found evidence of a direct relation between the severity of shock and the extent of the reduction in blood volume. This has been clearly demonstrated in recent experimental studies on traumatic and hemorrhagic shock in dogs (4, 5) in which blood volume was determined with more dependable methods. Within the past two years, there have also been reports of similar observations on cases of shock among civilians (6, 7, 8, and
others).The aim of the present investigation was: (1) to determine more precisely the relation between the loss in blood volume and the severity of shock in man, in order to provide a sound basis for estimating the amount of blood needed for replacement after various types and degrees of injury; (2) to determine the cause of blood volume reduction in traumatic shock; and, (3) to test the view, held until recently by some investigators, that hemoconcentration is a criterion of shock.
MATERIAL AND METHODSThe plasma volume was measured with T-1824 by extrapolation of a corrected time log-concentration curve as described in the preceding report (9) ; the total blood volume was calculated from the plasma volume and the arterial hematocrit. The serum protein concentration was determined by the falling drop (10) and refractometric.