Patent Description:
The subject invention is directed to laparoscopic surgery, and more particularly, to a disposable filter cartridge with an internal gaseous seal for use with a multimodal gas delivery system employed during laparoscopic surgical procedures requiring smoke evacuation from the abdominal cavity of a patient.

Laparoscopic or "minimally invasive" surgical techniques are becoming commonplace in the performance of procedures such as cholecystectomies, appendectomies, hernia repair and nephrectomies. Benefits of such procedures include reduced trauma to the patient, reduced opportunity for infection, and decreased recovery time. Such procedures within the abdominal (peritoneal) cavity are typically performed through a device known as a trocar or cannula, which facilitates the introduction of laparoscopic instruments into the abdominal cavity of a patient.

Additionally, such procedures commonly involve filling or "insufflating" the abdominal (peritoneal) cavity with a pressurized fluid, such as carbon dioxide, to create what is referred to as a pneumoperitoneum. The insufflation can be carried out by a surgical access device (sometimes referred to as a "cannula" or "trocar") equipped to
deliver insufflation fluid, or by a separate insufflation device, such as an insufflation (veress) needle. Introduction of surgical instruments into the pneumoperitoneum without a substantial loss of insufflation gas is desirable, in order to maintain the pneumoperitoneum.

During typical laparoscopic procedures, a surgeon makes three to four small incisions, usually no larger than about twelve millimeters each, which are typically made with the surgical access devices themselves, typically using a separate inserter or obturator placed therein. Following insertion, the inserter is removed, and the trocar allows access for instruments to be inserted into the abdominal cavity. Typical trocars often provide means to insufflate the abdominal cavity, so that the surgeon has an open interior space in which to work.

The trocar must provide a means to maintain the pressure within the cavity by sealing between the trocar and the surgical instrument being used, while still allowing at least a minimum freedom of movement of the surgical instruments. Such instruments can include, for example, scissors, grasping instruments, and occluding instruments, cauterizing units, cameras, light sources and other surgical instruments. Sealing elements or mechanisms are typically provided on trocars to prevent the escape of insufflation gas. Sealing elements or mechanisms typically include a duckbill-type valve made of a relatively pliable material, to seal around an outer surface of surgical instruments passing through the trocar.

Further, in laparoscopic surgery, electrocautery and other techniques (e.g. harmonic scalpels) create smoke and other debris in the surgical cavity, reducing visibility by fogging the view from, and coating surfaces of endoscopes and the like. A variety of surgical smoke evacuation systems are known in the art.

Additionally, SurgiQuest, Inc. , Milford, Conn. USA has developed unique surgical access devices that permit ready access to an insufflated surgical cavity without the need for conventional mechanical seals, and it has developed related gas delivery systems for providing sufficient pressure and flow rates to such access devices, as described in whole or in part in <CIT>.

The present invention relates to a multimodal gas delivery system for performing multiple surgical gas delivery functions, including insufflation, smoke evacuation, recirculation and filtration of insufflation fluids and gases. The use of a single multimodal system reduces operating costs by requiring the purchase of only one system while achieving multiple functions, and also thereby reduces the amount of equipment needed in an operating room, thus reducing clutter and allowing space for other necessary equipment.

<CIT> discloses a system for insufflation and recirculation of insufflation fluid in a surgical procedure. The system includes a control unit having a fluid pump, a supply conduit, a return fluid conduit and a pressure-controlled valve. The fluid pump is adapted and configured to circulate insufflation fluid through the system. The supply conduit is in fluid communication with an output of the fluid pump and configured and adapted for delivering pressurized insufflation fluid to an output port of the control unit. The return conduit is in fluid communication with an input of the fluid pump for delivering insufflation fluid to the fluid pump and is configured and adapted for returning insufflation fluid from an input port of the control unit. The pressure-controlled valve is in fluid communication with the supply conduit and the return conduit, and is adapted and configured to receive a control signal and respond to the control signal by opening, thereby fluidly connecting the supply conduit and the return conduit with one another.

