Patent GB-1284826-A (GB)
Title: Apparatus for use in carrying out peritoneal dialysis
IPC: A61M1/28
Filed: 1970-05-27
Abstract: 1284826 Peritoneal dialysis apparatus LKB MEDICAL AB 27 May 1970 [4 June 1969] 25584/70 Heading A5R [Also in Division F1] A peritoneal dialysis apparatus comprises two identical vessels M1, M2 each having a liquid level detector D1, D3 respectively for determining when it is empty and a detector D2, D4 respectively for determining when it is is full of dialysis fluid, and a programmed control unit S responsive to the detector outputs to control air valves V7 and V8 by means of which either upper outlet 2, 4 of vessels M1, M2 respectively may communicate with a vacuum source, such as the suction side of an air pump P, for drawing liquid into one vessel whilst the other vessel communicates with a source of pressurised air, such as the pressure side of the pump P, for forcing liquid from said other vessel, moisture traps 11, 12 and filters 13, 14 preferably being provided, the unit S also controlling fluid valves V1-V6 by means of which either lower outlet 1, 3 of vessels M1, M2 respectively may communicate selectively with a conduit L1 for connection to a source of dialysis fluid, or a conduit L3 for connection to a patient, or to a discharge conduit L2. During a fill-phase liquid is sucked from conduit L1 into one of vessels Ml or M2 whilst being discharged from vessel M2 or M1 respectively into the patient via conduit L3, and then liquid is sucked into vessel M2 or M1 respectively whilst being discharged to the patient from vessel Ml or M2 respectively and so on until a reversible counter R1 connected to detectors D2, D4 reaches a predetermined count. The fill-phase is followed by a dialysis phase, of duration adjustably determined by a timer Tl, which is followed by a drain-phase during which liquid is sucked from conduit L3 alternately into one vessel then the other whilst being discharged into conduit L2 alternately from said other vessel and then said one vessel, counter R1 counting backwards. The drain-phase terminates either after a timer T2 times-out or when counter R1 reaches zero, whichever takes the longer, so that at least as much liquid is withdrawn from the patient as is introduced. A reversible counter R2 connected to detectors D2, D4 may be connected to an indicator J2 to show the instantaneous liquid balance during the completed portion of a dialysis treatment, i.e. the difference between the volumes of liquid introduced and withdrawn from the patient, and is connected via a gate G to a store ST after each dialysis cycle during the treatment. The magnitude of the liquid balance in the store ST may be displayed on indicator J2. The vessels M1, M2 conduits L1-L3 and connecting conduits L4-L8 therebetween are preferably arranged to be easily removed as a set after a single use, valves V1-V6 being electrically operated clamps acting on the exterior of the conduits which have resilient sections at least opposite the clamps. A portion of conduit L1 is formed by a metal tube 6 through which a controlled current may be passed to heat the dialysis liquid. In a modified apparatus, Fig. 3 (not shown), the upper outlets 4 and 2 are connected to closed resilient bellows (38) and (39) respectively during discharge of liquid from vessels M2 and M1 respectively, the exterior of the bellows being pressurised by pump P. The maximum volume of each bellows is only slightly greater than the volume of one of the vessels M1 or M2 so that air is not introduced into the patient in the event of a failure of either of the lower level detectors Dl, D3.