Gas separation: processes – Filtering
Reexamination Certificate
2000-04-07
2003-07-08
Hopkins, Robert A. (Department: 1724)
Gas separation: processes
Filtering
C055S385100, C055S503000, C604S035000
Reexamination Certificate
active
06589316
ABSTRACT:
FIELD
The present invention relates to smoke removal and filtering and, more particularly, to a smoke evacuation system for use in surgical procedures, including minimally invasive surgical procedures such as laparoscopy, during which cautery or a laser is used.
BACKGROUND
U.S. Pat. No. 5,578,000 (Greff et al.) discloses a smoke evacuation system including a trocar having a working channel, a stopcock or valve communicating with the channel, a source of wall vacuum, a fluid conduit connected between the stopcock of the trocar and the source of wall vacuum, a first filter for applying a first reduction in suction and separating smoke into its components and a residual gas, and a flow restriction to generate a second reduction in suction. The flow restriction is along a passage formed by the conduit, the filter and working channel.
Greff et al. note that smoke has been handled by simply allowing it to escape into the operating room, thereby subjecting the surgeon and staff to contaminants. They recognize that closed, recirculating systems involving two trocars have been used, as have probes which are inserted through a trocar, but that such systems do not adequately solve the problems associated with smoke and the removal thereof, e.g., contamination, smell and impaired visibility of a surgical site.
Other problems inadequately addressed by currently available evacuation systems are loss of the pressure in the pneumoperitoneum, and/or tissue drying, particularly if pressure loss is compensated for by increasing insufflation gas flow.
While the smoke evacuation system disclosed in the Greff et al. patent may be well suited for its intended purpose, it would be advantageous if the dependency on a remote, “in-wall” vacuum source could be eliminated thereby reducing the cost and complexity of the system.
SUMMARY
The present invention provides an improvement over currently known smoke evacuation systems, methods and techniques, including laparoscopic smoke evacuation systems such as the system disclosed in the Greff et al. patent.
In one embodiment, the present invention provides a smoke evacuating system for use during surgical procedures comprising a filter for operable coupling to a surgical site, said filter exhibiting a pressure drop ranging from approximately 0.5 to 20 mm/Hg, with a preferred pressure drop ranging from approximately 1 to 3 mm/Hg. The filter may be coupled directly to the patient.
In another embodiment, the present invention provides a smoke evacuating system for use during surgical procedures, particularly minimally invasive procedures, involving a surgical site having an associated higher than ambient pressure, wherein the system comprises a filter with a inlet side (the side generally closest to the surgical site) and an outlet side and a fluid conduit extending between the surgical site and the filter. The fluid conduit defines a substantially unobstructed fluid flow path between the surgical site and filter, and the higher than ambient pressure and a pressure drop associated with the filter generate and enable a fluid flow in the fluid flow path, the filter causing a low pressure drop (i.e., pressure differential from side to side) in the fluid flow from the inlet side to the outlet side.
In yet another embodiment, the present invention provides a smoke evacuating system for use during surgical procedures, particularly minimally invasive procedures, including a conduit for operable coupling to a surgical site, said conduit operably carrying a filter exhibiting a pressure drop ranging from approximately 1 to 3 mm/Hg and defining a substantially unobstructed fluid flow path between the surgical site and the filter. The conduit may include a connector for being connected to a trocar or other tubular member. An on/off valve may be incorporated to control the flow of fluid through the conduit, whereby, when the valve is open, the flow path from the surgical site to the filter is substantially unobstructed.
An advantage of the present invention is that it eliminates dependency on a built-in, in wall vacuum source. It does not require high vacuum suction and the requisite high resistance filters or combination of flow restrictors or reducers and filters. Further, it simplifies smoke evacuation and filtering by eliminating the need for multiple, in-line structures (filters, resistors, etc.) for stepping down or reducing suction.
While the present invention may be used in surgical procedures, it may also be used in industry to remove smoke and/or chemicals from areas such as workstations. For example, it might be used at or adjacent to chip or electronic equipment manufacturing stations to reduce workers'
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exposure to smoke produced as connections are formed. Similarly, it might be used to reduce exposure to etching chemicals.
A feature of the present invention is a balanced smoke evacuation system wherein a filter with a relatively low pressure drop performs a filtering function and a flow regulating function, helping to preserve the pressure at or in a pressurized surgical site such as a laparoscopy with a pneumoperitoneum while providing for sufficient flow therefrom to remove smoke from the site, thereby reducing the need for substantial or constant reinsufflation of the surgical site.
Surgical aerosols, or bio-aerosols, include smoke from burning tissue, but also often include moisture, steam or mist produced by cells as they are heated and/or ruptured by certain surgical instruments such as lasers or ultrasonic scissors (e.g., “Harmonic Scissors” by Ethicon). Additionally, some surgeons are now using heated, humidified gas for insufflation to help maintain a normal body temperature and to help reduce tissue dessication. One embodiment of the invention is adapted for use in surgical procedures during which surgical aerosols, particularly moist or moisture containing aerosols, are produced and/or in which heated and/or humidified gas is used by including a space or region into which moisture can move, gather and/or be collected without diminishing flow rate or the efficiency of the filter.
Another embodiment of the invention includes an elbow member adapted to be coupled between a trocar and the conduit to position the conduit to reduce any potential inconvenience to the surgeon and/or staff during a procedure.
An advantage of the smoke evacuation system of the present invention is that it provides for the intra-operative or intra-procedural evacuation and filtration of smoke from a pressurized surgical site, e.g., the abdominal cavity, without requiring suction and without rapidly exhausting the pressurizing gas or causing a substantial pressure reduction at the pressurized surgical site. Other advantages are that the invention does not require an operator, it continuously removes smoke from the pressurized cavity (once the valve in valved embodiments is opened) to improve visibility without venting, it reduces operating time, it eliminates surgical smoke from the operating room, thereby reducing the health risk stemming from exposure to such smoke, it eliminates the need to apply suction to a patient thereby reducing potential tissue damage, and it is inexpensive.
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Drogue Jeffrey K.
Schultz Leonard S.
Dorsey & Whitney LLP
Hopkins Robert A.
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