Pharmacokinetics and clinical utility of sodium bromide (NaBr) as an estimator of extracellular fluid volume in horses.

The research study was conducted to understand the physiology of bromide in horses and its feasibility as a marker to calculate the extracellular fluid volume. Researchers found that extracellular fluid volume in horses can be accurately estimated using bromide concentrations.

Research Methodology

• The research was conducted on six healthy mares. Sodium bromide was administered to these mares through intravenous infusion at a dosage of 30 mg/kg of body weight.
• The infusion was provided over a span of 3 minutes. Blood samples before and at various time intervals ranging from 0.5 hours to 53 days post-infusion were collected for analysis.

Analyzing Pharmacokinetics

• Key indicators for bromide’s pharmacokinetics were measured, such as the harmonic mean of the elimination half-life, clearance, area under the curve, and volume of distribution (steady state).
• The elimination half-life averaged at 126 hours (5.2 days). Clearance was at 1.4 +/- 0.09 mL/(kg x h), area under the curve stood at 17,520 +/- 1,100 microg x h/mL, and volume of distribution (steady state) was found to be 0.255 +/- 0.015 L/kg.

Calculating Extracellular Fluid Volume (ECFV)

• The researchers then calculated the corrected bromide space using the volume of distribution (steady state) and the equilibrium serum bromide concentrations.
• The corrected bromide space, used as an estimation of extracellular fluid volume, was found to be 0.218 +/- 0.01 L/kg.

Conclusion

• The researchers concluded that it is possible to estimate the extracellular fluid volume in horses by measuring bromide concentrations in a serum sample taken prior to the infusion of sodium bromide and a sample taken five hours afterwards.
• This technique is beneficial in assessing equine health as it facilitates monitoring body fluid balances more accurately and can assist in early detection of possible diseases.