Abstract: The present disclosure provides a method and apparatus for measuring or monitoring oxygenator blood volume of a treatment device such as an oxygenator by analyzing an indicator passing through the oxygenator blood volume. Measuring the oxygenator blood volume can be done externally of the vein or artery, or in tubing leading to a blood treatment system which carries the blood exterior of the body of the patient or within the body of the patient. The present system can also monitor tubing volume of flowing blood upstream or downstream of the blood treatment device. The present system thus provides for measuring the volume of an extracorporeal circuit and creates an opportunity to control circuit performance and give an early warning of clotting to improve the quality of a variety of extracorporeal procedures with the use of relatively simple technology.

Abstract: A system and method for measuring fluid flow and pressure in a flexible conduit is disclosed. An embodiment of the system and method uses an ultrasound sensor for determining volume of flow and a tonometric system for determining pressure along a common length of a flexible conduit.

Abstract: A method facilitating the measurement of hemodynamic parameters by injection of an indicator in an indicator dilution technique using an extracorporeal circuit connected to a patient, includes reducing a pressure spike associated with the introduction of the indicator into the extracorporeal circuit. The method diverts blood flow during an indicator introduction and then returns the diverted blood back into the extracorporeal circuit after the introduction is completed.

Abstract: A method and various devices are disclosed that facilitates the measurement of hemodynamic parameters by injection of an indicator in an indicator dilution technique using an extracorporeal circuit connected to a patient. Specifically, the invention deals with problems caused by the spike in pressure in an extracorporeal line that result from the injection of a bolus. The method and various devices provide for diversion of blood during an indictor injection process and then return of the diverted blood back into the system after the injection is completed. The variations of the invention use diversion lines, accommodating cases and other devices that are designed to accumulate blood displaced during injection and then returning the blood to the extracorporeal circuit after injection.

Abstract: A sensor probe provides a pair of unique signal paths through a test material, wherein one configuration of the probe provides identical external portions of the signal paths such that a selected parameter of a measuring signal passing along at least two of the unique signal paths is measured. From these measurements, a method is provided for calculating at least one parameter of the test material, wherein the parameter can include an intrinsic parameter as well as a condition of state.

Abstract: A catheter for retrograde orientation in a blood flow is used to determine the blood flow rate by thermodilution measurements. The determination of the blood flow rate accommodates injectate induced thermal influences on a dilution thermal sensor, wherein the thermal influences can occur prior to introduction of the injectate into the blood flow.

Abstract: A method for determining cardiac output in conjunction with flow through an extracorporeal circuit, wherein flow through an arterial line of the extracorporeal circuit is temporarily reversed and an indicator is passed through the cardiopulmonary circuit. A dilution curve is measured in the arterial line of the extracorporeal circuit during the reversed flow, and cardiac output is determined corresponding to the measured dilution curve.

Abstract: A catheter for retrograde orientation in a blood flow is used to determine the blood flow rate by thermodilution measurements. The determination of the blood flow rate accommodates injectate induced thermal influences on a dilution thermal sensor, wherein the thermal influences can occur prior to introduction of the injectate into the blood flow.

Abstract: An apparatus is provided for determining a calibration coefficient of a blood property sensor located in a blood system, wherein the blood system can include a vascular portion and an extracorporeal portion. The blood property sensor can be located in the extracorporeal portion to measure the change in a blood property corresponding to the passing of an indicator. The indicator can include a known amount of an introduced dilution indicator. The controller is provided for determining the calibration coefficient of the blood property sensor corresponding to the introduced dilution indicator in the measured change in the blood property.

Abstract: The measurement of blood flow in a dialysis shunt is obtained by injection of an indicator material into a venous line leading from dialysis equipment to the shunt. The blood flow in an arterial line leading from the shunt at a location downstream of the venous line to the dialysis equipment is monitored by an arterial line sensor for the presence of the indicator material. A detector connected to the sensor provides a dilution curve in response to the presence of the indicator material and the blood flow in the shunt is calculated from the area under the dilution curve. The locations of the arterial and venous lines in the shunt can be reversed to obtain a measurement of blood recirculation from the venous line into the arterial line.

