The Determination of the Circulating Blood Volume With Carbon Monoxide

Simultaneous Measurements of the Blood Volume in Man and Dog by Means of Evans Blue Dye, T1824, and by Means of Carbon Monoxide. Ii. Under Abnormal Conditions, Including Secondary Shock 1

“…Thus, it has been suggested that carbon monoxide measures a space larger than the vascular space because some carbon monoxide leaves the intravascular space and combines with the myoglobin of muscle and with the blood pigments in reservoirs such as the spleen and bone marrow. That the loss of carbon monoxide to myoglobin is not responsible for an appreciable error is supported by the finding, repeatedly confirmed by ourselves and by others (13,14), that AAA a few minutes after the inhalation of the gas. Even strenuous exercise, which greatly increases the flow of blood through the muscles and so might be expected to facilitate a loss of carbon monoxide to them, does not appreciably affect the carbon monoxide concentration of the blood (13,14).…”

“…That the loss of carbon monoxide to myoglobin is not responsible for an appreciable error is supported by the finding, repeatedly confirmed by ourselves and by others (13,14), that AAA a few minutes after the inhalation of the gas. Even strenuous exercise, which greatly increases the flow of blood through the muscles and so might be expected to facilitate a loss of carbon monoxide to them, does not appreciably affect the carbon monoxide concentration of the blood (13,14). The slight drop in concentration of carbon monoxide in the blood, observed by Asmussen within the first few minutes of giving carbon monoxide and attributed by him to loss of carbon monoxide to the pigment stores, can just as well be explained by the process of distribution within the vascular space.…”

Simultaneous Measurements of the Blood Volume in Man and Dog by Means of Evans Blue Dye, T1824, and by Means of Carbon Monoxide. I. Normal Subjects 1

“…An attempt was made to leave as little oxygen in the bag at the end of the rebreathing period as was compatible with comfort in breathing. Rebreathing continued for 15 or 20 minutes, although absorption and mixing were actually complete in less than 15 minutes (10,23). Before or within a minute after disconnecting the rebreathing system from the patient, a second 10 cc.…”

The Measurement of the Circulating Red Cell Volume by Means of Two Radioactive Isotopes of Iron 1

“…The use of a diffusible gas, CO, having a high affinity for human hemoglobin, was suggested as a means of tagging red cells by Chang and Harrop (12). Following inhalation of CO, a certain proportion would be absorbed into and remain within the red cells for a considerable period.…”