<CIT> discloses a trocar for use in a minimally invasive surgical procedure that includes an elongated body, nozzle means and means for delivering a pressurized flow of fluid to the nozzle means. The elongated body has a generally tubular configuration with coaxially arranged inner and outer walls and longitudinally opposed proximal and distal end portions, with the inner wall defining a lumen to accommodate passage of an instrument therethrough. The nozzle means is operatively associated with the inner wall of the body for directing pressurized fluid into the lumen to develop a pressure differential in an area within a region extending from a location adjacent a distal end portion of the lumen to a location adjacent a proximal end portion of the lumen, to form a fluid seal around an instrument passing therethrough.

<CIT> discloses a valve assembly and method for selectively controlling a flow of pressurized fluid from a fluid source to trocar assemblies. The valve assembly includes a first coupling configured and adapted to couple to a primary trocar assembly for directing pressurized fluid and a second coupling to couple to a secondary trocar assembly. A third coupling is provided to couple to a source of pressurized fluid for directing pressurized fluid from the source to the first and second couplings. Also disclosed is at least one valve member adapted and configured to be operable in at least first and second operating positions.

<CIT> discloses a surgical gas delivery system. The surgical gas delivery system includes a device housing supporting a control unit and a filter interface having a seat for receiving a filter cartridge, the filter cartridge having a filter housing defining an interior reservoir, wherein sensors are coupled to the control unit for sensing a level of liquid within the reservoir of the filter cartridge to prevent contamination of the device, and wherein a set of blocking valves are provided in the device housing for interacting with the filter cartridge when it is received in the filter interface to control flow through suction and pressure lines of the device, and wherein the control unit is adapted to recognize a characteristic of the filter cartridge received in the filter interface.

<CIT> discloses systems for insufflation and recirculation of insufflation fluid in a surgical procedure that include a control unit having a fluid pump, a supply conduit, a return fluid conduit and a pressure-controlled valve. The pressure-controlled valve is in fluid communication with an insufflation gas supply, the supply conduit and the return conduit and is adapted and configured to respond to pressure control signals to adjust position and thereby system flow parameters, to reduce entrainment of air from the surrounding environment, and to increase the concentration of insufflation gas in an operative space, and/or to reduce an overpressure condition in the operative space.

The subject invention is directed to a new and useful system for delivering gas during a laparoscopic surgical procedure performed within a patient's abdominal cavity and is defined by the subject matter of the independent claim. The system includes, among other things, a gas delivery device having a housing with a port for receiving insufflating gas from a gas source. The system further includes a disposable gas conditioning unit or cartridge configured for operative association with the gas delivery device.

The gas conditioning system includes a first internal flow path for receiving pressurized gas delivered from the pump, a second internal flow path for delivering insufflating gas to the abdominal cavity at a desired flow rate and pressure and for facilitating periodic static pressure measurements from the abdominal cavity, and a third internal flow path for returning pressurized gas to the pump.

The first internal flow path includes a nozzle assembly configured to accelerate the pressurized gas delivered by the pump and thereby generate a continuous pressure barrier contained within the gas conditioning unit. The pressure barrier or working zone that inhibits the egress of insufflating gas from the abdominal cavity and functions to maintain a stable pneumoperitoneum during a surgical procedure.

The gas conditioning unit includes a generally cylindrical housing having an inlet end and an opposed outlet end. The gas delivery device includes an engagement port for detachably receiving the gas conditioning unit. The outlet end of the gas conditioning unit includes an outlet cover having a first outlet port corresponding to the first internal flow path, a second outlet port corresponding to the second internal flow path and a third outlet port corresponding to the third internal flow path.

The inlet end of the gas conditioning unit includes an inlet cover having a first inlet port corresponding to the first internal flow path which communicates with a first conduit, a second inlet port corresponding to the second internal flow path which communicates with a second conduit and a third inlet port corresponding to the third internal flow path which communicates with a third conduit.

