US3677248A

US3677248A - Surgical irrigation apparatus and method of using same

Info

Publication number: US3677248A
Authority: US
Inventors: Charles J Mcphee
Original assignee: American Hospital Supply Corp
Current assignee: Kendall Mcgraw Laboratories Inc
Priority date: 1970-08-27
Filing date: 1970-08-27
Publication date: 1972-07-18
Anticipated expiration: 1989-07-18
Also published as: CA943421A; BE783029A

Abstract

Apparatus for delivering large quantities of sterile medical liquid at both a fast flow rate and a low pressure to a resectoscope used by a physician in performing prostate surgery. Each of several 2-liter bottles suspended above the patient has an outlet tube providing for simultaneous concurrent flow of liquid and air between the bottle and an air trap chamber of the apparatus. In the process of maintaining a constant supply of bubble-free liquid to the resectoscope for flushing out blood and tissue, any randomly selected bottle of the apparatus that becomes empty can be disconnected from its outlet tube and replaced with a full bottle without disrupting the liquid supply to the air trap chamber from any other bottle of the apparatus.

Description

United States Patent McPhee 51 July 18, 1972 SURGICAL IRRIGATION APPARATUS AND METHOD OF USING SAME [72] Inventor: Charles J. McPhee, Sylmar, Calif. [73] Assignee: American Hospital Supply Corporation [22] Filed: Aug. 27, 1970 21 Appl. No.: 67,375

[52] US. Cl ..128/227,137/l27, 141/319, 222/416 [51] Int. Cl. ..A6lm 3/00 [58] Field of Search 128/227, 228, 213, 214, 272, 128/275, DIG. 12, DIG. l3; 137/123-127, 602-607; 222/129, 145, 416; 141/311, 319-323, 285 [56] References Cited UNITED STATES PATENTS 3,217,711 11/1965 Pecina et al. ..l28/2l4 3,110,308 11/1963 Bellamy,-Jr. 128/272 X 2,775,240 12/1956 Morrisey, Jr. et al... ....128/214 2,542,461 2/1951 Bay ....128/228 2,027,588 1/1936 Hannon..... ....l28/227 2,954,028 9/1960 Smith ..l28/214 2,594,639 4/1952 Gossett ...l28/2l4 X 3,216,418 11/1965 Scislowicz ..l28/214 FOREIGN PATENT OR APPLICATIONS 737,249 6/1966 Canada ..128/2l4 OTHER PUBLICATIONS Intravenous Transfusion Set for Infants" The Lancet, April 27, 1963, p. 923- 924 Primary ExaminerRichard A. Gaudet Assistant Examiner-J. Yasko Att0rneyLarry N. Barger and Robert T. Merrick [57] ABSTRACT Apparatus for delivering large quantities of sterile medical liquid at both a fast flow rate and a low pressure to a resectoscope used by a physician in performing prostate surgery. Each of several 2-1iter bottles suspended above the patient has an outlet tube providing for simultaneous concurrent flow of liquid and air between the bottle and an air trap chamber of the apparatus. In the process of maintaining a constant supply of bubble-free liquid to the resectoscope for flushing out blood and tissue, any randomly selected bottle of the apparatus that becomes empty can be disconnected from its outlet tube and replaced with a full bottle without disrupting the liquid supply to the air trap chamber from any other bottle of the apparatus.

19 Claims, 6 Drawing Figures Patented July 18, 1972 4 Sheets-Sheet 2 has J 449 /9 66 INVE1\T0R g /fii 5 C'HA ' Patented July 18, 1972 4 Sheets-Sheet Z 671146465 J M PHCC'E ATTOE/Vmfy Patented July 18, 1972 3,677,248

' 4 Sheets-Sheet 4 SURGICAL IRRIGATION APPARATUS AND METHOD OF USING SAME BACKGROUND A very common surgical operation performed in males as they grow older is a Transurethral Resection (T.U.R.) commonly known as a prostate operation. In performing a prostate surgery, the physician uses a resectoscope which he inserts into the patients urethral canal to view the prostate gland, which is shaped somewhat like a doughnut and located at the base of the bladder. As the physician cuts away portions of the prostate gland to provide a free passage for urine through the gland to the urethra, there is considerable blood and tissue that can obstruct the physicians view through the resectoscope. During the surgery, this blood and tissue are flushed out through the urethra with a stream of water or other liquid.

In the past there have been many problems in supplying the flushing liquid to the resectoscope. Because the liquid must be sterile to avoid possible contamination and infection of the patient, tap water which is available in large quantities is not ordinarily used. Instead, sealed containers of sterile liquid are suspended above the patient to feed the sterile liquid through a tube to the resectoscope. Since such large volumes of sterile liquid are needed often in excess of liters a single container with enough sterile liquid for a complete prostate surgery would be too heavy and cumbersome for a nurse to handle and lift to a hanger above the patient. Therefore, smaller containers of l or 2 liter size for example have been used, and these were continually changed as they became empty. Sometimes, when the bottles were changed, the liquid flow rate would change considerably causing a surging of the flushing liquid and making it harder for the physician to see the surgical site. Also, when changing containers, there was a problem of getting air bubbles or large slugs of air in the line leading to the resectoscope and such air would give the physician an obstructive view. This was because the air would not flush away the blood and tissue.

