The normal resting cardiac output: serial determinations by a dye dilution method.

The resting output of the normal heart has been investigated by many workers (Krogh and Lindhard, 1912; Christiansen et al., 1914; Stewart, 1921; Grollman, 1928; Hamilton et al., 1932; Nylin, 1933; Berseus, 1943; McMichael and Sharpey-Shafer, 1944; Cournand et al., 1945; Stead et al., 1945; Werko, 1947; Chapman et al., 1950; Doyle, et al., 1953; Donald et al., 1955; Goodyer et al., 1960; Reeves et al., 1961). Several authors have drawn attention to the limitations of the various methods used for the estimation of the cardiac output; these include the problem ofachieving a true basal state due to the mechanics and the excitement of the procedure itself and the difficulty in obtaining reproducible results. With the development of a photoelectric earpiece giving a linear response to concentration of dye (Gabe and Shillingford, 1961) and the use of Coomassie Blue dye as an indicator (Taylor and Shillingford, 1959) it has now become possible to make reliable serial determinations of the cardiac output in subjects lying comfortably at rest, without cardiac catheterization and arterial puncture.