Continuous recording of cerebral blood flow by means of a thermal diffusion method using a Peltier stack

The thermal diffusion method is known to be effective for making quantitative measurements of blood flow, but cannot be easily applied to problems concerning quantitative changes in blood flow. Carter et al. found that the thermal diffusion technique using a Peltier stack as the probe produced extremely stable recordings and was suitable for quantitative work. We made a more stable probe containing an air space and having a stainless cap that added weight. A stable recording of blood flow was then possible. For calibration of the probe, we used blood flow values measured by means of an electrolytic technique and the equation proposed by Carter et al. In the present study, we have shown that it is theoretically possible to perform the calibration even without obtaining data on blood flow after cardiac arrest. Experimentally, the validity of such calibration was confirmed. This technique for measuring blood flow should be applicable in various fields and its use in a clinical setting, particularly in the monitoring of blood flow during neurosurgical operations, can be expected.