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  • Author or Editor: Douglas T. Byars x
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Objective—To determine the effect of hydroxyethyl starch (HES) on colloid oncotic pressure (π) during fluid resuscitation of hypoproteinemic horses and to evaluate the clinical usefulness of direct and indirect methods for determination of π before and after infusion of a synthetic colloid.

Design—Prospective clinical study.

Animals—11 hypoproteinemic horses.

Procedure—Horses received IV infusions of 8 to 10 ml of a 6% solution of HES/kg (3.6 to 4.5 ml/lb) of body weight during fluid resuscitation. Blood samples were obtained for determination of plasma measured colloid oncotic pressure (πmeas) and plasma total protein and albumin (A) concentrations. Plasma globulin concentration (G) was calculated as the difference between plasma total protein and albumin concentrations. Calculated values for colloid oncotic pressure (πA + G) were determined by use of a predictive nomogram previously developed for horses.

Results—There was no significant difference between the means of πmeas and πA + G at the beginning of HES infusion. After HES infusion, the mean of πmeas was increased significantly from baseline for 6 hours. Mean plasma total protein and albumin concentrations and πA + G were decreased significantly from baseline for 24 hours. Differences between mean πmeas and πA + G after HES infusion were significant for 24 hours.

Conclusions and Clinical Relevance—There was good agreement between plasma πmeas and πA + G in blood samples obtained from hypoproteinemic horses immediately before infusion of HES. Use of a predictive nomogram did not, however, account for the oncotic effect of HES. Results of comparison of πmeas to πA + G after HES infusion suggest that a significant oncotic effect was maintained for 24 hours in the study horses. (J Am Vet Med Assoc 2001;218: 1130–1135)

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in Journal of the American Veterinary Medical Association


Objective—To create a mathematical model to assist in early prediction of the probability of discharge in hospitalized foals ≤ 7 days old.

Study Design—Prospective study.

Animals—1,073 foals.

Procedures—Medical records from 910 hospitalized foals ≤ 7 days old for which outcome was recorded as died or discharged alive were reviewed. Thirty-four variables including historical information, physical examination findings, and laboratory results were examined for association with survival. Variables associated with being discharged alive were entered into a multivariable logistic regression model. Accuracy of the model was validated prospectively on data from 163 foals.

Results—Factors in the final model included age group, ability to stand, presence of a suckle reflex, WBC count, serum creatinine concentration, and anion gap. Sensitivity and specificity of the model to predict live discharge were 92% and 74%, respectively, in the retrospective population and 90% and 46%, respectively, in the prospective population. Accuracy of an equine clinician's initial prediction of the foal being discharged alive was 83%, and accuracy of the model's prediction was 81%. Combining the clinician's prediction of probability of live discharge with that of the model significantly increased (median increase, 12%) the accuracy of the prediction for foals that were discharged and nonsignificantly decreased (median decrease, 9%) the accuracy of the predication for nonsurvivors.

Conclusions and Clinical Relevance—Combining the clinician's initial predication of the probability of a foal being discharged alive with that of the model appeared to provide a more precise early estimate of the probability of live discharge for hospitalized foals.

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in Journal of the American Veterinary Medical Association