My Medical Heritage - 2 of 4

Duane Graveline MD MPH
USAF Flight Surgeon
NASA Astronaut

The Burp Run

The burp run was one of the more unique features of the flight surgeon training program. I was about to receive firsthand experience with a common aviation malady known as motion sickness.

We were loaded into a C-47, affectionately known as a “Gooney Bird” and took off into a hot, humid afternoon heading for the low hills south of San Antonio, cruising at five thousand feet where thermals and pronounced turbulence were guaranteed.

"Okay, you guys," said the loadmaster, "I want you all to remember one thing - you dirty the plane and you clean the plane, so use the burp bags carefully."

Motion sickness is a terrible thing. A touch of it can ruin your trip but a severe case can impair your function to the point where you cannot operate an aircraft.

Twenty minutes passed before the sightseeing and joking subsided and the first cases of pallor and yawning started. Yawning, being somewhat contagious anyway, spread rapidly through we now subdued students.

An experienced flight surgeon knows that when yawning starts, watch out! This is true whether you are dealing with motion sickness, blood drawing, getting a shot or having a laceration sutured. Pallor, nausea and vomiting frequently follow.

After thirty minutes, fully half the class were vomiting and deathly ill. After forty-five minutes ninety percent were afflicted.

The only thing I could compare this flight to was an incredible scene where fifty-two second year medical students passed Miller-Abbot tubes (a tube for obstructive lesions in the small intestine that is inserted via a nostril and through the stomach) on themselves and each other to gain personal experience in the retching and vomiting that usually result.

"At first you get so sick you're afraid you might die," said the loadmaster. "Then you get so sick you're afraid you won't. Does anybody want to go home?"

The show of hands would have been one hundred percent except for a few guys so far gone they didn't care anymore.

Low-Pressure Chamber Training

Since all flight surgeons were going to be flying in aircraft operating at high altitudes, low-pressure chamber experience was necessary. The purpose of the chamber run, I was told, was to review altitude physiology, learn how to use the partial pressure mask, learn the correct operation of the ejection seat and learn the usual effects of lack of oxygen and reduced pressure.

Additionally, as I was to learn in a later life threatening experience, it is potentially life-saving to know your own personal reaction to lack of oxygen.

"Ordinarily, we give you guys the square peg in the round hole treatment," said the chamber instructor. "But since you all are doctors, we decided to give you something really hard for you to do. We want you to write your own name."

We had all been checked out in the use of oxygen masks, donning them after we were seated and going through the usual routine being certain to get a wink. Not to get a wink on the regulator usually meant a poor mask fit, which could result in lack of oxygen and unconsciousness.

As the chamber pressure decreased to 18,000 feet, the students were instructed to get up on one cheek whenever necessary because air within our body cavities was expanding rapidly and if anyone smelled anything, his mask didn't fit properly.

Leveling off at 18,000 feet temporarily, I was asked to remove my partner's mask for several minutes looking for unusual symptoms or behavior, following which it was my turn. I knew this step was largely to familiarize everyone with the equipment and lessen anxiety.

We then climbed to 25,000 feet for the name writing demonstration. Again, using the buddy system each student removed his mask and started writing his name on a piece of paper.

After a few minutes, everyone's writing became progressively distorted. After another minute or so, most writing became an unreadable scribble and many of us were slipping into unconsciousness as the mask was placed back on our face. After a few good breaths, everyone denied unconsciousness and loss of function and could not believe their writing.

I was impressed by this and amazed that individuals had absolutely no recall for their loss of function and unconsciousness. This lack of recall had never been mentioned in my medical school training and it certainly was relevant when asking a patient did he ever lose consciousness or faint. For the first time I realized that this kind of history by a patient is likely to be invalid.

Poor Mask Fit Experience

Several years were to pass before I was to use the oxygen mask training I had received and the time it took for me to remember my critical symptom almost cost me my life. I was cruising in a T-bird (a Lockheed T-33 Shooting Star jet trainer aircraft) at forty-three thousand feet, I could look up and see the beginning of the blackness of space, which lay beyond.

I was incredibly impressed by this sight which vividly dramatized how thin our atmosphere is. As comfortable as we were in our jet aircraft it was difficult to appreciate just how inhospitable it was out there. Sixty below zero and oxygen to sustain us for just fifteen seconds.

It was on this flight that I was reminded how critical our need for oxygen is and how dependent we are on our protective equipment. Murphy's law is just as true as any law of physics - if something can be screwed up it will be screwed up and I screwed up!

I was flying with Captain Joseph Loftus. "Joe," I said over the intercom, "we may have a radio failure. You are coming in weaker and weaker."

"Check your volume control, Doc, I hear you loud and clear," replied Joe.

I maxed out the volume control knob but Joe's voice kept getting weaker and weaker.

Failure to communicate would be grounds for aborting the trip for safety purposes. Joe was looking at me through the rear view mirror but with our sun visors down he could see none of my face. Finally, I was unable to hear Joe at all.

Things seemed unnaturally quiet. I could not hear even my own respirations, which was particularly strange. I tried a couple of deep breaths and still heard nothing but the “wink” on my oxygen regulator caught my eye. My brain definitely was foggy and I was aware of a loud ringing in my ears which reminded me of having ether anesthesia when I had my appendix out as a child.

I tried another deep breath and again saw a “wink”, then realization finally hit me. I was not getting a “wink” on my normal respirations, just on the deep ones! My mask was leaking around my face and I had been breathing cabin air.

The cabin altitude was at 27,000 feet. I was seriously hypoxic and was lucky enough to find out before I went unconscious. I pushed my regulator to safety setting, flooding my mask with one hundred percent oxygen and tightened the straps. My hearing came back within seconds with Joe blasting out over the intercom wondering what was going on.

I tried to figure out how with almost one thousand hours in jet aircraft I had managed to screw up so royally. I always did a mask check immediately after putting it on, while still on the ramp.

When checking the regulator I must have been taking deeper breaths than usual, so was getting a reassuring “wink”. With normal breathing some cabin air was coming in around the edges of the mask and I probably was getting only an occasional “wink”. Bad mistake!

I was permitted to live through this one because of the altitude chamber run where routine mask off demonstrations at twenty-five thousand feet are done to check your own symptoms. The ringing in my ears was the clue that saved my life.

Duane Graveline MD MPH
Former USAF Flight Surgeon
Former NASA Astronaut
Retired Family Doctor

July 2016