Feeding device and method for determining position of feeding tube

Abstract

A feeding device, feeding system and method for determining a position of a feeding tube are described. In particular, the present invention relates to a feeding device and method for determining the position of the distal end of a feeding tube based on a pressure correlation between the respective pressures measured by a distal pressure sensor and another pressure sensor located at the proximal end of the tube.

Description

Technical Field

[0001] The present invention relates to a feeding device, feeding system and method for determining the position of a feeding tube. In particular, the present invention relates to a feeding device and method for determining the position of the distal end of a feeding tube based on a pressure correlation between respective pressures measured by a distal pressure sensor and another pressure sensor located at the proximal end of the tube. Background Art

[0002] Feeding devices, in particular feeding devices for enteral feeding of patients, include a feeding tube that is inserted into the patient's stomach in order to provide nutrients to the patient's stomach. Such a tube is usually placed via a nasogastric tube, passed through the patient's nose (nasogastric tube) and remains there for a few days to a few weeks. It is very important to correctly place the tube in order to avoid that enteral nutrients enter other parts of the patient's stomach. It is particularly important that the tube is not misplaced, for example into the patient's lungs or bronchial tubes. Once the tube is placed, it is very important to check the correct positioning of the tube before each feeding is started in order to confirm that the tube has not been dislocated, for example the distal end of the tube is located in the esophagus or small intestine.

[0003] X-ray technology is often used to confirm proper placement of the feeding tube so that an X-ray image can be taken showing the stomach and distal end of the feeding tube in the correct position. Alternatively or additionally, a syringe can be used to draw acid from the stomach through the tube and the pH of the stomach fluid measured (usually pH <= 5.5).

[0004] However, X-ray technology is expensive, time consuming, and further potentially dangerous to the patient due to multiple exposures to radiation during enteral feeding. In addition, in the case of using X-ray technology and aspirating gastric fluid from the stomach and taking pH measurements, misinterpretation by untrained nursing staff may also have adverse effects. Summary of the invention

[0005] It is therefore an object of the present invention to provide a feeding device and method for reliably determining the position of a feeding tube within a patient in an efficient and cost-effective manner.

[0006] This object is achieved by a feeding device having the features of claim 1 , a method having the features of claim 9 and a feeding system having the features of claim 13 .

[0007] Preferred embodiments are defined by the dependent claims.

[0008] According to a first exemplary aspect, in order to better understand the present disclosure, a feeding device includes: a feeding tube, the feeding tube being used to be inserted into a patient's body and having at least one lumen extending from a distal end to a proximal end of the tube; a first pressure sensor, the first pressure sensor being disposed near the distal end of the feeding tube and configured to measure a pressure acting on the tube; a second pressure sensor, the second pressure sensor being disposed in the feeding tube and configured to measure a pressure acting on the tube, wherein the second pressure sensor is farther from the distal end of the tube than the first pressure sensor in a longitudinal direction of the tube; and a controller.

[0009] The feeding device relies on pressure signals (pressure values) derived from sensors located in the feeding tube, particularly sensors located at its distal end as well as the proximal end of the tube. Thus, the patient and caregiver (or clinician) are relieved from having to take an X-ray image every time they want to confirm the correct position of the feeding tube. Likewise, there is no need to remove gastric fluid from the stomach (withdrawal through the feeding tube), which increases patient comfort. The use of pressure sensors is also cost- and time-effective compared to employing X-ray techniques.

[0010] Furthermore, since the first pressure sensor and the second pressure sensor form part of the feeding tube, the position of the feeding tube can be periodically (or continuously) confirmed. This allows confirmation of the position of the tube during insertion into the patient, as well as checking whether the feeding tube has moved over time, even though the feeding tube was initially correctly placed with its distal end in the stomach. For example, due to peristalsis of the esophagus, stomach and / or small intestine, or movement of the patient, the feeding tube may move such that the distal end of the feeding tube may not be located in the stomach, but in the esophagus or small intestine, which may cause discomfort to the patient due to nutrients being supplied to the esophagus (aspiration) or small intestine instead of the stomach.

[0011] In this disclosure, reference is made to the distal end of a feeding tube because it typically has a feeding tube opening, i.e., an opening in the tube that leads to a lumen through which nutrients flow out of the stomach and (preferably) into the stomach. As an example, the tube may be cut so that the lumen is open at the distal end of the tube. It should be understood that the opening in a feeding tube may not be located at the very distal end of the tube, but may be located a short distance from the distal end of the tube. Therefore, any reference to the distal end and its location determination within the patient may be interchangeable with the feeding tube opening and the location determination of the opening.

[0012] In order to determine the correct position of the feeding tube in the patient's stomach, the controller is configured to: receive signals from the first pressure sensor and the second pressure sensor; calculate the pressure correlation between the respective pressures measured by the first pressure sensor and the second pressure sensor based on the received signals; and determine the position of the distal end of the tube in the patient's body based on the calculated pressure correlation. Due to the respective positions of the first pressure sensor and the second pressure sensor along the longitudinal direction of the feeding tube, the first pressure sensor and the second pressure sensor will measure the same or different pressures depending on their positions in the patient's body. For example, while the pressures in the esophagus, stomach, and small intestine are likely to be different from each other, the pressures in the trachea, bronchi, and lungs are likely to be unique and well-defined. By considering the pressure correlation between the pressure measured by the first sensor and the pressure measured by the second sensor, it can be easily deduced whether the distal end of the feeding tube is located in the stomach, that is, whether the feeding tube is correctly placed.

[0013] Because the controller determines the indication of the correct or incorrect position of the distal end of the feeding tube, no special skills need to be acquired for operating the feeding device, i.e., no special skills are required to read and interpret the sensor values. For example, the patient or caregiver does not need to operate special instruments (e.g., for withdrawing gastric fluid from the stomach) or operate special devices, such as X-ray, ultrasound, etc.

