id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-335855-bifx2nu9	Herrmann, Jacob	Modeling lung perfusion abnormalities to explain early COVID-19 hypoxemia	2020-09-28		.txt	text/plain	5612	318	46	Herein, a mathematical model demonstrates that the large amount of pulmonary venous admixture observed in patients with early COVID-19 can be reasonably explained by a combination of pulmonary embolism, ventilation-perfusion mismatching in the noninjured lung, and normal perfusion of the relatively small fraction of injured lung. Given a relatively small fraction of injured lung, with F inj ranging from 0 to 30%, both a complete shunt (i.e., zero oxygen uptake) and reversal of HPV (i.e., vasodilation in injured regions) are necessary conditions for F shu :F inj > 2 and P a O 2 :F i O 2 < 300 mmHg. By contrast, impairment of HPV alone is not sufficient to produce reported levels of severe hypoxemia at low values of F inj 1 . Therefore it appears unlikely that the degree of pulmonary shunt reported in COVID-19 patients (F shu = 50% and F shu :F inj = 3) could occur without a substantial degree of vasodilation and hyperperfusion in the small fraction of injured lung, if one also assumes there is negligible venous admixture from other mechanisms producing ventilation-perfusion mismatching.	./cache/cord-335855-bifx2nu9.txt	./txt/cord-335855-bifx2nu9.txt