Effects of different administration routes of dexmedetomidine on sleep quality in patients undergoing total knee arthroplasty

Postoperative insomnia affects up to 42% of patients undergoing total knee arthroplasty. Dexmedetomidine has been widely used in perioperative anesthesia and previous reports suggested that dexmedetomidine may be associated with the improvement of sleep quality after surgery. We hypothesized that intranasal administration of dexmedetomidine could improve sleep quality compared to postoperative intravenous infusion. A total of 72 participants were allocated into three groups: an intranasal dexmedetomidine group (intervention group 1, 1 µg/kg), an intranasal normal saline group (control group), and an intravenous dexmedetomidine group (intervention group 2, 0.6 µg/kg). Primary outcomes included sleep efficiency, total sleep time, sleep latency, sleep stage distribution (N1, N2, N3, and REM), number of awakenings, and PSQI scores. Secondary outcomes included psychomotor performance, AIS scores, VAS pain scores, and postoperative adverse events. Eventually, 66 participants were included for final analysis. Within-group comparisons: At T3, both Group A and Group C showed significant improvements from T1 in PSQI scores, subscale scores, sleep efficiency, total sleep time, sleep latency, percentage of REM and non-REM sleep, and number of awakenings (P < .05). No significant correlation was found between pain VAS and AIS scores at T2 and T3 (P > .05). At T4, PVT performance significantly improved in both Groups A and C compared to T1 (P < .05). At T5, PSQI scores and subscale scores remained significantly lower than at T1 in these two groups. Between-group comparisons: At T3, Groups A and C outperformed Group B in PSQI scores, subscales, sleep efficiency, total sleep time, sleep latency, percentage of non-REM sleep, and number of awakenings (P < .05). Group A also showed significantly better outcomes than Group C (P < .05). At T4, PVT results in Groups A and C were significantly superior to those in Group B (P < .05). Adverse event rates differed: hypotension and bradycardia were more common in Group C, while dry mouth was more frequent in Group A. Dexmedetomidine effectively increases objective sleep efficiency and the proportion of deep sleep in patients with postoperative insomnia following total knee arthroplasty. It prolongs total sleep time, shortens sleep onset latency, reduces wakefulness after sleep onset, and improves sleep architecture without suppressing alertness-related behaviors. Moreover, the improvement in sleep quality is maintained at 1 month postoperatively. Compared with intravenous infusion, intranasal administration exerts a smaller impact on hemodynamic stability and results in more pronounced improvements in sleep quality. Observed symptoms of nasal dryness were generally transient and self-limiting.