Patent Abstract:
A kit includes all the materials necessary for oral gastric lavage in a single pouch. The components, many of which are common hospital supplies, may thus be pre-selected to work together in critical applications and to resist clogging.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is based on provisional application No. 60/327,445 filed Oct. 5, 2001 and entitled “Oral Gastric lavage Kit With Matched Aspiration Stream Apertures” and claims the benefit thereof. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Field of the Invention 
   The present invention relates to a medical lavage apparatus and more particularly to an apparatus used for oral gastric lavage. 
   BACKGROUND OF THE INVENTION 
   Acute poisoning is a common cause of morbidity and mortality in children and adults. However, if ingested poison can be removed from the gastrointestinal track before being absorbed, the risk of severe poisoning is reduced. One method of removing ingested poison is that of oral gastric lavage in which the gastrointestinal track or stomach is successively irrigated and aspirated through a lavage tube inserted along the patient&#39;s gastrointestinal track to the stomach. 
   A common method of oral gastric lavage is described in U.S. Pat. No. 5,667,500 which uses parallel connected syringe cylinders having plungers and valves to allow both irrigation and aspiration through a single nozzle connected to a single lumen pliable lavage tube. Such a system requires continual, manual pumping by an attendant. 
   An improvement is taught in U.S. Pat. No. 5,890,516 which provides an aspiration valve allowing the use of an in-wall vacuum system, such as is commonly found in hospitals, for operation of the lavage system without manual pumping. In this device, a double lumen flexible tube is provided, one lumen delivering an irrigation liquid and the second being used for aspiration through the in-wall vacuum system. The aspiration valve allows continual adjustment of the aspiration pressure. 
   A problem plaguing all oral gastric lavage systems is clogging of the lavage apparatus, for example, from pill fragments contained in the patient&#39;s stomach. A number of methods have been used to attempt to reduce this problem. The above referenced U.S. Pat. No. 5,667,500 describes the use of special, large size, slit valves and back flushing of the lumen tube with irrigant, a procedure not available with the more convenient dual lumen design. U.S. Pat. No. 5,890,516 provides the aspiration valve with a funnel-shaped connector tapering smoothly to a sharp lip to reduce the possibility of particles becoming lodged at the interface between the aspiration valve and a dual lumen lavage tube. 
   These solutions are not wholly satisfactory and clogging of lavage systems is still common. 
   BRIEF SUMMARY OF THE INVENTION 
   The present inventors have recognized that clogging, particularly in the dual lumen design, can be significantly reduced by matching the components together in a single kit. Key to the matching is that the diameter of connections of all successive portions of the aspiration path from the distal portion of the lavage tube to the inlet to the collection vessel attached to the in-wall vacuum system must be greater than or equal to the diameter of the initial inlet apertures of the distal portion of the lavage tube. The potential for clogging may be thereby moved to the interface between the distal portion of the lavage tube and the stomach where the inventors believe that the multiple apertures, better accommodate some clogging without significant effect, and where clogging fragments may be more easily dislodged with the cessation of aspiration pressure. The inventors have further recognized that in the real world hospital environment, proper operation of the oral gastric lavage system requires that the components of the system be pre-collected in a single location and pre-selected to work together. Accordingly a kit containing all the components necessary for oral gastric lavage in a single package is highly desirable, even though many of the components are multi-use products generally available in a hospital environment and could be obtained if not in such a kit. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of components of the oral gastric lavage kit of the present invention showing the in-wall vacuum system and its collection vessel, the aspiration valve, the dual lumen lavage tube, the irrigation bag, and other components; 
       FIG. 2  is a cross-sectional view of the aspiration valve showing the key internal diameters; 
       FIG. 3  is a fragmentary perspective view of the aspiration valve of  FIG. 1  showing the introduction of an improved sealing ridge around the bleed air inlet; 
       FIG. 4  is a fragmentary view of the distal end of the dual lumen lavage tube showing its key dimensions; and 
       FIG. 5  is a plot of internal diameters plotted against distance along the aspiration path of the kit of FIG.  1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIG. 1 , an oral gastric lavage kit  10  of the present invention, such as may be collected and sealed in a plastic pouch  11 , is adapted for use with an in-line vacuum system  12  providing a vacuum line  14  received by a collection vessel  16  to draw air therefrom. 
   The collection vessel  16  serves as a trap for receiving solids and liquids drawn through inlet  18 , the latter which may be connected to vacuum tube  20  to provide a flexible source of suction for hospital procedures. The inlet  18  provides the last restriction through which material collected from the gastrointestinal track must pass before reaching the collection vessel  16  and present an opening size  22   a  that remains relatively standard from hospital to hospital. 
   In an alternative embodiment (not shown), the kit  10  includes a collapsible collection vessel that may be attached upstream of the vacuum tube  20  to reduce the transport distances required of pumped material. In this case, collection vessel  16  is not required and vacuum tube  20  is attached directly to the in-line vacuum system  12 . 
   The vacuum tube  20  will have an internal diameter of greater than this opening size  22   a  of the inlet  18  as it fits over the outside of the inlet  18 . The present invention provides a kit including this vacuum tube  20  and additional components as will be described. The vacuum tube  20  may include a vortex device  21  (shown in  FIG. 1 ) such as a “corkscrew” spiral made by an internal groove causing a vortex flow of liquid in the vacuum tube  20  placed near the inlet  18 . The vortex device improves the flow of air and liquid. On the distal end of the vacuum tube  20 , a corrugated elbow  23  is used to prevent kinking. 
