System for monitoring gas composition within a surgical cavity - Patents.com

Abstract

A system for monitoring gas composition within a surgical cavity during an endoscopic surgical procedure includes a gas recirculation system including a main gas flow circuit for fluid communication with the surgical cavity, the system including a sensor for monitoring gas species in a gas flow from the surgical cavity of a patient, the sensor being disposed in a channel branching off from the main gas flow circuit coming from the surgical cavity.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Patent Application No. 17 / 467,790, filed September 7, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] Field The present disclosure is directed to endoscopic surgery, and more specifically, to systems and methods for measuring gas composition within a surgical cavity during an endoscopic or laparoscopic surgical procedure. [Background technology]

[0003] 2. Description of Related Art Unintentional bowel perforation can occur during laparoscopic surgery. If undetected, sepsis can result. Due to the inherent visualization challenges associated with laparoscopic surgery, bowel perforation can escape visual detection by the surgeon. If perforation is suspected, locating and visualizing the perforation site can be difficult and time consuming.

[0004] Conventional techniques for intestinal perforation detection have been deemed satisfactory for their intended purposes. However, there continues to be a need for improved systems and methods for detecting perforated intestine during endoscopic surgical procedures, and more generally for monitoring gas species during endoscopic surgical procedures. The present disclosure provides a solution to this need. Summary of the Invention

[0005] A system for monitoring gas composition within a surgical cavity during an endoscopic surgical procedure includes a gas recirculation system having a main gas flow circuit for fluid communication between the surgical cavity and the gas recirculation system and a channel branching from the main gas flow circuit. A sensor is operatively associated with the channel for monitoring gas species in a gas flow through the main gas flow circuit. The channel branching from the main gas flow circuit can be a dead-end channel in the gas recirculation system. The main gas flow circuit can have a cross-sectional flow area having a main diameter, and the sensor is spaced from the main gas flow circuit along the channel by a distance ten or more times the main diameter distance, such that the sensor can detect gas species that reach the sensor by diffusion through the channel from the main gas flow circuit.

[0006] The compressor can be operatively connected to the gas recirculation system in the main gas flow circuit to move a flow of gas to and from the surgical cavity. The channel can be connected to the main gas flow circuit at a location in the main gas flow circuit downstream of the compressor. The main gas flow circuit can include an upstream portion for returning gas from the surgical cavity to the gas recirculation system and a downstream portion for supplying gas to the surgical cavity. The compressor can be separated between the upstream portion and the downstream portion. The channel can be connected to the downstream portion. A gas-tight access port can be connected to the upstream portion and the downstream portion to connect the gas recirculation system to the surgical cavity. The gas-tight access port, the upstream portion, the downstream portion, and the compressor can be configured to form a sealed recirculation circuit with the gas-tight access port disposed within the surgical cavity.

[0007] The controller can be operatively connected to the sensor to determine whether the gas species monitored in the gas flow from the surgical cavity are within their respective desired ranges and to take corrective action if the gas species are outside their respective desired ranges. The controller can be operatively connected to the circuitry of the sensor to monitor changes in electrical resistance of the sensor to determine the concentration of the gas species to which the sensor is exposed. The user interface can be operatively connected to the controller. The controller can be configured to alert the user via the user interface upon detection of the gas species at a predefined threshold. The controller can include a memory, the controller including machine readable instructions configured to cause the controller to write to the memory a history of the gas concentrations detected by the sensor over an interval of 1 to 60 seconds for recall upon gas levels exceeding the predefined threshold.

[0008] The sensor may include a metal oxide membrane and a heater configured to detect the presence of hydrogen in a concentration range of 100 parts per million (ppm) to 10 parts per thousand (ppt), inclusive. The sensor may be configured such that the presence of 10 ppt of hydrogen causes an electrical resistance across the sensor to drop to 10 kilohms or less.

