Frequency and causes of fluid absorption: a comparison of three techniques for resection of the prostate under continuous pressure monitoring.

Abstract

To compare in a prospective study three techniques for draining irrigation fluid during transurethral resection of the prostate (TURP) and to assess which method minimizes the risk of increased intravesical pressure and decreased plasma sodium level, as a sign of fluid absorption. The study included 90 patients with benign prostatic hyperplasia (BPH), randomized into three equal groups, who underwent TURP using different techniques for draining the irrigation fluid. Group 1 had suprapubic drainage via the Freka(R) CystTUR Standard device (Fresenius, Germany); group 2 underwent TURP with an Iglesias continuous-flow resectoscope; and group 3 had suprapubic drainage using the Korth 'flow controller' (Olympus, Germany). The intravesical pressure was monitored continuously during surgery; an 'increased' pressure was defined as being >20 cmH2O. As fluid absorption decreases the plasma sodium level during surgery, the latter was also determined and the difference before and after surgery calculated. The intravesical pressure was increased in 10% of those in group 1, 90% in group 2 and none of group 3. The differences between group 1 and 2 and between group 2 and 3 were significant (P<0.001). The differences in the decrease of plasma sodium levels in groups 1-3 were not significant, but there was a significant correlation (P=0.0075) between increased intravesical pressure and minimum levels of plasma sodium. The three techniques for draining irrigation fluid produced significant differences in 'increased' intravesical pressure. In general, the levels of plasma sodium were not significantly different among the three techniques but patients with lower plasma sodium levels tended to have an increased intravesical pressure. In these cases, fluid absorption seems to be avoidable by an appropriate drainage technique. Nevertheless, considerable fluid absorption can occur at pressures of <20 cmH2O.