A Critical Evaluation of Red Cell and Plasma Volume Techniques in Patients With Burns

Abstract

From the results in 110 patients, in whom 207 red cell volume estimations were made at various times after burning using either rIC r-, 32p., or Group NN-labelled cells, and 17 plasma volume estimations on the same patients using either T-1 824-or 13 I-labelled albumin, it is concluded that:(a) The 5"Cr red cell volume method is the most reliable method; it gives results which are probably not in error by more than ± 10% when the labelled cells are washed three times and so has a place in the assessment of the changes in red cell volume that follow a severe bum. In conjunction with a well type scintillation counter the radiation dosage received by the patient with 53Cr is about one-fifth of that with any other method.(b) The 32p method is slightly less reliable, as shown by on average higher supernatant radioactivity levels and a greater scatter in the rate of disappearance of the isotope from the circulation.(c) The Ashby (Group NN) method and the plasma volume and haematocrit method are inaccurate in patients with burns.