[Effects of different intraoperative lithotomy positions on the absorption of irrigation fluid during bipolar plasmakinetic resection of the prostate].

ABSTRACT

OBJECTIVE: To investigate the effect of intraoperative lithotomy position (LP) with a head-down tilt (HDT) on the absorption of intraoperative irrigation fluid in patients undergoing bipolar plasmakinetic resection of the prostate (PKRP). METHODS: Eighty BPH patients underwent PKRP, 40 in a conventional 0-degree position (0° LP) and the other 40 in a －10-degree HDT position (－10° LP), with 0.9% saline containing 1% ethanol as intraoperative irrigation fluid. We determined the alcohol concentration in the exhaled breath of the patients with a digital alcohol detector at the start of the operation and every 10 minutes afterwards. Meanwhile we recorded the operation time, the volume of intraoperative intravenous crystalloid infusion and the weight of the resected prostatic tissue, monitored the mean arterial pressure (MAP) and heart rate (HR) at 5 minutes before surgery, 30 minutes after the start of surgery and the end of surgery, and measured the concentrations of Na+, K+, Cl－ and Ca2+ with an arterial blood gas analyzer at 5 minutes before surgery and 1 hour after the start of surgery. RESULTS: There were no statistically significant differences in age, height, body weight and prostate volume, or in intraoperative MAP and HR between the 0° LP and －10° LP groups. Compared with the baseline, at 1 hour after the start of PKRP, the patients in the 0° LP group showed significantly decreased concentrations of K+ (ï¼»3.64 ± 0.29ï¼½ vs ï¼»3.49 ± 0.22ï¼½ mmol/L, P = 0.002) and Ca2+ (ï¼»1.16 ± 0.03ï¼½ vs ï¼»1.13 ± 0.04ï¼½ mmol/L, P = 0.001), increased concentration of Cl－ (ï¼»106.9 ± 2.2ï¼½ vs ï¼»108.7 ± 2.3ï¼½ mmol/L, P = 0.006), but no significant difference in the concentration of Na+ (ï¼»139.7 ± 1.5ï¼½ vs ï¼»139.4 ± 1.6ï¼½ mmol/L, P = 0.231), while those in the －10° LP group exhibited remarkably decreased concentration of Ca2+ (ï¼»1.14 ± 0.04ï¼½ vs ï¼»1.13 ± 0.04ï¼½ mmol/L, P = 0.016) but no statistically significant differences in the concentrations of Na+ (ï¼»140.3 ± 1.8ï¼½ vs ï¼»140.0 ± 2.0ï¼½ mmol/L, P = 0.156), K+ (ï¼»3.49 ± 0.36ï¼½ vs ï¼»3.47 ± 0.34ï¼½ mmol/L, P = 0.506) and Cl－ (ï¼»108.2 ± 2.6ï¼½ vs ï¼»109.1 ± 2.5ï¼½ mmol/L, P = 0.071). Over 1 500 ml of intraoperative irrigation fluid absorption was observed in 6 cases (15%) in the 0° LP group as compared with 4 cases (10%) in the －10°LP group, with no significant difference between the two groups. CONCLUSIONS: Lithotomy position with a 10-degree head-down tilt can reduce PKRP-induced decrease in the concentration of K+ and increase in that of Cl－ without affecting the levels of the other electrolytes.