The effect of nephrostomy tract infiltration of ketamine on postoperative pain and peak expiratory flow rate in patients undergoing tubeless percutaneous nephrolithotomy: a prospective randomized clinical trial

Ketamine, as a systemic and local analgesic, has been used to reduce postoperative pain in many studies. The present study was designed to assess the analgesic efficacy of nephrostomy tract infiltration of ketamine in postoperative pain after tubeless percutaneous nephrolithotomy (PCNL). Sixty-six patients with renal stone who were candidates for PCNL were randomized to two groups with 33 patients in each group. In group K, 20 mL saline solution containing 1.5 mg/kg ketamine was infiltrated into the nephrostomy tract and in group C, 20 mL saline solution was infiltrated into the nephrostomy tract at the end of surgery. The postoperative pain scores, sedation scores, time to first rescue analgesia, rescue analgesic requirement, peak expiratory flow rate (PEF), and hemodynamic parameters were compared between two groups. Sixty-six patients with a mean age of 45.29 ± 15 years and an age range of 18–60 years participated in this study. There was no significant difference in the demographic data and duration of surgery between the two groups. The mean VAS scores were significantly lower in the intervention group compared with the control group at the recovery, and 4 and 6 h postoperatively (p = 0.001). The mean time to first rescue analgesia in the postoperative period was significantly lower in the control group (64.5 ± 8.1 min) compared with the intervention group (122 ± 18.4 min). The trend of first opioid administration was significantly lower in the ketamine group p < 0.009. There was no significant differences in PEF between the two groups in the postoperative period (p = 0.622). In conclusion infiltration of ketamine into the nephrostomy tract provides superior analgesic and sedative effects in PCNL surgery without significant changes in PEF.