Does a smaller tract in percutaneous nephrolithotomy contribute to high renal pelvic pressure and postoperative fever?

OBJECTIVE

High renal pelvic pressure brings systemic absorption of irrigation fluid containing bacteria or endotoxins, which leads to postoperative fever. We inspected the renal pelvic pressure (RPP) in vivo during minimally invasive percutaneous nephrolithotomy (MPCNL) to investigate whether a 14- to 18-French percutaneous tract and perfusion would bring high RPP and postoperative fever.

PATIENTS AND METHODS

Between July 2005 and December 2007, 80 patients were selected for RPP measurement during MPCNL. The RPP was measured by a baroceptor connected to the open-ended ureteric catheter, which was indwelling retrogradely in the renal pelvic. A computer recorded the RPP each second, and all the data were evaluated statistically with SPSS 12.0 software.

RESULTS

During MPCNL with 14-, 16-, 18-, and double-16-French percutaneous tracts, the mean RPP was 24.55, 16.49, 11.22, and 6.64 mm Hg, respectively. Logistical analysis suggested that postoperative fever did not correlate to gender (P = 0.195), age (P = 0.641), urinary tract infection (P = 0.663), white blood cell > or = 10 x 10(9)/L in routine postoperative blood examination (P = 0.751), or an occurrence of renal pelvic pressure > or = 30 mm Hg in the operation (P = 0.662), although infection calculi (P = 0.000), percutaneous tract (P = 0.029), mean RPP (P = 0.036), mean RPP > or = 20 mm Hg (P = 0.013), accumulated time of RPP > or = 30 mm Hg (P = 0.010), and RPP > or = 30 mm Hg longer than 50 s (P = 0.024) may contribute a postoperative fever.

CONCLUSION

Renal pelvic pressure generally remains lower than the backflow level (30 mm Hg) during MPCNL via a 14- to 18-French percutaneous tract. Any factors that brought about poor drainage would result in temporarily elevated RPP greater than 30 mm Hg, and many such occurrences of high pressure would have an accumulating effect, which means enough backflow to cause bacteremia and postoperative fever.