[0014] In one embodiment variant, the controller may be configured to calculate the pressure correlation by calculating an absolute pressure value of the first pressure sensor and an absolute pressure value of the second pressure sensor at the same measurement time. If the absolute pressure value of the first pressure sensor and the absolute pressure value of the second pressure sensor are approximately equal, and the pressure signal from the first pressure sensor and the pressure signal from the second pressure sensor indicate opposite pressures at the first pressure sensor and the second pressure sensor, the controller may determine that the location of the distal end is the patient's stomach. For example, the pressure measured by the first sensor may be a positive pressure, and the pressure measured by the second sensor may be a negative pressure of approximately the same value as the positive pressure of the first sensor.

[0015] Approximately the same or approximately equal in the present disclosure means that the corresponding values ​​are equal or vary within a range of + / -10%, preferably within a range of + / -5%. For example, if the absolute value of the first sensor is 15 mmHg, the absolute value of the second sensor can be between 13.5% and 16.5%, preferably between 14.25% and 15.75%. It will be appreciated that the pressure value of the second pressure sensor can be negative. Similarly, at the same measurement time means approximately at the same time, i.e. within a time window of -0.5 seconds to +0.5 seconds. In addition, there may be an overall difference of 10 mmHg between the esophagus and an empty stomach, particularly if the stomach is empty.

[0016] In the case where the feeding tube is correctly placed in the patient, i.e. the distal end of the tube is in the stomach, the patient's breathing will induce opposing pressure patterns in the stomach and esophagus, which are usually separated by the diaphragm. Thus, if a first pressure sensor is located at the distal end of the tube in the stomach, and a second pressure sensor is located in the esophagus, the pressure signals measured by these sensors will indicate approximately the same value of absolute pressure at the same measurement time, but with opposite algebraic signs. This is particularly important when natural ventilation is present. Mechanical ventilation of a person may lead to different results.

[0017] Alternatively, the controller may determine that the absolute pressure value of the first pressure sensor and the absolute pressure value of the second pressure sensor are not the same, but may calculate a pressure difference. However, if the pressure curve of the first pressure sensor and the pressure curve of the second pressure sensor show opposite pressure patterns with different amplitudes, the controller may still determine that the distal end of the tube is located in the stomach and the second pressure sensor is located in the esophagus.

[0018] It should be understood that for any embodiment variant described herein, the distance between the first pressure sensor and the second pressure sensor along the longitudinal direction of the feeding tube must be sufficient to allow the first sensor to be placed in the stomach and the second sensor to be placed in the esophagus. For example, the distance between the first pressure sensor and the second pressure sensor may be between 3 cm and 50 cm, preferably between 8 cm and 25 cm for an adult. For infants and neonates, the distance should be chosen to be shorter due to the smaller organs.

[0019] Alternatively or additionally, the second pressure sensor may not be a single sensor, but rather a plurality of sensors disposed along the tube. For example, all sensors (including the first sensor and any second sensors) may be disposed along the tube, starting at any portion of the tube and terminating at the distal end of the tube (with the first pressure sensor). Thus, the first pressure sensor and one or more "second" pressure sensors may be located in the stomach, while the next sensor along the tube toward the proximal end would be disposed in the esophagus. The controller may still determine the opposite pressure curves of the first pressure sensor and one of the second pressure sensors, thereby determining the correct position of the feeding tube. This may be confirmed by calculating the pressure correlation between the first pressure sensor and the (one or more) "second" pressure sensors, and the "second" pressure sensors should all be located in the stomach, and the "second" pressure sensors should have a pressure curve that is approximately equal to the pressure curve of the first pressure sensor.

[0020] In another embodiment variant, the controller may be configured to calculate the pressure correlation by determining (or calculating) the pressure difference between the respective pressures measured by the first pressure sensor and the second pressure sensor. Thus, a simple subtraction of the pressure value (or absolute pressure value) measured by the first pressure sensor and the pressure value (or absolute pressure value) measured by the second pressure sensor may be calculated.

[0021] Alternatively or additionally, the controller may be configured to calculate the pressure correlation by determining (or calculating) the frequency of the pressure peaks measured by the first pressure sensor or the second pressure sensor. In other words, the controller may be configured to identify two or more pressure peaks of the pressure measured by the first pressure sensor or the second pressure sensor, and derive the frequency of these pressure peaks. For example, the frequency may be defined by the time period between two consecutive pressure peaks (i.e., pairs of consecutive pressure peaks).

[0022] Furthermore, alternatively or additionally, the controller may be configured to calculate the pressure correlation by determining a time lag between a pressure peak value measured by the first pressure sensor and a pressure peak value measured by the second pressure sensor. Thus, a time correlation between a pressure peak value of the first sensor and a pressure peak value of the second sensor is determined. Preferably, such a time correlation may be based on the fact that the respective pressure peak values ​​of the first pressure sensor and the second pressure sensor directly follow each other, i.e., there are no other pressure peak values ​​within the determined time lag. Of course, it is also possible to only consider pressure peak values ​​of the same algebraic sign.

[0023] Furthermore, alternatively or additionally, the controller may be configured to calculate the pressure correlation by determining a sudden and unexpected value of at least one of the first pressure sensor and the second pressure sensor. For example, if one or both of the pressure sensors deliver a value above or below a threshold, a misalignment of the tube may be identified.

[0024] In any case, the controller can be configured to determine the position of the distal end based on the determined pressure difference, and / or the determined frequency, and / or the determined time lag. In other words, the pressure correlation takes into account the pressure difference of one or both sensors and / or the frequency of the pressure peaks, and / or the time lag between the pressure peaks of both sensors.

[0025] In another embodiment variant, the controller may be configured to determine that the location of the distal end is the patient's stomach if the time lag is less than a threshold or zero and the pressure difference is less than a threshold or zero, and the pressure signal of the first pressure sensor and the pressure signal of the second pressure sensor indicate opposite pressures. This pressure correlation corresponds to the embodiment variant described above in which a breathing pattern is identified based on opposite pressure curves derived from the esophagus and the stomach.