Abstract: A method is provided for employing a transit time ultrasound sensor, wherein the sensor can be used for the measurement of liquid flow in a conduit, the sensor having an acoustic path formed of materials matched in ultrasound properties to a flow under test, and designed to conform to the shape of the conduit. The transit time ultrasound sensor can be configured as a clamp on device, wherein the conduit walls are constructed from such an ultrasonically-matched material. Alternately, the transit time ultrasound sensor can be employed in a perivascular configuration, wherein the ultrasonically-matched material is operably intermediate the blood vessel and the sensor.

Abstract: A method for determining cardiac output in conjunction with flow through an extracorporeal circuit, wherein flow through an arterial line of the extracorporeal circuit is temporarily reversed and an indicator is passed through the cardiopulmonary circuit. A dilution curve is measured in the arterial line of the extracorporeal circuit during the reversed flow, and cardiac output is determined corresponding to the measured dilution curve.

Abstract: The measurement of blood flow in a dialysis shunt is obtained by injection of an indicator material into a venous line leading from dialysis equipment to the shunt. The blood flow in an arterial line leading from the shunt at a location downstream of the venous line to the dialysis equipment is monitored by an arterial line sensor for the presence of the indicator material. A detector connected to the sensor provides a dilution curve in response to the presence of the indicator material and the blood flow in the shunt is calculated from the area under the dilution curve. The locations of the arterial and venous lines in the shunt can be reversed to obtain a measurement of blood recirculation from the venous line into the arterial line.

Abstract: A method and apparatus for determining an initial flow rate in a conduit is disclosed. A known change is made to the flow to be measured, resulting changes (or values corresponding to these changes), or relative changes in the flow to be measured are monitored and the initial flow in the conduit is calculated from the value of the known change and monitored changes. Devices to practice the method include catheters having one or two sensors and one or two sites for introducing the volume change.

Abstract: A method and apparatus for determining cardiac output in conjunction with flow through an extracorporeal circuit, wherein flow through an arterial line of the extracorporeal circuit is temporarily reversed and an indicator is passed through the cardiopulmonary circuit. A dilution curve is measured in the arterial line of the extracorporeal circuit during the reversed flow, and cardiac output is determined corresponding to the measured dilution curve.

Abstract: A transit time ultrasound sensor is employed for the measurement of liquid flow in a conduit, the sensor having an acoustic path formed of materials matched in ultrasound properties to the flow under test, and designed to conform to the shape of the conduit. The sensor can be configured as a clamp on device, wherein the conduit walls are constructed from such an ultrasonically-matched material. Alternately, in a perivascular configuration, the ultrasonically-matched material is operably intermediate the blood vessel and the sensor.

Abstract: A method and apparatus for determining an initial flow rate in a conduit is disclosed. A known change is made to the flow to be measured, resulting changes (or values corresponding to these changes), or relative changes in the flow to be measured are monitored and the initial flow in the conduit is calculated from the value of the known change and monitored changes. Devices to practice the method include catheters having one or two sensors and one or two sites for introducing the volume change.

Abstract: A method and apparatus for determining an initial flow rate in a conduit is disclosed. A known change is made to the flow to be measured, resulting changes (or values corresponding to these changes), or relative changes in the flow to be measured are monitored and the initial flow in the conduit is calculated from the value of the known change and monitored changes. Devices to practice the method include catheters having one or two sensors and one or two sites for introducing the volume change.

Abstract: A transit time ultrasound sensor is employed for the measurement of liquid flow in a conduit, the sensor having an acoustic path formed of materials matched in ultrasound properties to the flow under test, and designed to conform to the shape of the conduit. The sensor can be configured as a clamp on device, wherein the conduit walls are constructed from such an ultrasonically-matched material. Alternately, in a perivascular configuration, the ultrasonically-matched material is operably intermediate the blood vessel and the sensor.