: 30 to 40 breaths per minute 6 months: 25 to 40 breaths per minute 3 years: 20 to 30 breaths per minute 6 years: 18 to 25 breaths per minute 10 years: 17 to 23 breaths per minute Adult: 12 to 18 breaths / min Elderly over 65 years old: 12 to 28 breaths / min Elderly over 80 years old: 10 to 30 breaths / min The control unit may incorporate a frequency filter that filters these respiratory frequencies or other respiratory frequencies to separate temperature variations associated with respiration from the temperature signal over time.

[0029] The control unit / monitor can use these frequencies to determine whether the temperature variations are associated with respiration. This signal needs to be analyzed over multiple breaths, and as a result, it may take the control unit longer to analyze than the impedance / conductance signal. It may take 8 to 15 seconds or 10 to 20 seconds to determine whether the temperature signal represents respiration. As a result, the temperature measurement can be used as a secondary indicator regarding the placement of the device, i.e., as a confirmation of placement by the impedance sensor indicator. The user may be prompted by the device to temporarily stop the advancement of the device while this confirmation is being performed.

[0030] Figures 3 and 4 show the measured values of a gastric access device with two temperature sensors, one sensor at 18 cm from the distal tip of the device and one sensor at 40 cm from the distal tip of the device. FIG. 3 shows the temperature measurement values when the device is placed in the patient's esophagus or stomach. FIG. 4 shows the temperature measurement values when the device is placed in the patient's trachea or lung. In some embodiments, at least one temperature sensor may be configured to be disposed within the trachea when the tip of the device is in the patient's lung.

[0031] FIG. 4 shows the variation of the temperature signal associated with respiration that is not present in FIG. 3. When the temperature sensor is in contact with or embedded in the tissue, temperature variations in the environment around the tissue may not be detected even if there are temperature variations. This is shown in the top graph of FIG. 4. As the device is advanced into the lung, the most distal sensor becomes buried in the tissue and the temperature signal becomes flat. In the second temperature sensor located more proximally, temperature variations are clearly shown in the lower graph of FIG. 4. Because of such a phenomenon, two or more temperature sensors are effective, and the control unit searches for temperature variations associated with respiration from at least one of the temperature sensors. Also, the temperature sensor (or any sensor) may be disposed at different locations in the longitudinal and / or circumferential directions of the device. For example, the temperature sensors can be arranged in the radial direction of the gastric access device, 180 degrees apart from each other, and / or along the longitudinal direction.

[0032] In some embodiments, a temperature sensor is used to detect the temperature at the time and location where the device first enters the body. The temperature sensor may detect temperature variations due to the patient's breathing in the throat when the device is inserted. These variations may stop when the device passes through the junction between the trachea and the esophagus. Since this distance is a relatively short distance (about 5 to 15 cm) within the patient's body, the flattening of the temperature variations at this distance can be an indicator that the device is properly descending and propagating between the esophagus and the trachea. Thus, the flattening or disappearance of the temperature variations at a relatively short distance into the patient's body is a further indicator that the device is properly positioned. Alternatively, the fact that the temperature variations do not flatten or increase in magnitude when the device is advanced indicates that the device is advancing into the trachea. The distance beyond the lips where the device has advanced may be automatically determined by the system using dimensional markings or indicators along the longitudinal portion of the device's shaft and a camera or other detection mechanism at the lip / device inlet.

[0033] In some embodiments, one or more temperature sensors on the feeding tube can detect the ambient temperature prior to the tube being inserted into the patient's body. In some embodiments, an ambient temperature sensor built into the control unit, or an ambient temperature sensor at the proximal end of the feeding tube remaining outside the patient's body, etc., can be used to continuously or intermittently measure the ambient temperature over time. The ambient temperature sensor may be separated from both the feeding tube and the control unit, but is in communication with the control unit. The ambient temperature can be used to determine the relative temperature of the patient at anatomically different locations by comparing the temperature detected by the sensor on the feeding tube with the ambient temperature. In this way, relative temperatures can be measured at different locations within the anatomical tissue along the feeding tube. Also, the average temperature may be obtained by looking at the attenuated temperature signal. The average or attenuated temperature signal may not show the same fluctuations in lung temperature or there may be no fluctuations in esophageal temperature, but if the ambient temperature is lower than body temperature, the average lung temperature will be lower than the esophageal temperature. By monitoring the average / attenuated temperature at one, two, or along the feeding tube while advancing the device, the control unit can roughly determine the position of the device within the anatomical tissue. Different signals at different locations along the longitudinal portion of the feeding tube provide temperature information (either average temperature or temperature fluctuations), indicating whether the segment of the feeding tube is in the pharynx, trachea, esophagus, lung, stomach, intestine, or in contact with tissue. Other sensors, such as impedance / conductivity sensors, can also be used to assist in location identification. For example, if the temperature sensor is measuring body temperature and there are no temperature fluctuations, the portion of the feeding tube equipped with these sensors may be in the stomach or in contact with tissue. It may be possible to distinguish between the two with a conductivity / impedance sensor. Also, sensor types such as ECG and pH can be used.

[0034] Figure 5 is a diagram showing the manner in which the gastric access device enters the lungs through the trachea. This is an undesirable situation and is identified as such in the embodiments of the gastric access device. With the impedance / conductivity sensor, a significant increase in conductivity as shown in the graph of Figure 2 cannot be detected. In addition, the temperature sensor detects temperature variations associated with breathing as shown in Figure 4. These signals are received by the control unit / monitor 502 via a wired or wireless connection 508 that is connected to the gastric access device 112 via the hub 510. The sensors on the access device 112 are electrically connected to the hub 510 via leads within the device 112 from the various sensors to the hub 510. The monitor 502 is also connected to the nutrition pump 504 via a wired or wireless connection 506 and may control the patient's nutrition supply via the nutrition supply lumen of the device 112 or via an individual nutrition supply tube. The monitor interprets one or more of these signals and indicates that the device needs to be retracted because it is not properly positioned.

[0035] Figure 6 is a diagram showing the gastric access device disposed within the patient's stomach. In this situation, the impedance / conductivity sensor indicates high conductivity and one or more temperature sensors indicate no temperature variations associated with breathing. The monitor interprets one or more of these signals and indicates that the device is properly positioned within the stomach.

[0036] Figure 7 is a flowchart showing an overview of the functionality of a control unit that communicates with a gastric access device equipped with one or more impedance / conductivity sensors and one or more temperature sensors. Box 702 represents that the control unit is instructing the user to advance the device into the patient's body. As the device advances, the control unit receives signals from the sensors incorporated in the gastric access device. The control unit can continue to instruct the user to advance the device until the impedance / conductivity sensor detects high conductivity or low impedance, or until one or more temperature sensors detect temperature variations associated with breathing.

[0037] When the control unit receives a signal from a temperature sensor indicating temperature fluctuations associated with breathing, as shown in Box 714, when the temperature sensor has passed the RGJ (Respiratory-Gastric Junction), the control unit indicates to the user that the device is likely in the trachea or lung, and as shown in Box 716, instructs the user to retract the device.

[0038] During the advancement of the device, as shown in Box 704, if the sensor first detects high conductivity, the gastric access device is in the stomach and the sensor may be detecting the contents of the stomach. The control unit can indicate that the device is in the stomach, or request a temporary stop of several seconds from the user by displaying or playing a temporary stop signal, collect the signal data of the temperature sensor, and determine whether there are fluctuations associated with breathing detected by the temperature sensor. As shown in Box 706, when these fluctuations are detected when the temperature sensor has passed the RGJ, the control unit can determine that the access device may have entered the lung and, as shown in Box 708, instruct the user to retract the device. If no temperature fluctuations are detected, as shown in Box 710, the control unit may confirm that the device is correctly positioned in the stomach, as shown in Box 712.

[0039] In addition to, or instead of, impedance / conductivity sensors and temperature sensors, other sensors can be used to determine the position of the gastric access device within anatomical tissue. For example, one or more electrocardiogram (ECG) sensors can be used to determine whether the gastric access device is above or below the heart. If the device is below the heart, it is likely to be in the stomach since it is not likely to be in the lungs or trachea. FIG. 8 shows the relative anatomical tissues of the lungs 108, heart 110, and stomach 104. Note that the stomach is below the heart and the lungs are above the heart or at about the level of the heart. Some embodiments of the gastric access device may include an ECG sensor 802 in addition to the impedance sensor 804. These sensors, like the other sensors of the gastric access device disclosed herein, have leads or wires that extend along the longitudinal portion of the device and connect the device to the device hub 510. The device hub is electrically connected to a monitor that receives signals from the various sensors. In some embodiments, both sensor types utilize the same electrodes.

