Ethanol monitoring of transurethral prostatic resection during inhaled anesthesia

The purpose of this study was to examine the precision of a method of breath-alcohol analysis used to monitor absorption of irrigating fluid during transurethral resection of the prostate performed under inhaled anesthesia. A breath-alcohol analyzer (Alcolmeter SD-2) was placed between the endotracheal tube and the Bains' circuit. The concentration of ethanol in the breath, serum sodium concentration, and volumetric fluid balance were measured at 10-min intervals during 38 operations when the irrigating fluid contained 1.5% glycine and 1% ethanol. Ethanol monitoring detected absorption rates that exceeded 14 +/- 8 mL/min (mean +/- SD). In 17 patients in whom hyponatremia developed immediately in connection with absorption, the volume of irrigating fluid absorbed (up to 1950 mL) could be predicted from a single expired-breath test with a standard error of 325 mL. When the alcohol measurements were corrected for absorption time, the standard error was 215 mL. Seven other patients received 2.2% wt/vol glycine as irrigating fluid, and ethanol (0.35 g/kg) was administered by intravenous infusion. The direct and indirect measurements of the blood-alcohol concentration agreed well. These results confirm that ethanol monitoring is a viable technique during inhaled anesthesia for transurethral resection of the prostate.