   Referring now also to  FIG. 2 , the oral gastric lavage kit  10  further includes an aspiration valve  24  providing for upstream control of the pressure of the vacuum to an amount less than that present at the vacuum tube  20 . Generally, the aspiration valve  24  provides a step-tapered end  26  receiving the vacuum tube  20  by interference fit of the inner diameter of the vacuum tube  20  against an outer ridged surface of the step-tapered end  26 . The aspiration valve  24  provides a conically expanding central channel through the aspiration valve  24  to an opposite flare end  35  which may receive the oral gastric lavage tube  40 . Notably, the flare end  35  of the aspiration valve  24  opposite the step tapered end  26  provides for a thin lip  30  that may fit snugly against the inside of the oral gastric lavage tube  40  to provide a relatively smooth inner wall transition from oral gastric lavage tube  40  to the inner passage  29  thus minimizing the change of particles and the like catching and clogging the pathway. The principal features of this valve are described in U.S. Pat. No. 5,890,516, hereby incorporated by reference. 
   The opening size  22   b  of the step tapered end  26  and the opening size  22   c  of the flare end  35  of the aspiration valve  24  are selected to be no smaller than the size  22   e  of the distal portion of the oral gastric lavage tube  40  as will be described below. 
   The aspiration valve  24  includes a bleed-air inlet  34  allowing ingress of air to reduce the suction drawn on the oral gastric lavage tube  40 . Air flow through the bleed-air inlet  34  may be controlled by sliding inlet cover  36  which may be moved to variably occlude the bleed air inlet port  34 . 
   Referring to  FIG. 3 , the valve described in the aforementioned &#39;516 patent is modified over that description by the introduction of a sealing ridge  38  around the bleed-air inlet  34  providing improved sealing and retention of the sliding inlet cover  36 . 
   Referring now to  FIGS. 1 and 4 , the oral gastric lavage tube  40  may be a coaxial tube including an outer lumen  41  for aspiration and an inner lumen  42  for irrigation. Dual lumen gastrointestinal tubes may be obtained from Mallinckrodt under the trade name Lavacuator gastrointestinal tube and are available in sizes 18, 22, 28, 32, and 36 French and in length 48 inches. Preferably, however, the oral gastric lavage tube  40  would have an inner diameter of 34 French. The oral gastric lavage tube  40  may include a radio opaque stripe  43  to assist in location of the tube under fluoroscopic examination and may include graduations  47  in centimeters together with centimeter numbers to assist the attending physician in placement of the oral gastric lavage tube  40  in the gastrointestinal tract. 
   The inner lumen  42  may terminate at a proximal end with a funnel connector  44  to be received by corresponding cone connector  46  of connector line  49  of a 3500 cc irrigation bag  50 . The connector line may include a ratchet clamp  52  for metering the irrigant flow. The irrigation bag  50  provides a cap  54  and hanger  56  for suspension on an IV pole according to techniques well known in the art. 
   Referring to  FIG. 4 , the outer lavage tube includes a number of eye holes  58  at its distal end  45 . The inner lumen  42  which is adhered to one wall of the outer lumen  41  is terminated at the distal end  45  and has much smaller eye holes  63  for providing irrigation fluid from the irrigation bag  50 . 
   Referring to  FIGS. 1 and 5 , the eye holes  58  are elliptical in shape and have size  22   e  less than the sizes  22   a - 22   d  as measured by the minor diameter of the ellipse of the eye holes  58  and preferably a size of 20 French. An open end  61  of the oral gastric lavage tube  40  may be sealed or may be left open provided its diameter is less than sizes  22   a - 22   d  as described above. By incorporating the vacuum tube  20 , the aspiration valve  24 , and oral gastric lavage tube  40  into one kit, the relative sizes of the eye holes  58  and of all intervening restrictions  22   a - 22   d  may be controlled so as to significantly reduce clogging in a dual lumen system. 
   As a matter of convenience, the oral gastric lavage kit  10  may also include other convenient elements including a bite block  60  of the style that is commercially available in the art, a biohazard bag  62  for disposal of the lavage kit when complete, a 140 cc syringe  64  with a 34 French tip for introducing the charcoal suspension and injecting air into the lavage tube  40  for placement verification with a stethoscope. The irrigation bag  50  and its associated parts are included to ensure compatibility with the desired oral gastric lavage tube  40 . The kit may also include a lubricant  68  for lubricating the oral gastric lavage tube  40  for insertion into the GI track. Alternatively, the oral gastric lavage tube  40  may be precoated with a commercially available hydrophilic coating that becomes lubricious when made wet such as is manufactured by Hydromer of Somerville, N.J. and others. 
   Other elements of the oral gastric lavage kit  10  may include a container of activated charcoal suspension  66  such as is commercially available, sorbitol  71 , a disposable gown  69 , and an emesis bag  70 . Separate sorbitol and charcoal containers are provided to allow the attending physician to elect not to use the sorbitol while still using the charcoal.

Technology Classification (CPC): 8