BIO 115 Lecture Notes - Lecture 20: Restrictive Lung Disease, Pulse Oximetry, Hypoventilation
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Recite causes of hypercapnia and hypocapnia, msk1b, 3a. Hypercapnia can be explained by every variable in the equation: Cns damage resulting in cns depression (trauma, tumor, drugs) Low rr - hypoventilation, neuromuscular disease, obesity. Low vt - obstructive or restrictive lung disease, High vd/vt - pe, emphysema, hyperinflation, shallow breathing, High v(dot)co2 - increased co2 production (heightened metabolism) Fever, excess movement, seizures, over-feeding, hypermetabolic states such as hyperthyroidism. Hypocapnia is caused by increased v(dot)e: anything that stimulates hyperventilation. Describe the haldane effect, msk1a, d, msk 3a, d. Deoxygenation of blood increases its ability to carry carbon dioxide; conversely oxygenated blood has a reduced capacity for carbon dioxide . Should be less than 10 mmhg - indicates hypoxemia if greater than 10 mmhg: a-a gap normally increases with age: a-a difference = 2. 5 + 0. 25(age, a-a difference normally increases with supplemental oxygen, so it is. Most useful in the assessment of patients breathing room air (fio2 =
