IMPORTANCE Perioperative respiratory adverse events (PRAEs) are the most common complication during pediatric anesthesia, and they may be affected by the administration of preoperative sedatives. OBJECTIVE To investigate the effect of intranasal dexmedetomidine or midazolam used for premedication on the occurrence of PRAEs.

Background Patients often suffer moderate or even severe pain after total hip arthroplasty; such pain seriously affects early postoperative recovery. This study aimed to investigate the analgesic efficacy of ultrasound-guided transmuscular quadratus lumborum block combined with fascia iliaca compartment block for elderly patients undergoing total hip arthroplasty. Methods Fifty-four patients scheduled for total hip arthroplasty were included in this randomized controlled study. The patients were randomly assigned to receive only transmuscular quadratus lumborum block (group Q) or transmuscular quadratus lumborum block combined with fascia iliaca compartment block (group QF) with ultrasound guidance. Postoperatively in both groups, paracetamol 1 g was regularly administered at 6 h intervals and patient-controlled intravenous analgesia was administered. The primary outcome was cumulative sufentanil consumption via patient-controlled intravenous analgesia 24 h postoperatively. The secondary outcomes included pain degree, time to the first analgesic requirement, joint range of motion, quality of recovery, and the incidence of postoperative complications. Results Fifty patients were included, and their data were analyzed. The cumulative sufentanil consumption in group QF was significantly lower during the first 24 h after surgery than that in group Q, and the cumulative sufentanil consumption in group QF was reduced at 6–12 and 12–18 h after surgery. The postoperative pain intensity was lower in group QF than in group Q (linear mixed-effects model, the main effect of treatment: P < 0.001). Compared with group Q, group QF had higher quality of recovery and joint range of movement. The time to the first analgesic requirement was longer in group QF than in group Q (log-rank, P < 0.001). There was no statistically significant difference in complications postoperatively between the two groups. Conclusions Our study provides a multimodal, opioid-sparing analgesic regimen for elderly patients undergoing total hip arthroplasty. The combination of transmuscular quadratus lumborum block and fascia iliaca compartment block provides a significant advantage for early postoperative functional recovery. Further studies are required to confirm the minimum effective dose. Trial registration The study was registered on the 21st December 2020 (retrospectively registered) on the Chinese Clinical Trial Registry: ChiCTR2000038686.