Objective To investigate the effect of esketamine combined with sufentanil for postoperative patient-controlled intravenous analgesia (PCIA) on rebound pain after single nerve block.

Methods From January 2021 to December 2022, 80 patients undergoing upper limb fracture surgery in Jinshan Hospital, Fudan University with single nerve block anesthesia were included and randomly divided into two groups: the Ket group (esketamine combined with sufentanil PCIA) and the Ctrl group (sufentanil PCIA), with 40 patients in each group. Several indicators were recorded, including pain scores at 8 h, 12 h, 24 h, and 48 h postoperatively, the time to first pain and its score, pain scores 30 min after pressing the PCIA pump self-control button, as well as opioid consumption at 24 h and 48 h postoperatively, and the number of PCIA button presses. Rebound pain was defined as a sudden transition from “no pain” to “severe pain” (NRS≥7) requiring pressing the PCIA self-control button.

Results Rebound pain occurred in 17 (45.95%) patients in the Ctrl group and 12 (36.36%) patients in the Ket group, with no statistically significant difference. The Ket group had significantly lower sufentanil consumption and fewer PCIA presses at 24 h postoperatively compared to the Ctrl group (P=0.007). At 48 h postoperatively, there was no significant difference in sufentanil consumption and PCIA presses among patients who experienced rebound pain in the two groups. At 30 min after pressing the PCIA button for breakthrough pain, 12 patients (100.00%) in the Ket group had NRS＜4, compared to 3 patients (17.65%) in the Ctrl group, with a statistically significant difference (P=0.02).

Conclusions Compared with using sufentanil alone for PCIA, the combination of esketamine and sufentanil does not reduce the incidence of rebound pain following single nerve block in upper limb fracture surgery. However, the combination of esketamine and sufentanil may provide a faster relief of rebound pain.