[0009] A method for detecting a perforated bowel during a surgical procedure includes detecting with a sensor the presence of a gas species indicative of a perforated bowel, the gas species reaching the sensor by diffusion from a main gas flow circuit of a gas recirculation system in fluid communication with the surgical cavity, and outputting an alarm upon detecting the gas species at a threshold indicative of a perforated bowel.

[0010] The sensor can be disposed in a channel branching off from the main gas flow circuit, the channel being a dead-ended channel, and detecting includes detecting the gas species without bulk gas flow through the dead-ended channel. The detecting can include sampling gas from the main gas flow circuit with the sensor, and sampling the gas includes sampling gas from a location in the main gas flow circuit downstream of a compressor operably connected to a gas recirculation system in the main gas flow circuit to transfer a flow of gas to and from the surgical cavity. Transferring the flow of gas to and from the surgical cavity can include flow of gas to and from the surgical cavity through a gas-tight access port connecting between the gas recirculation system and the surgical cavity, the gas-tight access port and the gas recirculation system forming a sealed recirculation circuit with the gas-tight access port disposed in the surgical cavity.

[0011] The controller may be operatively connected to the sensor to determine whether the monitored gas species in the gas flow from the surgical cavity are within their respective desired ranges and, if the gas species are outside their respective desired ranges, initiate an output to the output device to alert a user to take corrective action. The controller may be operatively connected to the circuitry of the sensor to monitor changes in the electrical resistance of the sensor to determine the concentration of the gas species to which the sensor is exposed.

[0012] The method can include outputting a history of gas concentrations detected by the sensor at intervals of 1 to 60 seconds to call out when a gas level of the gas species exceeds a predetermined threshold. The sensor can include a metal oxide membrane and a heater, and detecting the gas species includes detecting the presence of hydrogen in a concentration range of 100 parts per million (ppm) to 10 parts per thousand (ppt), inclusive, using the metal oxide membrane.

[0013] These and other features of the disclosed systems and methods will become more readily apparent to those skilled in the art from the following detailed description taken in conjunction with the drawings. [Brief description of the drawings]

[0014] Preferred embodiments thereof will now be described in detail with reference to certain figures so that those skilled in the art to which the disclosure pertains will readily understand how to make and use the disclosed apparatus and method without undue experimentation.

[0015] [Figure 1] 1 is a schematic diagram of an embodiment of a system constructed in accordance with the present disclosure showing a gas recirculation system used during a surgical procedure; [Diagram 2] 1 is a schematic diagram of an embodiment of a gas delivery device. [Diagram 3] 3 is a schematic diagram of the gas delivery device of FIG. 2 showing a sensor circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Reference is now made to the drawings, in which like reference numerals identify like structural features or aspects of the present disclosure. For purposes of explanation and illustration, and not limitation, a partial view of one embodiment of a trocar assembly in accordance with the present disclosure is shown in FIG. 1 and generally designated by the reference numeral 100. Other embodiments of systems in accordance with the present disclosure, or aspects thereof, as described below, are provided in FIGS. 2-3. The systems and methods described herein can be used to monitor gas species within a surgical site during an endoscopic surgical procedure, for example, to detect perforated bowel.

[0017] As shown in FIG. 1, the system 100 includes a gas-tight access port gas recirculation system 102. The gas recirculation system 102 can be designed to cooperate with a programmable multi-mode gas recirculation system. The multi-mode gas recirculation system can be of the type described in commonly assigned U.S. Patents Nos. 9,375,539 and 10,905,463, the disclosures of which are incorporated herein by reference in their entireties. Briefly, the gas recirculation system 102 includes a multi-lumen filtered tubing set (e.g., tubing set 124 shown in FIG. 2) including a dual lumen portion and a single lumen portion, a first gas-tight single lumen access port operably connected to the dual lumen portion of the tubing set, and a second valve-sealed single lumen access port operably connected to the single lumen portion of the tubing set. The dual lumen portion has a pressurized gas line and a return gas line to facilitate continuous recirculation of gas to the jet of the gas-tight trocar, referred to herein as the main gas flow circuit 104. The single lumen section has at least a gas supply line and a sensing line 105 for delivering insufflation gas to the patient's surgical cavity 106 (e.g., from the insufflation manifold 103) and periodically sensing the pressure within the patient's surgical cavity. Additionally, the single lumen section supplies gas at a rate in excess of the minimum required for leak compensation to evacuate smoke from the surgical cavity. This excess flow, along with entrained smoke and escaped gas from the perforated bowel, if any, returns to the compressor via the return line.

