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Thirty women with pregnancy-induced hypertension (PIH) scheduled for Caesarean section under general anaesthesia were studied to evaluate the efficacy of sublingual nifedipine in attenuating the pressor response to laryngoscopy and tracheal intubation. The patients were randomly given either the contents of a nifedipine capsule 10 mg or placebo sublingually 20 min before induction of anaesthesia. Blood pressure and heart rate were recorded at various time intervals. There was a decrease in mean arterial blood pressure (MAP) after pretreatment with nifedipine (P < 0.01). The increase in MAP during laryngoscopy and intubation was higher in the control group compared with nifedipine pretreatment group (P < 0.01). During laryngoscopy and intubation, MAP decreased by 3 mmHg in the nifedipine pretreatment group, while there was an increase of 14 mmHg in the control group. Heart rate increased in both the groups during the laryngoscopy and tracheal intubation (P < 0.01) but the increase was higher in the nifedipine group than in the control group (P < 0.05). Neonatal Apgar scores in both the groups were comparable. These results suggest that sublingual nifedipine is effective in attenuating the hypertensive response to laryngoscopy and intubation but not the tachycardiac response in parturients with PIH.

The efficacy of sublingual nifedipine in attenuating the pressor responses to laryngoscopy and intubation was studied in 40 patients undergoing elective surgery. Anaesthesia was induced with thiopentone 5.5 mg kg-1 i.v. and tracheal intubation was facilitated with suxamethonium 1.5 mg kg-1 i.v. Patients were allocated randomly to receive sublingual nifedipine 10 mg or placebo capsules 10 min before induction. Patients receiving placebo capsule showed significant increases in heart rate and arterial pressure associated with tracheal intubation (P less than 0.001). The increases in arterial pressure and rate-pressure product were reduced in nifedipine treated patients (P less than 0.001). Heart rate increased significantly in both groups immediately after intubation.

Forty healthy patients (ASA class 1) of both sexes, aged between 20 and 45 years, undergoing routine surgical procedures were included in this double-blind randomized study. They were divided into two groups of 20 each. Patients in group A received no pretreatment, while patients in group B received oral clonidine 5 micrograms kg-1 90 min before induction of anesthesia. All patients received thiopentone (5 mgs kg-1) followed by suxamethonium (1.5 mgs kg-1) to facilitate endotracheal intubation. Control patients showed a significant increase in heart rate and blood pressure; they were significantly lower in the clonidine treated group immediately after intubation (p less than 0.001). The data suggest that the rise in heart rate and blood pressure associated with laryngoscopy and intubation during a routine induction sequence can be attenuated by the use of oral clonidine.

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: Tracheal intubation in children can be achieved by deep inhalational anaesthesia or an intravenous anaesthetic and a muscle relaxant, suxamethonium being widely used despite several side-effects. Studies have shown that oral intubation can be facilitated safely and effectively in children after induction of anaesthesia with propofol and alfentanil without a muscle relaxant. Remifentanil is a new, ultra-short acting, selective mu-receptor agonist that is 20–30 times more potent than alfentanil. This clinical study was designed to assess whether combination of propofol and remifentanil could be used without a muscle relaxant to facilitate tracheal intubation in children. : Forty children (5–10 years) admitted for adenotonsillectomy were randomly allocated to one of two groups to receive remifentanil 2 μg·kg−1 (Gp I) or remifentanil 3 μg·kg−1 (Gp II) before the induction of anaesthesia with i.v. propofol 3 mg·kg−1. No neuromuscular blocking agent was administered. Intubating conditions were assessed using a four-point scoring system based on ease of laryngoscopy, jaw relaxation, position of vocal cords, degree of coughing and limb movement. Mean arterial pressure (MAP) and heart rate (HR) measured noninvasively before induction of anaesthesia to 5 min after intubation (seven time points). : Tracheal intubation was successful in all patients without requiring neuromuscular blocking agent. Intubating conditions were clinically acceptable in 10 of 20 patients (50%) in Gp I compared with 18 of 20 patients (90%) in Gp II ( P < 0.05). MAP and HR decreased in both groups after induction of anaesthesia ( P < 0.01). Both HR and MAP were significantly lower in Gp II compared with Gp I after tracheal intubation ( P < 0.01). No patient in the present study developed bradycardia or hypotension. : We conclude that remifentanil (3 μg·kg−1), administered before propofol (3 mg·kg−1) provides acceptable tracheal intubating conditions in children, and completely inhibited the increase in HR and MAP associated with intubation. [ABSTRACT FROM AUTHOR]