Organ perfusion systems

Abstract

An organ perfusion system comprises: a perfusion fluid circuit ( 16 ) arranged to circulate perfusion fluid through the organ; a surrogate organ ( 126 ) arranged to be connected into the circuit in place of the organ so that the circuit can circulate fluid through the surrogate organ; and organ sensing means arranged to distinguish between the presence of the organ in the circuit and the presence of the surrogate organ in the circuit. The sensing means may comprise one or more pressure sensors ( 136, 137, 138 ), or a flow meter ( 125 ). Further aspects relate to adjusting the content of at least one component, such as oxygen or a nutrient, in the perfusion fluid. Bubble detection means ( 113 ), and means ( 74 ) to measure the amount of fluid secreted by or leaked from the organ, may also be provided.

1 . A perfusion system for perfusing an organ, the system comprising: a perfusion fluid circuit arranged to circulate perfusion fluid through the organ; a surrogate organ arranged to be connected into the circuit in place of the organ so that the circuit can circulate fluid through the surrogate organ; and organ sensing means arranged to distinguish between the presence of the organ in the circuit and the presence of the surrogate organ in the circuit. 
     
     
         2 . A system according to  claim 1  wherein the organ sensing means comprises at least one pressure sensor arranged to measure the pressure of the perfusion fluid at at least one point in the circuit. 
     
     
         3 . A system according to  claim 2  wherein the organ sensing means is arranged to measure the difference in pressure between two points in the circuit. 
     
     
         4 . A system according to  claim 2  or  claim 3  wherein the organ sensing means comprises one pressure sensor arranged to measure the pressure of perfusion fluid flowing towards the organ, and one pressure sensor arranged to measure the pressure of perfusion fluid flowing away from the organ. 
     
     
         5 . A system according to any foregoing claim wherein the organ sensing means comprises a flow meter arranged to measure the rate of fluid flow at at least one point in the circuit. 
     
     
         6 . A system according to any foregoing claim wherein the control means is arranged to operate in two different modes, one of which is a perfusion mode suitable for perfusion of an organ and one of which is a preparation mode suitable for preparing the system for perfusion of an organ. 
     
     
         7 . A system according to  claim 6  wherein the control means is arranged, in both of the modes, to control the content of at least one component of the perfusion fluid, but to control the fluid flow in the perfusion circuit in a different way in each of the two modes. 
     
     
         8 . A system according to any foregoing claim further comprising adjustment means for adjusting the content of at least one component in the fluid, measuring means for measuring the content of said at least one component in the perfusion fluid, and control means arranged to control the adjustment means so as to keep said measured content within a target range. 
     
     
         9 . A perfusion system for the perfusion of an organ, the system comprising a perfusion fluid circuit for circulating perfusion fluid through the organ, adjustment means for adjusting the content of at least one component in the fluid, measuring means for measuring the content of said at least one component in the perfusion fluid, and control means arranged to control the adjustment means so as to keep said measured content within a target range. 
     
     
         10 . A perfusion system according to  claim 9  wherein the at least one component is at least one of: oxygen; carbon dioxide; and a nutrient. 
     
     
         11 . A perfusion system according to  claim 8  or  claim 9  wherein the at least one component comprises oxygen, and the adjustment means comprises oxygen adding means arranged to add oxygen into the fluid. 
     
     
         12 . A perfusion system according to any of  claims 7  to  11  wherein the at least one component comprises carbon dioxide, and the adjustment means comprises carbon dioxide extraction means arranged to extract carbon dioxide from the fluid. 
     
     
         13 . A perfusion system according to any of  claims 7  to  12  wherein the at least one component is at least one of: oxygen and carbon dioxide; the system further comprising nutrient measuring means arranged to measure the content of at least one nutrient in the fluid, a nutrient supply, and nutrient adding means arranged to add the nutrient from the supply into the fluid, wherein the control means is arranged to control the nutrient adding means to add the nutrient if the content of the nutrient falls below a target range. 
     
     
         14 . A perfusion system according to any of  claims 7  to  13  further comprising a thermometer arranged to measure the temperature of the fluid, and thermal adjustment means arranged to adjust the temperature of the fluid, wherein the control means is arranged to control the thermal adjustment means to maintain the temperature of the fluid within a target range. 
     
     
         15 . A perfusion system according to any of  claims 7  to  14  further comprising an analysis duct through which the fluid can flow, wherein the measuring means is arranged to measure the fluid in the analysis duct. 
     
     
         16 . A perfusion system according to any of  claims 7  to  15  wherein the measuring means is arranged to operate during perfusion of the organ and the control means is arranged to operate during perfusion of the organ to maintain the target range or ranges. 
     
     
         17 . A perfusion system according to any of  claims 7  to  16  wherein the control means includes a memory arranged to store at least one limit of said range, or of at least one of said ranges, and the control means is arranged to compare the measured content with said at least one limit. 
     
     
         18 . A perfusion system according to any of  claims 7  to  17  further comprising a user interface arranged to enable a user to input at least one limit of said range, or of at least one of said ranges. 
     
     
         19 . A system according to any foregoing claim further comprising a bubble detection means arranged to detect bubbles in the fluid during perfusion, wherein the control means is arranged to respond to detection of bubbles by the bubble detection means. 
     
