Using CPAP during red-eye flights

I had an scary medical incident during a flight a few weeks ago. It may be unrelated to sleep apnea, but this flight was the first time I had ever used a CPAP machine on an airplane --- so I’d like to explain exactly what happened. Hopefully some participants in this forum may have knowledge or observations to share. Anyone not interested, please skip to the next post!

My flight was from Quito to Florida in the USA, leaving around midnight. I fly a lot on business but hadn’t flown overnight in twenty years, so I was concerned about being able to sleep overnight without snoring/gasping and keeping others awake and being tired the next day. I’ve been using CPAP every night for about two years and didn’t know how I’d feel the next day if I skipped a whole night.

Since I also expected to be spending a couple of nights during this trip without electricity, I decided to buy a portable CPAP machine that could run off a battery. I settled on a Transcend auto machine without humidifier after reading user comments on this forum and at cpap.com.

Before I left on this trip, I used my new Transcend machine with my regular Dreamstation nasal mask for two full nights. It was fairly noisy, and I missed my Philips Respironics humidifier, but it seemed to work fine. The Transcend has a rounded bottom and doesn’t sit flat on a table, so I glued some rubber feet to the bottom to keep it quiet and firmly in one place during the night. I also used the machine for two nights in Ecuador on battery power, mainly to test the battery I bought from the Transcend manufacturer. All four nights passed without incident.

At 1:00, about an hour into my return flight, I pulled the machine and battery out of my bag and masked up. It was a little strange doing that in public, and awkward because I didn’t know where to set the machine, but I fell right asleep. Nothing like aircraft noise to drown out CPAP noise! I slept fitfully, which I attribute to all the conversations and lights around me, but I could feel that I was breathing normally and kept dozing back off comfortably. Around 2:45 I realized I was VERY warm; I rolled up my sleeves for relief, then aimed the air vent directly at me for more relief. Then it dawned on me that something was wrong with ME and I took off my mask, grabbed my wife’s arm to alert her -- then woke up with three very alarmed people in my face asking if I knew where I was and if I could breathe OK.

I’ve fainted out a few times in my life so once my mind cleared enough to form a couple of words I deduced what must have happened. My wife said my skin was hot and very sweaty and I was unresponsive for a minute or maybe less; she said my eyes were rolled upward and I couldn’t focus. The flight attendants gave me an ice pack and oxygen mask and measured my pulse around 50. During the next 45 minutes I went from very hot to very cold to feeling OK again, with my pulse slowly increasing to 65. At that point I thought I might fall asleep so I took off the oxygen mask, put on my CPAP mask, turned the Transcend on, and relaxed. Within ten minutes I was burning up again and quickly removed the CPAP mask. My wife was able to get the oxygen mask back on before I passed out a second time. Needless to say I was not going to fall asleep again on that flight!

The paramedics checked me out on arrival and everything looked A-OK. But I’m left wondering what really happened. The airport paramedics said they see this a few times every day, people passing out during flights for no obvious reason and with no damage to themselves. I asked them if CPAP was a common factor and they said not to their knowledge (to my relief). Apparently the oxygen level in airplanes is troublesome for some people because planes are pressurized only to the equivalent of 8,000' elevation.

I had just spent 10 days in Quito at 10,000', so 8,000' should have been an improvement as far as breathing; but I was awake and flying all night, and at 65 I’m no spring chicken, with a few other health problems that might contribute to fainting.

The next day that I began wondering if CPAP played any role. I remember seeing an old advertising photo of someone wearing a Transcend CPAP on their head, which seemed ridiculous to me, but in fact I couldn’t find anywhere to put the CPAP machine during my flight so maybe it wasn’t so ridiculous after all. I had put the battery on the floor and nestled the machine into the narrow seat next to me, which in retrospect seems pretty careless because the machine’s air intakes could get blocked that way. At the time I wasn’t concerned about that because my understanding was that if a CPAP machine failed for any reason and my oxygen level dropped, my mouth would open and I’d wake up, but that’s the worst that would happen.

