The effects of low-dose ephedrine on intubating conditions following low-dose priming with cisatracurium

Abstract

Study objective: To determine whether low-dose ephedrine plus priming with low-dose cisatracurium improves intubating conditions.

Design: Prospective, randomized, double-blinded study.

Setting: Operating room.

Patients: 124 ASA physical status I and II patients scheduled for elective surgery.

Interventions: Patients were randomly assigned to 4 groups (n = 31): Group PE (priming + ephedrine), Group P (priming), Group E (ephedrine), and Group NPE (no priming, no ephedrine). All patients were induced with propofol two mg/kg and sulfentanil 0.15 μg/kg. In the priming groups, 0.005 mg/kg (10% ED(95)) cisatracurium was given, followed three minutes later by 0.145 mg/kg of cisatracurium. In Groups E and NPE, a single dose of 0.15 mg/kg cisatracurium was given. Intravenous ephedrine 70 μg/kg was given in Groups PE and E. Tracheal intubation was attempted 60 seconds after the intubating dose of cisatracurium and was considered successful only if performed within 20 seconds.

Measurements: Intubating conditions were graded. Heart rate and non-invasive blood pressure, at one-minute intervals, were recorded during and 5 minutes after induction.

Main results: The tracheas of all patients in Group PE were successfully intubated within 20 seconds versus 74% in Group P, 77% in Group E, and 64% in Group NPE (P < 0.001 vs. Group PE). Intubating conditions were graded good to excellent in all PE patients, but in only 52% of Groups P and E, and 48% of NPE patients (P < 0.001). Hemodynamic variables were comparable among groups (P = ns).

Conclusions: Low-dose ephedrine plus priming with low-dose cisatracurium before an intubating dose, significantly improved clinical intubating conditions at 60 seconds.