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

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.