Optimal dose of dexmedetomidine for prevention of shivering in percutaneous nephrolithotomy

Objective To study the optimal dose of dexmedetomidine for prevention and treatment of perioperative shivering in percutaneous nephrolithotomy. Methods One hundred and twenty patients who underwent selective percutaneous nephrolithotomy with spinal anesthesia in Dongguan Hospital Affiliated to Jinan University and the First Affiliated Hospital of Jinan University from November 2016 to November 2017 were randomly divided into four groups, with 30 cases in each group. Patients in D1, D2 and D3 groups received dexmedetomidine at loading doses of 0.5μg/kg, 0.75μg/kg, 1.0μg/kg respectively after anesthesia, and the infusion time was 15 min. Then continuous pump injections were given at speed of 0.4μg/(kg·h) until the end of surgery. While, 0.9% sodium chloride injection was given to the control group. Vital signs, shivering classification, Ramsay score, volume of irrigant and perioperative adverse reactions were recorded. Results Eleven patients experienced grade 4 shivering in group N, and 8 patients experienced grade 3 shivering in group D1. The incidence of shivering in group D2 and group D3 was 6.7% and 3.3%, respectively, which was significantly lower than that in group D1 (36.7%) and group N (26.7%)(P< 0.05, respectively). However, there was no significant difference between D2 and D3 groups (P> 0.05). Five patients in group D2 and 6 patients in group D3 had bradycardia(HR< 60 beats/min), and 0.3-0.5 mg atropine was administered. Five patients had dry mouth in the D3 group. The patients who had shivering in group N and group D1 received intravenous administration of tramadol 50-100 mg, and they had varying degrees of nausea and vomiting, then 5 mg of intravenous ondansetron was given; No nausea and vomiting, bradycardia, respiratory depression was occurred in other patients in each group at all time points. Conclusion Dexmedetomidine can effectively prevent intraoperative shivering in patients undergoing percutaneous nephrolithotomy with the optimal dose of 0.75μg/kg. It can not only reduce the incidence and severity of shivering, but relieve anxiety and improve patient comfort at the same time, without adverse drug reactions and significant impact on ventilation in the prone position.