The housing of the gas conditioning unit includes a pressure chamber located within the first internal flow path and communicating with the first outlet. The housing of the gas conditioning unit further includes a central nozzle chamber having a cylindrical wall supporting the nozzle assembly. The central nozzle chamber communicates with the pressure chamber through an internal delivery port.

The nozzle assembly includes a cylindrical jet set having a pair of axially spaced apart outer sealing rings for sealingly isolating the nozzle assembly within the central nozzle chamber. The central nozzle chamber includes a plurality of circumferentially disposed spaced apart axial fins or vanes located distal to the cylindrical jet set of the nozzle assembly for directing gas flow away from the working zone. The central nozzle chamber communicates with a breathing tube proximal to the cylindrical jet set that is open to atmosphere to facilitate entrainment of air into the gas delivery system under certain operating conditions.

A first filter element is disposed within the pressure chamber for filtering pressurized gas delivered from the pump. The housing of the gas conditioning unit includes a diverter plate which interacts with the outlet cover to define a conditioning cavity disposed in the second internal flow path and configured to support a second filter element for filtering insufflating gas from the gas source.

The housing of the gas conditioning unit also includes a vacuum chamber located within the third internal flow path. The vacuum chamber communicates with the nozzle chamber through a plurality of gas transfer ports to permit spent gas from the nozzle assembly to return to the pump for repressurization and circulation. A third filter element is disposed within the vacuum chamber for filtering gas returning to the pump from the patient's abdominal cavity.

The housing of the gas conditioning unit further includes a reservoir chamber located within the third internal flow path, downstream from and in fluid communication with the vacuum chamber through a fluid transfer port. The reservoir chamber will accommodate fluid and debris drawn into the housing of the gas conditioning unit by the suction of the pump. A fluid level sensor is arranged within the reservoir for detecting a predetermined fluid level therein, and alarm set points are associated with these sensors.

The first conduit includes a fitting for communicating with a first surgical access port, and the first surgical access port includes a mechanical valve or seal associated with a central lumen thereof for accommodating the introduction of surgical instruments into the abdominal cavity. The second conduit includes a fitting for communicating with a second surgical access port responsible for insufflation of and pressure measurement from the abdominal cavity. The third conduit includes a fitting for communicating with a third surgical access port responsible for smoke evacuation from the abdominal cavity.

These and other features of the surgical gas delivery system and the gas conditioning device of the subject invention and the manner in which both are manufactured and employed will become more readily apparent to those having ordinary skill in the art from the following enabling description of the preferred embodiments of the subject invention taken in conjunction with the several drawings described below.

So that those skilled in the art to which the subject invention appertains will readily understand how to make and use the gas delivery system of the subject invention without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein:.

Referring now to the drawings wherein like reference numerals identify similar structural features or aspects of the subject invention, there is illustrated in <FIG> and <FIG>, a new and useful system for delivering and circulating medical gas (e.g., carbon dioxide) during a laparoscopic surgical procedure performed within a patient's abdominal cavity that involves the evacuation of smoke generated from an electrocautery device or other instrument (e.g., harmonic scalpels), which would otherwise reduce visibility within the cavity by fogging the view from, and coating surfaces of endoscopes and the like.

The gas delivery system, which is designated generally by reference numeral <NUM> includes, among other things, a gas delivery device <NUM> having a housing <NUM> with a rear connector or port <NUM> for receiving pressurized insufflation gas from a gas source <NUM>. As shown, the gas source <NUM> is a portable supply canister. However, it is envisioned that the medical or insufflating gas could be supplied from another source, including for example, a remote storage tank (e.g., house gas) as is well known in the art. A pump assembly <NUM> is enclosed within the housing <NUM> of delivery device <NUM> for circulating pressurized gas throughout the system <NUM> to maintain a stable pneumo-peritoneum during a surgical procedure.

