title: Effective compliance of the circulation in the upright sitting posture.
abstract: The effective compliance is defined as the relation of change in blood volume to change in central venous pressure. It was measured in 8 upright sitting male subjects and amounted to 3.3 ml/(mm Hg X kg BW). It is, therefore, by about 50% greater than the effective compliance in the supine subject which amounts to 2.3 ml/(mm Hg X kg BW). . This difference is probably due to the posture dependent blood volume distribution in the low pressure system whose "upper" and "lower" sections have nonlinear pressure-volume characteristics. Immersion to the neck reduces the effective complicance to about half the control value (1.9 ml/(mm Hg X kg BW) which probably constitutes the effective compliance of the intrathoracic circulatory compartment.
mesh_terms: D000328:Adult; D001794:Blood Pressure; D001810:Blood Volume; D002496:Central Venous Pressure; D003187:Compliance; D006321:Heart / Q000502:physiology*; D006339:Heart Rate; D006470:Hemorrhage; D006801:Humans; D008297:Male; D011187:Posture