United States Patent (19) Steiner et al.

Transcription

1 United State Patent (19) Steiner et al. (54) INSUFFLATOR 76 Inventor: Rolf Steiner, Schietingertr.-22, 7270 Nagold-Gundringen; Volker Walz, Walddorfertr. 40, 727 Rohrdorf, both of Fed. Rep. of Germany (21) Appl. No.: 567, Filed: Aug. 15, Foreign Application Priority Data Jun. 15, 1990 IDE Fed. Rep. of Germany ) Int. Cl.... A61M 13/00 52 U.S. C /26; 604/23; 128/747; 141/83; 141/ Field of Search /4, 23-31; 128/747, 748; 141/83, 94, 95, ) Reference Cited U.S. PATENT DOCUMENTS 3,870,072 3/1975 Lindemann /26 4,527,600 7/1985 Fiher et al /94 4,676,774 6/1987 Semm et al /747 4,874,362 10/989 Wiet et al /747 USOO552745A 11 Patent Number: (45) Date of Patent: 5,152,745 Oct. 6, ,966,578 10/1990 Baier et al /26 5,006, 109 4/1991 Dougla et al /26 5,006,997 4/1991 Reich /31 5,013,294 5/1991 Baier /747 5,098,375 3/1992 Baier /23 Primary Examiner-Stephen C. Pellegrino Aitant Examiner-Ralph A. Lewi 57 ABSTRACT By mean of the invention, the preure in a cavity can be meaured, without ever reducing the ga flow to zero. Thi i achieved by bleeding an intermediate ve el lightly with it inlet valve cloed and it outlet valve open and then being able to extrapolate from the pre ure decreae whether the deired preure ha been reached. If the reult of the extrapolation indicate that the deired preure ha not been reached, then pump ing i repeated, meauring i repeated and o on and o forth until the extrapolation indicate that the deired preure ha been reached. Thu extrapolation are made intead of allowing the intermediate veel to empty completely. 11 Claim, 4 Drawing Sheet

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6 1. INSUFFLATOR The invention relate to an inufflator by mean of which the preure of a fluid inufflated into a body cavity can be meaured and controlled. BACKGROUND OF THE INVENTION Such a device i known for German Patent Specifica tion 3,000,218, which correpond to U.S. Pat. No. 4,464,169. Such body cavitie are, above all, cavitie in the body of human and animal, epecially the abdomi nal cavity. But body cavitie are alo region which are not cavitie per e, uch a the gap in the knee joint which can be widened to form a body cavity by pump ing it up. Device of the known type require a large number of component and meauring element. Moreover, in all the intrument, the meaurement of the preure in the body cavity i carried out in uch a way that the ga through-flow i reduced to zero. The maximum obtain able throughflow i thu retricted coniderably. Fur thermore, the ga throughflow ha an appreciable pula tion. SUMMARY OF THE INVENTION The object of the invention i to provide a mean by which, during the meaurement of the preure in the cavity, there i no need to reduce the throughflow of the fluid to a zero value or virtually to a zero value. According to the invention, thi object i achieved by mean of an inufflator having the following tructural feature: an inlet line, a firt valve device following aid inlet line, a econd valve device provided downtream of aid firt valve device, an intermediate veel for aid fluid provided be tween aid firt and aid econd valve device, an outlet line downtream of aid firt valve device and aid intermediate veel a logic device adapted to calculate the preure of aid fluid in aid body cavity from at leat two falling preure of aid intermediate veel that occur ucce ively in time and to control aid firt and econd valve device, a preure indicator controlled by aid logic device for indicating the preure of aid fluid in aid body cavity, and a preure/voltage converter connected between aid intermediate veel and aid logic device. When the econd valve device i opened, the preure in the intermediate veel decreae according to pe cific regularity. If the condition were ideal, including a contant flow reitant, then the preure in the interme diate veel would decreae exactly according to an e-function. If two value of an e-function and it de creae contant Tau are known, it trend can be deter mined. In particular, it i poible to determine the par ticular lowet value which it approache aymptoti cally. The aymptotic value i equal to the preure in the cavity. The decreae contant Tau i calculated from the reitance" intermediate veel volume. However, for variou reaon the reitance i not contant. For exam ple, different hollow needle are ued at the end of the outlet line and themelve have a differing reitance. Depending on the ite of the outlet line, which i flexible 5,152, in the end region, it reitance too varie. It can alo happen that the hollow needle aume differing nar rowing of it cro-ection from the outet or during it ue. Finally, reitance i alo of differing amount a a reult of turbulence. For example, it can be greater at a higher preure than at low preure and o on and o forth. Since the decreae contant Tau i therefore not known or i known only inexactly, in practice three (or more) meauring point are required. The aymptote can be calculated from thee. If the precalculated aymptotic curve i below the deired preure in the cavity, further pumping mut be carried out until the aymptote correpond to the deired pre Sc, The logic device can conit of a microproceor, the programming of which doe