Calculation of lavage volume in transurethral prostate resection (TURP)

Abstract

Evaluation of the relationship between ethanol concentration in expired air and the amount of absorbed irrigation fluid in patients who undergo a transurethral resection of the prostate. 76 patients were evaluated in a prospective study. The irrigation fluid contained 1.92 w/w% of ethanol. The ethanol concentration in breath was measured at least every 10 minutes with a Alcotest 7410 (Dräger) or a Biomed 3010 (Biotest). Documented values: breath ethanol concentration, mean arterial pressure, heart rate, haemoglobin concentration, serum sodium concentration, the amount of irrigation fluid, the time of operation, special events, therapeutic interventions. A modification of the Widmark formula was used for calculating the amount of absorbed irrigation fluid from the breath ethanol concentration. A rise of the ethanol level above 0.2/1000 was observed in 10 patients. No clinically significant difference in heart rate and blood pressure during surgery between the 24 patients with no alcohol in breath and the 10 patients with more than 0.2/1000 was observed. Prolonged duration of resection and greater amount of used irrigation fluid correlated with higher ethanol concentration in breath. During the study period no patient developed the clinical features of a transurethral resection syndrome. If 2 w/w% of ethanol is added to the irrigation fluid, breath ethanol concentration under 0.2/1000 may be considered harmless, while values above 0.2/1000 are predictors of massive absorption of irrigation fluid. In our patients, the addition of ethanol to the irrigation fluid has been a suitable and easy way to monitor the absorption of irrigation fluid, if the ethanol concentration in the breath is measured every ten minutes. If 2 w/w% of ethanol have been added to the irrigation fluid, the absorbed volume (E) can be estimated using the formula: E = 37.5 x body weight (kg) x ethanol concentration (/1000).