Inhalation device with a novel pressure measuring device

Abstract

The present invention relates to an inhaler with a novel pressure measuring device for minimally invasive surgery. The novel device allows to reliably measure the pressure in a body cavity while at the same time ensuring that the gas supply line is not blocked.

Description

[Technical field]

[0001] The present invention relates to an inhaler with a novel pressure measuring device. The new device makes it possible to reliably measure the pressure in the body cavity and at the same time ensures that the gas supply line is free. [Background technology]

[0002] Various designs of inhalers are known from the prior art. Inhalers usually have a tube that delivers medical gas into a body cavity (e.g. the abdominal cavity). The gas creates a positive pressure that expands the cavity so as to provide sufficient space for visual inspection or therapeutic intervention. An optional embodiment allows to aspirate the gas out of the abdominal cavity via a second tube. In particular, this type of embodiment is used in therapeutic interventions using electrosurgical devices or lasers to remove and filter harmful smoke gases.

[0003] In practice, it has proven difficult to accurately determine the pressure in a body cavity. Also, various configurations of measuring devices for determining the pressure in a body cavity are known. The possibility of measuring the pressure using a pressure sensor in the body cavity itself brings about the disadvantage that in addition to the necessary medical equipment, a pressure sensor must also be positioned in the body cavity. On the one hand, this means that an additional element is added in the body cavity with associated connections that take up space and at the same time represent a risk of infection. On the other hand, this leads to higher costs for the pressure sensor. For this reason, it must be designed in a complex manner, either requiring cleaning and sterilization or as a disposable item.

[0004] Thus, an embodiment has been established in which the pressure sensor is not located in the body cavity itself, but in one of the tubes that is somewhat distant from the body cavity. A particular disadvantage of this sensor arrangement is the pressure difference between the body cavity and the measurement location (e.g., the location of the tube) caused by the tube, the trocar, and possibly other devices. This pressure loss is not easy to determine and is the subject of much research. The further the pressure sensor is from the body cavity, the greater the difference in the measured pressure from the pressure in the body cavity. The closer the pressure sensor is to a gas supply (e.g., a valve-controlled pump) or to a suction pump, the greater the difference caused by the active operation of the pump or valve (e.g., pressure pulses). Furthermore, the effect is compounded by errors resulting from the fact that, when the tube is closed, the flow cannot move to and from the body cavity. Such an obstruction can be caused by a bent tube or by the fact that the patient's opening is closed by the body tissue. Thus, if the tube is obstructed, the pressure sensor measures only the pressure in the tube and not the pressure in the body cavity. This causes considerable safety concerns.

[0005] German Utility Model No. 202004021703 further discloses a device for delivering substances (e.g. chemotherapeutic agents) into an aspirated body cavity, which, however, cannot avoid the occurrence of the above-mentioned measurement errors, in particular, cannot detect blockage of the tube. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] German Utility Model No. 202004021703 Summary of the Invention [Problem to be solved by the invention]

[0007] To overcome the above-mentioned disadvantages of existing pressure measurement systems, a problem arises of providing an inhaler that ensures accurate pressure measurements and that reliably detects when a tube blockage occurs. [Means for solving the problem]

[0008] The present invention therefore relates to an inhaler for minimally invasive surgery, a) a gas connection for gas cylinders or domestic gas (1); b) a first pressure and flow control unit (2) equipped with a proportional valve; c) a supply line (3) with a cross section of 5.5-15 mm configured for a gas flow of 0-50 L / min at 2-3 bar, having a first controllable valve (4), a first gas pressure sensor (5), a first gas flow sensor (6) and a connection to a first trocar (7) in a cavity (8); d) a sensor line (9) with a cross section of 2-5 mm having an optional throttle (10) configured for a gas flow of less than 1 L / min at 2-3 bar, with a second controllable valve (11), and a second gas pressure sensor (12), and a connection to a second trocar (13) in the cavity (8); e) a computing unit (14) for controlling the inhalation and for evaluating the measurement data of the first gas pressure sensor (5) and the second gas pressure sensor (12), The sensor line (9) is connected to a first pressure and flow control unit (2) and a second controllable valve (11) allows a pulsed gas flow into the cavity (8) controlled by a computing unit (14).