Another problem with prior systems for delivering liquid to a resectoscope was the pressure used to deliver such large volumes of liquid at fast flow rates. To increase the flow rates the liquid containers were hung very high above the patient to increase the head pressure of the liquid and hence its flow rate. Sometimes a nurse even had to use a step stool or overhead winch to hang and change the sterile liquid containers. To get the fast flow rates necessary for good flushing action during surgery, it was believed that high pressures were needed, even though high pressure delivery of flushing liquid was known to' cause problems. To begin with, high pressure delivery could cause excessive turbulence or splattering of the liquid, decreasing its optical clarity. Also, the flushing liquid under high pressure could build up excessive static pressure in the patients bladder during and after the bladder became filled with the flushing liquid. Finally, it was a laborious task for a nurse to run up and down a step stool, lugging a 2-liter bottle of liquid every time a bottle suspended from a high perch became empty.

As mentioned above, surgical irrigation of a prostrate operation has several unique problems including supplying high liquid volumes, maintaining fast flow rates; and the trouble with high pressure, air slugs, frequent bottle changes, etc. Because of these special problems, surgical irrigation is considered in a separate category from other medical administration procedures such as oxygen administration of gas to a patient's lungs, or intravenous administration of blood or parenteral liquid at a slow drip-drip-drip rate into a patients vein. The applicants invention here deals with surgical irrigation and with overcoming the problems of previous surgical irrigation systems.

SUMMARY OF THE INVENTION of a prostate surgery. The apparatus has several large glass or plastic bottles, 2-liter for example, containing sterile liquid suspended above the patient, and each bottle has an outlet tube connected to a mouth of the bottle. These outlet tubes have lower ends leading to an enlarged air trap chamber which separates liquid and air and drains the liquid through a tube to a resectoscope. Each outlet tube has a passage sufficiently large for simultaneous concurrent flow of liquid and air providing each bottle with its own independently operating liquid-air interchange system with the air trap chamber. Thus, any randomly selected bottle of the apparatus that becomes empty can be disconnected from its outlet tube and replaced with a full bottle without disrupting the fast, steady liquid supply to the air trap chamber from other bottles of the apparatus. As long as at least one bottle of the apparatus has some liquid in it, the apparatus will continue to deliver bubblefree liquid to the resectoscope at a constant low pressure. This constant low pressure delivery is brought about by a hydrophobic air inlet check valve at a mouth of each supply bottle that establishes a generally constant hydrostatic head independant of the liquid level in the bottle. While liquid is flowing into the air trap chamber from the supply bottles, any air collected in the air trap chamber can work its way back up the outlet tubes to the supply bottles. In one version of the invention the air can also exit to the atmosphere through a unique check valve at a top of the air trap chamber.

THE DRAWINGS FIG. 1 is a front elevational view of the apparatus assembled for supplying low pressure bubble-free liquid at a fast flow rate to a resectoscope from glass bottles;

FIG. 2 is an enlarged sectional view of an outlet tube between one of the bottles and the air trap chamber showing the independently operating liquid-air interchange system;

FIG. 3 is an enlarged sectional view of the top portion of the air trap chamber showing a modification of the air trap chamber with a special check valve to assist in removing air from the air trap chamber; 1 I

FIG. 4 is a top plan view of the check valve taken along line 44 of FIG. 3;

FIG. 5 is a front elevational view showing the apparatus with semirigid thermoplastic bottles with walls that flex inwardly in response to a partial vacuum created when liquid begins to drain, and these walls thereafter move outwardly to suck back air to replace the drained liquid; and

FIG. 6 is a front view of the apparatus as supplied to the hospital for connecting to the bottles of sterile liquid and to the resectoscope, the air trap chamber of the apparatus being shown in perspective view.

DETAILED DESCRIPTION Referring specifically to these drawings, FIG. 1 shows the apparatus as it is used with four 2-liter glass bottles. These bottles numbered 1, 2, 3, and 4 are hung above the patient by hanging bails 5, 6, 7 and 8, and these bottles have mouths 9, l0, l1 and 12 that form the lowest points of the bottles when hung in an inverted position as shown in FIG. 1. Bottles 1 and 2 are shown in solid lines dispensing liquid, with bottle 2 being the fuller of the two. Bottles 3 and 4 are shown in dotted line to show that these bottles became empty and were lowered to the position shown in full solid line for exchanging the empty bottles for two full bottles 3a and 4a. When the two full bottles 3a and 4a are substituted for empty bottles 3 and 4, the full bottles will be hung in the position of the dotted lines formerly occupied by bottles 3 and 4.

As can be seen from FIG. I, each bottle has an outlet tube, here designated as 13, 14, 15 and 16, and these tubes are connected at their upper ends to closures l7, l8, l9 and 20, fitted to the bottle mouths and at their

lower ends

21, 22, 23 and 24 to an inlet structure of an enlarged air trap chamber 25. This inlet structure can be a cap 30 with four separate ports that connect to the outlet tubes. Each outlet tube has an on-off clamp designated as 26, 27, 28 and 29, and in the drawings, these outlet tube clamps are shown in the open position. While the empty bottles 3 and 4 are being exchanged for full bottles as in FIG. 1,

clamps

28 and 29 are closed. The bottles 1 and 2 keep a fast steady supply of liquid flowing to the air trap chamber 25. At this point, it is important to recognize that each bottle has its own outlet tube for delivering liquid to the air trap chamber, and the change over of the empty bottles 3 and 4 for full bottles does not interrupt the supply of liquid from bottles 1 and 2. Each outlet tube has its own independently operating liquid-air'exchange system with the air trap chamber 25. Thus, any air introduced into the air trap chamber can work its way back up into the bottles to replace liquid flowing to the air trap chamber. The details of these liquid-air interchange systems will be discussed in more detail with, reference to subsequent drawings after we explore the entire apparatus of FIG. 1.

