Effects of different administration methods of dexmedetomidine on postoperative delirium and recovery in elderly male patients undergoing laparoscopic hernia repair: a randomized, observer-blinded controlled trial

To compare the effects of different methods of administration of dexmedetomidine (Dex) on postoperative delirium (POD) and recovery in elderly male patients who underwent laparoscopic hernia repair. A total of 318 elderly male patients undergoing laparoscopic hernia repair under standardized general anesthesia from October 2023 to October 2024, who fell under the American Society of Anesthesiologists (ASA) grade I–Ⅲ and were aged 65 years or older, were selected for this study. They were divided into 3 groups according to a random number table: the intranasal administration group (DS group, 0.6 μg/kg intranasal Dex administered 10 min before the induction of anesthesia, on the evening of the operation, and in the following evening), intravenous dexmedetomidine infusion group (DV group, 0.6 μg/kg intravenous infusion administered 10 min before the induction of anesthesia, as well as the provision of an intravenous patient-controlled analgesia pump containing 1.2 μg/kg Dex), and the blank control group (DN group, intravenous infusion of an equivalent volume of normal saline 10 min before the induction of anesthesia, on the evening of the operation, and in the following evening). The primary outcome measure was the incidence of POD, which was assessed using the Confusion Assessment Method (CAM) [1] within 1–3 days after surgery. The secondary outcome measures included the Pittsburgh Sleep Quality Index (PSQI) [2], Athens Insomnia Scale (AIS) [3], Hospital Anxiety and Depression Scale-Anxiety subscale (HADS-A) [4], Visual Analog Scale (VAS) [5], and Quality of Recovery-15 (QoR-15) [6] scores at 3 days after surgery. The occurrence of adverse reactions and the incidence of chronic pain 3 months after surgery were also recorded. Compared with the DN group, the DV and DS groups exhibited a lower incidence of POD on postoperative Day 1 (6.7% vs. 10.6% vs. 25.2%, P < 0.05). No statistically significant differences were noted in the incidence of POD on postoperative Day 3 among the three groups (P > 0.05). Compared with the DN group, the DV and DS groups exhibited superior VAS, PSQI, AIS, HADS-A, and QoR-15 scores on postoperative Day 1 (all P < 0.05). Compared with the DS and DN groups, the DV group had superior QoR-15 scores on postoperative Day 1 and HADS-A scores on postoperative Day 2. No statistically significant differences were observed in the VAS, AIS, and QoR-15 scores on postoperative Day 3 or in the incidence of chronic pain at 3 months postoperatively among the three groups (all P > 0.05). No significant differences were noted in the incidence of postoperative hypotension, hypoxemia, or nausea and vomiting among the three groups (P > 0.05). However, the incidence of postoperative bradycardia was higher in the DV group than in the other two groups (19.0% vs. 3.9% vs. 7.7%, P < 0.05). Both intravenous and intranasal Dex can reduce the incidence of POD and enhance the quality of early postoperative recovery in elderly male patients undergoing laparoscopic hernia repair. The underlying mechanism may involve alleviating postoperative pain, improving sleep quality, and reducing anxiety levels. Compared with intravenous infusion, intranasal Dex is associated with a lower incidence of postoperative bradycardia. Trial registration This study was retrospectively registered at www.chictr.org.cn on February 2, 2026 (registration number: ChiCTR2600118115).