1. At which lung capacity is there no pressure difference between the alveoli and body surface?
2. What effect will breathing at an increased FRC have upon lung compliance?
decreases it, as the gradient decreases?
3. Patient short of breath on mild exercise, has pulmonary evaluation:
From spirometer trace and determination of FRC, how would you calculate residual volume (RV)? [earlier, we’re told FRC, FVC and FEV1 have been determined]
TLC=6.4L, RV=2.0L (both greater than 100% expected).
FVC =4.0L which is 93% expected; FEV1=2.4L
He breathes slowly with large tidal volumes.
Is this restrictive or obstructive pulmonary disease, explain why?
I thought it was obstructive, as obstructive can be when FEV1 is < 80% of FVC. (and 2.4 is < 80% of 4L). Also, in restrictive disease tidal volume tends to be low.
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When you talk about oxygen saturation of say 90% - does this just mean that 90% of Hb have at least 1 molecule of O2 bound to it? It's the "at least" bit I'm unsure about.
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At altitude do you get hypocapnia? (if hypoxia -> hyperventilate -> CO2 blown off?)