[0018] 3, the main gas flow circuit 104 provides fluid communication between the gas recirculation system 102 and the surgical cavity 106. The system 100 includes a sensor 108 for monitoring gas species in the gas flow in the main gas flow circuit 104 coming from the patient's surgical cavity 106. The sensor 108 is disposed in a channel 110 that branches off from the main gas flow circuit 104 coming from the surgical cavity 106. The channel 110 is a dead-end channel in the gas recirculation system 102, i.e., there is an inlet 112 to the channel 110 for gas to diffuse from the main gas flow circuit 104 into the channel, but there is no outlet from the channel 110. The main gas flow circuit 104 has a cross-sectional flow area with a major diameter D1. The sensor 108 is spaced from the main gas flow circuit 104 along the channel 110 by a distance L1 that is ten or more times the main diameter D1 (L1≧10×D1), so that the sensor 108 can detect gas species that reach the sensor 108 by diffusing from the main gas flow circuit 104 through the channel 110. Although the channel 110 is shown as not tortuous, a more tortuous path can be used for the channel 110, so long as the distance L1 is adjusted for tortuousness.

[0019] The compressor 114 is operably connected to the gas recirculation system 102 in the main gas flow circuit 104 to move the flow of gas to and from the surgical cavity 106. The compressor 144 can be any suitable compressor assembly for recirculating surgical gases through the gas-tight access ports 122 by way of a gas-tight manifold. In certain embodiments, the compressor 114 is driven by a brushless DC (direct current) motor, which can be advantageously controlled to regulate the pressure and flow rate of gas in the gas recirculation system 102. Alternatively, the compressor 114 can be driven by an AC motor, although DC motors are relatively smaller and lighter and therefore more advantageous from a manufacturing standpoint.

[0020] The channel 110 connects to the main gas flow circuit 104 at a location within the main gas flow circuit 104 downstream of the compressor 114, e.g., at an inlet 112. The main gas flow circuit 104 includes an upstream portion 116 for returning gas from the surgical cavity 106 to the gas recirculation system 102 and a downstream portion 118 for supplying gas from the compressor 114 to the surgical cavity 106. The compressor 114 drives gas flow from the surgical cavity 106 with separation between the upstream portion 116 and the downstream portion 118, and a gas circulation valve manifold 120 regulates the flow of gas to and from the surgical cavity for insufflation, stable pneumoperitoneum, smoke evacuation, and / or the like.

[0021] Gas circulation valve manifold 120 can include first and second outlet line valves (e.g., proportional valves allowing infinitely variable adjustment of the gas flow rate between minimum and maximum flow conditions) operably associated with insufflation manifold 103 to control the flow of insufflation gas to valve sealing access port 122. Gas circulation valve manifold 120 can include primary proportional valves operably associated with insufflation manifold 103 disposed upstream of the first and second outlet line valves to also control the flow of insufflation gas to the first and second outlet line valves.

[0022] The gas circulation valve manifold 120 can include a high pressure gas fill valve operably associated with the compressor 114 adapted and configured to control gas delivered from the surgical gas source 107 into the gas seal manifold 110. The valve manifold can include a smoke vent valve operably associated with the compressor 114 for dynamically controlling gas flow between the primary flowpath 104 and the delivery manifold 103 under certain operating conditions.

