To the Editor:—
For difficult airway management in pediatric patients, a technique using a laryngeal mask airway (LMA ™; Laryngeal Mask Company, Nicosia, Cyprus), a fiberoptic bronchoscope (FOB), wire insertion, and an endotracheal exchange catheter has been described. 1,2We have employed a similar technique in adults when dealing with an unanticipated difficult airway after induction of anesthesia. In an anesthetized patient, the technique is as follows: insertion of an appropriate-sized LMA ™ and ventilation of the patient; passage of a FOB through a collapsible elbow connector, through the LMA ™, and into the trachea; passage of a guide wire (0.081-cm diameter, 145-cm length; Cook Urological, Spencer, IN) through the FOB suction port and into the trachea; withdrawal of the FOB, leaving the wire in place; passage of an endotracheal tube exchange catheter (Cook Critical Care, Bloomington, IN) over the wire and into the trachea; withdrawal of the LMA ™; and insertion of a standard endotracheal tube over the exchange catheter. Direct laryngoscopy is useful at this point to guide the endotracheal tube through the mouth and under the epiglottis. Assuming that ventilation with a LMA ™ is successful, this technique allows almost continuous control of the airway with manual or mechanical ventilation except during the last step; an unhurried sequential approach allowing deliberate use of the FOB; minimal trauma, as the devices employed are designed for soft tissue use; and final intubation with a conventional endotracheal tube of adequate size. Of note, we have observed that a standard LMA ™ works best rather than an intubating type.
Larger endotracheal tubes (sizes ≥ 7.0) may be difficult to insert directly through a LMA ™ over a FOB, and the endotracheal tubes used with intubating airways have a higher pressure cuff than standard tubes. This is of greater importance when postoperative ventilation is anticipated. Smaller endotracheal tubes placed over a FOB and through a LMA ™ may secure an airway but may result in problems with weaning or may be generally unsuitable for prolonged ventilation, especially in large patients.
We have used this technique successfully many times during the last 3 yr, and it is now our initial approach to the unanticipated difficult airway in patients undergoing cardiovascular surgery.