[0026] In yet another embodiment variation, the controller may be configured to determine that the location of the distal end is the patient's stomach if the pressure difference is above a threshold, wherein preferably the pressure measured by the first pressure sensor is greater than the pressure measured by the second pressure sensor. There is typically a pressure difference between the esophagus and the stomach, particularly if the stomach is empty. For example, the pressure in the stomach may be greater than the pressure in the esophagus. By way of example only, the pressure difference may be between 5 mmHg and 20 mmHg, preferably between 7 mmHg and 13 mmHg, and most preferably 10 mmHg.

[0027] In another embodiment variation, the controller may be configured to determine that the distal location is the patient's stomach if the frequency of the pressure peaks of the first pressure sensor is about 2.0 to 3.7 peaks per minute, preferably 2.5 to 3.2 peaks per minute. For example, a patient's stomach will typically contract frequently, especially if the stomach is full (e.g., after feeding). Such stomach contractions may be identified by regular pressure peaks (i.e., by the frequency of the pressure peaks of the first pressure sensor).

[0028] In another embodiment variation, the controller may be configured to determine that the location of the distal end is the esophagus of the patient if the time lag is greater than a threshold value, wherein the threshold value is between 0.5 seconds and 20 seconds, and preferably between 1 second and 8 seconds. In other words, if two pressure sensors are arranged in the esophagus and the patient swallows, a pressure peak may be identified at the second pressure sensor shortly after a pressure peak is identified at the first pressure sensor. The peristalsis of the esophagus, in particular the peristalsis between the upper and lower esophageal sphincters, moves toward the stomach, so that each pressure sensor will output a pressure signal, thereby identifying a pressure peak with a time delay (time lag) depending on the swallowing pattern in the esophagus.

[0029] It will be appreciated that the time lag depends on the distance between the first pressure sensor and the second pressure sensor, or in the case of more than two sensors, on the distance between each pair of adjacent sensors. For example, the typical speed of peristalsis of the esophagus is about 3 cm / s to 4 cm / s. The preferred distance between the first pressure sensor and the second pressure sensor is 10 cm to 25 cm, and the time lag between the pressure peak of the first sensor and the pressure peak of the second sensor is about 2.5 seconds to 8 seconds.

[0030] In addition, the controller can be configured to determine that the location of the distal end is the patient's stomach if the time lag is greater than the threshold and a pressure drop at the first pressure sensor can be identified shortly before a pressure peak at the first pressure sensor used to calculate the time lag. Swallowing patterns along the esophagus can be identified by pressure peaks that typically start from a baseline, while when peristalsis reaches the lower esophageal sphincter, the pressure in the stomach decreases before having a flat pressure peak.

[0031] Therefore, the pressure correlation between the second pressure sensor and the first pressure sensor due to swallowing of the patient can be used to determine whether the distal location is the esophagus or the stomach.

[0032] In yet another embodiment variation, the controller may be configured to determine that the location of the distal end is the patient's lung (or trachea or bronchus) if the pressure difference is less than a threshold value and the pressure peak of the first pressure sensor and the pressure peak of the second pressure sensor are both positive or both negative, wherein preferably the threshold value is between 0.5 mmHg and 6 mmHg, and most preferably between 0.5 mmHg and 2 mmHg. Specifically, if the pressure peaks are measured at approximately the same time and the respective pressure values ​​are both positive or both negative, it is likely that the feeding tube has been placed in the trachea, bronchus or lung, which are all fluidly connected to each other. Therefore, during inspiration and expiration, the pressure measured by the first sensor and the pressure measured by the second sensor will have approximately the same value and be both negative or positive, respectively.

[0033] In another embodiment variant, the feeding device may further include at least one wire electrically connecting the first pressure sensor and / or the second pressure sensor to the controller. Alternatively or additionally, the feeding device may further include at least one optical fiber optically connecting the first pressure sensor and / or the second pressure sensor to the controller. The wire and / or the optical fiber may be embedded in the material of the tube so that the wire is protected by the material of the tube. It should be understood that the first pressure sensor and the second pressure sensor may be connected to the controller via respective wires / optical fibers or a single wire / optical fiber.

[0034] In another embodiment variant, the feeding device may further comprise a second lumen, which fluidly connects the first pressure sensor and / or the second pressure sensor to the surrounding gaseous environment of the feeding device. This allows the first pressure sensor and / or the second pressure sensor to be able to operate relative to the surrounding gaseous environment pressure.

[0035] For example, the first pressure sensor and / or the second pressure sensor can be a differential pressure sensor, one side of which is in fluid communication with the surrounding gas environment via the second lumen. The opposite side of the pressure sensor can face the periphery of the feeding tube, i.e., can face the tissue surrounding the feeding tube of the patient, such as the esophagus, stomach, trachea, etc. Thus, the pressure in the cavity of the patient's body can act on the differential pressure sensor and the surrounding gas environment through the second lumen. This allows all sensors in the feeding tube to be accurately measured relative to the same reference pressure (i.e., the pressure of the surrounding gas environment).

[0036] In yet another embodiment variant, the first pressure sensor and / or the second pressure sensor is at least partially enclosed in a housing having a greater rigidity than the feeding tube. Such a pressure sensor provides better protection for the actual sensing element and avoids bending stresses from the tube from influencing the pressure measurement, for example by bending the pressure sensor / element itself.

[0037] In another embodiment variation, the feeding device may further include a feeding pump configured to pump nutrients into the first lumen at or near the proximal end. The feeding pump may be connected to the first lumen via a commonly used connector, such as an ENFit connector (according to ISO80369-3) or a Luer lock connector. Optionally, the reservoir may be connected via a supply kit, which is connected to the feeding tube via the ENFit connector. In order to move the nutrient product from the reservoir into the patient, a pump insert is part of the supply kit. The pump insert is placed in the pump to start pumping.

