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We have studied the haemodynamic changes, QT intervals and catecholamine responses to induction of anaesthesia and tracheal intubation in 24 ASA I patients allocated randomly to receive either propofol 2.5 mg kg-1 or thiopentone 5 mg kg-1 over 60 s. After disappearance of the eyelash reflex, the lungs were ventilated with 100% oxygen for 3 min. The trachea was intubated after administration of vecuronium. With thiopentone, heart rate (HR) was greater than with propofol before intubation (P < 0.05). During induction, systolic (SAP) and diastolic arterial pressure (DAP) decreased more with propofol than with thiopentone. The QT interval was prolonged only during induction with thiopentone. In both groups, HR, SAP, DAP and the QT were increased in response to intubation (P < 0.001). The SAP and QT interval responses to intubation were significantly greater with thiopentone than with propofol (P < 0.05). One patient in the thiopentone group with a significantly prolonged QT interval had episodes of bigeminy and ventricular tachycardia. In both groups, concentrations of noradrenaline in mixed venous plasma increased after intubation (P < 0.001). Concentrations of adrenaline increased after intubation only in the thiopentone group (P < 0.001).

We have compared impingement of the tracheal tube against the larynx using a standard preformed tube, warmed preformed tube or two flexible spiral-wound tracheal tubes with different tip designs, in 100 adult patients undergoing orotracheal fibreoptic intubation under general anaesthesia, in a prospective, randomized study. The rates of impingement were 20 of 30 with the standard tube, 12 of 30 with the warmed standard tube (P=0.07) and eight of 20 with both spiral tubes. However, impingement with the spiral tubes took longer to overcome if a sharp tipped rather than an obtuse tipped tube was used. Manipulations after impaction led to oesophageal intubation on one patient, and in one patient fibreoptic intubation failed. We conclude that resistance to the tracheal tube occurred frequently when the spiral-wound tubes were used.
Key words: intubation tracheal; intubation tracheal, technique; equipment, tubes tracheal

We have compared impingement of the tracheal tube against the larynx using a standard preformed tube, warmed preformed tube or two flexible spiral-wound tracheal tubes with different tip designs, in 100 adult patients undergoing orotracheal fibreoptic intubation under general anaesthesia, in a prospective, randomized study. The rates of impingement were 20 of 30 with the standard tube, 12 of 30 with the warmed standard tube (P = 0.07) and eight of 20 with both spiral tubes. However, impingement with the spiral tubes took longer to overcome if a sharp tipped rather than an obtuse tipped tube was used. Manipulations after impaction led to oesophageal intubation in one patient, and in one patient fibreoptic intubation failed. We conclude that resistance to the tracheal tube occurred frequently when the spiral-wound tubes were used.

We have studied the effect of glycopyrronium on the anaesthetic action and absorption of topical lignocaine in 10 healthy, non-smoking volunteers. Lignocaine 100 mg was sprayed on the oral mucosa 15 min after random administration of glycopyrronium 4 micrograms kg-1 or normal saline i.v. Glycopyrronium decreased the mean analgesia score from 2 to 0.1 (2 = baseline; 0 = anaesthesia) at 4 min compared with a change from 2 to 0.5 after normal saline (P < 0.05). All scores returned to baseline by 40 min and 20 min in the glycopyrronium and control groups, respectively. The mean (SD) peak plasma lignocaine concentration was 0.57 (0.29) microgram ml-1 after glycopyrronium and 0.31 (0.10) microgram ml-1 after saline (P < 0.05) and were attained in 17 min (range 10-40 min) and 29 min (range 8-40 min), respectively. Pretreatment with glycopyrronium enhanced absorption and prolonged the analgesic action of topically administered lignocaine.

We have compared four methods of topical anaesthesia of the nostril for fibreoptic airway endoscopy in a randomized study with 31 unpre-medicated volunteers, each serving as his or her own control. Lignocaine spray, EMLA cream, three cotton swabs soaked in 4% lignocaine solution, or 2 % lignocaine gel was applied in a nostril for 3 min. Application of lignocaine spray was rated as the most unpleasant and EMLA cream the least unpleasant. Spray and gel caused an increase in arterial pressure. Anaesthesia of the mucosa, tested by passing a bronchoscope through the nose to the oropharynx was best with lignocaine spray or gel. Gel or EMLA, but not the local anaesthetic applied with swabs, obscured vision. When slight obscurity of vision is not a problem, local anaesthetic gel is recommended for anaesthesia of the nasal mucosa. Premedication or sedation is recommended for all the methods described here.

The effects of the new, highly selective alpha2-adrenergic agonist, dexmedetomidine, were studied in a randomized, placebo-controlled, double-blind trial in 24 ASA I patients. Dexmedetomidine 0.6 μg kg−1 or saline was given i.v. 10 min before induction of anaesthesia. The required dose of thiopentone was significantly (P < 0.001) smaller in the dexmedetomidine group (mean 4.4 (SD 0.9) mg kg−1) than in the control group (6.9 (1.6) mg kg−1), and the drug attenuated the cardiovascular responses to laryngoscopy and tracheal intubation. The concentration of noradrenaline in mixed venous plasma was smaller in the dexmedetomidine group during all phases of induction (P < 0.01). During surgery, fentanyl was required in a dose of 0.5 (0.6) mg kg−1 and2.8 (2.6) mg kg−1 in the dexmedetomidine and control groups, respectively (P < 0.001). During 2h postoperative follow-up, oxycodone 0.06 (0.06) mg kg−1 and 0.16 (0.1) mg kg−1 (P < 0.05) was given to the two groups respectively.