Abstract:
Smoke evacuation apparatus designed to provide safe and efficient filtration and evacuation of smoke plume generated by laser-surgical, electrosurgical, radiosurgical, and electrocautery devices. A filter assembly is removably mounted on a front panel of the apparatus housing and is thus easily accessible from the front side which typically faces the user. The filter assembly at its front is provided with a hose connector to which the suction hose of the system is conveniently attached, and the front of the filter assembly is configured with a symbol, such as a letter or number, that represents an identification of the system supplier or manufacturer, and the hose connector is mounted on that symbol identifier.

Description:
The invention is directed to apparatus designed to provide safe and efficient filtration of smoke plume generated by laser-surgical, electrosurgical, radiosurgical, cautery, hyfrecators and electrocautery devices. 
     BACKGROUND OF INVENTION 
     Surgical smoke evacuation systems are designed to capture the smoke and plume generated during surgical procedures in which there is thermal destruction of tissue or bone. The plume from vaporized tissue contains small particles and gases that could be potentially hazardous. If not evacuated the materials can become airborne and deposit in the respiratory tracts of the surgical team. The type of surgical instruments, the characteristics of tissue, and the surgeon=s technique affect the quantity and characteristics of the smoke plume. A surgical smoke evacuator is in essence a vacuum pump, usually footswitch operated, that incorporates one or more filters to remove particles from the suctioned air-stream at the surgical site. A hose, typically of plastic, disposable or reusable, connects the pump to a disposable or autoclavable wand serving as a nozzle that is usually held about 5 cm. from the tissue to remove smoke generated by the surgical procedure. Because the constraints of some surgical procedures can prevent placement of the nozzle close to the tissue, smoke evacuators should capture smoke effectively at up to 15 cm. Adequate protection from potentially dangerous smoke plume can only be achieved when the plume is successfully captured before it comes into contact with the patient and surgical staff. This smoke entrainment requires that the evacuator airflow change the smoke direction and draw it into the hose via the wand. 
     An example of a smoke evacuation system is described in our U.S. Pat. No. 6,001,077, the contents of which are herein incorporated by reference, and is commercially-available from Ellman International, Inc. of Oceanside, N.Y. This system features a viral paper filter in the suction hose and a charcoal filter inside the system housing. Changing the hose filter requires disassembling the hose and removing and disposing of the filter assembly, and reinstalling a fresh filter. Changing the charcoal filter requires opening of the housing, removing the filter bowl for the filter, and replacing the spent filter with a new filter and reassembling. This can be unnecessarily time consuming. 
     SUMMARY OF INVENTION 
     A principal object of the invention is surgical smoke evacuation apparatus that overcomes one or more of the drawbacks listed above. 
     This and other objects of the invention are achieved in accordance with one feature of the invention by provision of a smoke evacuation system wherein the filter assembly is mounted in the form of a unitary body, such as a cartridge, on a housing panel, and is easily removed and replaced as a unitary body by the user grasping the filter assembly where it is accessible from the outside, pulling it out from its position on the housing, and replacing the entire filter assembly as a unit without having to contact the filter elements. 
     In accordance with a further feature of the invention, the filter assembly is removably mounted on a front panel of the housing and is thus easily accessible from the front side which typically faces the user. 
     In accordance with still another feature of the invention, the filter assembly at its front is provided with a hose connector to which the suction hose of the system is conveniently attached. A further feature is to configure the front of the filter assembly with a symbol, such as a letter or number, that represents an identification of the system supplier or manufacturer, and mounting the hose connector on that symbol identifier. Preferably, the symbol is in 3-dimensions (3-D) so it stands out from the unit. 
     As still another feature, the symbol identifier is configured to serve as a handle to simplify a user grasping the filter assembly during the removal step. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention, like reference numerals or letters signifying the same or similar components. 