[0038] According to a second exemplary aspect, in order to better understand the present disclosure, a method for determining the position of a feeding tube includes at least the following steps:

[0039] - inserting a feeding tube into a patient, wherein the feeding tube has at least one lumen extending from a distal end to a proximal end of the tube;

[0040] - receiving a signal from a first pressure sensor disposed near the distal end of the feeding tube;

[0041] - receiving a signal from a second pressure sensor disposed in the feeding tube and configured to measure pressure acting on the tube, wherein the second pressure sensor is further away from the distal end of the tube in a longitudinal direction of the tube than the first pressure sensor; and

[0042] - calculating a pressure correlation between respective pressures measured by the first pressure sensor and the second pressure sensor based on the received signals; and

[0043] - determining the position of the distal end of the tube within the patient based on the calculated pressure correlation.

[0044] The method may be performed by using a feeding device, such as the feeding device of the first aspect or one of its embodiment variations.

[0045] In one embodiment variant, calculating the pressure correlation may include calculating the absolute pressure value of the first pressure sensor and the absolute pressure value of the second pressure sensor for the same measurement time; and determining the position may include determining that the position of the distal end is the patient's stomach if the absolute pressure value of the first pressure sensor and the absolute pressure value of the second pressure sensor are approximately equal and the pressure signal from the first pressure sensor and the pressure signal from the second pressure sensor indicate opposite pressures at the first pressure sensor and the second pressure sensor. Thus, the method allows the identification of a breathing pattern based on inverted pressure curves measured in the stomach and the esophagus (i.e., on both sides of the patient's diaphragm).

[0046] In another embodiment variant, the calculating the pressure correlation may include one or more of the following:

[0047] - determining a pressure difference between respective pressures measured by said first pressure sensor and said second pressure sensor;

[0048] - determining the frequency of pressure peaks measured by said first pressure sensor and said second pressure sensor; and

[0049] - determining a time lag between a pressure peak measured by the first pressure sensor and a pressure peak measured by the second pressure sensor.

[0050] In this case, determining the position may include determining the position of the distal end based on the determined pressure difference, and / or the determined frequency, and / or the determined time lag.

[0051] Furthermore, said determining the position may then comprise:

[0052] - if the time lag is less than a threshold or zero, and the pressure difference is less than a threshold or zero, and the pressure signal of the first pressure sensor and the pressure signal of the second pressure sensor indicate opposite pressures, determining that the location of the distal end is the patient's stomach;

[0053] - if the pressure difference is above a threshold, wherein preferably the pressure measured by the first pressure sensor is greater than the pressure measured by the second pressure sensor, determining the location of the distal end to be the patient's stomach;

[0054] - if the frequency of the pressure peaks of the first pressure sensor is about 2.0 to 3.7 peaks per minute, preferably 2.5 to 3.2 peaks per minute, determining the location of the distal end to be the patient's stomach;

[0055] - if the time lag is greater than a threshold, wherein the threshold is between 0.5 and 20 seconds, and preferably between 1 and 8 seconds, determining the location of the distal end to be the patient's esophagus; or

[0056] - If the pressure difference is less than a threshold value, and both the pressure peak value of the first pressure sensor and the pressure peak value of the second pressure sensor are positive values ​​or both are negative values, wherein preferably the threshold value is between 1 mmHg and 6 mmHg, and more preferably between 1 mmHg and 2 mmHg, then the distal end position is determined to be the patient's lungs.

[0057] According to a second exemplary aspect, for a better understanding of the present disclosure, a feeding system comprises a feeding device according to the first aspect or one of its embodiment variants and an output device communicating with the feeding device and configured to provide an output signal indicating the determined position of the distal end of the tube.

[0058] For example, the output device can be configured to provide visual and / or audible signals regarding the location of the distal end of the feeding tube. The output device can indicate that the distal end of the feeding tube is placed in a portion of the respiratory system, esophagus, or stomach based on a determination by a controller of the feeding device.

[0059] Thus, once a feeding tube is placed, such as through the nose and esophagus (nasogastric tube), even an untrained patient or caregiver can interpret the results from the controller, and the output device will indicate whether the tube is located in the trachea or esophagus, and then in the stomach, based on the pressure correlations identified by the controller of the feeding device. After the feeding tube is correctly placed, the patient or caregiver can regularly identify via the output device whether the distal end of the tube is still located in the stomach. Alternatively or additionally, the output device can output an alarm if the pressure correlation indicates a change in the position of the distal end of the tube, such as moving toward the small intestine or esophagus, or having been pulled into the esophagus.

[0060] As an example only, the output device can be a small device so that it is portable and easy to use. For example, a mobile phone, tablet computer or similar computing device can be used to implement the output device. Of course, such computing device can also include a controller as a controller of the feeding device.

[0061] In an embodiment variant, the feeding device, in particular the feeding tube, may also include another sensor configured to measure the pH value of the surrounding fluid. For example, such a pH sensor may be located at the distal end of the tube. Based on the measured pH value, the position of the distal end in the patient's stomach can be confirmed. This allows to improve the reliability of the feeding device.

[0062] In another embodiment, the feeding device, in particular the first pressure sensor and / or the second pressure sensor, can be configured to change the output signal if light and / or sound act on the sensor. The controller can also be configured to determine the change in the pressure signal received from the first pressure sensor and / or the second pressure sensor over a short period of time. The period of time can be initiated by the user of the feeding device, for example, when light or sound or (electrical / mechanical) vibration is applied from the outside of the patient, or automatically. As an example only, the output device can be equipped with a light-emitting device and / or a sound-emitting device so that the feeding system, and in particular the controller, can be aware when light and / or sound are emitted from the outside of the patient. If the controller determines that the pressure value received from the first pressure sensor and / or the second pressure sensor increases or decreases slightly when light and / or sound are emitted toward the patient, a pressure correlation can be determined. The user of the system can then recognize the pressure difference at the output device and / or the controller to confirm the correct or incorrect position of the distal end of the feeding tube. For example, the user can hold the light-emitting device and / or the sound-emitting device at a position of the abdominal wall corresponding to (close to) the stomach so that the light and / or sound affect the first pressure sensor and / or the second pressure sensor.

