Clinical research of different loading doses of dexmedetomidine for preventing elderly postoperative shivering

Objective To investigate different dosage of dexmedetomidine for preventing elderly postanesthetic shivering. Methods 100 ASAⅠ~Ⅱelderly patients(60~ 80 ages)scheduled for laparotomy were enrolled in this study. According to a computer- generated list of random numbers, patients were randomly allocated to receive dexmedetomidine in the four groups: group A(0.9% normal saline),group B(dexmedetomidine 0.25μg/kg), group C(dexmedetomidine 0.5μg/kg),group D(dexmedetomidine 0.75μg/kg). The occurrence of postanesthetic shivering and adverse reactions in perioperative period and post operation were observed. Results The incidence rate shivering were 24% and 20% in group C and D,which were significantly lower than 64% in group A(χ2= 5.333,6.876,all P 0.05). Rectal temperature was no difference among four groups(F= 1.271,P> 0.05). Extubation time was shorter in group A(21.6±4.0)min than that in group D(24.4±2.8)min(F= 6.194,P< 0.05). Conclusion Our results suggest that dexmedetomidine 0.5 or 0.75 μg/kg can prevent shivering after general anesthesia effectively. But potential for delayed extubation time with dexmedetomidine was noted. The loading dose of 0.5μg/kg dexmedetomidine is recommeded to prevent elderly shivering after general anesthesia. Key words: Anesthesia, general; Shivering; Postoperative complications; Aged; Dexmedetomidine