Measurement of ED50 of instant injection mixture of dezocine and fentanyl for preventing fentanyl-induced coughing

Abstract

Objective To investigate the efficacy and the median effective dose(ED50) of rapid infusion of dezocine and fentanyl for preventing fentanyl-induced coughing during induction of anesthesia. Methods Thirty-one patients aged from 24 to 49 years, ASA Ⅰ-Ⅱ, undergoing elective surgery through general anesthesia were enrolled. According to Dixon ’s up-and-down method, the first patient was injected with 0.050 mg/kg dezocine and 6 μg/kg fentanyl before induction of anesthesia within 2 seconds, if the patient had a cough reflex within 2 minute, the next patients would receive 1.2 times dose of previous dezocine until the cough reflex was suppressed, or otherwise reduce 1.2 times dose of previous dezocine until the patients appeared cough reflex. The time after the patients enter the operating room (T1), after mixture of dezocine and fentanyl injected 2 minutes (T2), the HR, MAP and SpO2 were monitored and recorded. Results The numbers of patients with different doses appeared cough reflex when mixtures of dezocine for preventing fentanyl cough reflex : 0.012 mg/kg for 3 patients, 0.014 mg/kg for 7 patients, 0.017 mg/kg for 3 patients, and 0.020 mg/kg and above for nobody. The ED50 of the dezocine for preventing fentanyl-induced coughing was 0.018 mg/kg (95% CI: 0.017-0.019) with Dixon’s up-and-down method. After quickly injecting mixture 2 minutes, only the HR significantly increased in the cough group (P<0.05), and there were no significant differences between and within groups. Conclusions Instant injection mixture of dezocine and fentanyl could prevent fentanyl-induced coughing and ED50 is 0.018 mg/kg (95% CI: 0.017-0.019). Key words: Dezocine; Fentanyl; Fentanyl-induced coughing; Dixon’s up-and-down; Median effective dose