[0063] The present disclosure is not limited to the aspects and variations of the described form and order. Specifically, the description of the various aspects and variations should not be understood as a specific limiting grouping of features. It should be understood that the present disclosure also encompasses combinations of aspects and variations that are not explicitly described. Therefore, each variation or optional feature can be combined with any other aspect, variation, optional feature or even combination thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Preferred embodiments of the present invention will now be explained in more detail with reference to the accompanying schematic drawings, in which:

[0065] Figure 1 The patient's internal organs are schematically illustrated;

[0066] Figure 2 A feeding device is schematically illustrated;

[0067] Figure 3 The distal end of the feeding tube is schematically illustrated;

[0068] Figure 4 schematically illustrates pressure correlations between spaced-apart pressure sensors during swallowing;

[0069] FIG5 schematically illustrates a flow chart of a method for identifying appropriate feeding tube position based on breathing pattern;

[0070] Figure 6 a flow chart schematically illustrating a method of determining pressure correlation and appropriate feeding tube position; and

[0071] Figure 7 The feeding system is schematically illustrated. DETAILED DESCRIPTION

[0072] Figure 1 The internal organs of the patient 1, in particular the organs of the respiratory system and the digestive tract, are schematically illustrated. For enteral feeding, a feeding tube should be placed with its distal end in the stomach 2, which can be reached, for example, via the patient's nose (not shown), through the esophagus 3. The stomach 2 begins downwards with the duodenum 4, from which the intestine begins. When feeding through the stomach 2, the distal end of the feeding tube should not be placed in the duodenum 4, because the nutrients are prepared for gastric feeding, i.e., the nutrients should first be digested by the stomach 2 rather than by the intestine 4. Likewise, nutrients should not be fed into the esophagus 3, because the nutrients may flow back toward the pharynx and larynx of the patient 1 instead of being digested by the stomach 2. Both situations can make the patient 1 very uncomfortable.

[0073] Furthermore, the nose is connected to the respiratory system, in particular to the trachea 5 and the lungs 6. Therefore, when a feeding tube is placed through the nose, the tube may enter the trachea 5 instead of the esophagus 3. This should be avoided because providing nutrients into the trachea 5 or the lungs 6 through a feeding tube is very dangerous for the patient.

[0074] Figure 2 An exemplary feeding device 50 is schematically illustrated to facilitate a better understanding of the present disclosure. The illustrated feeding device 50 includes a feeding tube 100 to be inserted into a patient 1. The feeding tube 100 has at least one lumen 120 ( Figure 3 ). It should be noted that the proximal end 105 may not be Figure 2 The controller 150 does not end as shown in the figure, but may extend further along the longitudinal direction of the tube 100 , even to the controller 150 .

[0075] Feeding device 50 also includes a first pressure sensor 131 disposed near distal end 110 of feeding tube 100. First pressure sensor 131 should be placed as close as possible to distal end 110 of feeding tube 100 in order to measure the pressure in the immediate vicinity of distal end 110. Pressure sensor 131 is configured to measure the pressure acting on tube 100 at a location corresponding to first pressure sensor 131.

[0076] Furthermore, the feeding device 50 includes a second pressure sensor 132 disposed in the feeding tube 100. The second pressure sensor 132 is located farther from the distal end 110 than the first pressure sensor 131 in the longitudinal direction of the tube 100. The second pressure sensor 132 is also configured to measure the pressure acting on the tube 100 at a position corresponding to the second pressure sensor 132.

[0077] There may also be additional sensors along the proximal direction of the tube 100, which are not shown for clarity.

[0078] The feeding device 50 may further include a controller 150 configured to receive signals from the first pressure sensor 131 and the second pressure sensor 132. Based on these pressure signals, the controller 150 calculates a pressure correlation of the respective pressures measured by the first pressure sensor 131 and the second pressure sensor 132. The pressure correlation is then used by the controller 150 to determine the position of the distal end 110 of the tube 100 within the patient 1.

[0079] For example, the first pressure sensor 131 and / or the second pressure sensor 132 may be connected to the controller 150 via at least one wire 135 or optical fiber 135. The wire or optical fiber 135 provides an electrical connection or an optical connection between the pressure sensors 131, 132 and the controller 150, respectively. Therefore, the controller 150 can read the pressure signal of each pressure sensor 131, 132 at any time.

[0080] Figure 3 The distal end 110 of the feeding tube 100 is schematically illustrated in greater detail. Figure 3 The portion of the feeding tube 100 shown in FIG. Figure 2 The feeding tube 100 shown in FIG. Figure 2 Note that for the sake of clarity, Figure 3 The wire or optical fiber 135 has been omitted.

[0081] It should be understood that the opening of the lumen 120 in the tube 100 is illustrated at the distal end 110 of the tube as only one example. The distal end 110 of the feeding tube 100 may be closed, with an opening (not shown) into the lumen 120 formed at a lateral side of the tube 100. This allows nutrients to flow out of the tube 100 at the lateral side. If a lateral opening into the lumen 120 is provided in the feeding tube 100, the first pressure sensor 131 may be provided near the lateral opening (rather than at the distal end 110). The first pressure sensor 131 should be placed as close to the opening of the lumen 120 in the feeding tube 100 as possible in order to measure the pressure directly around the opening.

[0082] The feeding device 50, in particular the feeding tube 100, may further include a second lumen 125 that fluidly connects the first pressure sensor 131 and / or the second pressure sensor 132 to the surrounding gas environment of the feeding device 50. For example, the second lumen 125 may extend in the longitudinal direction of the tube 100 up to the controller 150 or at least to a portion of the tube 100 that will not be inserted into the patient 1.

[0083] This allows the use of a differential pressure sensor as the first pressure sensor 131 and / or the second pressure sensor 132. One side of such a differential pressure sensor is in fluid communication with the surrounding gas environment through the second lumen 125. In order to prevent the pressure of the cavity in the patient 1 from acting on the pressure sensors 131, 132 from the second lumen 125, the second lumen 125 is closed at the distal end 110 of the tube 100, for example, at the first pressure sensor or with the first pressure sensor.

[0084] On the other hand, the first lumen 120 has an open end at the distal end 110 of the tube 100. This allows the patient 1 to be fed nutrients through the first lumen 120.