[0009] Further embodiments of the invention, including associated methods of operation, are described below and are the subject matter, in part, of the accompanying and dependent claims. [Brief description of the drawings]

[0010] [Figure 1a] 1 shows a basic structure with the components as claimed in claim 1. [Figure 1b] The results of the pressure measurement of the second pressure sensor (p12) are shown compared to the actual pressure in the cavity (p8) as a function of gas flow in the sensor line. [Figure 1c] In the case of occlusion, ie, when the sensor line (9) is removed from the second trocar without pulsating the second controllable valve, the pressure profile is shown. [Figure 2a] An embodiment of the invention is shown with a check valve (15). [Figure 2b] The measurement results are shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Principles and Simple Implementations of the Invention The invention is shown in principle in figure 1. A gas connection for a gas cylinder or household gas can be seen, which leads to a first pressure and flow control unit equipped with a proportional valve. In turn, a line leads to a controllable valve. The first pressure and flow control unit can provide a gas flow of up to 50 liters / min at a pressure of 2-3 bar. Furthermore, a gas flow sensor for measuring the gas flow can be seen, as well as a first gas pressure sensor. The supply line leads to the body cavity via a tube and a trocar.

[0012] It can also be seen that the sensor line branches between the first pressure and flow control unit and the first controllable valve. This sensor line has a rather small cross section (3-5 mm) and is configured for a gas flow of less than 1 liter / min at the pressure of 2-3 bar mentioned above. The gas flow through the sensor line is preferably less than 0.5 liter / min, most preferably less than 0.1 liter / min. The sensor line may include a throttle for the purpose of limiting the gas flow. Optionally, the throttle may be adjustable or controllable. The sensor line first leads to a second controllable valve and then to a second gas pressure sensor. The sensor line also leads to the body cavity via a second tube and a second trocar. As shown in FIG. 1b, during operation, a discontinuous pulsed gas flow through the sensor line can be set by means of the second controllable valve. For example, a single pressure pulse of 20-50 mmHg can be delivered to the sensor line for 1-3 seconds, followed by a non-pulsed period of 3-20 seconds. Due to the relatively low gas flow through the sensor line, the gas flow through the sensor line does not actually affect the pressure in the cavity. During the gas pulse, on the other hand, the pressure measured by the second gas pressure sensor in the sensor line increases considerably and drops again after closing the second controllable valve until it is identical to the pressure in the body cavity. Thus, the actual pressure in the body cavity corresponds to the equilibrium pressure during the non-pulsed period. In case of an occlusion of the sensor line, the pressure measured by the second gas pressure sensor increases and maintains an increased pressure level for a long time (see FIG. 1b). Such a pressure behavior clearly indicates an occlusion of the sensor line. In this case, an alarm signal is triggered if the increase in pressure measured by the second gas pressure sensor lasts longer than twice the pulse width.

[0013] Thus, in order to detect a blockage in the sensor line, a pulsed gas flow through the sensor line is of primary importance. In the absence of gas flow pulses, detection of a sensor line blockage is not possible in this embodiment of the invention. Comparison of the measurements of the first gas pressure sensor (5) and the second gas pressure sensor (12) is essential to the function of the device described in accordance with the present invention and to the inhalation method performed with said device.

[0014] The triggered alarm signal can be optical and / or acoustic in nature. It is also possible to automatically limit the gas inflow during inhalation to avoid excessive pressurization of the cavity.

[0015] However, the structure of the inhaler according to the invention also allows the modification of the operating mode described below. In this operating mode, a continuous gas flow through the sensor line is ensured by keeping the second controllable valve always open. If a constant gas flow passes through the sensor line, a pressure can be read out at the second gas pressure sensor that depends on the pressure in the cavity. However, the pressure measurement at the second gas pressure sensor needs to be corrected by the pressure losses in the line and the trocar between the second gas pressure sensor and the cavity. For this purpose, the following equation 1 is applied: equation 1 p cavity =p sensor -p sensor line

[0016] The pressure drop in the sensor line is approximately constant at the noted low gas flows through the line and can be determined by measurement or calculation.

[0017] In this mode of operation, when an occlusion occurs, the pressure measured by the second gas pressure sensor increases. A pressure increase of at least 20 mmHg occurs within 1-2 seconds and drops almost as quickly when the occlusion is relieved, for example if the tube is temporarily bent. Such a rapid pressure increase or loss can only occur in the case of an occlusion in the sensor line. The pressure increase in the body cavity in the case of poor control of the gas supply line will be significantly slower.