[0040] The ECG sensor detects the electrical activity of the heart, including signals that contain, for example, a P zone, a Q zone, an R zone, an S zone, a T zone, a U zone, the origin of the signal, etc. The signals have magnitude and frequency, and the various zones may contain peaks of various positive and negative magnitudes. The gastric access device may be equipped with two or more ECG sensors on the device itself, such as sensor 804. Alternatively, the gastric access device may have one or more ECG sensors, and the system may include an external ECG sensor 806. Also, the external ECG sensor is electrically connected to the monitor, either wired or wirelessly. As the gastric access device advances, the ECG signal is continuously received by the monitor. Since the ECG sensor detects the electrical activity of the heart, the signal changes as the sensor passes through the esophagus, past the heart, and towards the stomach. These changes can be in the magnitude or direction (positive or negative) of one or more zones of the ECG signal. This change may vary depending on the position of the ECG sensor within the system. For example, a system with one ECG sensor on a feeding tube and one ECG on the sternum may exhibit different changes than a system with two or three ECG sensors on the feeding tube. This change may vary depending on the system configuration, but when the sensor passes through the heart, at least the relative position of one or more ECG sensors (the sensors on the feeding tube) with respect to the heart changes, so in the case of a given system configuration, the change is detected by the control unit.

[0041] Figure 8 shows the aspect of the feeding tube of the gastric access device when the sensor is approaching the height of the heart. At this point, it is still unclear from the measured values of the ECG sensor whether the access device is in the esophagus or the lung. However, as the device is advanced downward into the esophagus, the measured values of the ECG change to signs indicating that the device is passing through the heart. For example, the ECG signal may invert, a specific zone of the ECG may invert, the magnitude of the signal may change, or the magnitude of a specific zone of the ECG may change. Once the control unit detects this signature, it is determined that the gastric access device is in the stomach below the heart. The external ECG sensor 806 may or may not be present.

[0042] The ECG sensor, when used in combination with other sensors such as impedance / conductivity sensors and temperature sensors, helps to confirm the position of the gastric access device in the stomach. Any sensor type can share the same electrodes as other sensor types.

[0043] FIG. 9 shows a gastric access device according to an embodiment in which the ECG sensor is incorporated into a nose or nostril or mouth or face patch 902. This sensor can be placed outside the nose, inside the nose, outside the mouth, inside the mouth, or other locations on the face. This sensor may be incorporated, for example, into the nutrition tube itself of the gastric access device as part of the tape that holds the device in place.

[0044] FIG. 10 is a flowchart showing an overview of the functions of a control unit that communicates with a gastric access device equipped with one or more impedance / conductivity sensors and one or more ECG sensors. Box 1002 represents that the control unit is instructing the user to advance the device into the patient's body. As the device advances, the control unit receives signals from the sensors incorporated in the gastric access device. The control unit can continue to instruct the user to advance the device until the impedance / conductivity sensor detects high conductivity or low impedance, or one or more ECG sensors detect a change in the ECG signal indicating that the device has passed under the heart.

[0045] As shown in Box 1014, when the control unit receives a signal from the ECG sensor indicating that the device is below the heart, the control unit can indicate to the user that the device is likely in the stomach. Alternatively, or in addition, the control unit can also use the signal from the conductivity sensor to confirm the placement. As shown in Box 1016, when the control unit has not received a signal indicating high conductivity or low impedance from one or more impedance sensors on the device, the device does not seem to be in the stomach. Therefore, as shown in Box 1018, the control unit can instruct the user to retract the device. However, as shown in Box 1020, when the control unit receives a signal indicating high conductivity or low impedance from one or more impedance sensors on the device, the control unit indicates to the user that the device is likely in the stomach, as shown in Box 1022.

[0046] During the advancement of the device, if the sensor first detects high conductivity as shown in Box 1004, the gastric access device may be in the stomach. The control unit indicates that the device is in the stomach and / or the control unit may analyze the ECG sensor signal data to determine whether the ECG signal signature indicates that the device has passed through the heart. If this signature is detected as shown in Box 1006, the control unit determines that the access device is likely in the stomach and communicates as shown in Box 1008. If the ECG sensor signal signature indicates that the device has not passed below the heart as shown in Box 1010, the control unit indicates that the device may not be in the stomach and may indicate to retract and then advance the device again as shown in Box 1012.

[0047] Steps 1006 and 1014 (and similarly, step 704 of FIG. 7) indicating that the ECG signal indicates that the device is below the heart may include sub-steps of confirming that the end of the nutrient tube has not deviated to produce an inaccurate signal signature. This can be done by checking the impedance / conductivity between different sensors or between different pairs of electrodes and checking whether those different sensors or different pairs of electrodes are close to each other as compared to when the nutrient tube is relatively straight. For example, the control unit can quickly check whether there is an abnormally high conductivity between the most distal impedance sensor and the next closest impedance sensor. The control unit can subsequently check whether there is an abnormally high conductivity between the most distal impedance sensor and an impedance sensor one sensor away from the most proximal impedance sensor, etc. If there is no abnormally high conductivity between two impedance sensors on the nutrient tube, it is highly likely that the nutrient tube has not deviated and the ECG signal signature is reliable.

[0048] In the flowcharts presented thus far, the flow of the embodiment with two types of sensors has been shown. However, it should be understood that one type of sensor can verify or question the placement of the device based on the other type of sensor, and that the embodiments of the gastric access device can incorporate one, two, three, or more types of sensors. The sensors may operate independently, for example, for a specific patient type or under a specific environment, or may operate in cooperation as in the flowcharts introduced here. In addition, not all sensors are used for all patients. For example, embodiments of the present device can include, for example, three types of sensors: a temperature sensor, an impedance / conductance sensor, and an ECG sensor. Depending on the various patients and environments, one, two, or three types of sensors can be used. For example, the three sensors are used for most patients, but in a warm room, the temperature sensor may not be used. As another example, an ECG sensor may not be used for a patient with arrhythmia. In some embodiments, there are two types of sensors, and one or two types of sensors can be used for most patients and environments. In some embodiments, more than two types of sensors are provided for redundancy in placement verification.

[0049] Figures 11A, 11B, 12, and 13 are diagrams showing some embodiments of a gastric access device. Figure 11A shows the main device shaft 1102, the nutrition supply pump connector 1104, and the monitor connector 1106. Figure 11B is an enlarged view of the portion within the oval contour of Figure 11A. Figure 11B includes electrodes 1108, and any pair of electrodes represents an impedance / conductivity sensor. The pairs of electrodes constituting the sensors do not have to be adjacent to each other. Also shown is a temperature sensor 1110 such as a thermistor or a thermocouple, and further, an opening 1112 for the supplied nutrition to exit the device is shown. Also, Figure 11B shows an example of the distance from the tip of the device to various sensors. Figure 11B shows a device having two temperature sensors 1110 that are 180 degrees apart from each other in the circumferential direction and are at different points along the longitudinal portion of the device. Figure 12 shows four temperature sensors 1110, and the sensors are opposed to each other 180 degrees in the circumferential direction at two different positions along the longitudinal portion of the device. Although two locations are illustrated here, the temperature sensors may be installed at one location or at two or more locations. Figure 13 shows temperature sensors 1110 arranged so as to completely surround the device 360 degrees around. In these embodiments and other embodiments, when the device enters the lung, the temperature sensor can detect the fluctuations associated with breathing, and the control unit of the device can instruct the user to retract the device. As shown in Figure 4, having temperature sensors at multiple locations (either circumferentially, longitudinally, or both) helps to detect temperature fluctuations due to breathing in more situations. In some embodiments, the temperature sensors are arranged so as to be spaced apart from each other by more than 90 degrees in the circumferential direction. In some embodiments, the temperature sensors are arranged so as to be spaced apart from each other by more than 45 degrees in the circumferential direction. In some embodiments, at least two temperature sensors are arranged at one location in the circumferential direction. In some embodiments, at least three temperature sensors are arranged at one location in the circumferential direction. In some embodiments, at least four temperature sensors are arranged at one location in the circumferential direction. In some embodiments, at least two temperature sensors are arranged in the circumferential direction along the longitudinal portion of the device.In some embodiments, at least three temperature sensors are circumferentially arranged along the longitudinal portion of the device. In some embodiments, at least four temperature sensors are circumferentially arranged along the longitudinal portion of the device. Also, other configurations are envisioned. For example, temperature sensors can be installed in the monitor and a fluid path from the sensor to the nutrient tube can be ensured. Also, sensors other than temperature sensors can be arranged in the same way.

[0050] One or more temperature sensors can be arranged such that when the distal tip of the device is in the lung, it is in the trachea. For example, this sensor can be arranged at a position about 250 to 350 cm from the distal tip. Alternatively, it is also possible to arrange this sensor at a position about 200 to 400 cm from the distal tip. Alternatively, for a small patient, this sensor can also be arranged at a position about 100 to 150 cm from the distal tip. Alternatively, it is also possible to arrange this sensor at a position about 100 to 200 cm from the distal tip.