[0085] The pressure correlation calculated by the controller 150 may reflect the various natural pressures caused by the organs of the patient 1. Figure 4 A first example is illustrated schematically illustrating the pressure correlation along the esophagus 3 during swallowing. The esophagus 3 (from top to bottom, i.e. from the throat to the stomach) comprises the pharynx 11, the upper esophageal sphincter 12, the junction of striated and smooth muscles 13, and the lower esophageal sphincter 14 ( Figure 4 The stomach is not shown in the figure 2).

[0086] Once the patient 1 swallows, peristalsis (associated with the associated moving contractions of the esophagus 3 due to muscle contractions) moves from the top to the bottom of the esophagus 3. For example, since the pharyngeal peristalsis is very fast (up to 40 cm / s), a bolus of food or saliva can travel through the pharynx 11 in less than a second. The time it takes for food or saliva to travel through the esophagus 3 (for an adult) is about 5 to 6 seconds, with a peristaltic speed of about 3 to 4 cm / s. Figure 4 As shown, such swallowing causes the pressure peak to "move" along the object placed in the esophagus 3. If pressure sensors (e.g., first pressure sensor 131 and second pressure sensor 132) are located in the esophagus 3, pressure peaks can be measured at different locations along the esophagus 3 as shown. At the lower esophageal sphincter 14 and stomach 3, the measured pressure decreases (falls) before reaching the pressure peak due to the opening of the lower esophageal sphincter 14 (i.e., allowing fluid communication between the esophagus and the stomach).

[0087] Thus, if the feeding tube 100 is arranged in the esophagus 3, in particular the distal end 110 of the tube 100 is still located in the esophagus 3, the pressure correlation can be calculated by the controller 150 based on the time lag (the time difference between the pressure peak of the pressure signal of the second pressure sensor 132 and the pressure peak of the pressure signal of the (later) first pressure sensor 131). Likewise, if the distal end 110 of the tube 100 and therefore the first pressure sensor 131 is located inside the stomach 2, the controller 150 can recognize the pressure drop before reaching the pressure peak, which occurs after the time lag relative to the pressure peak of the second pressure sensor 132 arranged in the esophagus 3. The controller 150 can then calculate the pressure correlation indicating that the distal end 110 is located in the stomach 2.

[0088] Other exemplary pressure correlations will now be explained with respect to FIG. 5 , which schematically illustrates a flow chart of a method for identifying an appropriate feeding tube position based on a breathing pattern. First, it is confirmed in step 210 whether the sensors 131 , 132 are connected to the controller 150 and functioning. If not, the process ends. For example, corresponding feedback may be provided to the user, including outputting a failure message to the user to indicate a malfunction of the feeding device 50.

[0089] Otherwise, the two pressure sensors 131, 132 are initialized in step 222. Thereafter, pressure signals are acquired in steps 224 to 228, for example, at a predefined sampling rate. As an example only, sampling may be performed for about 10 seconds to 30 seconds at a sampling rate frequency of 0.1 Hz to 0.5 Hz. The pressure signal of each sensor 131, 132 may be transmitted to the controller 150, which receives such pressure signals at step 220. Thereafter, the controller 150 may calculate the pressure correlation based on the received signals.

[0090] Merely as an example, in step 230, the frequency of the pressure peaks of the first pressure sensor 131 and the frequency of the pressure peaks of the second pressure sensor 132 may be derived from the signals received in step 220. The frequencies may be compared with expected frequencies in a corresponding step 235. For example, the breathing of the patient 1 will cause repeated pressure changes in the stomach and esophagus 3, since these two organs are close to the diaphragm and lungs 6 of the patient 1 and will move during breathing. Likewise, gastric contractions of a full stomach 2 will also occur regularly, so pressure peaks of a certain frequency may be expected.

[0091] If the expected frequency is not found, the controller 150 may determine that the tube 100 is not properly positioned in step 238. For example, the controller 150 may be configured to output other feedback, such as an alarm or similar visual and / or audible signal.

[0092] If an expected frequency is found in step 235, optional signal conditioning may be performed in step 240. For example, outlier selection, moving averages, or bandpass filtering may be applied.

[0093] Alternatively, the controller 150 may perform trend analysis (e.g., pattern recognition) on each received pressure signal in step 250. Such trend analysis may include monitoring pressure values ​​over time, particularly pressure peaks, duration of pressure peaks, frequency of pressure peaks, etc. Such trend analysis allows classification of pressure signals, such as breathing, feeding, digestion, etc.

[0094] Thereafter, in step 260, a pressure correlation between the respective pressures measured by the first pressure sensor 131 and the second pressure sensor 132 is calculated. For example, the received pressure signal and the further processed pressure signal are compared with each other. This may include identifying certain patterns, which may be identified based on the trend analysis of step 250. These patterns may be compared with each other (for example, in step 260). By way of example only, the pressure correlation may include calculating an absolute pressure value of the first sensor 131 and the second sensor 132 at the same measurement time, and comparing the absolute pressure values, in particular, comparing whether the two absolute pressure values ​​are approximately equal. If the pressure signals from the first pressure sensor 131 and the second pressure sensor 132 as illustrated in step 250 of FIG. 5 indicate opposite pressures at the first pressure sensor and the second pressure sensor, an opposite or reverse pattern may be identified in step 270. Since this opposite pressure pattern typically occurs during breathing, in step 280, the controller 150 can determine the correct position of the tube 100, specifically that the distal end 110 of the tube 100 is located in the stomach 2, while a portion of the tube 100 including the second pressure sensor 132 is located in the esophagus 3.

[0095] Now go to Figure 6 , schematically illustrates a flow chart showing a method of determining pressure correlation and appropriate feeding tube position. For example, as in the method of FIG. 5 , in step 220 pressure signals from the first pressure sensor 131 and the second pressure sensor 132 may be received, such as at the controller 150 .