[0023] The valve manifold may include a bypass valve positioned between the outlet side of the compressor 114 and the inlet side of the compressor 114 to control gas flow in the main flow path 104 under certain operating conditions. The gas circulation valve manifold 120 may also include an air vent valve operatively associated with the inlet side of the compressor 114 to control the inclusion of atmospheric air in the system 100 under certain operating conditions. For example, the air vent valve allows atmospheric air to be introduced into the gas sealed circuit to increase the air mass (i.e., standard volume) in the circuit.

[0024] The valve manifold can include an overpressure relief valve operatively associated with the outlet side of the compressor 114 to control the release of gases from the system 101 to atmosphere under certain operating conditions. The gas circulation valve manifold 120 can include first and second shutoff valves operatively associated with the inlet flow paths to the primary flow path 104, which can be employed during self-testing prior to a surgical procedure, as disclosed in U.S. Patent No. 9,199,047.

[0025] The first and second shutoff valves may be in communication with a shutoff valve pilot (e.g., a solenoid valve) contained within the air delivery manifold 103. The gas circulation valve manifold 120 may further include a low pressure relief valve downstream of the primary proportional valve and upstream of the first and second outlet line valves to control the release of gas from the system 100 to atmosphere under certain operating conditions. The valve manifold may include a ventilation exhaust valve located downstream of the primary proportional valve and upstream of the outlet line valves to control the release of gas from the system 100 to atmosphere under certain operating conditions.

[0026] Although the channel 110 connects to the downstream portion 118, embodiments in which the channel 110 connects to the upstream portion 116 (upstream of the compressor 114) are also within the scope of the present disclosure. The downstream arrangement of the channel 110 shown in FIG. 1 increases the gas temperature in the vicinity of the sensor 108, which essentially reduces the relative humidity of the gas diffusing into the channel 110 compared to the relative humidity in the upstream portion 116. This is beneficial to the accuracy and lifespan of the sensor 108, which improves at lower relative humidities. In embodiments having an arrangement of the channel 110 branching off from the upstream portion 116, it is beneficial to compensate for the relative humidity.

[0027] The gas-sealed access port 122 is connected to the upstream portion 116 and the downstream portion 118, e.g., via a tubing set 124, for connecting the gas recirculation system 102 to the surgical cavity 106. The gas-sealed access port 122 is of the type disclosed in commonly assigned U.S. Pat. No. 8,795,223, which is incorporated herein by reference. When used in conjunction with the gas recirculation system 102 as described above, the gas-sealed access port 122 is adapted and configured to provide access to the body cavity for gas-sealed instruments while maintaining a stable pressure within the body cavity (e.g., a stable pneumoperitoneum within the peritoneal or abdominal cavity). The gas-sealed access port 122, the upstream portion 116, the downstream portion 118, and the compressor 114 are configured to form a continuous recirculation circuit with the gas-sealed access port 122 disposed within the surgical cavity 106 (e.g., as described above). The compressor assembly 114 and its associated components (which may include, for example, the intercooler / condenser, the gas seal manifold, and the air delivery manifold 103) are all enclosed within a common housing, for example, as shown in FIG. 3, which includes the user interface (e.g., interface 128) and control electronics, for example, as disclosed in commonly assigned U.S. Pat. No. 9,199,047, which is incorporated herein by reference.

[0028] The controller 126 is operatively connected to the sensors 108 to determine whether the gas species monitored in the gas flow from the surgical cavity 106 are within their respective desired ranges and to take corrective action if the gas species are outside their respective desired ranges. The corrective action can include an action by the system 100 itself (e.g., adjusting the concentration of the gas) or the corrective action can include an action by the surgeon (e.g., locating and treating the perforation). The gas species sensors can be similar to those disclosed in commonly assigned U.S. Patent Application Nos. 16 / 000,254 and 16 / 000,378, both of which are incorporated herein by reference in their entireties. The user interface 128 is operatively connected to the controller 126. The controller 126 is configured to issue an alert, which can be an audio and / or visual alert or a written message, to the user via the user interface 128 when a gas species is detected at, above, or near a predetermined threshold. The controller includes a memory 130, and the controller 126 includes machine readable instructions configured to cause the controller 126 to write to the memory 130 a history of gas concentrations detected by the sensor at 1-60 second intervals for recall when a gas level exceeds a predetermined threshold. The controller 126 can cause the history to be displayed on the user interface 128.