[0051] In some embodiments, one or more temperature sensors can be arranged outside the gastric access device. In some embodiments, one or more temperature sensors can be completely arranged within the wall portion of the gastric access device. In some embodiments, one or more temperature sensors can be arranged within the wall portion of the gastric access device such that the temperature sensors are exposed outside the device.

[0052] At least one of the ECG sensor and the temperature sensor may be separate from the impedance / conductance sensor, or may utilize some or all of the same electrodes. In embodiments using the same electrodes, different types of sensing (such as temperature, ECG, impedance / conductance, etc.) can be used alternately with the same electrodes, used at different locations or timings of the procedure, or used with different patients. Different or the same lead wires can be used for different functions of one electrode. Any of the sensors may use electrodes that completely surround the device, or may use electrodes that only partially surround the device.

[0053] FIG. 14 shows details of the monitor 502 in some embodiments. One or more display areas can display information to the user. For example, in the illustration, a tube placement display area 1402, a real-time nutrient supply rate display area 1404, and a nutrient supply rate over time area or nutrient supply rate trend area 1406 are shown. Other display areas may include gastric reflux inputs such as GRV / gastric emptying trend over time, real-time GRV / gastric emptying, placement instructions ("retreat", "pause", "continue", etc.), warning displays, warnings for avoidance, identification of reflux events, management, etc. Also, audible prompts and / or warnings can be streamed. The control buttons 1408 may include a power button, a setting button, etc., and may be physical buttons or touch panel buttons.

[0054] The configuration display area 1402 may include a graphic representation of anatomical tissues including the esophagus, stomach, and lungs / trachea. This display may include colors indicating correct placement, doubtful placement, and incorrect placement. For example, when one or more sensors detect that the device is inside the stomach, the stomach may blink or be displayed in green. When one or more sensors detect that the device is in the lungs, the lungs may blink or be displayed in red. If neither the stomach nor the lungs are detected by the sensors, the esophagus may blink in green or another color to instruct the user to continue moving forward. The distance the device has moved within the patient's body can be incorporated into the assessment of the placement. In some embodiments, the control unit communicates with sensors such as optical sensors that automatically measure the length of the device within the patient's body. When signals from multiple sensor types conflict, or when signals from any one sensor type conflict, the corresponding part of the body is displayed blinking or in orange.

[0055] More detailed information may be displayed in another location on the monitor. In some embodiments, after the body region indicator blinks, it may turn on when the information is confirmed. For example, when the device enters the stomach and the impedance sensor detects high conductivity, the shape of the stomach blinks in green (or indicates to the user to temporarily stop the advancement of the device, or indicates to stop before the user or the control unit starts the nutrient supply), preliminarily indicating that the control unit has determined that the device is inside the stomach. The control unit may subsequently continue to collect temperature sensor data over several seconds to tens of seconds. If this data determines that it is highly likely that the device is not in the lungs (there are no fluctuations associated with breathing), the shape of the stomach changes from a green blink to a green light (or the indication of a stop disappears), and the user can start the nutrient supply or continue the advancement of the device.

[0056] Alternatively, when the temperature sensor detects temperature fluctuations, the shape of the stomach may change to orange or red, indicating that it may have entered the lungs. Additionally, or alternatively, in this scenario, the lungs may turn red or orange. The control unit may instruct the user to retract the device or prevent the start of the nutrient supply function.

[0057] The pause for collecting temperature data can be at least 1 second, at least 3 seconds, at least 5 seconds, at least 7 seconds, at least 10 seconds, at least 15 seconds, etc. The pause may be in a form that instructs the user not to advance the device and / or not to start the nutrient supply via the device. With this pause, the control unit can prevent the start of nutrient supply by the device until the pause ends and the stomach is positively identified and confirmed.

[0058] Also, as indicators displayed on the display or indicated by sound or touch (such as vibration), - Pause - Pause for x seconds - Pause until the indicator (visual, sound, touch) instructs the device to advance or retract - Retract the device by x cm - Advance the device by x cm - Retract the device by x cm and then pause - Advance the device by x cm and then pause - Retract the device by x cm and then advance again, etc.

[0059] In some embodiments, the placement display 1416, and / or other displays, may alternatively or additionally be provided on the nutrition tube 1412 and / or on remote devices 1418 such as mobile phones, tablets, computers, servers, electronic medical records, etc. In some embodiments, the control unit functionality is fully or partially included in the remote display. For example, some embodiments of the device may not include the monitor housing 1410 and may include a stand-alone nutrition tube 1412 with a display 1416. This small display is fully portable and can incorporate all or part of the monitor / control unit functionality. Part of the monitor functionality may be incorporated into the remote electronic device 1418. Also shown is the nutrition supply input line 1414. The monitor housing 1410 may include a docking area where the nutrition tube docks so that the nutrition tube can operate with the placement display 1416 or with the full monitor display included in the housing 1410 when the nutrition tube is docked to the monitor.

[0060] Other display areas include data views such as a temperature data view and an ECG data view that graphs signals from sensors. Other display areas include backflow information such as risk, event, management, context (i.e., history) information, and trends.

[0061] The nutrition supply rate may depend on the detected GRV / stomach emptying and may be controlled automatically, semi-automatically, or manually by the control unit. Semi-automatic control means that small adjustments are made automatically and large adjustments prompt the user.

[0062] Figures 15A and 15B are diagrams showing a gastric access device according to one embodiment that includes one or more tissue sensing electrodes 1502 for detecting the impedance / conductivity of tissue upon contact with the tissue. These sensors can be used to identify the location of the LES (lower esophageal sphincter), UES (upper esophageal sphincter), and / or pyloric sphincter, or other regions of anatomical tissue. Since the sphincter has a smaller diameter compared to the surrounding tissue, it tends to be easier to identify with contact sensors. These can be identified by detecting that tissue is in contact with the electrodes around the gastric access device. That is, two or more electrodes may be placed on the periphery of the device to determine tissue contact between the electrodes (e.g., when the sensor is within a region of small diameter of anatomical tissue).

[0063] In some embodiments, the diameter of the shaft of the device may be larger at the location of the tissue sensing electrodes than in other regions of the device. In some embodiments, the diameter of the shaft of the device at the location of the tissue sensing electrodes may be expandable and / or contractible, such as a cage or balloon, to increase contact with the tissue.

[0064] Figure 15B is a cross-sectional view of the device of Figure 15A. Note that the tissue electrode 1502 may protrude outside the outer shaft 1504 of the device, in which case the electrode is more likely to contact the tissue. In some embodiments, the protruding electrode may be retractable or may protrude by different distances from the shaft of the device. One, two, three, or more electrodes are provided at any one or more positions along the shaft on the periphery of the device. Also shown in the figure is an electrode lead 1506 enclosed in the outer shaft 1504. The positions of the LES, UES, and pyloric sphincter are determined by the degree of contact with the tissue (how many electrodes on the periphery are in contact with the tissue) and the length of the device within the patient's body.

[0065] For example, if the sensor is inserted about 15 to 20 cm into the body (measured from the incisors), the UES can be identified. If the sensor is inserted about 30 to 50 cm into the body, the LES can be identified. If the sensor is about 50 to 100 cm, the pyloric sphincter can be identified. These measurement targets can be narrowed down considering the patient's physique. In addition, in order to distinguish anatomically different tissue regions, electrodes / sensors for different tissues can be used along the longitudinal portion of the device's shaft. Also, based on the diameter, i.e., the distance that the tissue electrode protrudes from the shaft, it is possible to determine which sphincter the electrode is detecting.

[0066] In this embodiment, similar to the temperature sensor 1110, the impedance / conductance electrode 1108 may or may not be included. In some embodiments, in addition to detecting the impedance / conductivity of the tissue, the electrode 1502 may also be used to determine GRV / gastric emptying, or the placement of the device.

[0067] Some embodiments of the gastric access device include the ability to avoid reflux phenomena, detect reflux phenomena or device movement, and manage reflux phenomena, for example, by aspirating reflux substances from the patient. The same sensors used for positioning may be used, or other sensors may be used.

[0068] Figures 16A and 16B are diagrams showing a gastric access device according to an embodiment including one or more tissue electrodes / one or more sensors 1502 and one or more reflux sensors 1602. One or more reflux sensors are arranged in the more proximal part of the shaft and can detect gastric reflux in the esophagus above the LES. These sensors are configured to detect gastric reflux after the device is placed in the patient. These sensors are arranged so that there is one or more in the esophagus after device placement. These sensors may be electrodes that detect impedance / conductivity, pH sensors, or other sensors. There may be one electrode or multiple electrodes at any position along the shaft on the circumference of the device's shaft.