    
    
     
       SUMMARY OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of one form of the surgical smoke evacuation apparatus of the invention; 
         FIG. 2  is an enlarged front schematic view of the front panel showing its controls and indicators; 
         FIG. 3  is an interior perspective view of the smoke evacuation apparatus of  FIG. 1  with the top removed; 
         FIG. 4  is a view similar to that of  FIG. 1  but showing the filter assembly separated from the housing; 
         FIG. 5  is an enlarged rear perspective view of the filter assembly of  FIG. 3 , also showing the end of a hose that would in use be connected to the connector at the front of the filter assembly; 
         FIG. 6  is an interior partly cross-sectional view of the filter cartridge identifying its filter components; 
         FIG. 7  is a perspective view of a modification of the filter assembly of  FIG. 4 ; 
         FIG. 8  is a side view of the modification of  FIG. 7 ; 
         FIG. 9  is a front view of the modification of  FIG. 7   
         FIG. 10  is a side view of a further modification of the filter assembly of  FIG. 4 ; 
         FIG. 11  is a perspective view of a further modification of the filter assembly of  FIG. 4 ; 
         FIG. 12  is a side view of the modification of  FIG. 11 ; 
         FIG. 13  is a schematic block diagram of the apparatus electronics to provide the functions described below, illustrating the connections between the various system components and the controls and indicators on the front panel. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The above-identified patent, whose contents have been incorporated by reference, describes surgical smoke evacuation apparatus that employs two spaced independent filters in series in the suction path. The first filter is a viral pre-filter in the hose which is capable of filtering micro-organisms bigger than 0.02 microns in size. Following the pre-filter is a charcoal filter in the housing that efficiently removes odors. The construction of the latter has in common with that of the invention a housing for a vacuum blower optionally with a muffler coupled to the interior filter. The inlet connection is by a hose. 
     The apparatus of the invention, a preferred embodiment  10  of which is illustrated in  FIG. 1 , comprises a main housing  12  that provides a main control panel  14  on the front side and an auxiliary control panel  16  on the left side. At the right side of the front panel is mounted a removable filter assembly  18  according to the invention, more details of which are provided below. The front  20  of the filter assembly projects forwardly from the housing and is configured with a symbol  22 , in this case a tilted or angled lower case “e” in Helvetica font. The “e” represents or symbolizes the source of the apparatus or supplier, which in this case is the first letter of the Ellman name which is part of the company name which supplies the system previously described. Where the bottom part of the “e” ends  23  is mounted an air inlet  24  or connector for removably receiving the hose connector typically mounted at the end of a plastic vacuum hose  25  as illustrated schematically in  FIG. 5 . The mounting of the hose connector at the end of the symbol avoids visual obstruction of the displayed symbol. Inside the housing  12  (see  FIG. 3 ) is provided for example a brushless DC blower motor  26  available commercially from many suppliers and having in this case an enlarged air inlet  28  coupled by way of a simple tubular adapter  30  to the perforated rear  32  ( FIG. 5 ) of the filter assembly. Two louvers acting as air outlets  34  for the filtered air are at the rear. In operation, an internal 2-stage fan (the details of which are not shown) develops a suitable suction at the air inlet  24  by discharging a powerful stream of air at its outlet  34 . The discharged air exits the housing via a muffler (not shown) and a sound-deadening mesh (not shown) over the louvers  34 . Standoffs  36  isolate the unit from its support. The speed of the motor  26  may be controlled in a known manner. Typically, the suction generated is inversely proportional to the air flow rate. 
     The vacuum hose  25  is connected at one end to the housing air inlet  24 . In the referenced patent U.S. Pat. No. 6,001,077, the hose is connected in-line to an external pre-filter, followed by a charcoal filter inside the housing. While it is possible to include both these filter components inside the removable cartridge  18 , in accordance with the present invention, for improved and safer filtering action it is preferred that a six components system be employed comprising, in the order named: 
     a prefilter  38  whose function is to trap and remove gross particulate and casual fluid; 
     a viral paper filter  40  capable of filtering extremely small micro-organisms, and is also available commercially from many suppliers. The filter described in U.S. Pat. No. 5,874,052 may be one example of such a suitable filter for capturing particulates and micro-organisms; 
     a porous membrane  42  to retain charcoal particulates from the downstream filter component  44 ; 
     an activated carbon filter  44  for the removal and adsorption of odors and toxic gases produced by burning tissues; 
     another porous membrane  46  to retain charcoal particulates from the upstream filter component  44 ; 
     an expanded foam and paper media  48  used to trap activated carbon particles from migrating out of the upstream carbon filter  44 . 