[0018] In another embodiment of the invention, a non-return valve is included in the sensor line between the second trocar and the second gas pressure sensor, already open at a back pressure of 8-12 mmHg on the side of the cavity. In a specific embodiment of the invention, the non-return valve can open at a lower back pressure, for example, at 3 mmHg-5 mmHg, or even at 1 mmHg-3 mmHg. In this way, it can be checked whether the sensor line is properly connected to the cavity and is not blocked. If it is not connected to the cavity or if a blockage occurs between the cavity and the second sensor, the non-return valve remains closed. This situation can be detected by the fact that opening the second controllable valve causes a rapid increase in the pressure measured at the second gas pressure sensor, but not at the first gas pressure sensor (see FIG. 2b). When properly connected, the pressure measured at the second gas pressure sensor increases even slower. At the same time, the pressure measured at the first gas pressure sensor increases. In this embodiment, it is also necessary to generate a pulsed gas flow through the sensor line. In the absence of a gas flow pulse, detection of a sensor line blockage is not possible.

[0019] Furthermore, in this case it is also necessary, if appropriate, to know the pressure loss across the sensor line in order to correct the measurement at the second pressure sensor (see FIG. 2b).

[0020] In a simplified embodiment of the invention (not shown), the sensor line to which the second gas pressure sensor is connected leads into the cavity through a second trocar, the sensor line not being connected to the first pressure and flow control unit. In this case, a second controllable valve is not necessary. In this embodiment, a blockage of the sensor line can occur only by comparing the measurements between the first and second gas pressure sensors. For this purpose, the first controllable valve of the supply line must be closed so that the measurements of the first gas pressure sensor are not influenced by the gas inflow. When closing the first valve, i.e. during a pause in the inhalation, both gas pressure sensors must display the same pressure, possibly taking into account the gas pressure loss across the line (see above). If the pressure values ​​deviate by more than 5 mmHg (in special cases more than 1 mmHg), a blockage of the line or some other disturbance of the gas flow must be assumed.

[0021] Text description of the illustration image024.gif. Figure 1 shows the device according to the invention as described at the beginning. Figure 1a shows the basic structure with the components according to claim 1. Only the computing unit is not shown. A second controllable valve (11) allows a pulsating gas flow in the cavity (8).

[0022] Figure 1b shows the pressure at the second pressure sensor (p ) compared to the actual pressure in the cavity (p ) as a function of gas flow in the sensor line. 12) shows the results of a pressure measurement. The upper curve shows the position of the second controllable valve (11) in the "on" or "off" state. The lower curve shows the pressure measured at the second pressure sensor (12) or in the body cavity. A gas pulse in the sensor line results in a corresponding pressure pulse at the second pressure sensor (12) with roughly the same pulse width. In case of an occlusion of the sensor line (right side of the figure), there is an increase in pressure at the second pressure sensor (12) that lasts much longer than the pulse width of the pressure pulse. The actual pressure in the body cavity (p8) is constant in this example. If the measured pressure increase lasts much longer than the pulse width of the pressure pulse from the second controllable valve (11) without a corresponding pressure increase being registered by the first pressure sensor (5), it can be concluded that the sensor line (9) can be occluded and an alarm can be triggered.

[0023] Figure 1c shows the pressure profile in the case of occlusion, i.e. when the sensor line (9) is removed from the second trocar without pulsating the second controllable valve: in this case, the pressure measured at the second pressure sensor remains constant even as the pressure p8 in the cavity (8) increases.

[0024] Figure 2a shows an embodiment of the invention with a check valve (15). Figure 2b shows the measurement results. When the sensor line (9) is not connected to the second trocar (13), a short pressure pulse through the second controllable valve (11) causes a long-lasting pressure increase (p 12 As soon as the sensor line (9) is properly connected to the second trocar (13), the pressure (p 12) runs parallel to the actual pressure in the cavity (8). The pressure difference Δp shown on the chart results from the volumetric flow rate in the sensor line (9). When the valve (11) is closed, the pressure difference will be small, but not equal to zero due to pressure losses in the line (see equation 1). This embodiment of the invention is also possible without the second controllable valve (11), and is therefore optional. However, in the absence of the second controllable valve (11), an improper connection of the sensor line (9) to the second trocar (13) is detectable, but an occlusion between the cavity (8) and the second gas pressure sensor (12) cannot be detected.