[0069] When the backflow sensor is in the presence of backflow fluid, its conductivity increases and its impedance decreases. Since it is advantageous to avoid contact between the backflow sensor and the esophageal tissue, the backflow sensor 1602 may be disposed in the recess 1604 of the outer shaft of the device. This is shown in the cross-sectional view of FIG. 16C. FIG. 16B shows a cross-sectional view of the tissue sensor area. A plurality of backflow sensors along the longitudinal portion of the shaft of the device will help to identify the degree of backflow, i.e., how far up the esophagus it is, whether the backflow is progressing, retreating, and / or there is a risk of aspiration. Alternatively, the backflow sensor may be at a position relatively the same as or slightly protruding from the outer peripheral surface of the shaft of the device.

[0070] FIG. 17 shows the embodiment shown in FIG. 16A with the addition of an expandable member 1702 and a suction tube 1704. The backflow sensor 1706 may be used to identify the presence of backflow as described above. If backflow is detected, or if backflow is detected and determined to be risky, the control unit may expand the expandable member, which is a mechanism such as an inflatable balloon, and suction the suction tube to remove the backflow from the esophagus. The backflow sensor can detect that the backflow has been removed and reduce the expandable member to stop the suction. These actions may be performed manually based on an alert or automatically by the control unit.

[0071] Some embodiments may include a suction tube 1704 without the expandable member 1702. In these embodiments, it is necessary to control the suction level so that the contents of the stomach are not suctioned into the esophagus. The suction tube can be placed anywhere above or below the LES. In some embodiments, the suction tube can be moved along the shaft to accurately determine the suction position. This positioning of the suction tube may be determined by the level of backflow determined by signals from a plurality of backflow sensors along the longitudinal portion of the shaft of the device.

[0072] FIG. 18 is a diagram showing the state in which the embodiment shown in FIG. 17 is arranged in anatomical tissue. The tissue sensor 1502 can assist in the placement of the device. For example, by confirming the position of the LES, the physician can know that the opening of the device has passed through the LES and entered the stomach, and is in a placement state where nutrition can be supplied. The expandable member 1702 is shown just above the LES, and the reflux sensor 1706 is shown in the esophagus. The suction tube 1704 is shown further above the esophagus here, but it may be higher or lower in the esophagus.

[0073] The suction lumen of the suction tube is connected to the suction device 1802. The suction device 1802 may be a pump, a valve that controls wall suction, or another suction mechanism. The suction line 1804 may or may not pass through the hub 510.

[0074] FIG. 18 shows the main device shaft of the gastric access device and its concentric suction tube. FIG. 19 shows another embodiment where the suction tube 1902 is next to the main device shaft of the gastric access device or along one side of the device. In some embodiments, the suction tube may be a separate device that can be introduced and removed separately from the main shaft of the gastric access device. Alternatively, the suction tube may be arranged through the lumen of the gastric access device or may be arranged outside but as part of the shaft of the gastric access device.

[0075] In some embodiments, aspiration of reflux is initiated and / or continued based on a signal from a reflux sensor indicating the presence of reflux in the esophagus. In some embodiments, the control unit / monitor may be programmed to periodically apply a small amount of aspiration to the aspiration device to remove any undetected reflux and / or to test for reflux. Such periodic aspiration is performed regardless of whether reflux has been detected. During such periodic aspiration, the expandable member may or may not expand. By performing aspiration periodically, the risk of reflux can be effectively removed without relying on detection of reflux. Preferably, these periodically scheduled reflux aspiration events apply a sufficiently low level of aspiration such that gastric contents are not aspirated in embodiments where there is no expandable member or where the expandable member is not expanded. If reflux is detected (in anatomical tissue or in the aspiration tube or other location), or if collected during a periodically scheduled reflux aspiration event, the control unit can be programmed to increase or extend the aspiration event to ensure all reflux is aspirated. Also, the control unit may trigger expansion of the expansion member if the aspiration level or duration of the reflux aspiration event is increased.

[0076] Embodiments that include periodically scheduled reflux aspiration events may not include a reflux sensor on the device. However, other reflux sensors may be incorporated to determine whether reflux is being aspirated outside the body. For example, the reflux sensor may be located outside the body, in the control unit, in the waste receptacle, in the aspiration line, in the hub, etc. Periodically scheduled reflux aspiration events may be scheduled every 5 minutes, every 10 minutes, every 30 minutes, every 60 minutes, or every 5 to 30 minutes, or every 30 to 60 minutes, or other suitable time frames. The schedule can be freely set by the user. The interval may be varied according to past reflux phenomena. For example, if reflux is detected once or more than once, the scheduled reflux aspiration events may become more frequent. This change can be made manually or automatically.

[0077] In some embodiments, low-level suction can be used continuously or semi-continuously. In these embodiments, the expansion member may not be expanded during continuous suction so that the esophagus is not blocked for a long time. This continuous mode can be activated constantly during nutrition supply or as a result of one or more reflux events.

[0078] In some embodiments, the expansion member can be expanded to block the esophagus for a longer time and function substantially as an artificial LES to prevent reflux.

[0079] The embodiments shown herein, as shown in FIGS. 15 to 20, may or may not include additional GRV sensors as shown in FIGS. 11A, 11B, 12, and 13.

[0080] FIG. 20 is a diagram showing a gastric access device according to an embodiment configured to identify and pass through the position of the pyloric sphincter to enable nutrition supply in the patient's intestine. The tissue sensing sensor 1502 is shown in the region of the pyloric sphincter 2002. Similar to the detection of the LES, the electrodes of the tissue sensing sensor can detect the pyloric sphincter. Since these regions of the tissue have a smaller diameter than the surrounding tissue, the tissue sensing electrodes can detect tissue contact by detecting an increase in conductivity or a decrease in resistance between the electrodes when the electrodes are in direct contact with the tissue. This contact can occur between pairs of single or multiple electrodes arranged circumferentially around the shaft of the device. In these small-diameter regions, more electrodes on the circumference of the device shaft are in contact with the tissue, so the tissue contact sensor / electrode signal can identify these regions based on the change in the sensor signal when the device passes through this region.

[0081] In some embodiments, the placement of the device at or beyond the pyloric sphincter can be identified or confirmed in other ways. Also, the device can be placed into the stomach using the same method. For example, a pH sensor can determine that the access device is post-pyloric or elsewhere. The various sensors described herein can be used to pick up a specific signature, such as pH variations, absolute or relative temperature, peristaltic movement, impedance / conductivity, etc. An ECG sensor can be used to measure the ECG signal that changes when the electrodes on the device move over anatomical tissue. For example, the ECG signal may change when the device passes through the midline of the patient. To identify that the distal end of the device is in the intestine, bright light or other detectable light that can be detected through the skin may be used on the device. The electrodes on the device can be used to detect proximity to each other in terms of impedance, conductivity, or other means. This can indicate when the device is following a sharp curve, i.e., when a portion along the longitudinal portion of the device is relatively close to another portion along the longitudinal portion of the device. See, for example, the embodiments disclosed in FIGS. 24 and 35. Force sensors or pressure sensors can also be used to evaluate the curvature of the device and determine whether it is in a curved portion of the intestine.

[0082] Some embodiments can include direct visualization, such as a camera or fiber optics, to determine and / or confirm placement of the device in the target anatomical tissue.

[0083] Some embodiments can include a function of distinguishing between the esophagus and the trachea by detecting the amount of air / gas sucked into the device when a vacuum is drawn through the lumen of the device. The ability to suck air / gas into the device is higher for the trachea than for the esophagus. To avoid the device contacting the tissue during vacuum drawing, one or more small air masses can be introduced into the device before vacuum drawing. Alternatively, or in addition, openings on the periphery of the device shaft can also be used.

[0084] In some embodiments, electromyographic activity can be measured using electrodes. This may be used to assist in placing the device at the target location.

[0085] Any of the embodiments disclosed herein may automatically aspirate reflux from the patient's esophagus based on reflux detection or based on a reflux aspiration schedule.

[0086] Sensors incorporated in the gastric access device can collect data continuously, intermittently, as needed, or only at specific times, such as when confirmation of wearing is required.

[0087] The devices disclosed herein include nasogastric tubes equipped with sensors configured to avoid accidental placement of the tube in the trachea or lungs and to assist in placement in the stomach. These sensors include temperature sensors for detecting respiratory variations, impedance / conductivity sensors for detecting the stomach, etc. These sensors may alternatively include temperature, impedance / conductivity, ECG. These sensors may alternatively include any two of temperature, impedance / conductivity, pressure, humidity, pH, ECG. These sensors may include any three of temperature, impedance / conductivity, pressure, humidity, pH, ECG.

[0088] Electrogastrogram (EGG) may be used to identify the position of a gastric access device within the stomach. The EGG sensor may be different from other sensor types, or may use the same electrodes as, for example, an ECG sensor or an impedance / conductivity sensor.