     Downstream of and immediately following the removable cartridge  18  is the duct  30  having an inlet opening configured to substantially match the outlet at the perforated rear panel  32  from the generally rectangular or square outlet of the removable cartridge, and having an outlet opening configured to substantially match the inlet of the suction motor  26 . The air flow through the filter is indicated by the arrow  50  in  FIG. 6 . 
       FIG. 5  is a rear view of the filter  18  and shows schematically the end of the hose (sometimes referred to as a wand)  25  to be mounted on the inlet  24  of the filter during use. 
     As mentioned, a feature of the invention is to locate a 3-D symbol  22  representing the source of the apparatus and positioning the wand or hose inlet  24  at an end  23  of the symbol to promote product/source identification, as well as indicate the filter removal location. The 3-D projecting symbol can also be used by the user to pull out the filter  18  when it needs replacement.  FIGS. 7-12  illustrate variations to improve the functioning of the symbol  22  as a handle for replacing the filter. 
     In the first modification of  FIGS. 7-9 , the symbol  54  is enlarged relative to the filter housing so that at least two edges extend externally of the housing, indicated at  56 . 
     In the second modification of  FIG. 10 , the symbol  22  is unchanged relative to the filter housing but the adjacent end  58  of the filter housing is recessed  60  so that at least two edges of the symbol are usable as a handle, indicated at  62 . 
     In the third modification of  FIGS. 11-12 , the symbol  64  is thickened and at least two opposed regions of the thickened symbol are recessed  66  to form a handle or grip for easy removal of the filter. Other variations for easier removal of the filter will be evident to those skilled in this art. 
     The controls for operating the apparatus include on a panel  16  ( FIGS. 1 and 13 ) on the left, starting from the left side, a socket  70  for an AC cable, a manual main on-off switch  72 , a connector  74  for an external footswitch  75  for electrical on-off operation of the unit, and a connector  76  for an external footswitch  77  for pneumatic on-off operation of the unit. 
     On the front panel  14  ( FIG. 2 ) are controls and indicators including: 
     service light indicators  78  warning of a filter replacement; 
     an indicator  80  with a column of lights indicating how much time left before replacement of the filter; 
     two buttons  81 ,  82 , the one with the smaller tilted symbol  84  for decreasing the suction motor speed and the adjacent one with the larger tilted symbol  85  (both symbols being the same as that  22  on the filter) for increasing the suction motor speed, the actual motor speed being indicated above by a horizontal row  86  of lights. 
     A suction motor  88  on-off switch is located at the bottom. 
       FIG. 13  illustrates one possible schematic electrical circuit for the unit. A microprocessor  90  controls the operation. Input signals arrive from the external controls  75 ,  77 , and from the internal suction control  91 . These signals are processed and output signals are passed on to the displays  80 ,  86  and to the motor  26 . 
     As a further improvement in automating the filter life indicators, optionally a conventional radio-frequency identifier tag (RFID) may be added to the filter, indicated by  93 , and a companion RFID unit  94  inside the housing and electrically connected to the microprocessor  90 . These tags are commercially available and communicate by way if an RF link  95 . The RFID tag  93  on the filter generates a coded message that informs the microprocessor  90  that the filter  18  is appropriate for the apparatus and a filter approved by the supplier to maintain warranties. The microprocessor  90  can be programmed to disable operation without an approved filter in place to ensure that safe filtered air is outputted from the apparatus. The filter life indicators (typically hours of use) are controlled by the number of times the apparatus has been switched on and the duration of the use. The use is monitored by an electronic timer in the microprocessor  90 . 
     An effective surgical smoke evacuator uses a high flow and intake velocity to capture the smoke with the wand, draw it through the hose, pass it through the filter to remove all unsafe or odorous elements, and recirculate the processed back into the operating room. The user-friendly apparatus of the invention performs these tasks efficiently and safely. It efficiently removes smoke from a surgical operatory area for better visibility, protects a medical team from smoke plume containing viruses, eliminates for the most part unpleasant smoke and odors, and also draws cool air over the surgical site. 
     While the invention has been described in connection with preferred embodiments, it will be understood that modifications thereof within the principles outlined above will be evident to those skilled in the art and thus the invention is not limited to the preferred embodiments but is intended to encompass such modifications.