Background: Intravenous oxycodone has been used as an adjunct to anesthetic agents. This study aimed to assess the optimal dose of intravenous oxycodone for the attenuation of the hemodynamic responses to laryngoscopy and endotracheal intubation.
Methods: A prospective, randomized, double-blind study was conducted. Ninety-five patients were randomly divided into 5 groups based on the oxycodone dose: 0, 0.05, 0.1, 0.15, 0.2 mg/kg. After administering the assigned dose of intravenous oxycodone, anesthesia was induced with thiopental. Heart rate (HR) and blood pressure (BP) were measured at baseline, before intubation, and 1, 2, and 3 minutes after intubation. The percentage increase of BP was calculated as (highest BP after intubation - baseline BP)/baseline BP × 100 (%). The percentage increase of HR was calculated in same formula as above. Hypertension was defined as a 15% increase of systolic BP from baseline, and probit analysis was conducted.
Results: Hemodynamic data from 86 patients were analyzed. The percentage increase of mean arterial pressure after intubation in groups 0.05, 0.1, 0.15, and 0.2 was significantly different from that in the control (P < 0.001). For HR, the percentage increase was lower than control group when oxycodone was same or more than 0.1 mg/kg (P < 0.05). Using probit analysis, the 95% effective dose (ED95) for preventing hypertension was 0.159 mg/kg (95% confidence interval [CI], 0.122-0.243). In addition, ED50 was 0.020 mg/kg (95% CI, -0.037 to 0.049). However, oxycodone was not effective for maintaining the HR in our study dosage. There were no significant differences in the incidence of hypotension during induction between groups.
Conclusions: Using 0.1 mg/kg of intravenous oxycodone is sufficient to attenuate the increase of BP and HR during induction period in healthy patients. The ED95, which was 0.159 mg/kg, can be useful to adjust the dosage of IV oxycodone for maintain stable BP during induction of general anesthesia.