A Review of the Diagnosis and Treatment of Fluid and Electrolyte Disorders in the Horse

Abstract

SUMMARY Disturbances of fluid and electrolyte balance may occur in the horse as a consequence of many disease processes. Disorders may be classified into 3 main categories, primary water loss, mixed water and electrolyte depletion and acid base disturbances. This paper reviews the changes which occur with each type of disorder and discusses methods of diagnosis and assessment of such imbalances. The principles of treatment are described and the management of fluid replacement therapy in 3 of the disorders, mainly acute intestinal obstruction, inability to drink and diarrohea is discussed. RÉSUMÉ Les troubles hydriques et électrolytiques sont, chez le cheval, la conséquence de nombreux processus pathologiques. On peut classer ces troubles en trois catégories: ceux où la dominante est la déhydration simple, ceux impliquant un déséquilibre acides‐bases et ceux impliquant un déficit hydrique et électrolytique. Cet article indique les changements qui se produisent avec chaque catégorie de troubles; précise également les moyens ou méthodes de diagnostic de ces perturbations. L'essentiel des traitements est décrit, notamment pour ce qui a trait au remplacement des fluides dans trois affections: l'obstruction intestinale aigue, l'impossibilité de boire, les diarrhées. ZUSAMMENFASSUNG Störungen im Wasser‐ und Elektrolytgleichgewicht des Pferdes treten in der Folge mancher Krankheitsprozesse auf. Die Störungen können in 3 Kategorien eingeteilt werden: primärer Wasserverlust, gemischter Wasser‐ und Elektrolytverlust und Säure‐Basenstörungen. Dieser Artikel beschreibt die Veränderungen für jeden Typ derartiger Störungen und die Methoden zur Diagnostik und Einschätzung solcher Verschiebungen. Die Grundsätze der Therapie werden wiedergegeben; es folgt eine Diskussion über den Flüssigkeitsersatz bei 3 Störungen: akute, intestinale Obstruktion, Unfähigkeit der Wasser‐aufnahme und Durchfall.

External balance of water and electrolytes in the horse

“…In prescribing body fluid therapy in the horse, veterinary clincicians (Waterman 1977;Rose 1981) have used the value of 54 mllkg body weight, being the free water intake determined by Tasker (1967), to establish daily maintenance requirements, although the mean total daily water requirements of the horse were found by the latter to be 62 ml/kg. It was anticipated that under the conditions of the present experiments (mean ambient temperature 16 to 25"C), total daily water losses, and consequently requirements, would have been much greater.…”

“…In the study conducted by Tasker (1967), the reverse was the case, with mean faecal water output being 2.5 times that of mean urine volume. As a result, the assumption in veterinary literature that faecal water loss invariably exceeds urinary loss (Waterman 1977;Carlson 1979) in the normal animal, may need revision. There would appear to be a wide variation in faecal water content in the normal horse, dependent on ration composition and individual animal variation.…”

Incidence, diagnosis and treatment of postoperative complications in colic cases

“…Much has been written on the treatment of shock and detailed recommendations are given in several reviews (Waterman 1977;Burrows 1981;Moore, Garner, Shapland and Schaub 1981b;Rose 1981;Hood 1982). No single case is identical to another but some guidelines do exist.…”

A physiological approach to fluid and electrolyte therapy in the horse

“…For example, a PCV of 0.40 litredlitre may represent normality or significant dehydration (Mason 1972;Waterman 1977;Carlson 1979). Elevations of these parameters indicate fluid loss from the vascular compartment.…”