Ventilatory techniques for central airway obstruction.

INTRODUCTION Central airway obstruction (CAO) refers to obstruction involving the trachea, mainstem, or lobar bronchi. These lesions can be either benign or malignant. Obstruction of these areas may lead to dyspnea, atelectasis, post-obstructive pneumonia, and death. Treatment options to relieve CAO include airway dilation, laser techniques, cryotherapy, and stenting. CAO is becoming more prevalent due to our aging population and increase in life expectancy. Otolaryngologists are increasingly called upon to manage these patients; therefore, it is important to know the various options available to control the airway and ventilate patients with CAO. Traditionally, CAO is managed either by flexible or rigid bronchoscopy. Flexible bronchoscopy has the advantage of the patient being awake; however, the scope partially occludes the lumen. Rigid bronchoscopy requires general anesthesia, but does not occlude the lumen, which allows for ventilation and easier control of hemorrhage into the airway. Jet ventilation is based on delivery of gas under high pressure through an unblocked catheter into the airway, which is open to ambient air. Jet ventilation allows for an unobstructed view of the airway. Jet ventilation can be performed supraglottically (above the glottis) or subglottically (below the glottis). High-frequency jet ventilation is the delivery of small tidal volumes at higher than physiological rates followed by passive expiration (Table I).