Attenuation of cardiovascular responses to laryngoscopy and tracheal intubation with verapamil

ABSTRACT

To evaluate the efficacy of verapamil in controlling hemodynamic responses to tracheal intubation under general anesthesia. We studied eighty normotensive patients [American Society of Anesthesiologists physical status [I]] undergoing elective surgery. They were randomly assigned to two main groups. Group I included 20 patients randomly allocated into two equal subgroups [1a and 1b]. Group II were divided into three subgroups with 20 patients each [IIc, IId and IIe] to receive saline [control], verapamil 0.05 milli grams/kilogram body weight, verapamil 0.1 milligrams /kilogram body weight. Patients with anticipated difficult tracheal intubation, hypertension, renal or hepatic diseases were excluded. The drugs were administered 60 seconds before commencing laryngoscopy. Anesthesia was induced with thiopentone 5 milligrams/kilogram body weight intravenously and fentanyl 2mcmicro g/kg intravenously, vecuronium 0.15 milligrams/kilogram body weight. During anesthesia, ventilation was assisted or controlled with 1% halothane and 50% nitrous oxide in oxygen. Laryngoscopy lasting 30sec. was attempted 2 minutes after administration of thiopentone and vecuronium. Patients receiving saline exhibited significant increase in systolic, diastolic arterial pressures mean arterial pressure, and heart rate associated with tracheal intubation. The increases in mean arterial pressure and heart rate were attenuated in patients treated with verapamil. These findings suggest that bolus injection of verapamil was an effective method of controlling hypertension and tachycardia associated with intubation. This technique may be useful in hypertensive patients and it may protect them from serious complications. Further studies in hypertensive patients might be helpful