[Reduction of circulatory reactions to intratracheal intubation--the effect of meptazinol].

A controlled, randomized, double blind assessment of the efficacy of meptazinol 3 mg kg-1 in reducing the circulatory responses to tracheal intubation was carried out in 20 ASA class I patients. After thiopentone 4 mg kg-1, meptazinol 3 mg kg-1 (ten patients) or saline (ten patients), and suxamethonium 1.5 mg kg-1 tracheal intubation was carried out, and the changes in pulse rate and arterial blood pressure compared between the groups and with control values. Significance was assessed at the 5% level (Student's t-test and paired t-test). Patients who received saline exhibited a rise in pulse rate, significant 1 and 2 min after intubation, and a significant rise in mean arterial pressure for 5 min after intubation. Patients who received meptazinol exhibited no significant rise in pulse rate, but a significant fall in pulse rate occurred from 5 min onwards. Mean arterial pressure rose significantly for 4 min after intubation but the rise was significantly less than that seen in the saline group. Suppression of spontaneous ventilation or movement in 50% of the group lasted for 7 min and 9 min after induction of anaesthesia in the control group and meptazinol treated group respectively. Meptazinol 3 mg kg-1 modifies the circulatory responses to tracheal intubation, preventing the tachycardia and reducing the hypertension, and causes a short delay in the onset of spontaneous respiration or movement.