Rats...dat's me.
The Hawk's second guess was right. PaO2/PaCO2 is the partial pressure of (whichever) gas in arterial blood, expressed in mm of mercury.
COPD is chronic obstructive pulmonary disease, what folks used to call chronic bronchitis and emphysema, only now lumped together.
These people often no longer respond to CO2 as a respiratory stimulus. The chemical driving force ( as opposed to the brain's neural driving centers) becomes oxygen. If we give too much, respirations slow down, CO2 starts to go up, to the point where it is a depressant, and voila, Houston, we have a big problem.
Hawk is right about the changes with pH, but that is a different story. (Gets even more confusing when you realize that the body can begin to go into anaerobic metabolism when oxygen isn't available, causing a further decrease in pH, from the lactic acid). Short term, the CO2 changes will do you in faster than the pH.
Let's not even get into fat people. (Obesity is, among other things, a restrictive lung disease...ya can't take a deep breath,cuz there is not enuf room to expand your lungs.) Oh, hell, we're there. Ugh, so eventually, they chronically underventilate, build up CO2, have blood levels which look very much like a COPDer. Lots of times develop obstructive sleep apnea, from too much bulk and the uvula dropping down, etc. The old name for all this was Pickwickian Syndrome, after Joe, the Fat Boy in Dicken's "Pickwick Papers".
As for water, air gets humidified when it goes into yer lungs, usually in the nose, but in my case the mouth. Temperature dependent...47mm Hg at body temp. (Theroretically, at whatever altitude the barometric pressure is 47, gaseous water would replace everything else in yer lungs, and you then get those scenes in the space movies where they begin to bubble theirs elves out of their mouths.)
There you have it; 16 weeks of respiratory physiology in 90 seconds.
Rats... dat's me |
