Intramuscular dexmedetomidine for prevention of shivering after general anesthesia in patients undergoing arthroscopic anterior cruciate ligament reconstruction

Background Postanesthetic shivering (PAS) can influence hemodynamic stability and recovery from general anesthesia. We tested the efficacy of intramuscular dexmedetomidine in prevention of PAS in patients undergoing arthroscopic anterior cruciate ligament reconstruction. Materials and methods In this prospective, randomized, and double-blind controlled study, 85 ASA I male patients, aged 18–40 years, scheduled for arthroscopic anterior cruciate ligament reconstruction under general anesthesia were enrolled. Forty-five minutes before the expected end of surgery, the patients were randomized to receive an intramuscular injection in the deltoid muscle of either dexmedetomidine 2.5 µg/kg (group D, n = 43) or isotonic saline (group C, n = 42). Extubation time, the incidence and grades of shivering, pain intensity, degree of sedation, and side effects were recorded. Results The mean ± SD extubation time was prolonged in the dexmedetomidine group than in the control group (8.4 ± 2.3 vs. 7.2 ± 2.6 min, respectively; P = 0.0268). The incidence of shivering was 64.28% in the control group compared with 11.62% in the dexmedetomidine group (P ≤ 0.0001), with lower intensity in group D. Assessment of pain intensity until 2 h postoperatively revealed significantly lower scores in dexmedetomidine-treated patients (P = 0.0239 at the second hour). Sedation scores were higher in the dexmedetomidine group until 4 h postoperatively (P = 0.032 at the fourth hour). The mean heart rates and blood pressure were significantly lower in group D than in group C (P 0.05) in most of the assessments until 6 h postoperatively. Conclusion Intramuscular dexmedetomidine provides effective prophylaxis against PAS without major side effects.