A graphical user interface <NUM> with associated control circuitry is provided within the housing <NUM> of gas delivery device <NUM> for controlling the operation of the pump assembly <NUM>, as well as the delivery of insufflating gas from supply source <NUM>. The interface and associated circuitry enables a user to readily adjust flow rates and supply pressures relating to the delivery, circulation and recirculation of gas and fluid throughout the system.

The gas delivery system <NUM> further includes a separate and preferably disposable gas conditioning unit <NUM>, which is dimensioned and configured for operative association with the gas delivery device <NUM>. As described in more detail below, the gas conditioning unit <NUM> is constructed in such a manner so that a continuous gaseous pressure barrier is generated within the housing of the unit itself, remote from the patient. This gaseous pressure barrier or working zone prevents the egress of insufflation gas from the abdominal cavity of the patient while maintaining a stable pneumoperitoneum within the abdominal cavity. This feature differs from the multimodal gas delivery systems disclosed in commonly assigned <CIT>, wherein the gaseous pressure barrier is generated within the housing of a specialized trocar at the surgical site.

The gas conditioning unit <NUM> includes a number of internal flow paths configured to facilitate the periodic delivery of insufflating gas, as well as the continuous circulation and recirculation of pressurized gas. In particular, a first internal flow path (i.e., the pressure path shown in <FIG>) is provided for receiving pressurized gas from the pump assembly <NUM> of the gas delivery device <NUM>. The first internal flow path is associated with a first conduit <NUM> that is connected to a first surgical access device or trocar <NUM>. The trocar <NUM> is the primary path for introducing surgical instrumentation into the abdominal cavity during a surgical procedure, and it has a mechanical seal installed therein. The pressurized gas is used to create a pressure barrier within the gas conditioning unit <NUM> that prevents the egress of gas from the abdominal cavity by way of conduit <NUM>. In doing so, it also maintains a stable pneumoperitoneum within the abdominal cavity of the patient <NUM>.

The gas conditioning unit <NUM> further includes a second internal flow path (i.e., the sense/insufflation path shown in <FIG>) for delivering insufflating gas from the gas delivery device <NUM> to the abdominal cavity of the patient <NUM> and for facilitating periodic static pressure measurements from the abdominal cavity by way of a second conduit <NUM> connected to a second surgical access device or cannula <NUM>. The duration of the insufflation interval between pressure measurements can vary, depending upon the patient and the operating environment. This flow and stop methodology for obtaining static pressure measurements from the abdominal cavity is well known in the art.

The gas conditioning unit <NUM> also includes a third internal flow path (i.e., the vacuum path shown in <FIG>) for returning pressurized gas to the pump assembly <NUM> of the gas delivery device <NUM> by way of a third conduit <NUM> connected to a second surgical access device or cannula <NUM>. The gas returned to the pump assembly <NUM> comes from two locations or sources. This includes the pressurized gas that was used to create the pressure barrier within the conditioning unit <NUM> and gas from within the abdominal cavity of the patient <NUM> that may be carrying smoke and debris resulting from an electrocautery procedure or the like.

With continuing reference to <FIG>, the gas conditioning unit <NUM> is adapted and configured for ready installation into and removal from the housing <NUM> of gas delivery device <NUM> by way of a interfitting lug arrangement. More particularly, as best seen in <FIG>, the generally cylindrical housing <NUM> of gas conditioning unit <NUM> includes a plurality of circumferentially spaced apart engagement lugs, including an L-shaped lug <NUM> and a square-shaped lug <NUM>. A third lug <NUM> can be seen in <FIG>. The three engagement lugs <NUM>, <NUM> and <NUM> are dimensioned and configured to interact with correspondingly shaped and positioned recesses <NUM>, <NUM> and <NUM> defined in the periphery of the cartridge engagement port <NUM> formed in the front panel of housing <NUM>, as shown in <FIG>.

