Jet Ventilation I

A 60 year old long-time smoker with metastatic lung cancer presents for a palliative bronchoscopic procedure. His lung cancer, which has unfortunately spread to his bones and throughout his body, has invaded into one of his bronchi, one of the branches of his windpipe. As it compressed the airway, the patient developed worsening shortness of breath. He was effectively breathing only with one lung. And although his disease was incurable, his pulmonologist wanted to improve his quality of life by opening up that compressed airway, relieving his shortness of breath.

When I met the patient, he was cachectic, thin and wasted as a result of his cancer and chemotherapy. His oxygen saturation was 92% on room air and I could not hear much air movement on his affected lung side. We placed an arterial line for blood pressure management because of cardiac comorbidities prior to inducing anesthesia. After we induced anesthesia, the pulmonologist placed a rigid bronchoscope, a large metal rod, through the mouth, past the vocal cords, and down into the lungs. We used the rigid bronchoscope to initiate jet ventilation, blasting high pressure oxygen into the lungs and allowing passive exhalation. Working closely with the proceduralist, we stopped oxygenating temporarily as he used laser to remove cancer from the inside of the bronchus. When he initially went in, the bronchus was 90% obstructed, and after removing the cancer and debris, it was almost completely open. Through this time, the patient's oxygen saturation, hemodynamics, and level of anesthesia were very stable.

After the pulmonologist finished, he took out the bronchoscope and we placed a laryngeal mask airway to maintain oxygenation and ventilation until the patient woke up. All his vitals looked great, we stopped the propofol and remifentanil, and he was breathing well on pressure support ventilation. The patient would start taking a breath and the machine would assist slightly to make sure he was taking in enough volume. The patient became fully awake and we took out the laryngeal mask airway and put him on a facemask. Over the next ten to fifteen minutes though, his work of breathing increased and his oxygenation decreased. He dropped from 100% saturation down to 85%. He was fully awake, following commands, taking deep breaths with good breath sounds, but his oxygenation simply would not improve. An arterial blood gas confirmed that something was wrong. Even though we placed him on a non-rebreather oxygen mask, he did not improve. He was shunting blood; that is, blood from the venous circulation was bypassing alveolar exchange units and going to the arterial side. No matter how much oxygen we gave, we could not improve his oxygen uptake. The rest of the case in tomorrow's blog.