Venous haemodynamics

Relative changes in venous blood volume with position have been measured in a group of normal human subjects and in patients with venous disease of the lower extremities. The method of measuring has been modified and new maneuvers added in order to adapt the method for routine clinical use and possibly increase the sensitivity and specificity of the procedure. At present the study is performed by tilting the patient on an electrically controlled bed after intravenous injection of sup(99m)Tc-albumin. The count-rates over both lateral calves are recorded using 2-in NaI(T1) crystals as an inductor of relative blood volume. Normal values and standard deviations have been calculated and found to disclose no statistically significant differences from previously reported values. The effect of anti-embolic stockings and a new tilt maneuver on eight normal volunteers is described. Clinical examples of results in a normal volunteer, in a patient with obstruction and in a patient with valvular incompetence are discussed. (author)