I read the Transcend instructions carefully before using it and the only thing that caught my attention (and upon re-reading after my flight REALLY catches my attention) is this warning: “When the device is turned on and functioning properly air flow from the device flushes the exhaled air out through the mask exhalation port. When the device is not operating, however, fresh air will not be provided through the mask and exhaled air may be rebreathed. Rebreathing of exhaled air for longer than several minutes can, in some circumstances, lead to suffocation.” So I’m wondering if my machine may not have been ‘functioning properly’ if its air intakes were getting blocked by the seat or my clothing. Because I wasn’t sleeping soundly and was paying close attention to my new machine and my breathing, I sure FELT like the machine was delivering plenty of air at the pressure I’m used to -- yet I passed out completely and came close to doing it a second time.

I have since consulted my regular doctor, who’s also a pulmonologist and sleep specialist, and he hadn’t heard of any other problems with CPAP during flights, or any problems with Transcend machines. A blocked air intake was the only reason he could think of that might connect CPAP to fainting, but he hadn’t heard of that happening before.

I wonder if anyone else reading this message is aware of similar experiences either with or without CPAP. I hope to visit Europe next year which will involve another overnight flight; I sure don’t want to repeat my last experience, which was handled incredibly well by the flight crew and the paramedics, but certainly alarmed my wife and all the other passengers!

And aside from airplanes, the warning in the Transcend instructions has really begun to bother me. I assumed it was lawyerly BS, or government-mandated boilerplate, and maybe it’s both -- but now that I’m looking, I see the exact same wording, in the same microscopic print, buried in the manual for my regular machine, Philips Respironics Remstar Auto A-Flex (system 60). Of course our machines should always be ‘functioning properly,’ but power failures do happen, and backup batteries can run down or malfunction, and machines can get pulled off bedside tables. I’m willing to take risks for the obvious benefits of CPAP therapy, but I had never dreamed anyone could suffocate because their CPAP machine stopped functioning properly . . . .

I don't know the Transcend, but while you worry about blocking air intakes, does your mask not have CO2 vents that for whatever reason might have been blocked - I realize you wondered about this in your note.

Or could the extra 02 in the cabin have interfered with the machine? Seems strange as it's designed for travel, but I'd certainly want to talk to the manufacturer regardless of what you can surmise went wrong.

Yes, this mast has vents. Two large ones -- one shooting straight out from my nose and another shooting out from the swivel fitting above my head.

I hadn't considered whether the vent above my head might have gotten blocked by the tall airplane seat. The front vent was completely unobstructed.

I was wearing the same mask I use every day at home (before and after this trip).

calusa wrote:my skin was hot and very sweaty and I was unresponsive for a minute or maybe less; she said my eyes were rolled upward and I couldn’t focus.

I don't know what happened to you, but clusters of long apneas could have caused these symptoms.

I never tried CPAP sitting up before, so I don't know if that would be a factor in generating apneas.

The Transcend machine only provides limited data; here's what I have for the night in question (at the top), plus the two earlier full nights on battery power (middle and bottom).



(I don't see any cluster of long apneas, but I've never used this software before.)

Nothing is obvious to link your event to CPAP or sleep apnea. And you said you had other health issues too which may be more relevant.

It sounds like you had vasovagel syncope (fainting) events in your sleep, which is unusual.

You probably need a cardiologist as your heart may be involved. The symptoms you describe can go along with a pause in the pulse rate (asystole) caused by the vasovagel event. And it's not at all unusual for sleep apnea sufferers to also have heart issues.

He didn't give me a technical explanation, but I guess my doctor's cardiologist referral means he's thinking exactly like you are. I should know more soon!

Since airline cabins are not always pressurized to ideal levels, that could have been a factor

Glad you got the referal. Expect a bunch of tests and if they don't find the problem then you may get a heart monitor inserted under your skin. If that shows your heart pauses during a fainting episode, expect a pacemaker.

Dehydration is a common cause of fainting, and very dry airline cabin air helps dehydrate you. Add tiredness and any alcohol, and that may have been the trigger. Pressure and CPAP are probably irrelevant.