After the liquid collects in the enlarged air trap chamber of FIG. 1, any air bubbles entrained in the liquid gushing through the inlet structure of the top cap of the air trap chamber moves to the top of the chamber and creates a liquidair interface 31 which is readily visible through transparent cylindrical chamber wall 32. Wall 32 can have volumetric calibrations, if desired, to give the physician or nurse a reading of how full the air trap chamber is running. The liquid in the lower portion of the air trap chamber drains out through a drain port 33 in a bottom cap 34 secured to the chamber wall. A flexible thermoplastic drain tube 35 connected at its upper end to the drain port 33 carries liquid from the air trap chamber to the drain tubes lower end which is connected to rigid adapter 36. Fitting around this adapter is an elastomeric sleeve 37 that is adapted to stretch over a hollow knob connector on a resectoscope to join the drain tube 35 with the resectoscope.

In FIG. 1, the lower end of drain tube 35, adapter 36 and elastomeric sleeve 37 are shown covered by a removable sterility protector which includes a retainer with a disc member 38 and a skirt 39 fitting around the drain tube. Removably fitting within the skirt is one end of a transparent protector housing 40 which is closed at outer end 41. The protector housing 40 is pulled away from the skirt 39 of the retainer immediately before the physician connects elastomeric sleeve 37 to the resectoscope. The purpose of the protector housing is to keep the elastomeric sleeve sterile until connected to the resectoscope. The resectoscope itself is old in the art and not part of this invention. Hence, the intricate details of the resectoscope are not shown in the drawings.

Now that we have discussed the overall surgical irrigation apparatus of FIG. 1, we move on to the more specific details of the internal structure of this apparatus shown in subsequent figures. As explained briefly above, each bottle has its own independently operating liquid-air interchange system with the air trap chamber. Thus, any randomly selected bottle that becomes empty can be taken down and exchanged with a full bottle without disturbing the liquid supply to the air trap chamber from any other bottle of the apparatus. FIG. 2 perhaps best shows how this liquid-interchange system works. As shown in the drawing, each outlet tube has a passage between its ends which is sufficiently large in diameter for simultaneous concurrent flow of liquid and air. I have found that a tube with a passage between 0.150 inch and 0.400 inch diameter works very well for this purpose. A tube with a passage substantially smaller, 0.100 inch for example, tends to cause the liquid to completely bridge across the passage because of the liquids surface tension and prevents air from working back up the tube at approximately atmospheric pressure while liquid is flowing down the tube. This same phenomenon happens with a small drinking straw. If the straw is filled with liquid and one places their finger over the top of the straw, the liquid will not drain from the straw. In applicants outlet tubes, the bores are sufiiciently large so liquid can flow downwardly and air flow upwardly at the same time to deliver liquid to the air trap chamber. When only one outlet tube clamp is open, liquid will flow into the air trap chamber to replace air moving back up to the bottle. Thus, no substantial vacuum is created in the air trap chamber preventing additional air from returning to the bottle. I have found that a single outlet tube with a .281 inch diameter passage, for example, can deliver liquid to the air trap chamber very quickly at flow rates up to 950 ml per minute at approximately atmospheric pressure.

The pressure here is described as approximately atmospheric, even though the pressure will sometimes be slightly higher than atmospheric as an air slug begins its journey up the outlet tube while liquid drains by gravity down the outlet tube. Because of the problems mentioned previously with high pressure delivery of liquid to the surgical site, it is the applicant's intent to administer liquid with his apparatus at low gravity feed pressure to the air trap chamber rather than with high pressure pumping mechanisms. This is because such high pressure could be transmitted down the drain tube 35 to the resectoscope and cause splattering and excessive pressure build up in the patients bladder. During the gravity feed of liquid in applicants apparatus, the pressure in the air trap chamber is preferably between to percent of the atmospheric room pressure outside the liquid supply apparatus.

The air in the air trap chamber 25 in FIG. 2 shown working its way back up the outlet tube 13 could have come from several sources. It could have come from tiny bubbles entrained in the liquid coming down the outlet tube, perhaps caused by shaking of the supply bottle. The bubbles might not have had time to separate from the liquid until they were in the air trap chamber. Air in the air trap chamber could have come from the air filled outlet tube 13 that was connected to a full liquid supply bottle. Liquid initially gushing down the outlet tube could have moved some of the air in the tube down into the air trap chamber. Regardless of where the air came from, it is important to get it out of the air trap chamber.

As explained above, the outlet tubes have passages large enough so the air can work its way back up to the supply bottle. It does require some time for air to work its way back to the bottles, and occasionally it is desired to get the air out of the air trap chamber quicker than the air removal shown in FIG. 2. This might occur when three or more bottles were started running with air filled tubes, and a large volume of air from the outlet tubes was moved into the air trap chamber. To speed up the air removal from the air trap chamber, 1 have provided a unique check valve 42 shown in FIGS. 3 and 4 to assist the outlet tubes in removing air from the air trap chamber.

The check valve shown as replacing one of the inlet tubes at an air opening in top cap 30 of the air trap chamber operates differently than most check valves which merely permit fluid to flow in one direction but not the other. The check valve of this invention is comprised of two components. First there is a hydrophobic filter 43 fitting within a groove of a hollow holder 44 which is wedged into the inlet port of top cap 30. The hydrophobic filter which may be a Teflon (duPont trademark -for fluroplastic) coated fabric or a microporous Teflon film which will allow air to pass through it but will not pass liquid. The second element of the check valve is a duck bill rubber flap valve 45 with a slit opening 46 that opens to outward air flow but closes to inward air flow. The flap valve fits over the upper end of the holder 44. The two elements of the check valve allow air but not liquid to leave the air trap chamber. Neither air nor liquid can enter the air trap chamber through the check valve. If desired, an air breathing protector cap can be fitted over the rubber flap valve to protect it from contamination.

