Effect of Different Administration Routes of Dexmedetomidine on Postoperative Delirium in Elderly Patients Undergoing Elective Spinal Surgery: A Prospective Randomized Double-Blinded Controlled Trial

BACKGROUND: Intravenous dexmedetomidine has been reported to decrease the occurrence of postoperative delirium (POD) in elderly patients. Nevertheless, some previous studies have indicated that intratracheal dexmedetomidine and intranasal dexmedetomidine are also effective and convenient. The current study aimed to compare the effect of different administration routes of dexmedetomidine on POD in elderly patients. METHODS: We randomly allocated 150 patients (aged 60 years or more) scheduled for spinal surgery to receive intravenous dexmedetomidine (0.6 μg/kg), intranasal dexmedetomidine (1 μg/kg) before anesthesia induction, or intratracheal dexmedetomidine (0.6 µg/kg) after anesthesia induction. The primary outcome was the frequency of delirium during the first 3 postoperative days. The secondary outcomes were the incidence of postoperative sore throat (POST) and sleep quality. Adverse events were recorded, and routine treatment was performed. RESULTS: Compared with the intranasal group, the intravenous group had a significantly lower occurrence of POD within 3 days (3 of 49 [6.1%] vs 14 of 50 [28.0%]; odds ratio [OR], 0.17; 95% confidence intervals [CIs], 0.05–0.63; P < .017). Meanwhile, patients in the intratracheal group had a lower incidence of POD than those in the intranasal group (5 of 49 [10.2%] vs 14 of 50 [28.0%]; OR, 0.29; 95% CI, 0.10–0.89; P < .017). Whereas, there was no difference between the intratracheal and intravenous groups (5 of 49 [10.2%] vs 3 of 49 [6.1%]; OR, 1.74; 95% CI, 0.40–7.73; P > .017). The rate of POST was lower in the intratracheal group than that in the other 2 groups at 2 hours after surgery (7 of 49 [14.3%] vs 12 of 49 [24.5%] vs 18 of 50 [36.0%], P < .017, respectively). Intravenous dexmedetomidine had the lowest Pittsburgh Sleep Quality Index score on the second morning after surgery (median [interquartile range {IQR}]: 4 [3–5] vs 6 [4–7] vs 6 [4–7], P < .017, respectively). Compared with the intranasal group, the intravenous group had a higher rate of bradycardia and a lower incidence of postoperative nausea and vomiting ( P < .017). The intranasal group was associated with the highest incidence of hypertension ( P < .017). CONCLUSIONS: For patients aged ≥60 years undergoing spinal surgery, compared with the intranasal route of dexmedetomidine, intravenous and intratracheal dexmedetomidine reduced the incidence of early POD. Meanwhile, intravenous dexmedetomidine was associated with better sleep quality after surgery, and intratracheal dexmedetomidine resulted in a lower incidence of POST. Adverse events were mild in all 3 administration routes of dexmedetomidine.