[0025] The reference numerals used in the figures have the following meanings: [Explanation of symbols]

[0026] (1) Gas cylinder or household gas connection (2) a first pressure and flow control unit equipped with a proportional valve; (3) Supply line (4) a first controllable valve (5) First gas pressure sensor (6) First gas flow sensor (7) First trocar (8) Cavity (9) Sensor line (10) Throttle (optional) (11) A second controllable valve (12) Second gas pressure sensor (13) Second trocar (14) Computing Unit (15) Check valve

Claims

1. 1. An inhaler for minimally invasive surgery, comprising: a) a gas connection (1) for a gas cylinder or domestic gas; b) a first pressure and flow control unit (2) equipped with a proportional valve; c) a supply line (3) with a cross section of 5.5-15 mm configured for a gas flow of 0-50 L / min at 2-3 bar, having a first controllable valve (4), a first gas pressure sensor (5), a first gas flow sensor (6) and a connection to a first trocar (7) in a cavity (8); d) a sensor line (9) with a cross section of 2-5 mm having an optional throttle (10) configured for a gas flow of less than 1 L / min at 2-3 bar, with a second controllable valve (11), and a second gas pressure sensor (12), and a connection to a second trocar (13) in said cavity (8); e) a computing unit (14) for controlling the inhalation and for evaluating the measurement data of the first gas pressure sensor (5) and the second gas pressure sensor (12), The sensor line (9) is connected to the first pressure and flow control unit (2), and the second controllable valve (11) allows a pulsed gas flow controlled by the computing unit (14) to flow into the cavity (8).

2. 2. The inhaler for minimally invasive surgery according to claim 1, further comprising a check valve (15), which is already open at a low back pressure of 8 to 12 mmHg on the side of the cavity and is positioned in the sensor line between the second trocar (13) and the second gas pressure sensor (12).

3. 1. An inhaler for minimally invasive surgery, comprising: a) a gas connection (1) for a gas cylinder or domestic gas; b) a first pressure and flow control unit (2) equipped with a proportional valve; c) a supply line (3) with a cross section of 5.5-15 mm configured for a gas flow of 0-50 L / min at 2-3 bar, having a first controllable valve (4), a first gas pressure sensor (5), a first gas flow sensor (6) and a connection to a first trocar (7) in a cavity (8); d) a sensor line (9) with a cross section of 2-5 mm configured for a gas flow of less than 1 L / min at 2-3 bar, with a second controllable valve (11), and a second gas pressure sensor (12), and a connection to a second trocar (13) in said cavity (8), and including an optional throttle (10); e) a computing unit (14) for controlling the inhalation and for evaluating the measurement data of the first gas pressure sensor (5) and the second gas pressure sensor (12); An inhaler comprising:

4. 1. An inhaler for minimally invasive surgery, comprising: a) a gas connection (1) for a gas cylinder or domestic gas; b) a first pressure and flow control unit (2) equipped with a proportional valve; c) a supply line (3) with a cross section of 5.5-15 mm configured for a gas flow of 0-50 L / min at 2-3 bar, having a first controllable valve (4), a first gas pressure sensor (5), a first gas flow sensor (6) and a connection to a first trocar (7) in a cavity (8); d) a sensor line (9) with a cross section of 2-5 mm having a second gas pressure sensor (12) and an optional throttle (10) configured for a gas flow of less than 1 L / min at 2-3 bar, with a connection to a second trocar (13) in said cavity (8); e) a computing unit (14) for controlling the inhalation and for evaluating the measurement data of the first gas pressure sensor (5) and the second gas pressure sensor (12), The inhaler, wherein the computing unit (14) is configured to compensate for pressure losses in the supply line (3) with the first trocar (7) and the sensor line (9) with the second trocar (13) and compare the compensated measurement values ​​of the first pressure sensor (5) and the second pressure sensor (6).

5. 10. A method for detecting an occlusion of a sensor line during operation of an inhaler according to claim 1, the inhaler comprising: a) a gas connection (1) for a gas cylinder or domestic gas; b) a first pressure and flow control unit (2) equipped with a proportional valve; c) a supply line (3) with a cross section of 5.5-15 mm configured for a gas flow of 0-50 L / min at 2-3 bar, having a first controllable valve (4), a first gas pressure sensor (5), a first gas flow sensor (6) and a connection to a first trocar (7) in a cavity (8); d) a sensor line (9) with a cross section of 2-5 mm having an optional throttle (10) configured for a gas flow of less than 1 L / min at 2-3 bar, with a second controllable valve (11), and a second gas pressure sensor (12), and a connection to a second trocar (13) in said cavity (8); e) a computing unit (14) for controlling the inhalation and for evaluating the measurement data of the first gas pressure sensor (5) and the second gas pressure sensor (12), the sensor line (9) is connected to the first pressure and flow control unit (2), and the second controllable valve (11) creates a constant gas flow in the cavity (8); The measured pressure profile of the second gas pressure sensor (12) is monitored by the computing unit (14), a correction of the measurement data is made based on pressure loss in the sensor line, and an alarm is triggered within 1 to 2 seconds if there is a significant increase in pressure of at least 2 mmHg.

