Postischaemic hyperaemia studied with a transcutaneous oxygen electrode used at 33-37 degrees C

The hyperaemic response in the vasculature of the forearm skin following induced ischaemia was studied with a transcutaneous oxygen (tcpO2) electrode. Electrode temperatures of 35-37 degree C allowed optimal recordings of the postischaemic reaction. During arterial occlusion there was a fall in tcpO2 to zero in 1-3 min. Re-establishment of circulation resulted in a biphasic reaction, with a steep rise overshooting the baseline recording by 1-3 kPa and a slower return to baseline level. At higher electrode temperatures (greater than 39 degree C) there was no overshoot due to hyperaemia. The postischaemic peak response was well reproducible from one occasion to another in the same subject. Simultaneous recording of energy consumption for the heating of the electrode permitted detection of artifacts and environmental changes unrelated to postischaemic hyperaemia, therefore validating the tcpO2 recordings but only at electrode temperatures greater than 35 degree C. The tcpO2 technique used at 35-37 degree C easily detects relative blood flow changes and seems suitable for comparative studies. The method is non-invasive and permits continuous recordings in well-defined skin areas in human subject; significant advantages compared with other methods available.