Fluid Balance Monitoring System with Fluid Infusion Pump for Medical Treatment

Abstract

Novel fluid delivery systems are disclosed to improve the delivery of bio-compatible fluids to a patient. The systems can include a housing having a bladder pressurized by a pressurization unit so that fluid flow rate can be controlled, changed and/or monitored. The systems can also include a scale and/or a flow control unit.

We claim: 
     
         1 . A bio-compatible fluid delivery system for controlled delivery of fluids to a patient from an intravenous (IV) bag connected to delivery tubing comprising:
 a central controller;   a pressurizing assembly adapted and dimensioned to receive and surround all or part of the intravenous (IV) bag;   a pressurization assembly in fluid communication with the pressurizing assembly and directed by the central controller wherein the pressurization assembly provides pressurization and depressurization of the pressurizing assembly thereby exerting force on the IV bag and a fluid flow through the delivery tubing;   a pressure transducer adapted to engage the delivery tubing, wherein the pressure transducer is in electrical communication with the central controller and measures pressure before and during flow though the delivery tubing and wherein a desired fluid delivery rate is established by the central controller including using measurements from the pressure transducer and calculation of a frictional pressure drop and a wall pressure of the delivery tubing during flow; and   a flow controller adapted to engage the delivery tubing at a location downstream of the pressure transducer and to restrict flow through the delivery tubing, the flow controller in electrical communication with and controlled by the central controller.   
     
     
         2 . The system of  claim 1 , wherein the pressurization and pressurizing assemblies are adapted and dimensioned to deliver over 600 mm Hg and the delivery tubing is adapted and dimensioned to connect with an intraosseous catheter. 
     
     
         3 . The system of  claim 1 , wherein the pressurization and pressurizing assemblies are adapted and dimensioned to deliver over 900 mm Hg and the delivery tubing is adapted and dimensioned to connect with an intraosseous catheter. 
     
     
         4 . The system of  claim 1 , further comprising an additional pressure transducer that measures a driving pressure exerted on fluid in the delivery tubing in an absence of flow. 
     
     
         5 . The system of  claim 1 , further comprising an additional pressure transducer that measures a gas pressure exerted on or pressure existent within the IV. 
     
     
         6 . The system of  claim 1 , wherein the pressurizing assembly is adapted to depressurize to ambient pressure in less than 10 seconds. 
     
     
         7 . The system of  claim 1 , wherein a desired fluid delivery rate calculation comprises determining a fluid flow Q by Poiseuille's equation: 
       
         
           
             
               Q 
               = 
               
                 
                   Δ 
                    
                   
                       
                   
                    
                   P 
                    
                   
                       
                   
                    
                   π 
                    
                   
                       
                   
                    
                   
                     r 
                     4 
                   
                 
                 
                   8 
                    
                   μ 
                    
                   
                       
                   
                    
                   L 
                 
               
             
           
         
         where r is a radius of the delivery tube having a length L, 
         ΔP is the frictional pressure drop across the delivery tubing, and 
         μ is a dynamic viscosity of a fluid flowing through the delivery tubing. 
       
     
     
         8 . The system of  claim 1 , wherein a fluid delivery rate calculation comprises empirically relating the frictional pressure drop and the delivery tubing wall pressure to determine an estimation of a fluid flow. 
     
     
         9 . The system of  claim 8 , wherein a driving pressure is obtained by measurement of the delivery tubing pressure in the absence of flow. 
     
     
         10 . The system of  claim 9 , wherein the driving pressure is initially obtained by measurement of the delivery tubing pressure in the absence of flow, and during flow is recursively estimated by relating a change in driving pressure to a change in volume, found by numerical integration of a computed flow. 
     
     
         11 . A bio-compatible fluid delivery system for controlled delivery of fluids to a patient from an intravenous (IV) bag containing a bio-compatible fluid and connected to delivery tubing comprising:
 a central controller;   a pressurizing assembly surrounding the IV bag, the pressurizing assembly in fluid communication with a pressure sensor that measures a pressure P 2  of an interior of the pressurization chamber;   a pressurization assembly in fluid communication with the pressurizing assembly and directed by the central controller, wherein the pressurization assembly provides pressurization and depressurization of the pressurizing assembly thereby exerting force on the IV bag and a fluid flow through the delivery tubing;   an electric gas delivery pump directed by the central controller that delivers a pressurizing gas to the pressurizing assembly;   a pressure release assembly directed by the central controller and in fluid communication with the interior of the pressurizing assembly; and   a flow controller adapted to engage the delivery tubing and to restrict flow through the delivery tubing, the flow controller in electrical communication with and controlled by the central controller,   wherein changes in a volume of the bio-compatible fluid disposed within the IV bag are continuously estimated by computing a series of measurements of electric work of pressurization expended by the electric gas pump.   
     
     
         12 . The system of  claim 11 , wherein changes in the volume of the bio-compatible fluid are continuously estimated by initially computing the volume of the bio-compatible fluid from the series of measurements of electric work of pressurization, and then continuously computing the volume from Boyle's Law and conservation of mass between pressurization intervals. 
     
     
         13 . The system of  claim 11 , further comprising temperature sensors in the interior of the pressurization chamber wherein changes in the volume of the bio-compatible fluid are continuously estimated by initially computing the volume of the bio-compatible fluid from the series of measurements of electric work of pressurization, and then continuously computing the volume from the ideal gas law and conservation of mass between pressurization intervals. 
     
     
         14 . A bio-compatible fluid delivery system for controlled delivery of fluids to a patient from an intravenous (IV) bag connected to delivery tubing comprising:
 a central controller;   a pressurizing assembly surrounding the IV bag, the pressurizing assembly in fluid communication with a pressure sensor that measures a pressure P 2  of an interior of the pressurization chamber;   a pressurization assembly in fluid communication with the pressurizing assembly and directed by the central controller, wherein the pressurization assembly provides pressurization and depressurization of the pressurizing assembly thereby exerting force on the IV bag and a fluid flow through the delivery tubing;   a calibration chamber in fluid communication with a pressure sensor that measures a pressure P 1  in the calibration chamber;   a calibration valve connecting to an interior of the pressurizing assembly with the interior of the calibration chamber, directed by the central controller;   a pressure release assembly directed by the central controller and in fluid communication with the interior of the pressurizing assembly; and   a flow controller adapted to engage the delivery tubing and to restrict flow through the delivery tubing, the flow controller in electrical communication with and controlled by the central controller.   
     
     
         15 . The system of  claim 14 , wherein a compressible gas volume of the interior of the pressurizing assembly, V 2 , is computed according to the following equation derived from Boyle's law and mass balance: 
       
         
           
             
               
                 V 
                 2 
               
               = 
               
                 
                   - 
                   
                     
                       Δ 
                        
                       
                           
                       
                        
                       
                         P 
                         1 
                       
                     
                     
                       Δ 
                        
                       
                           
                       
                        
                       
                         P 
                         2 
                       
                     
                   
                 
                  
                 
                   V 
                   1 
                 
               
             
           
         
         wherein V 1  is a volume of the calibration chamber. 
       
     
     
         16 . The system of  claim 14 , wherein changes in a volume of a bio-compatible fluid disposed in the IV bag are determined by intermittently computing the volume of the bio-compatible fluid from mass balance with the calibration chamber, and then continuously or intermittently computing the volume from Boyle's Law and conservation of mass between calibration intervals. 
     
     
         17 . The system of  claim 14 , further comprising a temperature sensor in the calibration chamber and a temperature sensor in an interior of the pressurizing assembly wherein a calibration equation is corrected for temperature using the ideal gas law.