Intravenous regional anaesthesia of the arm. Effect of the technique of exsanguination on the quality of anaesthesia and prilocaine plasma concentrations.

The effects of different techniques of exsanguination of the upper arm during intravenous regional anaesthesia on prilocaine plasma concentrations, quality of anaesthesia, toxic symptoms after deflation of the tourniquet and injection pressure of the anaesthetic were studied in 10 healthy male volunteers. The nondominant arm was exsanguinated using either Esmarch's bandage or elevation of the arm for 2 minutes plus arterial occlusion by compression of the brachial artery. The injection pressure after the prilocaine dose (3 mg/kg) was significantly higher in the elevation group (maximally 98 mmHg). There were no statistically significant differences in the onset of, or recovery from, anaesthesia between the groups. Various mild toxic symptoms were experienced in the central nervous system after deflation of the tourniquet. However, there was no correlation between the two techniques and the degree of severity of the toxic symptoms. The highest single venous plasma concentration (total) of prilocaine was 2.3 micrograms/ml measured from the contralateral cubital vein (elevation group, 2 minutes). The differences in prilocaine concentrations between the groups were not statistically significant.