side effect of albuterol + ipratropium bromide

I am posting this for my uncle, who has COPD.  He had been only using albuterol, and then ipratropium bromide was added to it.  About 3 1/2 months later, he had an episode where he passed out.  He was unconscious for about 30 minutes.  When he regained consciousness, he noticed the blood oxygen level meter read 73, then 78, then 83, and up from there.  He is concerned that the ipratropium bromide added to his normal albuterol eventually caused his blood oxygen level to drop, which resulted in losing consciousness.  He was told that his oxygen was low because he had been using empty tanks, but that was not the case, as he was not using those tanks as a source of oxygen.  The additional question to this is, was an extremely low level of blood oxygen the cause of his passing out, or was the low reading a result of it?  Is this a possible side effect of the combination of medications?  If not, what could have caused it?  Thank you.

[National Jewish Health]

It was recently reported that ipratropium bromide and tiotropium bromide posed a significantly increased risk of heart disease and stroke.  The following was the conclusion of that recent report in the Journal of the American Medical Association from September 24, 2008:  
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Inhaled anticholinergic (ipratropium) use for more than 30 days significantly increases the risk of cardiovascular death, MI, or stroke in patients with COPD by approximately 58%. This increase in the risk of cardiovascular death, MI, or stroke is particularly manifest in the long-term trials.

The precise biological mechanisms by which inhaled anticholinergics increase the risk of cardiovascular death, MI, or stroke among patients with COPD are uncertain. That means that, they are unknown!. These risks may or may not be real.
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Some individuals may experience a fall in oxygen saturation following the administration of an inhaled bronchodilator.  If severe enough, this could result in that person losing consciousness.  It is possible then that your uncle may be having an adverse response to the albuterol and/or ipratropium bromide.

You should discuss this with his doctor and arrange for your uncle to administer his inhaled medicine(s) in a safe environment, such as the doctor's office or emergency room (ER) where his blood oxygen levels and heart rhythm can be monitored.

As to the question of which came first, passing out or low oxygen level?  The answer is either 1 but more likely the passing-out was due to a low oxygen level.  However, if his breathing either slowed or stopped when he lost consciousness, a low oxygen level would follow the fainting.