     
         20 . A perfusion system comprising a circuit for circulating perfusion fluid through the organ, control means arranged to control the flow of fluid round the perfusion circuit, and bubble detection means arranged to detect the presence of bubbles in the fluid, wherein the control means is arranged to respond to detection of bubbles by the bubble detection means. 
     
     
         21 . A system according to  claim 19  or  claim 20  wherein the control means is arranged to respond to detection of the bubbles by at least one of: producing a warning output, and reducing the fluid flow through at least one part of the circuit. 
     
     
         22 . A system according to any of  claims 19  to  21  wherein the bubble detection means is arranged also to measure the flow rate of fluid in the perfusion circuit. 
     
     
         23 . A system according to any of  claims 19  to  22  wherein the bubble detection means comprises an ultrasound transducer. 
     
     
         24 . A system according to  claim 23  wherein the bubble detection means is arranged to determine both whether bubbles are present in the fluid and the flow rate of the fluid from the timing of ultrasound transmissions and detections. 
     
     
         25 . A system according to any foregoing claim further comprising measuring means arranged to measure the amount of fluid secreted by or leaked from the organ. 
     
     
         26 . A system according to  claim 25  further comprising a sump arranged to collect the secreted or leaked fluid, wherein the measuring means is arranged to measure the volume of fluid that enters the sump. 
     
     
         27 . A system according to  claim 25  or  claim 26  which is arranged to record and display the amount of fluid that is secreted or leaked. 
     
     
         28 . A system according to any foregoing claim further comprising a support stand on which at least some of the components of at least one of the perfusion circuit, the adjustment means and the control means are mounted, and a transport system on which the support stand can be mounted, wherein the transport system includes a cover arranged to cover the support stand and the components mounted on it. 
     
     
         29 . A system according to  claim 28  wherein the transport system includes a wheeled base. 
     
     
         30 . A system according to  claim 27  or  claim 28  wherein the transport system is arranged to support the support stand in transport position, or an operative position which is raised relative to the transport position. 
     
     
         31 . A system according to any or  claims 25  to  27  wherein the measuring means comprises a fluid collection volume, sensing means arranged to detect when a predetermined volume of the fluid has collected in the collection volume, and control means arranged to remove the fluid from the collection volume when said predetermined volume is reached. 
     
     
         32 . A system according to  claim 31  wherein the control means is arranged to record each occurrence of the predetermined volume being reached thereby to record the total volume of the fluid flowing from the organ. 
     
     
         33 . A system according to  claim 32  wherein the control means is arranged to determine the time between subsequent occurrences of the predetermined volume being reached. 
     
     
         34 . A system according to  claim 33  wherein the control means is arranged to determine, from said time, a flow rate of the fluid from the organ. 
     
     
         35 . A system according to any of  claims 31  to  34  further comprising display means arranged to display information relating to the amount of the fluid that flows from the organ. 
     
     
         36 . A system according to  claim 35  wherein the display means is arranged to display a flow rate of the fluid. 
     
     
         37 . A system according to  claim 35  or  claim 36  wherein the display means is arranged to display a total volume of the fluid. 
     
     
         38 . A system according to of  claims 31  to  37  wherein the measuring means further comprises an outlet from the fluid collection volume and a valve in the outlet, wherein the control means is arranged to open the valve to remove the fluid from the collection volume. 
     
     
         39 . A system according to any of  claims 31  to  38  wherein the measuring means comprises a level sensor arranged to sense when the fluid in the collection volume reaches a predetermined level. 
     
     
         40 . A system according to any of  claims 31  to  39  wherein the measuring means comprises a pump and the control means is arranged to operate the pump to remove the fluid from the collection volume. 
     
     
         41 . A system according to any of  claims 31  to  40  comprising an inlet duct, an outlet duct and an overflow duct connected together. 
     
     
         42 . A system according to  claim 41  wherein the collection volume is defined at least partly within the inlet duct. 
     
     
         43 . A system according to  claim 41  or  claim 42  wherein the collection volume is defined at least partly within the overflow duct. 
     
     
         44 . A system according to any of  claims 41  to  43  wherein the measuring means is arranged to detect the level of the fluid in at least one of the inlet duct and the overflow duct. 
     
     
         45 . A system according to any of  claims 41  to  44  further comprising a sump wherein the outlet duct and the overflow duct are both connected to the sump. 
     
     
         46 . A system according to any of  claims 41  to  45  further comprising a connector for connecting the measuring means via a cannula to the organ. 
     
     
         47 . A method of measuring fluid flowing from an organ, the method comprising collecting the fluid in a fluid collection volume, detecting when a predetermined volume of the fluid has collected in the collection volume, and removing the fluid from the collection volume when said predetermined volume is reached. 
     
     
         48 . A method according to  claim 47  further comprising recording each occurrence of the predetermined volume being reached thereby to record the total volume of the fluid from the organ. 
     
     
         49 . A method system according to  claim 48  comprising determining the time between subsequent occurrences of the predetermined volume being reached. 
     
     
         50 . A method according to  claim 49  comprising determining, from said time, a flow rate of the fluid from the organ. 
     
     
         51 . A method according to any of  claims 47  to  50  wherein the fluid is bile, or urine, or ascites, or interstitial fluid. 
     
     
         52 . A measuring system for measuring the amount of fluid flowing from an organ, wherein the system comprises a fluid collection volume, sensing means arranged to detect when a predetermined volume of the fluid has collected in the collection volume, and control means arranged to remove the fluid from the collection volume when said predetermined volume is reached.