6. 10. A method for detecting an occlusion of a sensor line during operation of an inhaler according to claim 1, the inhaler comprising: a) a gas connection (1) for a gas cylinder or domestic gas; b) a first pressure and flow control unit (2) equipped with a proportional valve; c) a supply line (3) with a cross section of 5.5-15 mm configured for a gas flow of 0-50 L / min at 2-3 bar, having a first controllable valve (4), a first gas pressure sensor (5), a first gas flow sensor (6) and a connection to a first trocar (7) in a cavity (8); d) a sensor line (9) with a cross section of 2-5 mm having an optional throttle (10) configured for a gas flow of less than 1 L / min at 2-3 bar, with a second controllable valve (11), and a second gas pressure sensor (12), and a connection to a second trocar (13) in said cavity (8); e) a computing unit (14) for controlling the inhalation and for evaluating the measurement data of the first gas pressure sensor (5) and the second gas pressure sensor (12), the sensor line (9) is connected to the first pressure and flow control unit (2), and the second controllable valve (11) generates a pulsed gas flow in the cavity (8); The measured pressure profile of the second gas pressure sensor (12) is monitored by the computing unit (14) and an alarm is triggered if a pressure increase persists for more than twice the pulse width.

7. 3. A method for detecting an occlusion of a sensor line during operation of an inhaler according to claim 2, the inhaler comprising: a) a gas connection (1) for a gas cylinder or domestic gas; b) a first pressure and flow control unit (2) equipped with a proportional valve; c) a supply line (3) with a cross section of 5.5-15 mm configured for a gas flow of 0-50 L / min at 2-3 bar, having a first controllable valve (4), a first gas pressure sensor (5), a first gas flow sensor (6) and a connection to a first trocar (7) in a cavity (8); d) a sensor line (9) with a cross section of 2-5 mm having an optional throttle (10) configured for a gas flow of less than 1 L / min at 2-3 bar, with a second controllable valve (11), and a second gas pressure sensor (12), and a connection to a second trocar (13) in said cavity (8); e) a computing unit (14) for controlling the inhalation and for evaluating the measurement data of the first gas pressure sensor (5) and the second gas pressure sensor (12); f) a check valve (15) which is already open at a back pressure of 8-12 mmHg on the side of the cavity and which is positioned in the sensor line between the second trocar (13) and the second gas pressure sensor (12); the sensor line (9) is connected to the first pressure and flow control unit (2), and the second controllable valve (11) creates a constant gas flow in the cavity (8); The measured pressure profile of the second gas pressure sensor (12) is monitored by the computing unit (14), a correction of the measurement data is made based on pressure loss in the sensor line, and an alarm is triggered within 1 to 2 seconds if there is a significant increase in pressure of at least 2 mmHg.

8. 5. A method for detecting an occlusion of a sensor line during operation of an inhaler according to claim 4, the inhaler comprising: a) a gas connection (1) for a gas cylinder or domestic gas; b) a first pressure and flow control unit (2) equipped with a proportional valve; c) a supply line (3) with a cross section of 5.5-15 mm configured for a gas flow of 0-50 L / min at 2-3 bar, having a first controllable valve (4), a first gas pressure sensor (5), a first gas flow sensor (6) and a connection to a first trocar (7) in a cavity (8); d) a sensor line (9) with a cross section of 2-5 mm having a second gas pressure sensor (12) and an optional throttle (10) configured for a gas flow of less than 1 L / min at 2-3 bar, with a connection to a second trocar (13) in said cavity (8); e) a computing unit (14) for controlling the inhalation and for evaluating the measurement data of the first gas pressure sensor (5) and the second gas pressure sensor (12), the computing unit (14) performs a compensation for pressure losses in the supply line (3) with the first trocar (7) and in the sensor line (9) with the second trocar (13); A comparison of the corrected measurements of the first pressure sensor (5) and the second pressure sensor (6) is performed; If the corrected measurements deviate from each other by more than 2 mmHg, an alarm is triggered.

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