[Early detection of TUR(transurethral resection) syndrome--ethanol measurement in ventilated patients]

A major complication of transurethral resection of the prostate (TURP) is the excessive absorption of irrigation solution resulting in hypervolemia and dilutional hyponatremia. Marking the irrigation fluid with ethanol is a method for the early detection of fluid absorption. Currently this method is being used in spontaneously breathing patients undergoing regional anaesthesia. The goal of this study was to determine whether this method is also reliable for patients undergoing general anaesthesia. Fifty-nine patients underwent TURP in either spinal anaesthesia (SPA), or general anaesthesia with semi-open (ITNO) and semi-closed (ITNC) systems. Plasma alcohol concentrations ([Eth]p), exhaled ethanol ([Eth]e), plasma sodium concentration ([Na+]), and central venous pressure (CVP) were measured. The irrigation fluid contained ethanol in an concentration of approx. 1%. We assumed that significant fluid absorption took place when [Eth]p exceeded 0.1/1000. Measurements were performed immediately prior to and during surgery at 10-minute intervals. [Eth]p correlated directly with [Eth]e for both forms of anaesthesia. [Eth]p and [Na+] correlated inversely both for SPA and ITNC. Changes in [Eth]p did not parallel changes in CVP. Clinically relevant episodes of fluid absorption were accompanied by the detection of exhaled ethanol in all groups. We conclude that measuring exhaled ethanol is a minimal invasive monitoring technique that allows the detection of significant fluid absorption in both spontaneously breathing as well as ventilated patients with sufficient sensitivity. The ethanol levels are not predictive of the sodium concentration both in SPA and general anaesthesia. Thus, additional determinations of [Na+] is recommended whenever [Eth]e exceeds 0.2/1000.