[0096] exist Figure 6, a fairly simple relative pressure correlation is calculated by selecting and analyzing samples in step 305, and the relative pressure difference between the two sensors 131, 132 is measured or calculated in step 307. This pressure difference can then be output in step 309 and analyzed in step 320. For example, if the pressure difference is approximately zero, the relative pressure difference can be used to identify that the tube 100 is incorrectly positioned, for example in the trachea 5 or lung 6 of the patient 1. On the other hand, there is a certain level of pressure difference between the esophagus 3 and the stomach 2, for example about 10 mmHg. Therefore, the position of the first pressure sensor 131 in the stomach 2 and the position of the second pressure sensor 132 in the esophagus 3 can be identified, and therefore the correct position of the tube 100 can be identified.

[0097] Another pressure correlation may indicate a breathing pattern, a swallowing pattern, or a contraction of the stomach 2. In any case, the frequency of the pressure peaks of the first pressure sensor 131 and / or the second pressure sensor 132 is analyzed in step 312, and a particular sample of the received pressure signals is selected and analyzed in step 314. Thereafter, in step 316, the pressure signals of the distal sensor 131 and the proximal sensor 132 (or vice versa) may be compared to identify breathing patterns and swallowing patterns. While a breathing pattern will have opposite pressure peaks in the esophagus 3 and stomach 2 due to the movement of the diaphragm, swallowing will induce a change in pressure with respect to the esophagus 3 and stomach 2. Figure 4 Likewise, in step 316, for any sensors located in the stomach 2, the pressure peaks can be compared to each other, which is indicative of stomach contractions during digestion.

[0098] Thus, in step 318, the corresponding rhythmic pattern can be identified and provided to the controller 150 for analysis in step 320. The analysis can include, for example, weighting the derived rhythmic pattern or pressure differential based on a preset or trained model. In any case, the controller 150 can identify an incorrect tube placement in step 238 or a correct tube placement in step 280.

[0099] Figure 7 A feeding system 75 is schematically illustrated, which may include a feeding device 50, such as Figure 2 and Figure 3 The device 50 shown in FIG. This feeding device 50 may include a feeding tube 100 inserted into the patient 1 and a controller 150.

[0100] In addition, an output device 180 may form part of the feeding system 75. The output device 180 may include a display and / or a speaker (not shown) to provide visual and / or auditory output to the patient 1 or a caregiver 185 (or a clinician, etc.). The controller 150 may communicate 170 with the output device 180 to inform the patient 1 or the caregiver 185 about the position of the distal end 110 of the tube 100. Such communication 170 may be wireless communication (e.g., Bluetooth, WLAN, etc.) or wired communication (USB, LAN, etc.).

[0101] Additionally, based on the pressure correlation and determination of the position of the distal end 110, a visual and / or audible signal indicative of the position may be output at the output device 180. The output indication may include specifying that the tube 100 is dislocated in the trachea 5 and / or lung 6, that the distal end 110 is dislocated in the esophagus 3 or duodenum 4, or that the distal end 110 is properly located in the stomach 2.

[0102] The feeding system 75 may also include a feeding pump 121 configured to pump nutrients into the first lumen 120 of the tube 100. Such a pump 121 may be integrated into the device holding the controller 150, and / or may be integrated into the output device 180.

[0103] Furthermore, the controller 150 may also be integrated into the output device 180 with or without the optional pump 121 .

[0104] In addition, the data output by the controller 150 may also be transmitted to an external device 190. Such an external device 190 may be connected to the output device 180 and / or the controller 150 via a network. The external device 190 may be configured to analyze and / or store data calculated and determined by the controller 150. The device 190 may be used by a doctor or clinic or a developer of the feeding device 50 to monitor the patient 1 and the feeding device 50.

[0105] The above description of the drawings should be understood as providing only exemplary embodiments of the present invention and should not limit the present invention to these specific embodiments.

Claims

1. A feeding device (50), comprising: A feeding tube (100) for insertion into a patient (1) and having at least one lumen (120) extending from a distal end (110) to a proximal end (105) of the tube (100); a first pressure sensor (131) disposed near the distal end (110) of the feeding tube (100) and configured to measure pressure acting on the tube (100); a second pressure sensor (132) disposed in the feeding tube (100) and configured to measure pressure acting on the tube, wherein the second pressure sensor (132) is located farther from the distal end (110) of the tube (100) than the first pressure sensor (131) in the longitudinal direction of the tube (100); and A controller (150), the controller being configured to: - receiving signals from the first pressure sensor (131) and the second pressure sensor (132); - calculating a pressure correlation between respective pressures measured by the first pressure sensor (131) and the second pressure sensor (132) based on the received signals; and - determining the position of the distal end (110) of the tube (100) within the body of the patient (1) based on the calculated pressure correlation.

2. The feeding device (50) according to claim 1, wherein: The controller (150) is configured to: - calculating the pressure correlation by calculating the absolute pressure value of the first pressure sensor (131) and the absolute pressure value of the second pressure sensor (132) at the same measurement time; as well as - If the absolute pressure value of the first pressure sensor (131) and the absolute pressure value of the second pressure sensor (132) are approximately equal, and the pressure signal from the first pressure sensor (131) and the pressure signal from the second pressure sensor (132) indicate opposite pressures at the first pressure sensor and the second pressure sensor, then the position of the distal end (110) is determined to be the stomach (2) of the patient (1).

3. The feeding device (50) according to claim 1, wherein: The controller (150) is configured to calculate the pressure correlation in the following manner: - determining a pressure difference between respective pressures measured by the first pressure sensor (131) and the second pressure sensor (132); and / or - determining the frequency of pressure peaks measured by the first pressure sensor (131) and the second pressure sensor (132); and / or - determining a time lag between a pressure peak measured by the first pressure sensor (131) and a pressure peak measured by the second pressure sensor (132), Therein, the controller (150) is configured to determine the position of the distal end (110) based on the determined pressure difference, and / or the determined frequency, and / or the determined time lag.

