No abstract

We have studied the effect of varying the timing of a prior dose of intravenous lignocaine 1.5 mg/kg on the cardiovascular and catecholamine responses to tracheal intubation. Forty healthy patients were given an intravenous injection of either placebo or lignocaine 2, 3 or 4 minutes before tracheal intubation. There was a significant increase in heart rate of 21-26% in all groups. There was no significant increase in mean arterial pressure in response to intubation in any group of patients given lignocaine before intubation, but in the placebo group, mean arterial pressure increased by 19.1% compared to baseline values (p less than 0.05).

SummaryArtcviul o\rr%en suturution in I32 putienrs IUIS meu.surrd using a Biox IV

The pressor and catecholamine responses to laryngoscopy and intubation were studied in nine patients with pregnancy-induced hypertension (PIH) and in eight normotensive controls. Five of the PIH patients had received oral labetalol as antihypertensive therapy. Mean arterial pressure (MAP) increased significantly from the pre-induction value in all groups 1 min after intubation, and also at 3 min in those with PIH who had not received labetalol. Arterial pressure was significantly greater in both PIH groups than in the control group at all times. However, the percentage increase in MAP on intubation was significantly less in the labetalol treated group than in either the untreated or the control groups. There were no significant differences between the groups in plasma concentrations of either noradrenaline or adrenaline; noradrenaline concentration increased significantly after intubation only in the control group. Labetalol appears to confer some protection against the pressor response to intubation in parturients with PIH.

No abstract