Should the liquid level rise to the hydrophobic filter level as shown in FIG. 3, the air trap chamber will continue to operate, because liquid in the air trap chamber cannot move through the check valve 42. Thus, the check valve not only controls direction of flow, but separates air from liquid as air exits the air trap chamber. Even when the air trap chamber is as full of liquid as in FIG. 3, the apparatus works very well. This is because the surgical irrigation apparatus has liquid gushing into the air trap chamber and does not depend on drop by drop transfer across a long air pocket to measure flow rate as in parenteral administration into a patients vein.

Either with the check valve of FIGS. 3 and 4 or without the check valve as in FIGS. 1 and 2, the apparatus will continue to deliver liquid at low pressure and fast flow rate to the resectoscope from the air trap chamber. The liquid flows out of the drain port 33 of the air trap chamber and through a drain tube 35 which has a longitudinal passage that is approximately the same size as each of the outlet tubes leading from the bottles. The liquid can freely run into the drain tube without bubbles or air slugs. At a lower end of the drain tube is a rigid adapter 36 with a passage of reduced size which leads to a resectoscope passage which is also reduced in size from the drain tube passage. Because the drain tube passage is substantially larger than the adapter and resectoscope passages, the liquid can flow to the location of adapter and resectoscope under low pressure. The physician can control the liquid flow to the resectoscope with on-off pinch clamp 47 which is within easy reach during the prostate surgery.

Another very important feature of the invention is the low pressure delivery of liquid caused by the closure systems at the mouths of the bottles. As shown in FIG. 2, each bottle has a closure plug 48 inserted into its mouth. The plug has a central tubular portion 49 with ribs 50 that wedge against an inner surface of the bottle neck and has an external flange 51 that fits against a lip of the bottle mouth. A tubular holder 52, with a groove and a hydrophobic filter 53 held in the groove, is wedgingly held within an air inlet port of the plug closure. The outlet tube has a rigid adapter 54 that is wedged into a liquid outlet port of the closure. With this arrangement, the hydrophobic filter in the air inlet port lets air bubble into the bottle at the lowest point of a mouth downward bottle. This air replaces the liquid that drains out of the bottle. While the liquid-air interchange systems are very important in getting the air out of the air trap chamber, the air from the air trap chamber is not sufficient to replace the several liters of liquid dispensed. Most of the several liters of air enters the supply bottles through hydrophobic filters such as 53. The hydrophobic filter can be of the same material described above for the hydrophobic filter in the air trap chamber check valve.

In working in the laboratory with this surgical irrigation system, I found that a very unusual thing happened with the closure system as shown in FIG. 2. Regardless of the height of liquid in the bottle, the hydrostatic head is established at approximately the level of the air inletting hydrostatic filter 53 of FIG. 2. This was unexpected because a closure system with an air tube extending up through the liquid establishes the hydrostatic head at the upper surface level of liquid in the bottle. With an air tube system, the hydrostatic pressure is constantly changing (decreasing) as the liquid level lowers when the bottle is draining. On the other hand, the bottle closure of FIG. 2, which has no air tube, maintains a constant hydrostatic head at the filter, whether the bottle is full, one-half full, or nearly empty. This has a decided advantage in surgical irrigation because the pressure does not diminish as the bottles drain.

I had always expected the hydrostatic head of the liquid bottle to be at the liquid surface of the FIG. 2 bottle until one day in the laboratory I flexed the outlet tube of one bottle to form a U-shape that performed as a pressure manometer. To my surprise, the head was at the hydrophobic filter and not at the upper liquid surface. Further laboratory tests verified that the hydrostatic head was at the hydrophobic filter.

The closure system that has the hydrophobic filter shown in the drawings works very well with either rigid glass bottles as shown in FIGS, 1 and 2 or with semirigid blow molded thermoplastic bottles shown in FIG. 5. The

thermoplastic bottles

55 and 56 themselves, with their indented waists, are the subject of another application, Ser. No. 767,356, now U.S. Pat. No. 3,537,598, invented by Elmer F. St. Amand and assigned to the assignee of the present application. I have discovered that when such blow molded semirigid thermoplastic bottles are used in combination with the surgical irrigation apparatus of this invention, the combination has a unique way of assisting in moving air from the air trap chamber back into the bot tles to replace liquid drained from the bottles. Unlike rigid glass bottles, the semirigid thermoplastic bottles of FIG. 5 have

walls

57, 58, 59 and 60 that flex inwardly slightly when liquid begins draining from the bottle. This is because a slight vacuum is created inside the bottle caused by an initial pressure drop across the air inletting filter at the mouth of the bottle when liquid is flowing very fast down the outlet tube to quickly supply an air filled outlet tube with liquid. As the walls flex inwardly, they store energy and thereafter, they move outwardly toward their normal position and this helps suck air back into the bottle from the air trap chamber. In FIG. 5, the bottle 56 on the right is full and has just been connected to the right outlet tube 68 and is moving air in the empty outlet tube 68 down into the air trap chamber 69. The bottle 55, on the left, has walls that are moving outwardly slightly to help suck air from the air trap chamber back into the left bottle through outlet tube 67. Because the bottle walls flex and spring back in response to pressure differences, the liquid levels of the two containers can oscillate slightly to equalize the pressure in the two bottles to maintain approximately the same flow rate from each bottle to the air trap chamber. In FIG. 5, the drain tube, clamp 47, adapter 36, elastic sleeve 37 are the same as in FIG. 1.

