The use of ethanol to monitor fluid absorption during transurethral resection of the prostate

Ethanol monitoring is a method for assessing fluid absorption during transurethral resection of the prostate. The method is based on the principle that absorption can be measured by expired-breath tests provided that an irrigating fluid containing ethanol 1% is used. A nomogram for transformation of the ethanol data into meaningful indices of fluid absorption, such as the volume of irrigant absorbed and the degree of hyponatraemia, has been approved for routine use within the European Union. To make a correct interpretation, however, one must learn how to distinguish the pattern of breath ethanol changes typical of absorption of fluid directly into the blood from the pattern associated with the rare intraoperative events in which fluid is deposited in a pool in the retro- or intraperitoneal space. The ethanol method is well documented, but it is still sparsely used outside Scandinavia, due to its lack of a patent and differing opinions concerning the need for measuring fluid absorption.