High-frequency jet ventilation--a review of its role in laryngology.

High-frequency jet ventilation (HFJV) is a safe, effective anaesthetic technique with a low risk of aspiration which has not yet gained wide acceptance in laryngology. Following anaesthesia and muscular relaxation the patient is intubated with a size 7FG infant feeding catheter and ventilation is achieved by delivering small bursts of anaesthetic gas at high frequency. The mechanisms of gas exchange are thought to be little different from those of conventional ventilation. We have found HFJV to be of value in laryngoscopy, laryngo-tracheal reconstruction, tracheoplasty, bronchoscopy and tonsillectomy. The advantages include: (a) ease of intubation, especially in the presence of a supraglottic mass; (b) improved surgical access compared with a conventional endotracheal tube; and (c) protection of the airway by the inherent 'auto-PEEP' effect. Care must be taken to ensure that conditions allow adequate exhaust of expired gas. Humidification of inspired gas is essential during prolonged procedures.

Interhospital transfers by helicopter: the first 50 patients of the Careflight project.

An interhospital helicopter transfer service was set up using a dedicated helicopter fitted with medical equipment and staffed by anaesthetists. The system proved to be safe and practical. Fifty patients were referred from 38 hospitals throughout the UK, with 84% of transfers preplanned. Patients were transferred a mean distance of 118 miles (range 35-397 miles) and there was no deterioration during transfer as measured by pre and post transfer sickness scores. Twenty-eight per cent of cases could not have been practically transferred by conventional means. The death rate of 20% was lower than that reported for specially equipped and staffed land transfer systems, which may indicate less physiological deterioration in the critically ill compared to road transfer. Dedicated helicopter transfer resulted in a 50% survival rate in patients with a sickness score over 18, a group found not to survive after land transfer. There was no correlation between distance moved and outcome. A helicopter transfer system using suitable equipment and staff is a practical and safe method of moving critically ill patients between hospitals, and may be preferable to land transfer for distances in excess of 25 miles.

Comparison of i.v. glycopyrrolate and atropine in the prevention of bradycardia and arrhythmias following repeated doses of suxamethonium in children.

The effectiveness of administration of glycopyrrolate 5 and 10 micrograms kg-1 and atropine 10 and 20 micrograms kg-1 i.v. immediately before the induction of anaesthesia, to prevent arrhythmia and bradycardia following repeated doses of suxamethonium in children, was studied. A control group was included for comparison with the lower dose range of glycopyrrolate and atropine. A frequency of bradycardia of 50% was noted in the control group, but this was not significantly different from the frequency with the active drugs. Bradycardia (defined as a decrease in heart rate to less than 50 beat min-1) was prevented when the larger dose of either active drug was used. It is recommended that either glycopyrrolate 10 micrograms kg-1 or atropine 20 micrograms kg-1 i.v. should immediately precede induction of anaesthesia, in children, if the repeated administration of suxamethonium is anticipated.