[0089] In some embodiments, an electromagnetic sensor can be used in addition to other sensors for placement.

[0090] While the embodiments disclosed herein describe accessing the GI tract to avoid the trachea / lungs, the same concept can be used to identify the position of the trachea / lungs and avoid the GI tract.

[0091] Figures 21A through 21C illustrate an embodiment of measuring / determining intra-abdominal pressure via a feeding tube. Figure 21A shows a gastric access device or, alternatively, a conventional feeding tube within the stomach. Figure 21B shows a column 2102 of air or other fluid introduced into the lumen of the tube. When the column of fluid is introduced, the control unit measures the pressure within the lumen. As the fluid fills the lumen, the pressure increases. When a portion of the gas / fluid, i.e., a bubble 2104, exits the lumen of the gastric access device / feeding tube, the pressure suddenly drops, indicating that the pressure within the column of fluid has overcome the pressure within the fluid of the stomach. The pressure of the fluid within the stomach is the same as or correlated with the patient's intra-abdominal pressure (IAP). Thus, the control unit can derive the patient's IAP by monitoring the pressure when the column of fluid is introduced into the lumen of the gastric access device / feeding tube. The fluid may be air or other gas, or water or other liquid. The column of fluid may be solid or intermittent. The IAP measurement sequence may be periodically executed by the control unit. The IAP measurement sequence can be performed before or after feeding. Since more fluid is present in the stomach after feeding, this period is preferred for measuring the IAP. Also, the IAP measurement may be performed manually by physically observing the pressure of a gauge similar to a blood pressure cuff.

[0092] In some embodiments, bubbles similar to bubble 2104 can be used to measure pressure fluctuations that help confirm the placement of the device in either the esophagus or the trachea.

[0093] Figures 22A through 22C show another embodiment of measuring / judging IAP via a feeding tube. Figure 22A shows an access device to the stomach, or alternatively, a conventional feeding tube within the stomach. The stomach may contain air / gas 2202. In this embodiment, the air / gas 2202 is removed by suction as needed. As shown in Figure 22B, the stomach is filled with a liquid or the like. This air / gas reduction step may or may not be necessary to obtain an accurate IAP measurement value. As shown in Figure 22C, a column of fluid, preferably a liquid 2204, is subsequently introduced into the lumen of the tube. And by measuring the pressure of the column of fluid, the pressure of the fluid within the stomach, that is, an indicator of IAP, can be measured. These steps may be performed by the control unit, manually, or both.

[0094] Figure 23 shows another embodiment of a GRV measurement system that can be used for measuring / judging IAP. This embodiment includes a bladder 2302 that can be a balloon or other bladder sensitive to pressure. The inflation / deflation of the bladder is performed via lumen 2304. Lumen 2304 can also be used to monitor the pressure within the balloon / bladder. This pressure serves as an indicator of IAP. The inflation / deflation and pressure measurement are performed automatically by the control unit or by command. The measurement may be performed automatically periodically or automatically at least either before or after nutrient supply.

[0095] Some embodiments of the gastric access device may include a function to test whether the feeding tube is bent or kinked. In one embodiment, the control unit may introduce pressurized fluid (gas or liquid) into the lumen of the feeding tube and measure the pressure required for the fluid to flow through the lumen. To determine the pressure range without kinking, the baseline pressure of the non-bent feeding tube can be detected. When the tube is bent or kinked, the required pressure increases. The control unit can measure and track this pressure over time and determine the state of the feeding tube based on the absolute pressure, relative pressure, change in pressure, or slope of the change in pressure over time.

[0096] The bending or kinking of the feeding tube can also be measured electronically, such as by measuring the proximity of the electrodes to each other. If the electrodes are closer to each other than the spacing along the feeding tube, there may be kinking or tight bending of the tube. This is possible by measuring at least one of the impedance and conductance between the electrodes. The pair of electrodes can be changed by the control unit to determine the proximity of the electrodes. Alternatively, the same pair of electrodes can also be used.

[0097] For example, refer to FIGS. 24 and 25. FIG. 24 shows a gastric access device having a pH, or temperature, or other sensor 2402, an opening (for supply) 2404, and electrodes 2406 including electrodes 1, 2, 3, 4, 5, 6, 7, and 8. The pairs of electrodes 1 and 2, 3 and 4, 5 and 6, 7 and 8 are used as pairs during nutrient supply or when placing a nutrient tube, and measure the conductance / impedance at the pair of electrodes. However, different pairs of electrodes can also be used. For example, electrodes 1 and 6 may be used as a pair. The distance between electrode 1 and electrode 6 can be determined by conductance / impedance. When the device is relatively straight, the distance between electrode 1 and electrode 6 is Z, but when the distance becomes shorter like Z' shown in FIG. 25, the control unit can automatically attempt to sound an alarm / warning or attempt a twist elimination procedure to eliminate the twist of the tube. Alternatively, this state may indicate that the device is in the patient's intestine. Note that for detecting bending, any pair of electrodes and the relative distance of that pair can be relevant. For example, even if there is bending / twisting, the conductance / impedance of the original pair of electrodes may not change, but the conductance / impedance of a more separated pair of electrodes may change. This combination can indicate the bending / twisting situation.

[0098] In some embodiments, the bending / twisting of the device is extreme and two electrodes on the device may contact each other, causing the signal to short-circuit. This information can be used in the evaluation of the twist.

[0099] In some embodiments, a piezoelectric member is incorporated into the device, and by monitoring changes in the electrical characteristics of the piezoelectric member, the orientation of the device (including whether it is bent / twisted or not) can be determined.

[0100] In some embodiments, one or more strain gauges can be used to evaluate the twist / bending of the device.

[0101] In some embodiments, one or more accelerometers can be used to determine the orientation of various parts of the device. In some embodiments, a weighted tip can be used to determine the orientation of the tip of the device.

[0102] In some embodiments, one or more pressure sensors are used in the placement of the device. For example, the pressure exerted on the device in the stomach is higher than the pressure exerted in the esophagus. In embodiments having two or more pressure sensors, if there is no difference between the two pressure measurements, this may indicate that one pressure sensor is in the stomach and one pressure sensor is in the esophagus. Two measurements of similar pressures may indicate that the device is kinked in the esophagus.

[0103] In some embodiments, the injection of a conductive fluid can be used to evaluate the bending / twisting of the device. After placement, a conductive fluid may be injected into the patient's mouth. In a situation where the device is not folded and bent in anatomical tissue, the electrodes first read an increase in the conductive signal gradually from the more proximal electrode to the distal electrode. If the device is folded and bent, the distal electrode may signal an increase in conductivity out of order, prior to the more proximal electrode signaling an increase in conductivity. Similarly, the device can perform a similar evaluation using a temperature sensor and a hot or cold liquid.

[0104] In some embodiments, automatic air injection is incorporated to reduce the twisting of the device. The control unit automatically injects a stream, i.e., a puff of air, into the device when the device is inserted. This air or gas functions to harden the device and prevent twisting during insertion. This process may be performed automatically throughout the insertion process, or only when resistance is felt, or when the device has maintained a certain distance within the patient's body.

[0105] In some embodiments, instead of or in addition to using a stylet, the device can be hardened using pressurized air or fluid within the lumen of the device.

[0106] In some embodiments, to prevent kinking, the device may be automatically vibrated or rotated during insertion.

[0107] In some embodiments, the distal tip has a corkscrew shape and can be rotated during insertion.

[0108] Some embodiments include a balloon or other expandable member that can prevent accidental withdrawal of the device after it has been placed. Additionally, the gastric access device may include a balloon that can be inflated against the esophagogastric junction after insertion into the stomach to prevent reflux into the esophagus and inadvertent withdrawal.

[0109] Also, any of the embodiments that include a function to determine device bend / kink can also be used to evaluate the shape of the device within anatomical tissue. That is, these embodiments can be used for general device shape modeling in addition to bend / kink detection.

[0110] FIG. 26 is a diagram showing a portion of the target anatomical tissue used when placing a gastric access device. The inlet 2602 may be the patient's nasal cavity or lip. The respiratory-gastric junction (RGJ) 2604 is the junction between the trachea and the esophagus. The lower esophageal sphincter (LES) 2610 is in front of the lower end of the esophagus, at the junction with the stomach. The pylorus 2612 is at the boundary between the stomach and the intestine. The trachea 2606 shows the junction between the trachea and the bifurcation point of the bronchi of the lungs. The bronchus 2608 shows the estimated maximum depth in the event of accidental insertion of a feeding tube. Below, approximate lengths for infants and adults at various lengths are shown.

[0111]

Table 1

[0112] Figure 27 shows a device similar to the device shown in Figure 13. In this embodiment, a temperature sensor 1110, such as a thermocouple, may use the same electrode as the impedance / conductivity electrode 1108. Also, an ECG or other signal can be obtained from the same electrode. Figure 13 shows an example of a gastric access device according to one embodiment, but the positions, spacings, and numbers of the sensors / electrodes may be different. Each electrode may use the same lead wire or different lead wires depending on its function.

