Total body water and ECFV measured using bioelectrical impedance analysis and indicator dilution in horses.

The research aims to refine a method for estimating total body water, extracellular fluid, and intracellular fluid volumes in horses using bioelectrical impedance analysis and indicator dilution techniques, a discovery that can enhance the predictability of such measurements in healthy, resting horses.

Research Context and Methods

• The researchers mainly sought to achieve two objectives: understanding how body water is divided in horses using indicator dilution techniques and simultaneously measuring bioelectrical impedance at different frequencies. This was to help formulate predictive equations that can help approximate the volumes of total body water (TBW), extracellular fluid volume (ECFV), and intracellular fluid volume (ICFV).
• They tested on eight horses and ponies with different body weights. Catheters were placed in the jugular veins of these horses, through which different indicators were introduced, such as deuterium oxide, sodium thiocyanate, and Evans blue to help measure TBW, ECFV, and plasma volume (PV).
• Bioelectrical impedance was then calculated via a tetrapolar electrode setup, with pairs of electrodes attached over the knee and hock.

Key Findings

• The research yielded specific sizes of TBW, ECFV, and PV per kg of body mass for the studied horses.
• There was a significant linear correlation among the measured variables. This correlation paved the way for the prediction of TBW, ECFV, ICFV, and PV based on horse length or height along with impedance measurements.

Conclusion and Implications

• The study concluded that the use of bioelectrical impedance analysis (BIA) could be effective in improving the predictability of estimates of ECFV and PV in rested and sufficiently hydrated horses in a non-invasive way.
• This means that the developed predictive models based on these findings can lead to more accurate diagnosis and treatment strategies for equine health conditions related to fluid imbalance, without causing discomfort to the horses through non-invasive methods.