With continuing reference to <FIG>, the housing <NUM> of gas conditioning unit <NUM> includes a front end cap <NUM> or inlet cover and a rear end cap <NUM> or outer cover. The front end cap <NUM> has three conduit connection tubes associated therewith. These include a first conduit connection tube <NUM> or central conduit connection tube that extends through an aperture <NUM> in the front end cap <NUM> and is operatively associated with the first conduit <NUM>, shown in <FIG> and <FIG>. Front end cap <NUM> also includes a second conduit connection tube <NUM> operatively associated with the second conduit <NUM> and a third conduit connection tube <NUM> operatively associated with the third conduit <NUM>, which are also shown in <FIG> and <FIG>.

The rear end cap <NUM> includes three outlet ports, each having an associated sealing ring. The first outlet port <NUM> communicates with the first internal flow path (i.e., the pressure path shown in <FIG>) and ultimately with the first conduit connection tube <NUM>. The second outlet port <NUM> communicates with the second internal flow path (i.e., the sense/insufflation path shown in <FIG>) and ultimately with the second conduit connection tube <NUM>. The third outlet port <NUM> communicates with the third internal flow path (i.e., the vacuum path shown in <FIG>) and ultimately with the third conduit connection tube <NUM>.

The first outlet port <NUM> includes a first O-ring seal <NUM>, the second outlet port <NUM> includes a second O-ring seal <NUM> and the third outlet port <NUM> includes a third O-ring seal <NUM>. The three O-rings seals <NUM>, <NUM> and <NUM> are seated and arranged in a co-planar manner on the rear end cap <NUM> to cooperate with corresponding features within the cartridge engagement port <NUM> in the front panel of housing <NUM>.

A similar co-planar arrangement of O-ring seals is disclosed in commonly assigned <CIT>. In addition, the rear end cap <NUM> includes a central breathing port <NUM>, which permits the entrainment of air into the recirculation flow under certain operating conditions. This will be described in more detail hereinbelow.

Referring now to <FIG>, there is illustrated the gas conditioning unit <NUM> with each of the components parts thereof separated from the cylindrical housing <NUM> for ease of illustration. Also shown are certain internal features of the housing <NUM> of conditioning unit <NUM>. Starting there, the housing <NUM> includes several internal cavities for supporting components and/or defining gas/fluid flow passages. At the front end of housing <NUM>, there is a vacuum chamber <NUM>, which is located within the third internal flow path (i.e., the vacuum path shown in <FIG>).

The vacuum chamber <NUM> is dimensioned and configured to support a cylindrical pleated filter element <NUM> (see also <FIG>). The pleated filter element <NUM> is preferably made from a porous non-woven or melt-blown filter media fabricated from a plastic material such as polypropylene or the like. Filter element <NUM> has an offset bore <NUM> to accommodate the passage of the central conduit connection tube <NUM> therethrough, when the unit <NUM> is fully assembled.

As best seen in <FIG> and <FIG>, the housing <NUM> of gas conditioning unit <NUM> further includes a reservoir chamber <NUM>, which is also located within the third internal flow path, downstream from and in fluid communication with the vacuum chamber <NUM>. More particularly, the reservoir chamber <NUM> communicates with the vacuum chamber <NUM> through a fluid transfer port <NUM> formed in the internal wall <NUM> of housing <NUM>. Any fluid or debris drawn into the housing <NUM> of the gas conditioning <NUM> unit by the suction of pump <NUM> in gas delivery device <NUM> accumulates first within the vacuum chamber <NUM> until it reaches the level of the transfer port <NUM>, whereupon such fluid enters into the reservoir chamber <NUM>.

Referring to <FIG>, prism shaped fluid level sensors <NUM> and <NUM> are arranged within the reservoir chamber <NUM> for detecting a predetermined fluid level therein. The structure and function of the fluid level sensors <NUM>, <NUM>, and the alarm set points and circuity associated therewith is described in greater detail in commonly assigned <CIT>.