[0029] 3, the controller 126 is operatively connected to a sensing circuit 132 of the sensor 108 to monitor changes in the electrical resistance of the sensor 108 to determine the concentration of the gas species to which the sensor 108 is exposed. More specifically, the sensor 108 includes a metal oxide film 134, the electrical resistance of which is monitored by the sensing circuit 132 and the controller 126. There is also a heater circuit 136 connected between the controller 126 and a heater 138 of the sensor 108, which provides temperature control of the metal oxide film 134 for accurate gas species measurement.

[0030] The metal oxide film 134 and heater 138 are configured to detect hydrogen present in or exposed to the metal oxide film 134 in the concentration range of 100 ppm (parts per million) to 10 ppt (parts per thousand), inclusive. The sensor 108 is configured such that the presence of hydrogen at 10 ppt causes the electrical resistance of the entire sensor (across the metal oxide film 134) to drop to 10 kilohms or less.

[0031] 3, a method of detecting a perforated intestine during a surgical procedure includes detecting the presence of a gas species, such as H2 gas, indicative of a perforated intestine with a sensor, e.g., sensor 108, which reaches the sensor by diffusion from a main gas flow circuit, e.g., main gas flow circuit 104, of a gas recirculation system, e.g., gas recirculation system 102, to maintain pressure within the surgical cavity, e.g., surgical cavity 106. The method includes outputting an alarm, e.g., outputting an audio and / or visual output via user interface 128, upon detecting that the concentration of the gas species has reached, exceeded, or near a certain level, e.g., a threshold indicative of a perforated intestine.

[0032] The sensor is disposed in a channel, for example, in channel 110 (a dead-ended channel) that branches off from the main gas flow circuit, and detecting includes detecting the gas species without bulk gas flow through the dead-ended channel. The detecting can include sampling gas from the main gas flow circuit with the sensor, the sampling gas from a location in the main gas flow circuit downstream of a compressor, for example, compressor 114, that is operably connected to a gas recirculation system in the main gas flow circuit to move the flow of gas to and from the surgical cavity. The movement of the gas flow to and from the surgical cavity includes the flow of gas to and from the surgical cavity through a gas-tight access port, for example, gas-tight access port 122, that connects between the gas recirculation system and the surgical cavity, and the gas-tight access port and the gas recirculation system form a sealed recirculation circuit with the gas-tight access port disposed in the surgical cavity.

[0033] A controller, e.g., controller 126, is operably connected to the sensors to determine whether the gas species monitored in the gas flow from the surgical cavity are within their respective desired ranges, and if the gas species are outside of their respective desired ranges, initiates an output to an output device to alert the user to take corrective action. The controller is operably connected to the sensor's circuitry, e.g., sensing circuit 132 in FIG. 3, to monitor changes in the sensor's electrical resistance and can determine the concentration of the gas species to which the sensor is exposed.

[0034] The method can include outputting a history of gas concentrations detected by the sensor at intervals of 1 to 60 seconds to call upon gas levels of the gas species above a predetermined threshold. The sensor can include a metal oxide film, e.g., film 134, and a heater, e.g., heater 138, and detecting the gas species can include using the metal oxide film to detect the presence of hydrogen in a concentration range of 100 parts per million (ppm) to 10 parts per thousand (ppt), inclusive.

[0035] The present disclosure uses gas concentration measurements to alert a user to the concentration of intestinal gas that is known to be released after intestinal perforation. The measurements and associated alerts can assist the surgeon in detecting a perforation and deciding whether to extend the surgical procedure and anesthesia time to visually search for the perforation.