[0113] Figure 28A shows the gastric access device shown in Figure 27 within a scale indicating the approximate lengths of different portions of the anatomical tissue. The dimensions vary greatly depending on age and individual, and may be narrower or wider than this scale, but this figure provides a visual scale for both the anatomical tissue and the gastric access device.

[0114] Figure 28B is a diagram showing an example of the placement of a gastric access device within a child's body. In this example, five impedance sensors (Z1 through Z5) and two temperature sensors (T1, T2) are placed at different device positions / insertion depths, mapping the device position in real time. Also, electrode pairs Z3 and Z5 include thermocouples joined to one electrode of each of electrode pairs Z3 and Z5, measuring temperature. The detected measurements are relayed to a control unit, processed by the control unit, and the anatomical tissue position of the device is classified. Also, this device has an internal sensor mounted in the nutrition supply / drug delivery lumen and can directly sample the enteral nutrition agent introduced. The placement of the gastric access device for nutrition supply is expected to have Z1 through Z3 within the stomach, Z4 approximately 1 to 4 cm proximal to the lower esophageal sphincter (LES), and Z5 proximal to Z4 within the esophagus. For guidance and confirmation of placement, the control unit provides the operator with continuous visual feedback regarding the position of the distal portion of the device.

[0115] In some embodiments, it is desirable to place one temperature sensor as close as possible to the distal tip of the device, but not so close that the temperature sensor generally hits tissue during advancement. This most distal temperature sensor aids in device placement. As the device is advanced, the most distal temperature sensor detects temperature fluctuations associated with drawing in ambient air while the sensor is over the RGJ, or a lower temperature. Further advancing the device into the esophagus, the temperature fluctuations should flatten out or the average temperature should increase. However, although undesirable, if the device enters the trachea, the most distal temperature sensor continues to detect temperature fluctuations or a temperature lower than body temperature even when entering the trachea. This undesirable advancement causes the system's control unit to issue a warning to the user and instruct the user to retract the device.

[0116] In some instances, the gastric access device may be in the trachea in an undesirable configuration, but since the most distal temperature sensor is in close contact with the tissue, it does not detect temperature fluctuations or temperatures lower than body temperature. The second, more proximal temperature sensor is arranged to detect temperature fluctuations or temperatures lower than body temperature if the device is mispositioned in the trachea. The more proximal temperature sensor is desirably arranged along the longitudinal portion of the device such that it passes through the RGJ before the distal end of the device enters too far into the bronchus.

[0117] Here, two temperature sensors are shown, but fewer or more temperature sensors may be arranged along the device. In some embodiments, each electrode on the device can detect impedance / conductivity, temperature, ECG, and possibly other parameters. The functions of different electrodes can be controlled by the control unit. The detected parameters can change alternately during placement and use, or the detected parameters can be linked to the patient's physique and the length of the anatomical tissue.

[0118] For example, the gastric access device includes 10 sets of electrodes. The patient can be a tall adult. Based on the patient's height and other measurements, appropriate functions are assigned to the electrodes along the device, thereby providing at least the most distal temperature sensor and the proximal temperature sensor so that at least one of the temperature fluctuations and average temperature in the trachea and esophagus can be detected while the device is being introduced into the patient. In some embodiments, the proximal temperature sensor is arranged such that it passes through the RGJ before the most distal temperature sensor advances too far into the bronchus. In some embodiments, the most distal temperature sensor is proximal to the pair of most distal electrodes. In some embodiments, the most distal temperature sensor is incorporated into the pair of most distal electrodes.

[0119] An additional electrode may be provided proximal to the most proximally used electrode. These electrodes are effective for tall or well-built individuals, but not useful for short or poorly built individuals. In this way, the same device can be used for patients with different body builds and anatomical tissues.

[0120] Also, by using the temperature, impedance / conductance, ECG, pH, and other sensors disclosed herein along the longitudinal portion of the device, any type of placement, including postpyloric placement, can be detected. For example, the device has electrodes along a substantial portion of its longitudinal portion, such that the control unit can receive sensor signals from all parts of the anatomical site where the device is placed when the device is advanced or after it has been advanced. The control unit can generate a temperature map, an impedance / conductivity map, an ECG map, a pH map, a combined parameter map, etc., and by analyzing these signatures, can determine the position of each electrode within the anatomical tissue. This allows the user to know where the tip of the catheter is, the opening for nutrient supply, etc.

[0121] Figures 29A and 29B are diagrams showing details regarding an embodiment in which one electrode is used for multiple sensors. These diagrams are configured such that a pair of electrodes can detect both impedance or conductance and temperature. By sharing electrodes in this way, cost and space are reduced, and miniaturization of the device is achieved. Impedance / conductivity electrode 1108 and temperature sensor 1110 are shown, and in these embodiments, it is one of the impedance / conductivity electrodes and is a band that is essentially conductive (i.e., metallic). This can be achieved by connecting the impedance / conductance electrode 1108 to the control unit via lead wire 2902 and connecting the thermocouple of the temperature sensor to the control unit via lead wire 2904. These diagrams show individual pairs of lead wires for different sensors, but in some embodiments, it is also envisioned that lead wires may be shared between two sensors or more sensors.

[0122] As shown in FIG. 29A, the lead wires generally extend along the longitudinal portion of the device. FIG. 29B is an electrical diagram showing, for the sake of explanation, these connections and a part of the related functions of the control unit. The lead wire 2902 connects the metal band, i.e., the electrode, to the impedance / conductivity logic region 2906 of the control unit. The lead wire 2904 connects the metal band, i.e., the electrode, to the temperature logic region 2908 of the control unit. These two logic regions are connected to a switch 2910, whereby the control unit can switch between conductivity / impedance or temperature measurements using the same one or more electrodes.

[0123] The switch 2910 may connect other logic regions / detection regions such as ECG and pH. Here, as in the case of temperature and conductivity / impedance, overlapping electrodes may be used. In the case of pH detection, a reference substance will be incorporated into the system in order to measure the pH using the electrodes. The ECG and pH sensors may use the same lead wires as the impedance / conductivity sensor.

[0124] In some embodiments, no physical or logical switch is required and the functions of the various lead wires / electrodes are driven by the logic within the control unit. Detecting two different parameters with the same electrode may occur temporally overlapping. For example, the control unit can simultaneously detect both temperature and impedance from the same electrode. If the sampling rate permits, the control unit can substantially simultaneously detect temperature, impedance, and ECG. For example, the sampling rate may be greater than 5 samples / second. Alternatively, for example, the sampling rate may be greater than 10 samples / second. Alternatively, for example, the sampling rate may be greater than 20 samples / second. Alternatively, for example, the sampling rate may be greater than 100 samples / second.

[0125] Another advantage of using a 360-degree, or nearly 360-degree, conductive band for these types of sensors is as follows.

[0126] Each impedance / conductivity sensor (which generally consists of two electrode rings, but may also consist of one, two, or more electrode rings) attempts to measure the minimum impedance or maximum conductivity path between the two rings. That is, the impedance / conductivity sensor is detecting 360 degrees around the circumference of the ring simultaneously. For example, when the two rings of the impedance / conductivity sensor are in contact with the gastric wall, the gastric wall tissue is only in contact with one side of the feeding tube, i.e., one side of the electrode ring. The sensor detects the high conductivity / low impedance of the above contact with the gastric wall tissue even if most of the circumference of the ring is not in contact with a high conductivity / low impedance environment. That is, the impedance / conductivity sensor using a 360-degree ring is essentially a spot sensor.

[0127] On the other hand, each temperature sensor may be a thermocouple joined to a 360-degree electrode or conductive ring. This joining causes the thermocouple to essentially detect the average temperature around the circumference of the ring. In the situation where the feeding tube, i.e., the temperature sensor, is pressed against the tissue, the temperature sensor detects the average temperature of the tissue and the environment surrounding the rest of the ring. Thereby, even if the feeding tube hits against the wall of the respiratory system, the temperature sensor can detect the respiration of the respiratory system and avoid false detection. That is, the temperature sensor using a 360-degree ring is essentially an environmental average sensor.

[0128] By using the same electrodes for the two types of sensors, the system can detect both tissue contact (switching to conductivity / impedance detection) and temperature environment (switching to temperature detection). The control unit can switch between these two according to the current need and the position of a specific sensor.

