Limitations of jet ventilation through the laryngoscope

A series is presented of 100 patients who underwent direct laryngoscopy under general anaesthesia. Our preferred technique of ventilation is jet insufflation by an injector attached to the blade of the laryngoscope, as it provides the surgeon with a quiet and completely exposed larynx. In nine cases, chest expansion was assessed as inadequate by the anaesthetist. These patients were obese with a short neck, and/or stiff-necked; thus, insertion of the laryngoscope was difficult and a good seal between it and the larynx could not be achieved. Arterial blood gas values in six of these patients demonstrated marked hypoventilation. To improve ventilation in these patients an alternative technique of insufflation through a nasotracheal catheter was used. Arterial blood gas values indicated that this method resolved the problem of hypoventilation. Although the catheter somewhat limits the view of the endolarynx, the improved ventilation outweighs the drawbacks of this technique. It is suggested that for the obese and/or stiff-necked patient, a nasotracheal catheter be used electively for ventilation.