With the surgical irrigation apparatus of this invention, various numbers of either the glass or blow molded plastic bottles can be used. An example of the apparatus is shown with four outlet tubes connected to glass bottles in FIG. 1 and another example with two outlet tubes connected to thermoplastic bottles is shown in FIG. 5. The surgical irrigation apparatus will always have a plurality of outlet tubes as shown, but these could be 2, 3, 4 or more to insure an adequate liquid supply to the air trap chamber by at least one bottle while other bottles of the apparatus that become empty are exchanged for full bottles.

FIG. 6 shows surgical irrigation apparatus with 4 outlet tubes as supplied to the hospital in sterile condition ready to be connected to liquid supply bottles and a resectoscope. The package in which the apparatus is sent to the hospital is conventional and is therefore not shown. The apparatus shown in FIG. 6 l have found works very well when made of the following materials; outlet tubes and drain tube of flexible polyvinyl chloride (PVC); cylindrical wall of the housing of transparent cellulose acetate butyrate thermoplastic; end caps of the air trap chamber and adapters of acrylonitrile-butadiene-styrene (ABS), the elastomeric tube of rubber or a highly plasticized polyvinyl chloride thermoplastic which exhibits elastic properties; and the protectors for the bottle closures and elastic sleeve protector of a suitable thermoplastic.

METHOD OF USE When the physician was a prostate surgery scheduled for the hospital operating room, the nurse prepares the patient and removes the apparatus of FIG. 6 from its sterilized package. It is noted that the outlet tubes each have a closure for fitting to a bottle mouth and these closures are supplied with the apparatus. Each closure has a protector cap designated as 61, 62, 63 and 64 over a plug portion of the closure to maintain it in sterile condition until ready for use. The nurse then opens the mouths of two bottles of sterile liquid, such as distilled water, normal saline, etc., and pulls 05 two protector caps from the closures. Next, these closures are plugged into the mouths of two liquid filled bottles, and with the clamps on these two outlet tubes closed, the bottles are suspended in a mouth downward position from a hanging rack above the patient. The nurse can open one of the

clamps

26, 27, 28 or 29 on an outlet tube connected to a bottle to start liquid running into the air trap chamber 25. Then the bottom clamp 47 can be opened for a short period to let liquid fill the drain tube 35 after which this bottom clamp is again closed. The air formerly in the drain tube is either flushed out through a loose fit between the protector sleeve 40 and retainer skirt 39 that forms a vent system, or the air can work its way back up to the air trap chamber 25. Then, when the physician comes into the operating room, he can go directly into the prostate surgery without having to bleed air from the drain tube 35.

When connecting the first two liquid filled bottles to supply the air trap chamber as explained above, it is preferred to hold the closure ends of the other two outlet tubes below the air trap chamber. Therefore, the second pair of lowered outlet tubes can also act as air vents to remove air from the air trap chamber. Air can vent between the closure and their protector caps which are either ribbed or grooved at 65 and have a bump 66 to keep a slight air passage between the cap and closure. After the first two bottles start a steady liquid supply to the trap chamber, the third and fourth bottles are opened and connected to their respective outlet tubes and hung on the hanging stand. Now, we have all four 2-literbottles feeding into the air trap chamber. Since each bottle has an air inlet at its lowest point in the mouth downward position and has no air tube, all bottles hung at the same height will have the same hydrostatic head, which is established at the hydrophobic filter 53.

After any one of the bottles runs dry, the nurse takes it down from the hanging stand and exchanges it for a full bottle and hangs up the new bottle. This can be done with any randomly selected bottle of the apparatus without disrupting the liquid supply of any other bottle of the system. Therefore, all a nurse needs to keep in mind when monitoring the supply bottles, is to change any bottle that becomes empty. She does not have to be concerned with any particular sequence of changing bottles to avoid air slugs or bubbles delivered to the resectoscope as might be the case where one bottle feeds into another bottle which then delivers the combined liquids. If only one of the several bottles in applicants surgical irrigation apparatus has liquid, the apparatus will operate at the low pressure, fast flow rate desired for flushing action in a prostate surgery.

In the above description, I have used specific examples to describe my invention. However, persons skilled in the art will understand how to make certain modifications to those specific examples without departing from the spirit and scope of the invention.

I claim:

1. A substantially free-fall, gravity-feed surgical irrigation apparatus comprising: a plurality of liquid-containing bottles with outlet ports adapted to be randomly-selected and supported above an irrigation site or discharged and replaced without interferring with irrigation procedures; a flexible outlet tube for each bottle with upper ends of these outlet tubes connected to the respective outlet ports, each of the outlet tubes including means defining a passage sufficiently large in cross sectional area from its upper end to its lower end for permitting substantially simultaneous counter-current flow of liquid and air at approximately atmospheric pressure during free-fall of liquid therethrough during a surgical irrigation procedure: an enlarged air trap chamber having an inlet structure at its top in direct-flow communication with lower ends of the outlet tubes and having an outlet port at its bottom, said air trap chamber having a size and capacity and free communication between the inlet structure and outlet port permitting free discharge of a randomly selected filled bottle to be inverted and the entire contents to be freely discharged thereinto at the hydrostatic head developed at the outlet port of the inverted bottle; means operatively connected to said air trap chamber and said bottles for permitting a liquid-air interface to form in said air trap chamber asliquid is permitted to freely discharge from said said outlet port while liquid and air are flowing counter-currently in said flexible outlet tube; and a flexible drain tube connected to the drain port and which includes a longitudinal passage therethrough to a lower end of the drain tube, said drain tube having a cross sectional area for permitting free-fall liquid to be directed at a low pressure and high volume without entrapped air bubbles to the irrigation site, each bottle through its outlet tube having means providing its own independently operating liquid-air interchange system with the air trap chamber, and any bottle being operable to continue to supply liquid to the air trap chamber while any other randomly selected bottle of the apparatus that becomes empty is replaced by a filled bottle.

