The Effects of N2O on Intubation Not Using Muscle Relaxant with Propofol-Alfentanil

Abstract

Background: The combination of propofol and alfentanil for nonrelaxant intubation produces hypotension and bradycardia. , a commonly used inhaled anesthetic, has been known to augment the anesthetic depth in propofol anesthesia. Conversely,was reported to increase the incidences of opioid-induced cough and rigidity. This study was designed to evaluate the effect of additionalon propofol requirement and intubating conditions. Methods: Eighty healthy premedicated female patients were divided intogroup (n = 40) and non- group (n = 40). In each group, they were randomly assigned to four subgroups according to the propofol dose (1.0-2.5 mg/kg). With or without(= 0.5), propofol and 30/kg of alfentanil were administered during the induction of anesthesia. Expired concentrations ofwere measured. Intubation was the attempted and intubating condition was scored (0-6). Incidences of cough and rigidity were also recorded. Dose of propofol for smooth intubation (score ＞ 5) was analyzed and compared between groups. The conditions for smooth intubation were analyzed with variables (expired concentration of , dose of propofol, age, incidences of hypotension, bradycardia, cough and rigidity) by logistic regression. Results: The expired concentration ofwas 33.0 3.8%. Propofol ED50 for smooth intubation was 1.67 mg/kg (1.26-2.19) in thegroup and 2.27 mg/kg (1.78-3.47) in the non- group. A smooth intubating condition was correlated well with increased concentrations ofand doses of propofol and inversely correlated with incidences of cough and rigidity. However, we failed to prove a significant difference in incidences of hypotension, bradycardia, cough and rigidity between the two groups. Conclusions: We cannot reduce the propofol requirement for smooth intubation without relaxant by using . The success rate of intubation was increased by additional .