SCINTIGRAPHIC RECORDING OF BLOOD-VOLUME SHIFTS

A scintigraphic device consisting of small scintillation probes tightl y fixed to the skin was developed to record intravascular blood volume shifts continuously and simultaneously at several sites. The aim of t he present study was to ascertain the reliability of the measurements obtained, show the blood shifts induced by common daily activities in healthy subjects and clarify the mechanisms responsible for hemodynami c changes. Methods: Measurements were made in three fields of the righ t lung, the liver, thighs and calves of 16 men during Valsalva maneuve r, hyperventilation, various posture changes and treadmill walking. So me tests were repeated. Results: The measured blood volume shifts were always in the expected direction and in accordance with those reporte d in the literature; they also were reproducible. Therefore, the measu rements were reliable. A pattern of blood volume changes peculiar to s ome common daily activities was recorded in subjects moving freely. In sights were obtained on the mechanisms responsible for the blood volum e shifts. Conclusion: Our noninvasive technique provides reliable cont inuous measurements of blood volume changes at several sites during co mmon daily activities and could be applied not only in healthy subject s but also in patients.