[0036] Insufflation is necessary for optical visualization during laparoscopic procedures. Standard insufflation delivers gas to the patient without the gas being returned to the gas recirculation system, whereas insufflation using a gas-tight access port continuously draws gas from the inflated surgical site while continuously returning air from a gas seal placed adjacent to the patient. Incorporating a gas sensor into the gas-tight recirculation circuit allows for continuous automatic gas monitoring without the need for additional equipment, additional surgical steps, or additional access ports.

[0037] By referring to the digital gas concentration records, physicians can rule out the need for subsequent surgical investigations if the patient develops symptoms associated with intestinal perforation post-operatively.

[0038] The methods and systems of the present disclosure, as described above and shown in the drawings, are provided for monitoring gas species within a surgical site during an endoscopic surgical procedure, for example, to detect a perforated bowel. While the apparatus and methods of the present disclosure have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and / or modifications may be made therein without departing from the scope of the present disclosure.

Claims

1. 1. A system for monitoring a gas composition within a surgical cavity during an endoscopic surgical procedure, comprising: a gas recirculation system including a main gas flow circuit for fluid communication between the surgical cavity and a gas recirculation system; a channel branching off from the main gas flow circuit; a sensor operatively associated with the channel for monitoring gas species in a gas flow through the main gas flow circuit; Equipped with The system wherein the channel is a dead-end channel within the gas recirculation system.

2. 2. The system of claim 1, wherein the main gas flow circuit has a cross-sectional flow area having a major diameter, and the sensor is spaced along the channel from the main gas flow circuit a distance greater than or equal to ten times the major diameter such that the sensor can detect the gas species that reaches the sensor by diffusion through the channel from the main gas flow circuit.

3. 10. The system of claim 1, further comprising a compressor operably connected to the gas recirculation system in the main gas flow circuit to move a flow of gas to and from the surgical cavity, the channel connecting to the main gas flow circuit at a location in the main gas flow circuit downstream of the compressor.

4. 4. The system of claim 3, wherein the main gas flow circuit includes an upstream portion for returning the gas from the surgical cavity to the gas recirculation system and a downstream portion for supplying the gas to the surgical cavity, the compressor being separate between the upstream portion and the downstream portion, and the channel connecting to the downstream portion.

5. The system of claim 4 , further comprising a gas-tight access port connected to the upstream portion and the downstream portion for connecting the gas recirculation system to the surgical cavity.

6. The system described in claim 5, wherein the upstream portion, the downstream portion, and the compressor are configured to form a continuous gas recirculation circuit with the gas-sealed access port located within the surgical cavity.

7. 10. The system of claim 1, further comprising a controller operatively connected to the sensors to determine whether the gas species monitored in the gas flow from the surgical cavity are within their respective desired ranges and to take corrective action if the gas species are outside their respective desired ranges.

8. 8. The system of claim 7, wherein the controller is operatively connected to the circuitry of the sensor to monitor changes in electrical resistance of the sensor to determine the concentration of the gas species to which the sensor is exposed.

9. 8. The system of claim 7, further comprising a user interface operatively connected to the controller, the controller configured to alert a user via the user interface upon detection of the gas species at a predetermined threshold.

10. 8. The system of claim 7, wherein the controller includes a memory and includes machine-readable instructions configured to cause the controller to write to the memory a history of gas concentrations detected by the sensor at 1-60 second intervals for recall when a gas level exceeds a predetermined threshold.

11. 10. The system of claim 1, wherein the sensor comprises a metal oxide membrane and a heater configured to detect the presence of hydrogen in a concentration range of 100 parts per million (ppm) to 10 parts per thousand (ppt), inclusive.

12. 12. The system of claim 11, wherein the sensor is configured such that in the presence of 10 ppt of hydrogen, the electrical resistance across the sensor drops to 10 kilohms or less.

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