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Effects of nilvadipine on the cardiovascular responses to tracheal intubation
K Mikawa1, N Maekawa, M Hasegawa
1Department of Anesthesiology, Kobe University School of Medicine, Japan.
Study Objective:
To evaluate the efficacy of nilvadipine given orally in attenuating the hypertensive response to laryngoscopy and intubation.
Design:
Controlled, randomized, double-blind study.
Setting:
Induction of anesthesia for elective surgery at a university hospital.
Patients:
Thirty normotensive patients (ASA physical status I) undergoing elective surgery were divided into three groups of ten patients each.
Interventions:
Either 2 mg of nilvadipine, 4 mg of nilvadipine, or a placebo (control) was administered orally 90 minutes before induction of anesthesia. Anesthesia was induced with thiopental sodium 5 mg/kg intravenously, and tracheal intubation was facilitated with vecuronium 0.2 mg/kg. During anesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide (N2O) in oxygen. Laryngoscopy lasting 30 seconds was attempted 2 minutes after administration of thiopental sodium and vecuronium.
Measurements And Main Results:
Patients receiving the placebo showed a significant increase in mean arterial pressure (MAP) and heart rate associated with tracheal intubation. The increase in MAP following tracheal intubation was significantly lower in nilvadipine-treated patients than in the control group (p less than 0.05). However, neither dose of nilvadipine attenuated the tachycardic response to intubation.
Conclusions:
Oral administration of nilvadipine before induction of anesthesia is a simple and practical method for attenuating pressor response to laryngoscopy and tracheal intubation after standard elective induction under additional 1% enflurane-N2O anesthesia.