title: The ratio of body haematocrit to venous haematocrit in open heart surgery and estimation of the blood volume in the large and small vessels.
abstract: Double tracer blood volume technique revealed in open heart surgery patients a wide variability of Fcells-value in about 11 per cent of cases investigated, from the "normal" 0.91 value. The possible calculational error of blood volume measurements by single-isotopic--haematocrit methods in the normal or subnormal LVH-ranges point to the superiority of plasma volume determinations in the calculation of the total blood volume. The calculation of the volume of the blood-component actually not-labelled during single-isotopic--haematocrit procedures can be so highly inaccurate because of the hidden deviation of Fcells-value, that such misleading arithmetics has no real value and therefore should be omitted. Estimation of the large vessel and small vessel volumes and haematocrits in patients showed a rough 70 per cent---30 per cent distribution of the circulating blood volume between large and small vessels and an LVH tosmall vessel haematocrit ratio of 2:1 to 2:1.5. This offers a possibility to divide the circulating blood volume into a haemodynamically active (large vessel area) and a metabolically active (small vessel area) part, which can have important diagnostic and prognostic implications.
mesh_terms: D001810:Blood Volume; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D002860:Chromium Radioisotopes; D004911:Erythrocyte Volume; D005112:Extracorporeal Circulation; D006400:Hematocrit; D006801:Humans; D010953:Plasma Volume; D012711:Serum Albumin, Radio-Iodinated; D014680:Veins
chemical_list: D002860:Chromium Radioisotopes; D012711:Serum Albumin, Radio-Iodinated