Determination of body water compartments in neonatal foals by use of indicator dilution techniques and multifrequency bioelectrical impedance analysis

Objective-To determine values for total body water (TBW), extracellular fluid volume (ECFV), intracellular fluid volume (ICFV), and plasma volume (PV) in healthy neonatal (< 24 hours old) foals and to create a multifrequency bioelectrical impedance analysis (MF-BIA) model for use in neonatal foals. Animals-7 healthy neonatal foals. Procedures-Deuterium oxide (0.4 g/kg, IV), sodium bromide (30 mg/kg, IV), and Evans blue dye (1 mg/kg, IV) were administered to each foal. Plasma samples were obtained following an equilibration period, and the TBW, ECFV, ICFV, and PV were calculated for each foal. An MF-BIA model was created by use of morphometric measurements from each foal. Results-Mean ± SD values were obtained for TBW (0.744 ± 0.024 L/kg), ICFV (0.381 ± 0.018 L/kg), ECFV (0.363 ± 0.014 L/kg), and PV (0.096 ± 0.015 L/kg). The 95% limits of agreement between the MF-BIA and indicator dilution techniques were within ± 2 L for TBW and ECFV. Conclusions and Clinical Relevance-Fluid volumes in neonatal foals were found to be substantially larger than fluid volumes in adult horses. Multifrequency bioelectrical impedance analysis may be a useful technique for predicting TBW, ICFV, and ECFV in neonatal foals.