not contitute an inventive tep and for which thi i eaily poible. It i not fully loaded by computing and control tak of thi type even when the implet type of microproceor i ued. The decribed embodiment include the following additional advantageou feature. The firt valve device i a CLOSED-OPEN valve device. By thi mean, imple condition are obtained at the inlet, it can be cheap and there i no problem in improving the fluid throughflow by mean of a plurality of parallel branche. The econd valve device i a CLOSED-OPEN valve device. The ame i true according to thi feature. For holding gaeou fluid, the intermediate veel i rigid. A a reult, the intermediate veel ha a contant volume, thi making the computation eaier. For holding incompreible fluid, the intermediate veel ha a pecific elaticity. By thee feature it would be poible alo to ue incompreible fluid, and the neceary computation can neverthele till be executed reliably. The input line lead to a branching point. At leat two branche, each including firt and econd valve device and an intermediate veel are arranged parallel to one another and merge via a junction point into the outlet line. And the firt and econd valve device in aid branche are connected to the logic device and are activatable in a manner offet in time period. Thi give rie to an epecially practicable form. Even large body cavitie, uch a, for example, a human abdomen, can then be inflated reaonably quickly. However, where body cavitie of large animal, uch a, for example, elephant, are concerned, it i adviable to provide a larger number of branche. In thee intance too, the throughflow quantity can be calculated by mean of a plurality of preure/volt age converter that connect the intermediate veel in the branche to the logic device. The firt and econd valve device are CLOSED OPEN valve device having variable CLOSED-OPEN time. A a reult thi time can be adapted to the variou working phae. For example, during the filling of he intermediate veel, the valve device at the inlet can be et to "OPEN for a longer time initially, a long a the intermediate veel i not yet full, and thi time can be reduced, the nearer the final preure. Alo, when the aymptote i to be calculated, it i poible to horten or lengthen the meauring time which erve for comput ing the aymptotic curve of the e-function or of func tion imilar to the e-function. The more filling cycle that are provided for the intermediate veel, the greater the difference between

7 5,152,745 3 the actually calculated preure of aid fluid in aid body cavity and the deired preure therein. Thi en ure that the deired preure in the intermediate veel can be approached a finely a poible. When the de ired preure i reached, the filling can then be cut off 5 completely. A fluid-quantity indicator i provided and i con trolled by the logic device. Thi afford not only a preure meaurement, but alo, without any further outlay in term of equipment, a quantity meaurement. 10 A buffer tore i provided following the econd valve device. By thee mean media flow in the hollow needle can be moothed, o that a continuou flow i obtained. The logic device i adapted not to open the firt and econd valve device imultaneouly. 15 BRIEF DESCRIPTION OF THE DRAWINGS The invention i now decribed by reference to pre ferred exemplary embodiment. In the drawing, FIG. 1 how a block diagram of a firt embodiment. FIG. 2 how a block diagram of a econd embodi et. FIG. 3 how a repreentation of a fall-off curve together with formula for computing the relevant vari 25 able. FIG. 4 how a preure/time diagram for the inter mediate veel 23. FIG. 5 how a time diagram of the preure in the abdomen. 30 FIG. 6 how a time diagram of the flowed ga vol e. DESCRIPTION OF PREFERRED EMBODIMENTS According to FIG. 1, a ga bottle 11 i followed by a hutoff cock 12. Thi i connected to a preure reducer 13. A ga-quantity upply indicator 14 branche off between thee two. The preure reducer 13 i followed by a nonreturn valve 16. While the preure reducer 13 reduce the preure to a few bar (for example 4), a preure reducer 17 lower thi preure to 50 mm Hg. An intermediate veel 18 branche off between 16 and 17 and i itelf connected to a relief valve 19. If 13 fail, then 19 blow off exce preure. 17 i connected to a huttle valve 21 which ha one inlet and two outlet. However, depending on the poition of the valve, ga i conveyed through only by way of one outlet or the other. A econd intermediate veel 23 i located in a firt branch 22 after the upper outlet of 21 and i followed by an outlet valve 24 which ha a CLOSED poition and an OPEN poition. Parallel to thi and of an exactly identical deign i a econd branch 26 with an interme diate veel 27 and an outlet valve 28. The intermediate veel 23, 27 are rigid and have a content of, for exam ple 0.25 liter. The outlet of 24, 28 lead to a junction point 29 leading to a ga meter 31. It can be een from thi whether any ga at all i flowing. Thi i not a through-flow meter. A relief valve 32 branche off 60 between 29 and 31, erve for afety purpoe and pre vent the poibility that the preure in the body cavity will rie above a particular value. 