Does Continuous Intrarenal Pressure Predict Post-Ureteroscopy Sepsis? A Novel Pilot Study

Purpose: Postoperative sepsis is a known complication of ureteroscopy, but whether intrarenal pressure (IRP) is indicative of postoperative sepsis remains unclear. Pyelovenous backflow is believed to occur when pressure exceeds 30 mmHg. Despite this, IRP is not routinely monitored during ureteroscopy. The present pilot study was designed to evaluate the relationship between IRP during ureteroscopy and postoperative sepsis. Materials and Methods: Patients undergoing ureteroscopy for kidney stones ( N = 100, 34% male, M = 56 years of age) had IRP continuously measured using the COMET™ II Pressure Guidewire. Three phases of ureteroscopy were identified: baseline (30 seconds before ureteral access sheath placement), post-access sheath placement, and treatment of the kidney stone. Data were analyzed using analysis of variance, odds ratio, risk ratio, and diagnostics statistics at p < 0.05. Results: The 12 patients that developed postoperative sepsis had significantly higher median baseline ( p < 0.04) and treatment phase ( p < 0.02) pressures than non-sepsis patients. The median baseline and treatment phase IRP above 30 mmHg were associated with twice the odds and twice the risk of sepsis compared to cases below this threshold, though these results were not statistically significant. IRP above the 30 mmHg threshold conferred accuracy for 84% of cases at baseline, with relatively high specificity (0.93) and high negative predictive values (0.89), but poor sensitivity (0.17) and positive predictive values (0.25). Older age ( p < 0.03) and history of sepsis ( p < 0.02) were also associated with postoperative sepsis risk. Conclusions: The present study found that baseline IRP was a significant predictor of sepsis following ureteroscopy for nephrolithiasis. These findings suggest that continuous IRP measurement during URS might prove valuable in predicting sepsis risk and may open new avenues for sepsis research.