2. Surgical irrigation apparatus as set forth in claim 1, wherein the apparatus has a separate valve for opening and closing the passage of each outlet tube, and has a valve for opening and closing the passage of the drain tube.

3. Surgical irrigation apparatus as set forth in claim 1, wherein the drain tubes passage is approximately the same size as each outlet tube passage and has a constriction adjacent its lower end, whereby the drain tube can run full of liquid to deliver large volumes of liquid at low pressure to the irrigation site without intermittant slugs of air.

4. Surgical irrigation apparatus as set forth in claim 1, wherein the drain tube has an elastic sleeve at its lower end adapted to stretch over and grip a medical instrument.

5. Surgical irrigation apparatus as set forth in claim 1, wherein the bottles are of rigid glass.

6. Surgical irrigation apparatus as set forth in claim 1, wherein each bottle has semirigid thermoplastic walls capable of storing energy by temporarily bending inwardly as liquid drains from the bottle and thereafter springing outwardly to suck air back into the bottle.

7. Surgical irrigation apparatus as set forth in claim 1, wherein each bottle has a mouth, and the apparatus includes a removable closure fitting across this mouth and having first and second ports through the closure; the upper end of the bottles flexible outlet tube being secured to the closure at its first port; and means secured to the closure at the second port for admitting air into the bottle and preventing liquid exit from the bottle through the second port when the bottle is suspended in a mouth downward position.

8. Surgical irrigation apparatus as set forth in claim 7, wherein the means for admitting air is a hydrophobic filter which establishes a hydrostatic head at approximately the level of the filter so the hydrostatic head is generally constant regardless of the liquid level in the bottle.

9. Surgical irrigation apparatus comprising: a plurality of liquid-containing bottles with outlet ports adapted to be supported above an irrigation site; a flexible outlet tube for each bottle with upper ends of these outlet tubes connected to the outlet ports, each of the outlet tubes defining a passage sufficiently large in cross sectional area from its upper end to its lower end for simultaneous concurrent flow of liquid and air at approximately atmospheric pressure; an enlarged air trap chamber having an inlet structure at its top in flow communication with lower ends of the outlet tubes and having an outlet port at its bottom; and a flexible drain tube connected to this drain port and which includes a longitudinal passage therethrough to a lower end of the drain tube for directing liquid to the irrigation site, whereby each bottle through its outlet tube has its own independently operating liquid-air interchange system with the air trap chamber, and any bottle can continue to supply liquid to the air trap chamber while any other randomly selected bottle of the apparatus that becomes empty is replaced by a filled bottle, the apparatus having an air opening to the atmosphere in the air trap chamber adjacent its top for assisting in air removal from the air trap chamber, and a check valve closing off the air opening, said check valve permits air but not liquid to flow outwardly through the air opening and prevents both air and liquid from flow into the air trap chamber through the air opening.

10. Surgical irrigationapparatus as set forth in claim 1, wherein the air trap chamber has a top cap with a separate inlet port connected to each outlet tube.

11. Surgical irrigation apparatus as set forth in claim 1, wherein the air trap chamber has a transparent cylindrical wall that is volumetrically calibrated.

12. Surgical irrigation apparatus as set forth in claim 1, wherein each outlet tube has a passage with a diameter between 0.150 and 0.400 inch.

13. Surgical irrigation apparatus as set forth in claim 1, wherein the air trap chamber has an internal pressure that is between 90 and 120 percent of the atmospheric pressure outside the air trap chamber when liquid is being supplied to the air trap chamber.

14. In surgical irrigation apparatus including a plurality of liquid containers each with an outlet connected to a downwardly extending flexible tube that has a lower end, the improvement of: an enlarged air trap chamber with an inlet structure in flow communication with the lower ends of the outlet tubes, the air trap chamber having an air opening to the atmosphere adjacent a top of the chamber and has a drain port adjacent its bottom; and a check valve secured across the air opening, which check valve permits air but not liquid to flow outwardly through the air opening, while preventing both air and liquid from flowing inwardly through the air opening.

15. The improvement in surgical irrigation apparatus as set forth in claim 14, wherein the check valve comprises the combination of a flap valve with inner and outer ends, and a hydrophobic filter connected with the inner end of the flap valve.

16. An assembly for use in surgical irrigation apparatus-including a plurality of liquid-containing bottles having mouths, which assembly includes: a plurality of closures with portions for connecting with the bottle mouths, said closures including a liquid outlet port through the closure; removable sterility protectors fitting over said portions of the closures; a flexible outlet tube connected at its upper end to the outlet port of each closure, each of the outlet tubes including means defining a passage sufficiently large in cross-sectional area from its upper end to its lower end for simultaneous counter-current flow of liquid and air at approximately atmospheric pressure during free gravity-flow of liq uid therethrough; an enlarged air trap chamber having an inlet structure at its top in direct-flow communication with the lower ends of the outlet tubs and having a drain port at its bottom, said air trap chamber having a size and capacity and free communication between the inlet structure and outlet port for permitting free discharge of a randomly selected filled bottle to be inverted and the en-contents to be freely discharged therein at the hydrostatic head developed at the outlet port of the bottles to which said closures have been attached; means operatively connected to said closures and said air trap chamber for permitting a liquid air interface to form in said air trap chamber as liquid is permitted to freely discharge from said outlet port while liquid and air are flowing counter-courently in said flexible outlet tube; a flexible drain tube connected to this drain port and having a passage of sufficient capacity for permitting liquid to freely fall therethrough at low pressure and high volume without entrapped air bubbles for directing liquid from its lower end to an irrigation site; and a removable protector housing fitted over a lower end of the drain tube, each outlet tube is adapted to provide an independent air-liquid interchange system between a bottle and the air trap chamber.