31 i followed by a flexible hoe 33, and to thi i connected a hollow needle A converter 35, 40 i connected both to 23 and to 27 and convert the preure prevailing in 23, 27 into a voltage. Thee voltage are fed to a control 38 via elec SO 55 4 trical line 36, 37. The control 38 et the huttle valve 21 and the outlet valve 24, 28 into one of their poition or the other via electrical line 39, 41 and 42. If 21 i OPEN for the branch 22, then 24 i CLOSED. It i alo true of 22 that, when 24 i OPEN, 21 i CLOSED for 22. The ame applie accordingly to the branch 26. In the control 38 there i a microproceor with function to be explained later. A buffer veel 70 can be provided after the junction point 29. The control 38 control a preure indicator 43 and a volume indicator 44. The block diagram according to FIG. 2 again how a large number of component. Difference are that the nonreturn valve 16 i omitted. Alo, there i no intermediate veel 18, the purpoe of which i to allow a ga bottle to be changed without interrupting the operation of the device. There i alo no ga meter 31, and intead of the relatively expenive relief vale 32 there i, here, an overpreure witch 46 which interrupt the ga flow to the hollow needle in the event of exce preure and which, for example doe not bleed off preure in the ame way a the relief valve 32. Above all, in the econd exemplary embodiment, there are intead of the huttle valve 21 two inlet valve 47, 48 which have only one OPEN and the CLOSED poition and which are et in their poition by the con trol 38 via electrical line 49, 51. There are therefore inlet and outlet valve of identical deign here, thu improving the repone behavior, price or the like. In FIG. 2, like part are deignated by the ame reference ymbol a in FIG. 1. It i aumed (FIG. 3) that the intermediate veel 23 ha been pumped up to a preure 50 mm Hg, 24 being cloed (FIG. 2) and 47 being open. By mean of 38 the inlet valve 47 i now cloed and 24 opened. Thi take place at the time 52. Ga now flow via 34 into the abdomen (not hown) and the preure in 23 fall according to the curve 53. However, in the actual ituation the outlet valve 24 i cloed again after the meaurement of Pe. But if it con tinue to remain open, the preure would fall further, a hown in FIG. 3. In a firt cycle, P2 i on the t-axi, and the more volume pae out of 23 into the abdomen, the higher P2 become. The line paing through P2 and parallel to the t-axi can be conidered a an aymptote. The preure i now meaured, in the exemplary em bodiment at interval of 100 mec. at the time te0, the time t-ti and the time t=tl --dt, the time interval all being equal. The control 38 learn of the falling preure Pa, Pi, and P. via the line 36. According to FIG. 3, the preure P2 i obtained by formula (1). Formula (2) indicate the value for x. Formula (3) i equivalent to formula (2). Since the deired preure in the abdomen ha previouly been et at the control 38, the control 38 can determine whether thi ha been reached or not reached by P2. The neceary computing and compar ing work can be carried out by the implet micro proceor, without it being overloaded. The program ming too per e doe not itelf preent any difficultie. The reitance can alo be calculated according to the formula (4), V being the volume of intermediate veel 23. The ga quantity which a flowed through can be calculated by mean of the formula (5). In thi, Pv i the preure in the filled intermediate veel (FIG. 4, No. 56, 58, 61), P1 i the preure in the (partially) emptied intermediate veel (FIG. 4, No. 57 and 59), Pu i the

8 5 ambient preure and V i once again the volume of the intermediate veel. FIG. 6 how that after four minute the ga volume in the patient remain contant at omewhat more than three liter. To have a meaure of the approximate ga quantity aborbed by the patient, a meaurement of the throughflow quantity i important. FIG. 5 ha the ame time cale a FIG. 6. It can be een, here, how the preure in the abdomen approache approximately 12 mm Hg. FIG. 4 which i of mot interet doenot have the ame time cale a FIGS. 5 and 6. On the contrary, here the time egment 1, 2, 3, 4, 5, each urrounded by a circle, have been hown enlarged and the time axi ha been broken at a repective interruption 54. In the per iod 1, at the point 55 the outlet valve 24 i cloed and the inlet valve 47 opened. After 110 mec, at the point 56, 47 i now cloed and 24 opened and the preure in 23 meaured. Ga now flow into the abdomen. After the ame time, namely after 110 mec, at the point 57 a meaurement i made again, 24 i cloed and 47 i opened. The preure now rie in 23. At the point 58, 47 i cloed and 24 opened, and the preure fall. The ame occur at point 59 a at point 578 and the ame at point 61 a at point 58. The peak point come increa ingly cloer to the 50 mm Hg line 62. The time interval for the meaurement and changeover, i alway the ame, namely 110 mec. In the timer period 2, the val ley have become very hallow. After the point 63, the intermediate veel 23 i no longer pumped up, but i now emptied only along the curve 53. At interval of 100 mec, P, P and Pare meaured, and the control 38 draw the abovementioned concluion. After the mea urement Pc, pumping i now carried out again, a previouly decribed, virtually up to the 50 mm Hg line, and P, P and P are meaured again. Of coure, the cycle