[0129] The control unit can determine the impedance by measuring the voltage drop across the electrode pair (amplitude of the periodic voltage signal) when an alternating current of a certain amplitude is applied. For example, the AC current can be 30 kHz and 100 μA (peak-to-peak). Temperature measurement can be obtained using a copper / constantan thermocouple (type T) thermally bonded to one of the electrode rings. This design solution enables 360-degree sensing that facilitates the measurement of true impedance and temperature even in the presence of intermittent tissue contact or other interfering factors. The position of the sensor is designed to accurately classify the anatomical position of the device based on the results of each sensor measuring the local environment. The gastric access device can be of different lengths to ensure an optimal sensor spacing based on the clinical nasal-ear-middle-waist (NEMU) method commonly used to determine the insertion length to ensure the final optimal position of the sensor within the patient's upper gastrointestinal (GI) tract. The impedance and temperature data can be delivered in real time to the control unit via a secondary non-fluid contact lumen. The sensor data may be analyzed by the control unit for two different functions: placement (at the time of device insertion or during periodic position monitoring) and gastric state determination (such as judging gastric emptying of GRV during nutrient supply).

[0130] For the placement function, a two-part simultaneous analysis can be used to classify the position of the device. That is, (1) a time-series temperature pattern recognition function, and (2) an impedance threshold classifier (ITC) for identifying the placement of the internal device tip such as in the esophagus, stomach, respiratory system, etc.

[0131] The temperature pattern recognition function can detect misplacement of the device into the airway by evaluating the temperature data from sensors T1 and T2 at a rate of approximately 5 Hz and identifying and classifying consecutive local maximum and minimum (LMM) values. Once the temperature pattern recognition function recognizes a pattern representative of two respiratory cycles in the LMM (usually occurring within 2 to 4 seconds in infants and longer in adults), misplacement into the airway is positively determined.

[0132] Simultaneously with, or in parallel with, the temperature analysis, the impedance measurement along the device is continuously or intermittently evaluated with the placement function. Generally, the impedance measurement value of the stomach is considerably lower than that of the esophagus. In some embodiments, a single threshold of 350 Ω is sufficient to distinguish the stomach from the esophagus. In some embodiments, the threshold classifier that defines the position is based on the impedance measurement values of at least two of the three distal sensors. This provides a robust approach that can ensure proper placement even in the presence of interfering factors such as intermittent tissue contact or air bubbles in the stomach.

[0133]

Table 2

[0134] The function of the gastric state calculates the composition of the patient's real-time gastric contents based on the following: namely, (1) impedance measurement of the patient's empty stomach before nutrient supply (this measurement can be performed using one or more most distal electrode pairs), (2) impedance measurement of the formulated medicine (detected using an internal sensor within the device lumen), (3) real-time average impedance value within the stomach (detected using one or more most distal electrode pairs), and (4) selection of an appropriate calibration curve from a library. Changes in the compositional pattern characteristics of the gastric contents are evaluated using both time series and trend analysis of latent variables in 4-hour, 8-hour, 12-hour, and 24-hour windows, and the gastric state can be automatically fed back. The categories of different statuses are as follows: namely, (1) nutrient supply is optimized, (2) the risk of nutrient supply intolerance is low (proceed with nutrient supply if the calorie target has not been achieved), and (3) the risk of nutrient supply intolerance is high (reduce nutrient supply if there are clinical signs of nutrient supply intolerance).

[0135] The arrangement and functional output of the gastric state are visually displayed on the control unit and fed back to the clinical staff in real time. The reusable pole-mounted control unit is equipped with a user interface display, can be powered from a standard outlet, and can be equipped with a built-in battery that supports continuous function for more than 12 hours. For the initial placement of the device, the operator receives the following notifications: namely, (1) orange esophagus: "The distal tip of the device is in the esophagus. Continue to advance", (2) red lung: "The distal tip of the device has entered the airway. Retract", and (3) green stomach: "The distal tip of the device is properly placed in the stomach". Once the gastric position is correctly set, the gastric state function of the control unit continuously monitors the changes in digestion and automatically feeds back the optimal nutrient supply method. Namely, (1) nutrient supply is optimized, (2) the risk of nutrient supply intolerance is low (proceed with nutrient supply), and (3) the risk of nutrient supply intolerance is high (reduce nutrient supply).

[0136] In some cases, the user may introduce a drug into the nutrient supply lumen of the feeding tube. This drug can be in the form of crushed tablets or other bulky substances. The nutrient supply lumen of the feeding tube is often blocked due to the added drug, and it is difficult to relieve the blockage. To prevent large particles of the drug from entering the feeding tube, a clog prevention mechanism can be used in combination with a gastric access device or any feeding tube.

[0137] Figure 30A shows a drug introduction attachment that can be used with any feeding tube. The drug grinder 3002 includes a rotating segment 3006 and a sheath 3008. A drug 3004 such as a tablet is introduced into a cavity within the rotating segment 3006. Teeth, or other grinding mechanisms (not shown), communicate with the cavity. By rotating the sheath after the tablet has entered the cavity, it is possible to prevent the drug from exiting the attachment. Two rotating segments are subsequently rotated relative to each other to grind the drug into particles of a size sufficient to enter the nutrient supply lumen of the feeding tube without clogging it. The grinding mechanism may be something like a pepper grinder. In some embodiments, the grinding operation may be a ratchet operation, where the drug is only ground when the segment is rotated in one direction and not when rotated in the opposite direction, which also has an operation similar to that of a pepper grinder.

[0138] As shown in Figure 30B, the grinder attachment 3002 is connected to a feeding tube or a gastric access device.

[0139] Figure 30C shows a clogging prevention mechanism according to an alternative example. This introducer attachment 3010 includes a limiter, a filter, a cutter, etc. for preventing large lumps of medicine from entering the nutrient tube. As shown in Figure 30C, the filter may be in the form of a wire mesh, i.e., a cross 3012. A wire filter can use stainless steel wire with a diameter of 0.003 inches (about 76.2 μm), for example. Figure 30D shows an introducer attachment 3010 including a constriction 3014 according to an embodiment. By narrowing it, large lumps of medicine are prevented from entering the nutrient tube. If the lumps of medicine in the nutrient supply are larger than the diameter of the constriction 3014, they will not be introduced into the nutrient tube. The constriction 3014 has a diameter smaller than the diameter of the nutrient supply lumen of the nutrient tube.

[0140] In other embodiments of the clogging prevention mechanism, a sharp blade may be provided for cutting large lumps of medicine extruded from the opening.

[0141] As shown in Figure 30E, the introducer attachment 3010 is connected to a nutrient tube or a gastric access device.

[0142] The control unit of any of the embodiments disclosed herein can include functions for analyzing and / or displaying situation data. For example, the history of backflow can be collected, analyzed, displayed, and used for the automatic control of the control unit. For example, patients with more backflow need to perform aspiration events more frequently or continuously. The control unit may determine a backflow aspiration schedule and / or an aspiration level in consideration of the degree and / or frequency of backflow events. Also, the contextual backflow information can also determine whether an expandable member is expanded during an aspiration event. Also, the nutrient supply, GRV, and placement information in the situation can be used in this way.

[0143] In some embodiments, the gastric access device can use electrodes along the device to detect passive electrical signals generated in the gastric wall. These signals can be used to evaluate the health state of the stomach, such as peristaltic movement.

[0144] GRV / gastric emptying can be tracked over time by the system by introducing additional elements with measurable parameters. In this case, the parameters are at a different level than the level of the gastric contents. The level of the parameters is detected by a sensor of the feeding tube, and the changes are analyzed over time to determine GRV / gastric emptying. For example, a fluid with a lower conductivity than the gastric contents (such as a nutritional supply) can be introduced into the stomach in a single bolus, or in multiple portions, or continuously, or over time. The sensor along the gastric access device may be a conductivity / impedance sensor, which can detect the conductivity / impedance along the device over time to determine GRV / gastric emptying. Also, other parameters such as temperature, pH, chemical content, optical parameters, etc. can be used.

[0145] In some embodiments, the sensor is also present inside the additive element delivery lumen of the device (which may be the nutritional supply lumen or another lumen). These one or more sensors may measure the parameters of the additive before adding it to the stomach, so that the parameter level of the additive is known before it is introduced into the stomach. Thereby, the control unit can more accurately determine GRV / gastric emptying. For example, in the above conductivity / impedance example, a pair of electrodes is present inside the nutritional supply lumen of the device, and the conductivity / impedance of the additive (which may be a nutritional supply) just before entering the stomach can be measured. The electrodes may be in the same plane as the inner surface of the nutritional supply lumen. This measured value can be incorporated into the GRV / gastric emptying analysis so as to accurately determine the change in the parameter due to GRV / gastric contents. This inner lumen sensor may be considered a "calibration sensor".

[0146] In some embodiments, when the control unit detects a nutritional supply or liquid inside the nutritional supply lumen of the device, it switches to the nutritional supply mode to monitor GRV.