With continuing reference to <FIG> in conjunction with <FIG> and <FIG>, the housing <NUM> of gas conditioning unit <NUM> further includes a pressure chamber <NUM> located within the first internal flow path (i.e., the pressure path shown in <FIG>). Pressure chamber <NUM> is dimensioned and configured to support a cylindrical pleated filter element <NUM> (see also <FIG>). Pleated filter element <NUM> is preferably made from a porous non-woven or melt-blown filter media fabricated from a plastic material such as polypropylene or the like.

Filter element <NUM> has a central bore <NUM> to accommodate a cylindrical breathing tube <NUM>. Breathing tube <NUM> communicates with the central breathing port <NUM> in the rear end cap <NUM> to facilitate the entrainment of ambient air into the system under certain operating conditions. As best seen in <FIG> and <FIG>, an annular barrier wall <NUM> separates and fluidly isolates the reservoir chamber <NUM> from the pressure chamber <NUM>. The barrier wall <NUM> is seated on an annular ledge <NUM> formed in the inner wall of the housing <NUM>.

The housing <NUM> of gas conditioning unit <NUM> also includes a central nozzle chamber <NUM> defined primarily by a cylindrical wall <NUM>, which is surrounded by pleated filter <NUM>. The central nozzle chamber <NUM> communicates with the pressure chamber <NUM> through an internal delivery port <NUM> (see <FIG> and <FIG>). The central nozzle chamber <NUM> supports a two-part annular nozzle assembly <NUM>, which is shown in a separated condition in <FIG>. The annular nozzle assembly <NUM> is described in greater detail in commonly assigned <CIT>.

In general, the annular nozzle assembly <NUM> includes upper and lower ring jet components <NUM> and <NUM>, which are connected to one another by a set of circumferentially spaced apart cooperating lugs 182a-182d and 184a-184d. The upper ring jet component <NUM> includes a central tubular portion <NUM> having a set of circumferentially spaced apart recessed areas <NUM> forming a set of spaced apart land areas <NUM>. The lower ring jet component <NUM> includes a continuous seating surface <NUM> for intimately receiving the tubular portion <NUM> of upper ring jet component <NUM>.

When the two ring jet components <NUM>, <NUM> are interfit together, an annular nozzle is formed between the land areas <NUM> of the tubular portion <NUM> and the continuous seating surface <NUM>. When pressurized air is delivered from the pressure chamber <NUM>, through the delivery port <NUM>, into the nozzle chamber <NUM>, and then through the nozzle <NUM> formed by the intimate engagement of the tubular portion <NUM> and the continuous seating surface <NUM>, a pressure barrier or working zone is created within the housing <NUM> of conditioning unit <NUM> to prevent the egress of insufflation gas from the abdominal cavity of a patient by way of conduit <NUM>. This is best seen in <FIG>.

The annular nozzle assembly <NUM> further includes a pair of axially spaced apart outer sealing rings 186a, 186b for sealingly isolating the nozzle assembly <NUM> within the central nozzle chamber <NUM>, as best seen in <FIG>. The central nozzle chamber <NUM> of housing <NUM> includes a plurality of circumferentially disposed spaced apart axial vanes or fins <NUM> located distal to the cylindrical jet set <NUM>, <NUM>. The vanes <NUM> are adapted and configured to direct the flow of spent gas (i.e., pressurized gas that has lost its momentum after being delivered from the jet set nozzle assembly <NUM>) away from the working zone.

The central nozzle chamber <NUM> communicates with the breathing tube <NUM>, which is located proximal to the nozzle assembly <NUM>. The breathing tube <NUM> is open to atmosphere and permits the entrainment of air into the recirculation flow of the gas delivery system under certain operating conditions. The breathing tube <NUM> includes a base portion <NUM> that forms an end cap for the nozzle chamber <NUM>.

Referring to <FIG> and <FIG>, the vacuum chamber <NUM> communicates with central nozzle chamber <NUM> through a plurality of gas transfer ports <NUM> formed in the internal wall <NUM> of housing <NUM>. The gas transfer ports <NUM> permit spent gas from the nozzle assembly <NUM> to return to the pump <NUM> for repressurization and circulation, as explained in more detail below. This is caused by suction created by pump <NUM>.

