EDKP 485 Lecture 9: EX PATHO 9
7 Feb 2017
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Document Summary
Decline of resting inspiratory capacity ic in copd = impact on breathing pattern & exertional dyspnea. *ic at rest & hyperinflation = predict how close vt expends to ic & how fast reach mechanical limit. Smaller room to breathe dictate how fast reach limit. Lung hyperinflation lowest = most airflow obstruction so lowest ic reach ventilation limit earlier. Same vt limit of 70% but reached earlier if more severe due to higher vt as % of ic. *severe hyperinflation already breathing close to max ic / tlc at rest. More severe = more rapid acceleration in symptomatic response. & reach dyspnea symptom-limit at lower level ventilation. *breathing position on pressure-volume curve dictated by disease severity. If small vt as % of ic = large insp. If large vt as % of ic = small insp. Prevalence & burden of physical activity-related dyspnea in copd. Self-reported breathlessness: mrc 1-no dyspnea vs mrc 5-very severe = bed rest.
