Use of oxygen bypass button of Boyle machine to trigger venturi ventillation during bronchoscopy.

Sir,—Your issue for November 1971 has just come to hand. The report by D. G. Moyes and M. A. Rogers (Brit. J. Anaesth., 43, 1099) emphasizes a real hazard in areas where ascaris is endemic, and is a salutary reminder that intubation of the trachea does not necessarily guarantee a clear airway. Obstruction from this cause has in fact been reported previously (Boulton and Cole, 1967). We recently had a similar experience. A 12-year-old boy was admitted with a diagnosis of tetanus, and was treated conservatively. His condition had improved sufficiently to warrant a reduction in the dosage of sedative drugs when he developed signs of respiratory insufficiency and retention of secretions. Following the injection of 15 mg of tubocurarine the trachea was intubated with a 6.5 mm cuffed tube. His condition improved after the institution of intermittent positive pressure ventilation and aspiration of the trachea. Twenty minutes later there was sudden difficulty in ventilation, which was followed rapidly by cardiac arrest. On examination extensive surgical emphysema was noted in the neck, and a needle inserted into the right pleural cavity revealed a tension pneumothorax. Removal of the endotracheal tube revealed the cause of the trouble. A large round worm (ascaris), doubled back on itself, was projecting from the tip of the endotracheal tube. In this position it acted as a non-return valve allowing inflation, but not deflation, of the lung.