Effect of a 24-hour infusion of an isotonic electrolyte replacement fluid on the renal clearance of electrolytes in healthy neonatal foals.
OBJECTIVE
To determine the effects of a 24-hour infusion of an isotonic electrolyte replacement fluid (IERF) on weight, serum and urine electrolyte concentrations, and other clinicopathologic variables in healthy neonatal foals.


METHODS
4 healthy 4-day-old foals.


METHODS
Prospective study.


METHODS
An IERF was administered to each foal at an estimated rate of 80 mL/kg/d (36.4 mL/lb/d) for 24 hours. Body weight was measured before and after the infusion period. Urine was collected via catheter during 4-hour periods; blood samples were collected at 4-hour intervals. Variables including urine production; urine and serum osmolalities; sodium, potassium, and chloride concentrations in urine and serum; urine and serum creatinine concentrations; urine osmolality-to-serum osmolality ratio (OsmR); transtubular potassium gradient (TTKG); and percentage creatinine clearance (Cr(cl)) of electrolytes were recorded at 0, 4, 8, 12, 16, 20, and 24 hours during the infusion period. Immediately after the study period, net fluid and whole-body electrolyte changes from baseline values were calculated.


RESULTS
Compared with baseline values, urine and serum sodium and chloride serum concentrations, urine and serum osmolalities, OsmR, and percentage Cr(cl) of sodium and chloride were significantly increased at various time points during the infusion; urine production did not change significantly. After 24 hours, weight, TTKG, serum creatinine concentration, and whole-body potassium had significantly decreased from baseline values.


CONCLUSIONS
Results suggest that administration of an IERF containing a physiologic concentration of sodium may not be appropriate for use in neonatal foals that require maintenance fluid therapy.
Buchanan
Benjamin R
BR
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
Sommardahl
Carla S
CS
Rohrbach
Barton W
BW
Andrews
Frank M
FM
D000818:Animals; D000831:Animals, Newborn / Q000097:blood / Q000652:urine*; D001774:Blood Chemical Analysis / Q000662:veterinary; D001834:Body Water / Q000737:chemistry; D002712:Chlorides / Q000097:blood / Q000652:urine; D003404:Creatinine / Q000097:blood / Q000652:urine; D004573:Electrolytes / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D005260:Female; D006736:Horses / Q000097:blood / Q000652:urine*; D007262:Infusions, Intravenous / Q000662:veterinary; D007552:Isotonic Solutions; D008297:Male; D008657:Metabolic Clearance Rate; D009994:Osmolar Concentration; D011188:Potassium / Q000097:blood / Q000652:urine; D011446:Prospective Studies; D012964:Sodium / Q000097:blood / Q000652:urine; D016482:Urinalysis / Q000662:veterinary; D014546:Urinary Catheterization / Q000662:veterinary
D002712:Chlorides; D004573:Electrolytes; D007552:Isotonic Solutions; D012964:Sodium; D003404:Creatinine; D011188:Potassium