Instantaneous pulmonary capillary blood flow can be measured by a plethysmographic method in conscious humans, a pneumotachographic method in anesthetized humans, and a plethysmographic or pneumotachographic method in anesthetized dogs. A program is written for a small digital computer which permits on or off line processing of these data. The values of pulmonary capillary blood flow plus right to left intrapulmonary shunt flow in dogs compare favorably to simultaneously determined values of cardiac output by dye dilution. However, variations among three consecutive estimations of capillary blood flow in dogs are significantly greater than dye dilution. Nevertheless, the repeatability of the plethysmographic method over a 25 minute period in sitting or supine conscious humans is excellent, possibly because the method is more precise at higher cardiac outputs. The noninvasive nature of the plethysmographic method together with rapid data processing by the computer appear to offer a practical approach to serial measurements of cardiac output and pulmonary hemodynamics in man.
|Title of host publication||BULL.PHYSIO-PATH.RESP.|
|Number of pages||14|
|State||Published - Dec 1 1973|
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