Finding PEEP In a Bottle (of Water): Thinking Outside The Box

As you read this I am flying to Honduras with International Relief Team on a head and neck surgery medical mission. I will attempt to post mission updates from the hospital compound, pending internet connections. Participating in a medical mission to the developing world is never easy.

Medical personnel trained in a high tech environment take for granted the complex monitoring devices, multiple choices of drugs, and plentiful support peronnel which simplify our job. When medical volunteers travel to the developing world they are often unprepared for the potential hazards produced by outdated technology, unfamiliar and sometimes poorly maintained equipment, poor sanitation, limited supplies, and a malnourished, often poorly educated population.

Let me give you an example of one rather exciting case from early in my volunteer experience.

I was on a medical trip to Vietnam in the 1980s with the plastic surgical team Operation Smile. Vietnam had only recently been open to visits by Americans following the war and at that time they lacked a lot in terms of medical supplies, equipment, and infrastructure.

Our patient was 13 years old and had suffered a catastrophic burn as a young child, which left her with severe facial and neck keloid scars pinning her chin to her chest. Anesthetizing her in an environment with no sophisticated tools like a fiberoptic bronchoscope was certainly taking a great risk, because if we lost the airway, there would have been no easy way to ventilate her with bag-valve-mask. On the other hand there were no other easy treatment options for this child who was increasingly unable to eat and breathe. The ability to transport her back to the United States for care was not politically possible at that time. We decided to proceed with the scar release and grafting.

Because there was a serious risk of losing the airway, the first challenge was to intubate her. We decided the best way was with awake intubation. We had considered scar release under ketamine and local, but felt there was no good way to numb the area. Without good local anesthesia, we would end up providing what essentially would be an intravenous general anesthetic with an uncontrolled airway — an even worse risk. The team agreed that if intubation were not possible, we would stop and not proceed with surgery.

After topicalizing and sedating her, the intubation still proved difficult because of the angles involved. We were worried about sedating her too deeply because of the severity of her airway deformity. The child therefore struggled a bit but after about 5 minutes we had intubated. We induced anesthesia once we had secured the endotracheal tube was secured.

Anesthesia was halothane and oxygen via a Bain circuit and freestanding vaporizer attached to an H cylinder. The only monitors were a blood pressure cuff, and a pulse oximeter brought from the United States.

photo Dr. Whitten gives anesthesia with an improvised anesthesia machine consisting of a halothane vaporizer duct taped to an H cylinder of oxygen and attached to a Bain arm.

Dr. Whitten gives anesthesia with an improvised anesthesia machine consisting of a halothane vaporizer duct taped to an H cylinder of oxygen and attached to a Bain arm.

Toward the end of the procedure she began to desaturate into the mid 80% range. Blood was suctioned from the endotracheal tube and as hypoxemia worsened, blood aspiration from presumed tracheal trauma was suspected. However, because breath sounds were remarkably unequal and the neck scar had been extensively dissected, pneumothorax could not be ruled out.

The only way to get an Xray was to go to radiology. No portable equipment existed. So off we went, pushing her bed and an H cylinder of oxygen on an industrial dolly across the pitch black, dirt covered compound to an XRay machine that was in a Quonset hut. Once there, we discovered the bed would not fit through the doorway. A quick visit to the emergency room yielded a hand carry stretcher and we placed her on it. Twenty minutes later after hand developing the X-Ray, the diagnosis of probably aspiration was confirmed. By this time hypoxemia was worsening. Oxygen saturation was now 75% and dropping.

A quick dash back to the perioperative area carrying the stretcher and pushing the oxygen dolly found us facing locked doors. The cleaning crew had assumed we were leaving for the night. After tracking down the key and now back with our Bain Circuit in the OR, positive pressure improved the oxygenation — at least until the oxygen tank abruptly went dry. Another H cylinder was rolled into the room and the regulators switched while we supported ventilation with an ambu bag.

The adjacent intensive care unit was filled with contaminated cases. There was no available functioning ventilator. Since she was oxygenating adequately as long as there was about 10 cm of positive end expiratory pressure (PEEP) maintained in the circuit with the Bain arm. Our Bain arm had no manometer so I was estimating the amount of PEEP with my “educated” hand.

To manufacture more consistent PEEP I attached a long length of suction tubing to the Bain exhalation port, which was the exact same size as an endotracheal tube adapter. I submerged the free end of the suction tubing onto 10 cm of sterile irrigation water in an irrigation bottle. As she exhaled into the circuit, the air exited through the tubing under 10 cm of water pressure.

Our team pediatrician and I slept with her in the recovering room, wrapped in sheets to ward off the clouds of mosquitoes. At 3 in the morning the pediatrician woke me saying the girl looked agitated. She was breathing fine and her saturation was better so I suctioned 5 cm of water out of the bottle, reducing her PEEP. She went back to sleep and the following morning we were able to extubate her.

I teach my students that they have to not only know what to do but why they are doing it. Knowing why you are doing something lets you improvise if you have to. We were able to adequately treat this patient’s complication in an austere environment without our usual high tech gear because we had a solid understanding of not just the physiology, but also the physics of how to generate PEEP. You always need to be prepared to think outside the box.

Follow the link to an article I wrote for Seminars in Anesthesia regarding preventing anesthesia mishaps during volunteer missions to the developing.

Anes in Distant Places

May The Force Be With You

Christine Whitten MD, author Anyone Can Intubate 5th Edition

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