[0147] When the gastric access device is in the nutrition supply mode, it can be placed in different states. For example, 1) the nutrition supply is optimized, 2) the risk of nutrition supply intolerance is low (if the calorie target is not achieved, the nutrition supply is advanced), 3) the risk of nutrition supply intolerance is high (if there are clinical signs of intolerance, the nutrition supply is reduced). In some embodiments, the gastric access device can measure the percentage concentration of food to gastric juice in the stomach over time based on the measurement of parameters of the additive (in this case, food). These embodiments may include a calibration sensor.

[0148] In some embodiments, the health of the digestive system can be evaluated by providing a bolus of the additive and tracking GRV / gastric emptying immediately after the bolus. The GRV / gastric emptying profile can be compared with the profiles of healthy and unhealthy humans and / or populations to determine the health status of a particular patient. For example, a bolus with a high concentration of glucose can be used and the GRV / gastric emptying after the bolus can be monitored. Other indicators such as blood glucose levels can also be monitored.

[0149] Any of the features in any of the embodiments disclosed herein may be combined with any of the other features and may be used in any of the embodiments disclosed herein.

[0150] Example of a data processing system FIG. 31 is a block diagram showing a data processing system that can be used in any embodiment of the present invention. For example, system 3100 may be used as part of the control unit / monitor disclosed herein. FIG. 31 illustrates various components of a computer system, but is not intended to represent a particular architecture or method of interconnecting the components, and thus such details are not relevant to the present invention. Also, network computers, handheld computers, mobile devices, tablets, cell phones, and other data processing systems having fewer or perhaps more components may also be used in combination with the present invention.

[0151] As shown in FIG. 31, a computer system 3100, which is an embodiment of a data processing system, includes one or more microprocessors 3103 and a bus or interconnect 3102 coupled to ROM 3107, volatile RAM 3105, and non-volatile memory 3106. The microprocessor 3103 is coupled to a cache memory 3104. The bus 3102 interconnects these various components with each other and also interconnects these components 3103, 3107, 3105, 3106 to a display control unit and a display device 3108, and an input / output (I / O) device 3110 that is a mouse, keyboard, modem, network interface, printer, and other devices well known in the art.

[0152] Typically, the input / output device 3110 is coupled to the system via the input / output control unit 3109. The volatile RAM 3105 is typically implemented as a dynamic RAM (DRAM) that continuously requires power to refresh or maintain the data in the memory. The non-volatile memory 3106 is typically a magnetic hard drive, a magneto-optical drive, an optical drive, or a DVD-RAM or other type of memory system that maintains data even after the power is removed from the system. Usually, the non-volatile memory, although this is not essential, can also be a random access memory.

[0153] FIG. 31 shows that the non-volatile memory is a local device directly coupled to the rest of the data processing system, but the present invention may utilize a non-volatile memory that is remote from the system; for example, a network storage device coupled to the data processing system via a network interface such as a modem or an Ethernet interface may be used. The bus 3102 may include one or more buses connected to each other via various bridges, control units, and / or adapters, as is well known in the art. In one embodiment, the I / O control unit 3109 includes a USB (Universal Serial Bus) adapter for controlling USB peripheral devices. Alternatively, the I / O control unit 3109 may include an IEEE-1394 adapter, also known as a FireWire (registered trademark) adapter, for controlling FireWire (registered trademark) devices.

[0154] Part of the foregoing detailed description has been presented from the perspective of algorithms and symbolic representations of operations on data bits in a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm, as used herein, is generally considered to be a self-consistent sequence of operations leading to a desired result. The operations are those requiring physical manipulation of physical quantities.

[0155] However, all of these terms and similar terms should be associated with appropriate physical quantities and should be borne in mind that they are merely convenient labels applied to these quantities. As is apparent from the above discussion, unless otherwise specified, throughout this specification, discussions using terms as set forth in the following claims refer to the actions and processes of a computer system or similar electronic computing device that manipulates and transforms data represented as physical (electronic) quantities in registers and memories of the computer system into other data similarly represented as physical quantities in memories or registers of the computer system, or other such information storage, transmission, or display devices.

[0156] The illustrated technology can be implemented using code and data stored and executed on one or more electronic devices. Such electronic devices can store and (internally and / or communicate with other electronic devices via a network) communicate code and data using computer-readable media such as non-transitory computer-readable storage media (e.g., magnetic disks; optical disks; random access memory; read-only memory; flash memory devices; phase change memory) and transitory computer-readable transmission media (e.g., electrical, optical, acoustic, or other forms of propagated signals - carrier waves, infrared signals, digital signals, etc.).

[0157] The processes or methods depicted in the foregoing figures may be executed by processing logic consisting of hardware (e.g., circuits, dedicated logic, etc.), firmware, software (e.g., embodied on a non-transitory computer-readable medium), or any combination thereof. It should be understood that although the processes or methods have been described above with respect to several sequential operations, some of the operations described may be executed in a different order. Additionally, some operations may be executed in parallel rather than sequentially.

[0158] All embodiments disclosed in this specification can incorporate features of other embodiments disclosed in this specification.

Claims

1. A gastric access device having a longitudinal portion, A control unit that communicates with the gastric access device, One or more impedance or conductivity sensors arranged along the longitudinal portion, wherein at least one impedance or conductivity sensor is arranged at or near the distal end of the longitudinal portion, and each of the one or more impedance or conductivity sensors communicates with the control unit, and the control unit is configured to receive a first signal indicating the impedance level or conductivity level of a fluid in contact with the one or more impedance or conductivity sensors within the subject's body. One or more impedance or conductivity sensors, One or more temperature sensors arranged along the longitudinal portion and communicating with the control unit, wherein the control unit is further configured to receive a second signal indicating the temperature level of the environment within the subject's body associated with respiration and in contact with the one or more temperature sensors. One or more temperature sensors, Comprising, The control unit is configured to receive the first signal, detect the presence or absence of fluctuations in the second signal, and determine whether the gastric access device is disposed within the subject's stomach based on both the first signal and the second signal. A nutrition tube system.

2. At least one of the at least one impedance or conductivity sensor and the one or more Of the temperature sensors constitutes a common electrode. The system according to claim 1.

3. The common electrode surrounds the gastric access device. The system according to claim 2.

4. The system according to claim 1, wherein the one or more temperature sensors include at least one sensor disposed at or near the distal end of the longitudinal portion.

5. The system according to claim 4, further comprising at least one second temperature sensor arranged along the longitudinal portion and proximal to the at least one sensor.

6. The system according to claim 1, wherein the control unit is further configured to receive the second signal and detect the fluctuation of the temperature level due to respiration.

7. The system according to claim 1, wherein the control unit is further configured to receive the second signal and determine an average value of the temperature level due to the respiration.

8. The system according to claim 1, wherein the second signal indicates the temperature level of air associated with respiration in the body of the subject.

9. The system according to claim 1, wherein at least one of the one or more temperature sensors is configured to detect an ambient temperature outside the subject.

10. The system according to claim 9, wherein the control unit compares the second signal with the ambient temperature outside the subject to determine whether the temperature detected by the one or more temperature sensors is a relative temperature at different anatomical locations in the body of the subject.

11. The system according to claim 1, wherein the control unit is further configured to monitor the state of the stomach within the stomach.

12. The system according to claim 11, wherein the control unit is configured to determine the volume of gastric residue in the stomach.

13. The system according to claim 11, wherein the control unit is configured to detect gastric reflux.

14. The system according to claim 1, wherein the first signal indicates the impedance level or conductivity level of the fluid in the stomach.

15. The system according to claim 14, wherein the control unit is configured to confirm placement within the stomach when the first signal indicates a conductivity higher or an impedance lower than the impedance or conductivity of the esophageal environment.

16. The system according to claim 1, wherein the gastric access device is sized to be disposed distally of the pyloric portion of the stomach.

17. The impedance or conductivity sensor includes electrodes, and the control unit is further configured to monitor detachment or bending of the longitudinal portion based on a comparison of signals between two of the electrodes.

18. The system according to claim 1, wherein the control unit is further configured to indicate a temporary stop of the advancement of the gastric access device to the subject.

19. The system according to claim 18, wherein the control unit is further configured to indicate the temporary stop for at least one second.

20. The system according to claim 1, further comprising a clogging prevention mechanism disposed adjacent to the opening of the gastric access device.

21. The system according to claim 1, wherein the one or more temperature sensors are at least two temperature sensors respectively disposed opposite to each other in the circumferential direction along the longitudinal portion.

22. The system according to claim 21, wherein the two temperature sensors are respectively disposed opposite to each other by 180 degrees in the circumferential direction along the longitudinal portion.

23. The system according to claim 1, wherein the one or more temperature sensors are at least two temperature sensors respectively disposed at different positions along the longitudinal portion.

24. The system according to claim 1, wherein the one or more temperature sensors are at least two temperature sensors respectively disposed at different positions along the longitudinal portion and opposite to each other in the circumferential direction.

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