Frighteningly Low Oxygen Levels

September 9, 2010 2:02 PM

You're not our doctor, but we wonder if you might have any ideas to help explain our dear friend's oxygen level never rising above 85-88.

His condition was discovered at a sleep study where he sometimes went as long as a minute and a half without breathing. He's extremely well functioning even though he's struggled with diabetes for years. He's had some recent blood sugar levels around 350 despite careful management. His doctors have so far had no ideas. We'd love to give him some information to help with preparation if anyone has seen this before.

posted by tangram1 to health & fitness (11 answers total)

Is he 20? 50? 80?
posted by desjardins at 2:06 PM on September 9, 2010

I'm assuming this is measured by a pulse oximeter, and at times when he's awake? I wouldn't be surprised if the apnea causes drops to that level*, but having regular episodes of awake O2 concentrations in that range would be pretty unusual.

I don't have many great insights for you-- my experience with this is NICU based-- but I do remember the doctors saying that the measurements of blood oxygen saturation are limited in what they tell you. For example, if you need to measure CO2 levels, you have to have a blood test. So the base reading isn't telling you how good the blood is at carrying away CO2. And it's telling you a relative level of saturation for the blood cells that are there. So patients with many (all?) kinds of anemia will show up with normal blood oxygen saturations but are not getting enough oxygen to the cells, because they don't have the number of red blood cells to carry the right amount of oxygen there.

In other words, whether this is really a problem for your friend may depend on how his brain and physical functions are. He could have a ton of red blood cells that are carrying adequate levels of oxygen to where he needs to go but not hitting relative saturation, I suppose. Hope that helps you with the speculation!

*When you have your own pulse ox, sometimes you play with it. I remember hooking mine up to myself and holding my breath. My all time record was 81 after close to two minutes of breath holding, and I was gasping pretty well after that.
posted by norm at 2:14 PM on September 9, 2010

His condition was discovered at a sleep study where he sometimes went as long as a minute and a half without breathing.

A side effect of sleep apnea is lowered blood saturation levels. This often resolves itself when the underlying cause is treated, through CPAP therapy, surgery, dental devices, etc., depending on the reason for the apnea. This is a good forum for anyone who has undergone a sleep study.
posted by availablelight at 2:30 PM on September 9, 2010 [1 favorite]

I am not a doctor. I have no medical training at all. This is a wild-ass guess.

If his O2sat readings were taken with a fingertip pulse oximeter and he has inconsistently-controlled diabetes, he might have some peripheral circulation difficulties. If his peripheral circulation is impaired, it might cause artificially low oxygen saturation readings.
posted by KathrynT at 2:40 PM on September 9, 2010

I am not a doctor. However, I had low oxygen levels when I had a pulmonary embolism. I had no other alarming symptoms. The doctors (based on my oxygen levels) asked if my chest hurt and I said yes just because they kept insisting and even said "I think it just hurts cause you keep asking if it does so I keep trying to feel it hurt, but it hurts really really little." It was not even 10% of the pain you get from gas and I really thought maybe I was imagining it. Anyway, a CT scan showed multiple clots.

That said, if your friend has no risk factors for clots, that's probably not it, but I thought I'd throw it out there.
posted by If only I had a penguin... at 2:59 PM on September 9, 2010

[I've been practicing primary care medicine for 15 years and have a particular interest in sleep medicine.] It's obviously some sort of sleep apnea, of which there are two types. Obstructive sleep apnea is common and is usually seen in overweight middle-aged men. Central sleep apnea is rare; it is seen in teens and young adults with brain malformations (which may be previously unknown) and in elderly who have heart disease or a history of stroke. A full sleep study (polysomnogram) will readily distinguish between these two forms.

If your friend has high blood sugar, then I'll wager he's a fat guy with OSA; the treatment is CPAP.


His doctors have so far had no ideas.

More likely, the chain of communication from the doctor to your friend to you has failed. Otherwise, your friend desperately needs a new doctor.
posted by neuron at 4:11 PM on September 9, 2010 [3 favorites]

My brother got sleep apnea diagnosed and uses a CPAP. He says he feels better than he has in years.
posted by theora55 at 4:15 PM on September 9, 2010

Have they gotten the same results with different pulse/ox sensors?

And this:
http://en.wikipedia.org/wiki/Pulse_oximetry#Limitations
posted by gjc at 4:40 PM on September 9, 2010

Pulse oximeters are not very reliable in several cases as they measure the colour of haemoglobin as it passes through the fingertip. This depends on several things including transparency of skin and tissue and haemoglobin levels. So for example people with very low haemoglobin levels can show high saturation levels with low actual oxygen level similarly it would be possible if someone had higher than normal haemoglobin to demonstrate artificially low levels of saturation with no real problem.
posted by london302 at 4:48 PM on September 9, 2010

What neuron said. Could be some other things too...does your friend have lung disease? Heart failure? AIDS? Could be a lot of things, but if his doctors really don't know and aren't investigating pretty aggressively, time to get a new doc ASAP.
posted by LittleMissCranky at 6:19 PM on September 9, 2010

I should have said that the doctors plan to work on the low oxygen symptom next week, having focused on the apnea in the hope that it would help. It has not, and while our friend is sleeping better than he has in years he feels no differently during the day nor has it improved his oxygen levels.
posted by tangram1 at 6:30 PM on September 9, 2010