초록 ▼

Heat is removed from the blood flow by heat exchange rather than cold-liquid injection; resulting temperature changes are monitored. Flow rate is found from monitored temperature and known parameters related to the amount of heat removed. Preferably heat is removed by pumping cold liquid into a seal

Heat is removed from the blood flow by heat exchange rather than cold-liquid injection; resulting temperature changes are monitored. Flow rate is found from monitored temperature and known parameters related to the amount of heat removed. Preferably heat is removed by pumping cold liquid into a sealed balloon or sheath along a catheter, which is in the blood stream. The balloon acts as a heat exchanger; its design optimizes that function. Temperature can be monitored by a thermistor or other sensor closer to the tip of the same catheter. Alternatively it appears possible to use blood-temperature measurements taken just outside the balloon, or even within the balloon, if the system is calibrated to account for the relation between the blood flow rate and the heat lost from balloon to blood. Heat removal can be either quasi steady-state or cyclical: that is, either heat is removed semicontinuously by a low-temperature-differential exposure and resulting steady-state temperatures observed semicontinuously; or heat is removed periodically in brief high-differential exposures, and temperature changes tracked in defined time periods during or after each exposure. In the latter case, a patient\s heat balance can be maintained by alternately adding heat in protracted low-differential exposures.

대표청구항 ▼

A process for determining flow rate of blood along a flow path in a living body, comprising the steps of: a. removing heat from such blood flowing through such body, by heat exchange at a position along such flow path, without liquid injection into such blood; b. monitoring temperature; c. determini

A process for determining flow rate of blood along a flow path in a living body, comprising the steps of: a. removing heat from such blood flowing through such body, by heat exchange at a position along such flow path, without liquid injection into such blood; b. monitoring temperature; c. determining flow rate from the monitored temperature and known parameters related to the amount of heat removed; d. periodic repetition of steps a-c; e. between each pair of successive periodic repetitions, adding heat to such flow of blood; whereby a balance of heat flow to and from such body is at least roughly preserved and temperature modulation of such blood flow is increased.