Evaluation of the i-STAT hand-held chemical analyser during treadmill and endurance exercise

This study examined the accuracy and precision of a hand-held, chemical analyser, i-STAT, in measuring selected blood constituents which may be of use in the diagnosis and management of metabolic disorders found in exercising horses. Venous blood samples were taken from 3 Thoroughbred geldings, fit and trained to exercise on a treadmill, both before and after exercise at a speed sufficient to elicit VO2max. The samples were analysed both with the i-STAT and with in-house analysers to compare the values of pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), bicarbonate (HCO3), lactate and base excess (BE). The i-STAT demonstrated acceptable accuracy and precision for determination of pH, PO2 and PCO2, and lactate. We concluded that these parameters could be reliably evaluated by the i-STAT. The i-STAT was further evaluated at veterinary checkpoints during a 60 and 100 mile endurance ride. Because a built-in thermostat prevents function when the temperature of the analyser is outside the optimum range (16-30 degrees C), it was necessary to insulate the i-STAT from extreme ambient temperatures. As this portion of the study was conducted in warm temperatures, the appropriate insulation was to maintain the i-STAT in an ice-cooled container except during actual blood analyses. Further investigation into the feasibility of using hand-held chemical analysers at the veterinary checkpoints during endurance rides is recommended.