17. Surgical irrigation apparatus comprising: a plurality of liquid-containing bottles, each with a mouth and adapted to be suspended in a mouth-downward position above an irrigation site with the liquid freely flowing therefrom under the force of gravity; a removable closure fitting across the mouth of each bottle and having first and second ports therethrough; through; a flexible outlet tube with an upper end connected to the first port of each respective closure, each outlet tube including means having a lower end and a passage between its ends sufficiently large in cross-sectional area for simultaneous counter-current flow of liquid and air at approximately atmospheric pressure; a pinch clamp on each outlet tube for opening and closing its passage; a hydrophobic filter fitting across the second port of the closure to admit air into the bottle and to prevent liquid exit from the bottle through the second port when the bottle is suspended in a mouth downward position, said bottles developing a hydrostatic head face therein when liquid in permitted to freely drain from theair trap chamber, each bottle through its tube forming an independent liquid-air interchange system with the air trap chamber, and any randomly-selected bottle and its system continuing to function after any other bottle of the apparatus becomes empty and is replaced by a filled bottle; a flexible drain tube connected at its upper end to the drain port of the air trap chambers bottom cap, and having a passage between its upper and lower ends that is approximately the same size as each outlet tube passage for permitting liquid to freely flow therethrough at a low pressure and high volume without entrapped bubbles; and adaptor with a constricted opening connected to the drain tubes lower end, said adapter having a cross section so the drain tube can run full of liquid to deliver large volumes of liquid at low pressure to the irrigation site without intermittant slugs of air; an elastic sleeve secured to the adapter for stretching over and gripping to a medical instrument; and a removable protector housing fitting over the elastic sleeve.

18. A method of surgical irrigation for continuously supplying a substantially air-free liquid to an irrigation site when effecting a Transurethral Resection or similar surgical procedure at a low pressure and large volume, comprising the steps of:

A. filling a plurality of containers with an irrigation liquid;

B. independently connecting each of the filled bottles to an an enlarged air chamber through independent outlet tubes and permitting air and liquid flowing therethrough to have counter-current flow therethrough as a filled bottle is emptied into air chamber;

C. connecting the air trap chamber to a drain tube for permitting liquid to drain therethrough at a low pressure and high volume without entrapped air bubbles therein;

D. randomly selecting two or more of the filled bottles,

suspending the same in a discharge attitude above an irrigation site;

E. emptying one of the suspended bottles into the air trap chamber while starting to empty another of the suspended bottles into the chamber before the first is completely empty so that liquid for irrigation is uninterrupted;

F. continuing to discharge liquid into the air trap chamber at a hydrostatic head developed at the bottle being discharged while replacing the emptied bottle with one that is filled; and

G. effecting the discharge of liquid through the air trap chamber while maintaining an air liquid interface in said air trap chamber during free gravity flow of liquid therethrough.

19. A method of surgical irrigation as set forth in claim 18 wherein there are four liquid containing bottles and four outlet tubes leading between the bottles and the air trap chamber, and the method includes the step of completely emptying any two randomly selected bottles and then disconnecting and replacing them with filled bottles while liquid is supplied to the air trap chamber by at least one of the other two bottles.

Claims

1. A substantially free-fall, gravity-feed surgical irrigation apparatus comprising: a plurality of liquid-containing bottles with outlet ports adapted to be randomly-selected and supported above an irrigation site or discharged and replaced without interferring with irrigation procedures; a flexible outlet tube for each bottle with upper ends of these outlet tubes connected to the respective outlet ports, each of the outlet tubes including means defining a passage sufficiently large in cross sectional area from its upper end to its lower end for permitting substantially simultaneous counter-current flow of liquid and air at approximately atmospheric pressure during free-fall of liquid therethrough during a surgical irrigation procedure: an enlarged air trap chamber having an inlet structure at its top in directflow communication with lower ends of the outlet tubes and having an outlet port at its bottom, said air trap chamber having a size and capacity and free communication between the inlet structure and outlet port permitting free discharge of a randomly selected filled bottle to be inverted and the entire contents to be freely discharged thereinto at the hydrostatic head developed at the outlet port of the inverted bottle; means operatively connected to said air trap chamber and said bottles for permitting a liquid-air interface to form in said air trap chamber as liquid is permitted to freely discharge from said said outlet port while liquid and air are flowing counter-currently in said flexible outlet tube; and a flexible drain tube connected to the drain port and which includes a longitudinal passage therethrough to a lower end of the drain tube, said drain tube having a cross sectional area for permitting free-fall liquid to be directed at a low pressure and high volume without entrapped air bubbles to the irrigation site, each bottle through its outlet tube having means providing its own independently operating liquid-air interchange system with the air trap chamber, and any bottle being operable to Continue to supply liquid to the air trap chamber while any other randomly selected bottle of the apparatus that becomes empty is replaced by a filled bottle.