Referring once again to <FIG>, the housing <NUM> of the gas conditioning unit <NUM> also includes a diverter plate <NUM> which interacts with the outlet cover <NUM> to define, among other features, a conditioning cavity <NUM> therebetween. The conditioning cavity <NUM> forms part of the second internal flow path, communicates with outlet port <NUM> in end cap <NUM>, and is configured to support a planar filter element <NUM> made from a non-woven mesh or the like for filtering insufflation gas delivered from the gas source <NUM>. Diverter plate <NUM> also includes a central aperture <NUM> to accommodate the passage of breathing tube <NUM>.

Referring now to <FIG>, during operation, insufflation gas is delivered from the gas source <NUM> into the conditioning cavity <NUM> through the second outlet port <NUM> in the rear end cap <NUM>. The gas is conditioned or otherwise filtered as it passes through planar filter element <NUM>. The filtered gas exists the conditioning cavity <NUM> through the crescent shaped side aperture <NUM> in diverter plate <NUM> and then flows into the internal side flow passage <NUM> of housing <NUM>. The insufflating gas then exits from the housing <NUM> by way of conduit tube <NUM> in the front end cap <NUM> for delivery to the patient <NUM> through flexible conduit <NUM>.

This same pathway shown in <FIG> is used to periodically sense abdominal pressure. That is, the flow of insufflation gas from gas source <NUM> is intermittently turned off by a valve (not shown) located in the housing <NUM> of gas delivery device <NUM>. As a result, there are intervals of time in which there is no flow through the sensing path (e.g. through path <NUM> in housing <NUM>). At such times, static pressure within the abdominal cavity can be measured by the gas delivery device <NUM> by way of conduit <NUM>. This pressure measurement is utilized to adjust the flow of gas to the abdominal cavity, for example.

Referring now to <FIG>, during operation, pressurized gas is delivered from the pump <NUM> in gas delivery device <NUM> through the first outlet port <NUM> in the rear end cap <NUM>. The pressurized gas then passes through the centrally offset circular aperture <NUM> in diverter plate <NUM> and then into the pressure chamber <NUM>, where it is conditioned or otherwise filtered by passing through pleated filter element <NUM>.

The pressurized gas then travels to the central nozzle chamber <NUM> by way of internal delivery port <NUM>. In the central nozzle chamber <NUM>, the pressurized gas is
directed through the nozzle assembly <NUM> where it forms a pressure barrier within the upper region of central tubular passage <NUM> that is operatively associated with the conduit tube <NUM>, as best seen in <FIG>. This pressure barrier or working zone prohibits the egress of insufflation gas coming up from the abdominal cavity through flexible conduit <NUM> and conduit tube <NUM>, while maintaining a stable pneumoperitoneum within the abdominal cavity of the patient <NUM>.

Referring to <FIG>, during operation, gas from the abdominal cavity of the patient is drawn into the housing <NUM> through conduit connection <NUM> of end cap <NUM> under the suction created by pump <NUM>. The gas that is drawn into the housing <NUM> may include bodily fluids, smoke from cauterization procedures and/or other debris from the ongoing laparoscopic surgical procedure. That flow of fluid/gas/solids is filtered within the vacuum chamber <NUM> by pleated filter element <NUM>. The filtered gas is drawn out of vacuum chamber <NUM> through the side port <NUM> and into the lateral flow path <NUM> formed in housing <NUM>. That gas then flows through the crescent shaped side aperture <NUM> in diverter plate <NUM> and out of the housing <NUM> through exit port <NUM> in the rear end cap <NUM>.

