BIPAP Oxygen Problem

I currently have been diagnosed with mild emphysema.  I recently underwent a sleep study at a sleep study lab.  While on bipap with 5 liters of oxygen, my pulse oximetry level dropped to 51.  The technician said it took her five minutes to awaken me and they suggested I go to the ER.  I did.  They ran several blood tests including an ABG test.  The results were as follows:  pH arterial, 7.46; PaCO2 arterial, 44.7; PaO2 arterial, 57.6; HCO3 arterial, 31.6; Base arterial, 7.3; O2 Sat arterial, 92; Pox Sat arterial, 91; CO HGB arterial 7.2; Critical value arterial, No.

The ER was unable to give any explanations.  Please note that prior to the above sleep lab study, I had taken a home noctural pulse oximetry test with similar drop in  in O2Sat. I also had two pulmonary clots in 2007.

Any answers, suggestions?

[National Jewish Health]

That you had clots to your lungs two years ago is significant, primarily to the extent that that occurrence puts you at increased risk of having recurrent clots.  In the absence of recurrence the 2007 event  is very likely to be unrelated to your current concerns regarding the sleep study.  “Mild emphysema” is seldom if ever associated with arterial blood gas (ABG) abnormalities.  Assuming that you live at sea level or not much higher, your arterial p02 is unquestionably abnormally low; the partial pressure of carbon dioxide at the upper limit of normal, but not high enough to account for the p02 of 57, on the basis of underventilation or what is sometimes called “lazy breathing”.  And, if the pulse oximetry level of 51% is accurate, that too is not consistent with “mild emphysema” and, whatever the cause, is very worrisome and dangerous.

It is also possible that the 5L/M oxygen, administered during the sleep test, may have suppressed what we call respiratory drive (the impulses that come from the respiratory center, in your brain, that tell you when to breathe and how much to breathe).

There are some serious questions about your sleep and your breathing that, in the interest of your health and safety, must be answered without further delay.  I strongly suggest that you seek consultation with a lung/sleep specialist (pulmonologist) soon.  Doctors associated with Sleep Centers generally have expertise in both pulmonary disease and sleep disorders and you might start there.

Good luck