3. Surgical irrigation apparatus as set forth in claim 1, wherein the drain tube''s passage is approximately the same size as each outlet tube passage and has a constriction adjacent its lower end, whereby the drain tube can run full of liquid to deliver large volumes of liquid at low pressure to the irrigation site without intermittant slugs of air.

7. Surgical irrigation apparatus as set forth in claim 1, wherein each bottle has a mouth, and the apparatus includes a removable closure fitting across this mouth and having first and second ports through the closure; the upper end of the bottle''s flexible outlet tube being secured to the closure at its first port; and means secured to the closure at the second port for admitting air into the bottle and preventing liquid exit from the bottle through the second port when the bottle is suspended in a mouth downward position.

10. Surgical irrigation apparatus as set forth in claim 1, wherein the air trap chamber has a top cap with a separate inlet port connected to each outlet tube.

16. An assembly for use in surgical irrigation apparatus including a plurality of liquid-containing bottles having mouths, which assembly includes: a plurality of closures with portions for connecting with the bottle mouths, said closures including a liquid outlet port through the closure; removable sterility protectors fitting over said portions of the closures; a flexible outlet tube connected at its upper end to the outlet port of each closure, each of the outlet tubes including means defining a passage sufficiently large in cross-sectional area from its upper end to its lower end for simultaneous counter-current flow of liquid and air at approximately atmospheric pressure during free gravity-flow of liquid therethrough; an enlarged air trap chamber having an inlet structure at its top in direct-flow communication with the lower ends of the outlet tubs and having a drain port at its bottom, said air trap chamber having a size and capacity and free communication between the inlet structure and outlet port for permitting free discharge of a randomly selected filled bottle to be inverted and the en-contents to be freely discharged therein at the hydrostatic head developed at the outlet port of the bottles to which said closures have been attached; means operatively connected to said closures and said air trap chamber for permitting a liquid air interface to form in said air trap chamber as liquid is permitted to freely discharge from said outlet port while liquid and air are flowing counter-courently in said flexible outlet tube; a flexible drain tube connected to this drain port and having a passage of sufficient capacity for permitting liquid to freely fall therethrough at low pressure and high volume without entrapped air bubbles for directing liquid from its lower end to an irrigation site; and a removable protector housing fitted over a lower end of the drain tube, each outlet tube is adapted to provide an independent air-liquid interchange system between a bottle and the air trap chamber.

17. Surgical irrigation apparatus comprising: a plurality of liquid-containing bottles, each with a mouth and adapted to be suspended in a mouth-downward position above an irrigation site with the liquid freely flowing therefrom under the force of gravity; a removable closure fitting across the mouth of each bottle and having first and second ports therethrough; through; a flexible outlet tube with an upper end connected to the first port of each respective closure, each outlet tube including means having a lower end and a passage between its ends sufficiently large in cross-sectional area for simultaneous counter-current flow of liquid and air at approximately atmospheric pressure; a pinch clamp on each outlet tube for opening and closing its passaGe; a hydrophobic filter fitting across the second port of the closure to admit air into the bottle and to prevent liquid exit from the bottle through the second port when the bottle is suspended in a mouth downward position, said bottles developing a hydrostatic head substantially at said filter when liquid is permitted to freely fall from the bottles; an enlarged air trap chamber including a transparent cylinderical housing, an upper cap secured to a top of the housing and having a separate inlet port in communication in communication with each outlet tube''s lower end, and a lower cap secured secured to a bottom of the housing and having a drain port therethrough; means operatively connected to said air trap chamber developing a liquid-air interface therein when liquid in permitted to freely drain from the air trap chamber, each bottle through its tube forming an independent liquid-air interchange system with the air trap chamber, and any randomly-selected bottle and its system continuing to function after any other bottle of the apparatus becomes empty and is replaced by a filled bottle; a flexible drain tube connected at its upper end to the drain port of the air trap chamber''s bottom cap, and having a passage between its upper and lower ends that is approximately the same size as each outlet tube passage for permitting liquid to freely flow therethrough at a low pressure and high volume without entrapped bubbles; and adaptor with a constricted opening connected to the drain tubes lower end, said adapter having a cross section so the drain tube can run full of liquid to deliver large volumes of liquid at low pressure to the irrigation site without intermittant slugs of air; an elastic sleeve secured to the adapter for stretching over and gripping to a medical instrument; and a removable protector housing fitting over the elastic sleeve.

18. A method of surgical irrigation for continuously supplying a substantially air-free liquid to an irrigation site when effecting a ''''Transurethral Resection'''' or similar surgical procedure at a low pressure and large volume, comprising the steps of: A. filling a plurality of containers with an irrigation liquid; B. independently connecting each of the filled bottles to an an enlarged air chamber through independent outlet tubes and permitting air and liquid flowing therethrough to have counter-current flow therethrough as a filled bottle is emptied into air chamber; C. connecting the air trap chamber to a drain tube for permitting liquid to drain therethrough at a low pressure and high volume without entrapped air bubbles therein; D. randomly selecting two or more of the filled bottles, suspending the same in a discharge attitude above an irrigation site; E. emptying one of the suspended bottles into the air trap chamber while starting to empty another of the suspended bottles into the chamber before the first is completely empty so that liquid for irrigation is uninterrupted; F. continuing to discharge liquid into the air trap chamber at a hydrostatic head developed at the bottle being discharged while replacing the emptied bottle with one that is filled; and G. effecting the discharge of liquid through the air trap chamber while maintaining an air liquid interface in said air trap chamber during free gravity flow of liquid therethrough.