Traditional and quantitative analysis of acid‐base and electrolyte imbalances in horses competing in cross‐country competitions at 2‐star to 5‐star level

Abstract

Background Early recognition and management of acid‐base, fluid, and electrolyte disorders are crucial for the maintenance of health and performance in equine athletes. Objectives To analyze changes in acid‐base and electrolyte status associated with exercise during cross‐country competitions at different levels using traditional and quantitative approaches. Animals Thirty‐eight eventing horses. Methods Prospective observational study. Jugular venous blood samples were collected before and after the cross‐country test of 25 international eventing competitions ranging from 2‐star (formerly 1‐star) to 5‐star (formerly 4‐star) level. Blood gas analysis was performed to determine pH, pCO2, Na+, Cl−, and K+ and calculate HCO3−, tCO2 base excess (BEECF), anion gap (AG), strong ion difference calculated from Na+, K+, Cl−, and lactate− (SID4), strong ion difference calculated from Na+, K+, and Cl− (SID3), strong ion gap (SIG), and total nonvolatile weak buffer concentration (Atot). Postexercise acid‐base imbalances, diagnosed on the basis of the traditional approach, and the simplified strong ion model were compared. Results Significant decreases in pH, Cl−, SID4, pCO2, HCO3−, tCO2, and BEECF as well as increases in K+, SID3, AG, TP, and Atot were observed between pre‐ and postexercise samples. The changes in acid‐base parameters were significantly affected by the competition level. Using the strong ion approach, a higher proportion of horses was diagnosed with postexercise metabolic acidosis. Conclusions and Clinical Importance Regarding the complex acid‐base changes in horses competing at cross‐country competitions, the quantitative approach provided a more detailed analysis of the different factors contributing to acid‐base balance than did the traditional approach.

Analytical Performance Evaluation of the New GEM® Premier™ 5000 in Comparison to the Epoc® Blood Gas Analyzer in Horses

“…Precision targets were met by the epoc machine for pH, PO 2 , Na + , K + , glucose, lactate, HCO 3 − , BE (ecf) and SO 2 , but not for PCO 2 , iCa 2+, HCT and Hb [ 14 ], while agreement was poor for Hct, Hb and BE when compared to the iSTAT or an ABL machine. Kirsch and co-workers [ 12 ] reported that the epoc was not meeting precision targets for pO 2 , pCO 2 and K + and that agreement was poor for pH, [HCO 3 − ] and [Na + ] when compared with the Cobas analyzer. Despite these variable results for precision and agreement with other machines, the epoc was chosen as a comparison machine for the GEM5000 in the present study, as its precision was generally accepted as satisfactory.…”

“…BGEA is especially indicated in patients in whom acid–base or electrolyte imbalances are suspected [ 1 , 2 , 3 ], such as in critically ill patients, where BGEA helps in monitoring patients and guides fluid support according to their needs. Likewise, the use of BGEA has been recommended to monitor exercising horses, as high-intensity exercise is associated with alterations in acid–base and electrolyte balance [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. In addition, arterial BGEA can be used to assess ventilation efficiency of the lungs [ 2 ], making it indicated for the monitoring of patients undergoing general anesthesia, patients suffering from cardiac or respiratory disease and critically ill foals [ 3 ].…”

Physicochemical Analysis of Mixed Venous and Arterial Blood Acid-Base State in Horses at Core Temperature during and after Moderate-Intensity Exercise

“…Previous studies that have applied Stewart’s physicochemical approach to acid-base analysis in exercising horses [ 10 , 11 , 12 , 13 , 39 , 47 ], as well as descriptive acid-base studies [ 4 , 5 , 48 , 49 ] have not applied temperature adjustments. High intensity exercise in horses results in large increases in core and peripheral temperatures [ 33 , 49 , 50 , 51 ], with core temperatures in excess of 43 °C reported at the end of high intensity exercise conducted in hot, humid conditions [ 49 ].…”

“…A third limitation is that temperature adjustments were applied using core body (PA) temperature, while temperatures in contracting muscles at the end of exercise approached 43 °C while peripheral temperatures only approached 39 °C [ 39 ]. Measurement variability can make it difficult to identify clear responses when the physicochemical approach is applied to small groups of animals because of the animal variability, in contrast to when the approach is used with individuals [ 13 , 28 ]. The animal variability reflects both the number of individual plasma variables that change as well as differences in strategies used to control each of the plasma variables over time [ 28 ].…”

“…There are numerous descriptive studies of acid-base balance in horses in response to different types of exercise [ 4 , 5 , 6 , 7 ], and as reviewed previously [ 8 ]. However, only a handful of studies have attempted to take a mechanistic approach to determine the physiological and physicochemical mechanisms that underly changes in plasma H + and TCO 2 concentrations [ 9 , 10 , 11 , 12 , 13 ]. Most studies are also hindered by the fact that jugular venous blood was sampled as the only blood source for analysis, and thus does not represent mixed venous blood nor arterial blood.…”