are ubtantially more numerou than a hown in FIG. 4 and thi alo emerge from a comparion with F.G. 5. In the time egment 4, the intermediate veel ha to be pumped up only a few time. For example, in the time egment 1 the intermediate veel 23 ha to be connected to the preure reducer 17 ten time, in time egment 4 only five time and in time egment 5 not at all. If P, P and P are meaured in the time egment 5, it i acertained that the deired preure in the abdomen ha been reached. How much ga mut then till flow into the abdomen i determined olely by mean of the ga aborption of the patient and a poible leak. Too much ga mut not diffue into the body, where a human or animal body i concerned, becaue otherwie too much ga of thi kind pae into the blood. In the period 5, for long pell the intermediate veel 23 i no longer charged at all or charged only very lightly, that i to ay, in thi time egment, there are long period in which 47 remain cloed and 24 open. During thi time P2 i meaured tatically. Thi applie to the branch 22. Exactly the ame i true of the branch 26, but phae hifted by half the meauring cycle. The ame lope of FIG. 4 mut therefore be imagined once again a being hifted by 55 m.ec. A moothing effect with regard to the junction point 29 would thereby be obtained, and the remainder of the voltage unevenne can then be moothed by mean of the buffer veel 70. Where there are 3 branche, there are 3 lope hifted repectively by a third of a period. More than one branch caue the curve to rie according to FIG. 5, o 5,152,745 O that the deired preure i reached earlier, and thi in turn mean, according to FIG. 6, that the ga volume required i inufflated ooner. We claim: 1. An inufflator by mean of which the preure of a fluid inufflated into a human or animal body cavity can be meaured and controlled, compriing: an inlet line, firt valve device following aid inlet line, a econd valve device provided downtream of aid firt valve device, aid econd valve device following aid inlet line, a econd valve device provided downtream of aid firt valve device, aid econd valve device being a CLOSED-OPEN device having variable CLOSED-OPEN time, an intermediate veel for aid fluid provided be tween aid firt and aid econd valve device, an outlet line downtream of aid firt valve device, aid econd valve device and aid intermediate veel, conduit mean for conveying fluid between aid inlet line and aid firt valve device and between aid firt valve device and aid intermediate veel and between aid intermediate veel and aid econd valve device and between aid econd valve device and aid outlet line, logic device, a preure/voltage converter connected between aid intermediate veel and aid logic device for apply ing ignal to aid logic device correponding to falling preure in aid intermediate veel, aid logic device being compried of mean for regi tering the value of aid ignal and mean for cal culating the preure of aid fluid in aid body cav ity a a function of ignal correponding to at leat two falling preure in aid intermediate veel that occur ucceively in time, aid logic device being arranged to control aid firt valve device and aid econd valve device, and a preure indicator controlled by aid logic device for indicating the preure of aid fluid in aid body cavity. 2. An inufflator a claimed in claim 1, wherein aid firt valve device i a CLOSED-OPEN valve device. 3. An inufflator a claimed in claim 1, wherein, for holding gaeou fluid, aid intermediate veel i rigid. 4. An inufflator a claimed in claim 1, wherein aid input line lead to a branching point, at leat two branche, each of which include firt and econd valve device and an intermediate veel, are arranged parallel to one another and merge via a junction point into aid outlet line, and aid firt and econd valve device in each of aid branche are connected to aid logic device and are activatable in a manner offet in time period. 5. An inufflator a claimed in claim 4, wherein a plurality of preure/voltage converter connect aid intermediate veel in aid branche of aid logic de vice. 6. An inuffiator a claimed in claim 1, wherein aid firt valve device i a CLOSED-OPEN valve device having variable CLOSED-OPEN time. 7. An inuffiator a claimed in claim 1 or 6, wherein aid logic device i compried of mean for calculating the preure of fluid in aid body cavity a a function of ignal correponding to the fall in preure in aid inter mediate veel whereby the more filling cycle that are provided for aid intermediate veel, the greater the

9 7 difference between the actually calculated preure of aid fluid in aid body cavity and deired preure therein. 8. An inufflator a claimed in claim 1, further com priing a fluid-quantity indicator controlled by aid logic device. 9. An inufflator a claimed in claim 1, further com priing a buffer veel following aid econd valve de Vice, 5,152,745 O An inufflator a claimed in claim 1, wherein aid logic device i compried of mean for preventing open ing of aid firt and econd valve device imulta neouly. 1. An inufflator a claimed in claim 1, wherein aid intermediate veel ha a defined module of elaticity that i effective for holding incompreible fluid in the preure range ued in aid conduit mean downtream of aid firt valve device. r k