The effects of irrigation fluid on core temperature in endoscopic urological surgery

A prospective observational study of 100 patients undergoing various types of endoscopic urological surgery including transurethral resection of the prostate (TURP), transurethral resection of bladder tumour (TURBT), percutaneous nephrolithotomy (PCNL) and Cystoscopies, was reformed to determine the temperature difference between preoperative and postoperative core temperatures and to determine whether this change was related to the age, weight, type of anaesthetic, operation duration, type of operation, amount of irrigant fluid used and whether warming the fluid to 370C made a difference to the degree of temperature change. All the above variables were recorded for each patient as well as the preoperative and postoperative temperatures. Statistical analysis was carried out using SPSS.

The mean age was 64 years and the mean weight was 75kg in the study. Seventy-six patients had a general anaesthetic while 24 had a spinal anaesthetic. The study included 29 TURPs, 10 TURBTs, six PCNLs and 55 Cystoscopies. Age and type of anaesthetic did not correlate significantly with temperature change. As weight increased patients tend to preserve their core temperature more efficiently. The highest degree of temperature drop was in the PCNL group. There was a significant relationship between the duration of operation and temperature drop (p<0.05) as well as the amount of irrigation fluid used (p<0.05). Average temperature drop for patients who underwent irrigation with fluid at room temperature (n=43) was 1.37 degrees C and 0.95 degrees C for those whose fluids were warmed to body temperature (n=57). This difference was statistically significant (p=0.03).

There is a drop in temperature in patients undergoing most endoscopic operations on the GU tract and this appears to be multifactorial in origin, relating significantly to weight, amount of irrigation fluid used, type and duration of operation. Warming irrigant fluid to body temperature appears to significantly reduce the degree of temperature drop with consequent potential benefit.