The suction from pump assembly <NUM> also draws the spent fluid/gas that had been used to develop the pressure barrier within the conditioning unit through the plural apertures <NUM> formed in the floor of the nozzle chamber <NUM>. That spent fluid/gas enters into the vacuum chamber <NUM>, flows through the side port <NUM> and into the lateral flow path <NUM>. The spent fluid/gas along with the filtered gas from the abdomen exits the housing <NUM> through exit port <NUM> and returns to pump <NUM>. The conditioned flow is repressurized by the pump <NUM> and recirculated back to the housing <NUM> through pressure aperture <NUM> for subsequent delivery to the nozzle assembly <NUM> in nozzle chamber <NUM>.

Referring now to <FIG>, as discussed above, the flexible conduits associated with the gas conditioning unit <NUM> are respectively connected to separate surgical access devices communicating directly with the abdominal cavity of a patient. These devices include a conventional valved trocar for enabling instrument access <NUM>, as shown in <FIG>. That is, trocar <NUM> includes a mechanical valve such as a duckbill valve or the like designed to mechanically inhibit the egress of insufflating gas from the abdominal cavity by way of the access port, in combination with the pressure barrier or working zone formed within conditioning unit <NUM> by nozzle assembly <NUM>. The access devices further include a first conventional cannula <NUM> for vacuum return associated with smoke evacuation procedures, and a second conventional cannula <NUM> for facilitating insufflation of and static pressure sensing from the abdominal cavity <NUM>.

Because a conventional trocar includes a standard leur-type fitting <NUM>, an adapter assembly <NUM> is provided to connect the large diameter conduit <NUM> to the fitting <NUM> of the trocar <NUM>. The adapter assembly <NUM> includes a single lumen tubing connector <NUM> having a first end <NUM> dimensioned and configured to receive the large diameter conduit <NUM> and a second end <NUM> of reduced sized for communicating with the trocar <NUM>.

Claim 1:
A system for delivering gas during a laparoscopic surgical procedure performed within a patient's abdominal cavity, comprising:
a) a gas delivery device (<NUM>) having a housing (<NUM>) with a port for receiving insufflating gas from a gas source (<NUM>), the housing of the gas delivery device (<NUM>) being configured for enclosing a pump (<NUM>) for circulating pressurized gas throughout the system;
b) a separate gas conditioning unit (<NUM>) having a housing (<NUM>) configured for operative association with the gas delivery device (<NUM>) and including:
i) a first internal flow path for receiving pressurized gas delivered from the pump (<NUM>);
ii) a second internal flow path for delivering insufflating gas to the abdominal cavity and for facilitating periodic static pressure measurements from the abdominal cavity; and
iii) a third internal flow path for returning pressurized gas to the pump (<NUM>); and
wherein the first internal flow path includes an internal nozzle assembly (<NUM>) that is located within the housing (<NUM>) of the gas conditioning unit (<NUM>) and is configured to accelerate the pressurized gas delivered by the pump (<NUM>) enclosed in the gas delivery device (<NUM>) to the gas conditioning unit (<NUM>) and thereby generate a continuous pressure barrier contained within the gas conditioning unit (<NUM>) that inhibits egress of insufflating gas from the abdominal cavity, wherein the housing (<NUM>) of the gas conditioning unit (<NUM>) is generally cylindrical and includes an inlet end and an opposed outlet end, and wherein the gas delivery device (<NUM>) includes an engagement port (<NUM>) for detachably receiving the gas conditioning unit (<NUM>),
wherein the outlet end of the housing (<NUM>) of the gas conditioning unit (<NUM>) includes an outlet cover I (<NUM>) having a first outlet port (<NUM>) corresponding to the first internal flow path, a second outlet port (<NUM>) corresponding to the second internal flow and a third outlet port (<NUM>) corresponding to the third internal flow path,
wherein the inlet end of the gas conditioning unit (<NUM>) includes an inlet cover (<NUM>) having a first inlet port corresponding to the first internal flow path which communicates with a first conduit (<NUM>), a second inlet port corresponding to the second internal flow path which communicates with a second conduit (<NUM>) and a third inlet port corresponding to the third internal flow path which communicates with a third conduit (<NUM>).