Bromide space,total body water,and sick cell syndrome

Displacements of the bromide space (Br-82-C, as a marker for the extracellular fluid compartment) are caused by an enhanced anatomical space and/or increased permeability of cells to bromide. The ratio Br-82-C: total body water (TBW) was evaluated to be 0.83±0.17 in critically ill patients (n=38) compared with the normal value of 0.46±0.04 (n=10). Because of normal TBW in critically ill patients (TBW=505±68 ml/kg), an increased bromide penetration into cells seems to be responsible for the enlarged ratio Br-82-C: TBW. Taking into consideration measurements in patients with malabsorption (Br-82-C: TBW=0.56±0.13; n=13) and carcinoma of the rectum and colon (Br-82-C: TBW=0.66±0.24; n=18) we think that the bromide space is a good measurement of the effective extracellular water.