Effects of Ropivacaine on Postoperative Pain and Peak Expiratory Flow Rate in Patients Undergoing Percutaneous Nephrolithotomy

BACKGROUND Postoperative analgesic effects of ropivacaine have been demonstrated in various surgical procedures; however, its beneficial effect on postoperative pain relief and ability to breathe out air in urological surgeries, particularly in local interventions such as percutaneous nephrolithotomy (PCNL), has remained uncertain. OBJECTIVES The aim of this study was to assess the efficacy of ropivacaine on postoperative pain severity and peak expiratory flow (PEF) in patients undergoing PCNL procedure. PATIENTS AND METHODS This randomized double-blinded clinical trial was performed on 55 consecutive adult patients aged 15 to 60 years who underwent Tubeless PCNL surgery. The patients were randomly assigned to instill 30 mL of ropivacaine 0.2% or 30 mL of isotonic saline with the same protocol. The parameters of visual analogue scale (VAS) (for assessment of pain severity) and PEF (for assessment of ability to breathe out air) were measured 4 and 6 hours after completing the procedure. Moreover, the amounts of opioids or analgesics administered within 6 hours after the operation were recorded. RESULTS We found no difference in the mean pain severity score between the case and control groups 4 hours (P = 0.332) and 6 hours (P = 0.830) after the operation. The mean PEF at baseline was similar in case and control groups (P = 0.738). Moreover, no difference was revealed in PEF index 4 hours (P = 0.398) and 6 hours (P = 0.335) after PCNL between the groups. The mean VAS scores 4 hours after the operation slightly decreased 2 hours later (P < 0.001) in the both groups. Moreover, in the both groups, a sudden decrease in PEF index was observed within 4 hours after the operation and increased with a mild gradient for the next 2 hours. No difference was found in the amount of postoperative analgesic used in the both groups. CONCLUSIONS Instillation of ropivacaine 0.2% (30 mL) within tubeless PCNL surgery does not have a significant effect on postoperative pain relief and improvement of PEF within 6 hours after the operation.