Jet Ventilation

One of the rarer forms of airway management used in anesthesia is jet ventilation. In cases where a breathing tube or device cannot be placed (either due to disease, anatomy, or surgical need), a jet ventilator can be used. Oxygen from a supply pipeline goes to a pressure regulator connected to a hand-held valve. Squeezing the valve blasts oxygen out of a narrow outlet. This can be connected to a ventilating bronchoscope, laryngoscope, or in an emergency, an angiocath placed through the neck into the trachea. Thus, one can direct pressure-controlled blasts of oxygen through a surgeon-manipulated device or emergency airway.

A young patient with subglottic stenosis presents in extremis with acute shortness of breath and stridor. He acquired subglottic stenosis as a premature infant when he was intubated for several weeks. As a result, his vocal cords are normal, but below his vocal cords, his trachea has narrowed significantly so that he breathes through a straw. The surgeons want to dilate the stenosis, but obviously cannot work around an endotracheal tube. Although the patient has had a tracheostomy in the past (an opening from the skin to the trachea bypassing the stenosis), the surgeons would like to avoid that. This is the perfect case for jet ventilation.

The patient was rushed up from the emergency department to the operating room. After placing monitors, we induced anesthesia with propofol and remifentanil. We paralyzed with rocuronium and used a continuous twitch monitor to maintain adequate paralysis. We handed the airway over to the surgeon who placed an anterior commissure laryngoscope. By attaching our jet ventilator to the laryngoscope, we could blast oxygen through the tip of the blade which sat just beyond the epiglottis.

The jet ventilator is pretty easy to use, but it is absolutely crucial to do it correctly. If the laryngoscope blade is misdirected, the high pressure oxygen can blast through the soft tissues around the trachea, leading to subcutaneous air, a pneumothorax, and other damage. Exhalation is passive so if jet ventilation is done too quickly, the patient will retain air until the lungs burst. Yet we still oxygenate at a pretty high frequency (60 breaths/minute). Passive exhalation also means CO2 will build up; at the end of the case, our end tidal CO2 was 80 (twice normal). We have to be careful not to insufflate the stomach and use the minimal pressure necessary to oxygenate. And we have to maintain paralysis, not only because the surgeons are working on a 2mm airway, but also because if a vocal cord closes and we use the jet ventilator, we will get permanent vocal cord damage. We coordinated closely with the surgeons as they worked in between the breaths we gave. The patient did outstanding, woke up without any problems, and had much more relief in his breathing. Although emergent shared airway cases can be complex and difficult, good communication and coordination allows a very safe anesthetic.