4. The feeding device (50) according to claim 3, wherein: The controller (150) is configured to: - if the time lag is less than a threshold or zero, and the pressure difference is less than a threshold or zero, and the pressure signal of the first pressure sensor and the pressure signal of the second pressure sensor indicate opposite pressures, determining that the position of the distal end (110) is the stomach (2) of the patient (1); - if the pressure difference is above a threshold, wherein preferably the pressure measured by the first pressure sensor (131) is greater than the pressure measured by the second pressure sensor (132), determining that the location of the distal end (110) is the stomach (2) of the patient (1); - if the frequency of the pressure peaks of the first pressure sensor (131) is about 2.0 to 3.7 peaks per minute, preferably 2.5 to 3.2 peaks per minute, determining that the position of the distal end (110) is the stomach (2) of the patient (1); - if the time lag is greater than a threshold, wherein the threshold is between 0.5 seconds and 20 seconds, and preferably between 1 second and 8 seconds, determining that the location of the distal end (110) is the esophagus (3) of the patient (1); or - If the pressure difference is less than a threshold value, and the pressure peak value of the first pressure sensor (131) and the pressure peak value of the second pressure sensor (132) are both positive or both negative, wherein preferably the threshold value is between 1 mmHg and 6 mmHg, and most preferably between 1 mmHg and 2 mmHg, then the position of the distal end (110) is determined to be the lung (6) of the patient (1).

5. The feeding device (50) according to any one of claims 1 to 4, further comprising: at least one wire (135), the at least one wire electrically connecting the first pressure sensor (131) and / or the second pressure sensor (132) to the controller (150); and / or At least one optical fiber (135), the at least one optical fiber optically connecting the first pressure sensor (131) and / or the second pressure sensor (132) to the controller (150).

6. The feeding device (50) according to any one of claims 1 to 5, further comprising: a second lumen (125), the second lumen fluidically connecting the first pressure sensor (131) and / or the second pressure sensor (132) to the surrounding gas environment of the feeding device (50), Preferably, the first pressure sensor (131) and / or the second pressure sensor (132) is a differential pressure sensor, and one side of the first pressure sensor and / or the second pressure sensor is connected to the surrounding gas environment fluid through the second lumen (125).

7. The feeding device (50) according to any one of claims 1 to 6, wherein: The first pressure sensor (131) and / or the second pressure sensor (132) are at least partially enclosed in a housing (133), the housing having a greater rigidity than the feeding tube (100).

8. The feeding device (50) further comprises: A feeding pump (121) is configured to pump nutrients into the first lumen (120) at or near the proximal end (105).

9. A method for determining a position of a feeding tube (100), the method comprising: inserting a feeding tube (100) into a patient (1), wherein the feeding tube (100) has at least one lumen (120) extending from a distal end (110) to a proximal end (105) of the tube (100); receiving (220) a signal from a first pressure sensor (131) disposed near the distal end (110) of the feeding tube (100); receiving (220) a signal from a second pressure sensor (132) disposed in the feeding tube (100) and configured to measure pressure acting on the tube, wherein the second pressure sensor (132) is located further from the distal end (110) of the tube (100) than the first pressure sensor (131) in a longitudinal direction of the tube (100); and calculating (260, 309, 318) a pressure correlation between respective pressures measured by the first pressure sensor (131) and the second pressure sensor (132) based on the received signals; and The position of the distal end (110) of the tube (100) within the body of the patient (1) is determined (270, 320) based on the calculated pressure correlation.

10. The method according to claim 9, wherein: Calculating the pressure correlation includes: calculating the absolute pressure value of the first pressure sensor (131) and the absolute pressure value of the second pressure sensor (132) at the same measurement time; and Wherein, determining the position includes: if the absolute pressure value of the first pressure sensor (131) and the absolute pressure value of the second pressure sensor (132) are approximately equal, and the pressure signal from the first pressure sensor (131) and the pressure signal from the second pressure sensor (132) indicate opposite pressures at the first pressure sensor and the second pressure sensor, then determining that the position of the distal end (110) is the stomach (2) of the patient (1).

11. The method according to claim 9 or 10, wherein: Calculating the pressure correlation includes: - determining a pressure difference between respective pressures measured by the first pressure sensor (131) and the second pressure sensor (132); and / or - determining the frequency of pressure peaks measured by the first pressure sensor (131) and the second pressure sensor (132); and / or - determining a time lag between a pressure peak measured by the first pressure sensor (131) and a pressure peak measured by the second pressure sensor (132), Wherein, determining the position comprises: determining the position of the distal end (110) based on the determined pressure difference, and / or the determined frequency, and / or the determined time lag.

12. The method according to claim 11, wherein: Determining the location includes: - if the time lag is less than a threshold or zero, and the pressure difference is less than a threshold or zero, and the pressure signal of the first pressure sensor and the pressure signal of the second pressure sensor indicate opposite pressures, determining that the position of the distal end (110) is the stomach (2) of the patient (1); - if the pressure difference is above a threshold, wherein preferably the pressure measured by the first pressure sensor (131) is greater than the pressure measured by the second pressure sensor (132), determining that the location of the distal end (110) is the stomach (2) of the patient (1); - if the frequency of the pressure peaks of the first pressure sensor (131) is about 2.0 to 3.7 peaks per minute, preferably 2.5 to 3.2 peaks per minute, determining that the position of the distal end (110) is the stomach (2) of the patient (1); - if the time lag is greater than a threshold, wherein the threshold is between 0.5 seconds and 20 seconds, and preferably between 1 second and 8 seconds, determining that the location of the distal end (110) is the esophagus (3) of the patient (1); or - If the pressure difference is less than a threshold value, and the pressure peak value of the first pressure sensor (131) and the pressure peak value of the second pressure sensor (132) are both positive or both negative, wherein preferably the threshold value is between 1 mmHg and 6 mmHg, and most preferably between 1 mmHg and 2 mmHg, then the position of the distal end (110) is determined to be the lung (6) of the patient (1).

13. A feeding system (75), comprising: A feeding device (50) according to any one of claims 1 to 8; and An output device (180) is in communication with the feeding device (50) and is configured to provide an output signal indicative of the determined position of the distal end (110) of the tube (100).

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