Abstract: Background: There is a need to evaluate the physiological effects of resuscitative fluids administered to sick neonatal foals admitted to intensive care units. Hypothesis/Objectives: The hypothesis was that administration of isotonic replacement solutions would result in improvements in blood gas parameters in sick neonatal foals. We aimed to compare electrolytes, acid base variables and blood gas results pre- and post-fluid therapy. Animals: 115 neonatal foals. Methods: Retrospective study of sick neonatal foals that received isotonic replacement fluids upon admission to a neonatal ICU. Foals had measurement of venous blood gases and electrolytes before and after initial fluid therapy. Variables were compared using a Wilcoxon signed-rank test. Results: The study included 115 foals. PlasmaLyte was administered to 92% of the foals. Significant decreases were found in the following analytes after fluid therapy: PCV, pre- and post-fluids (39[22-54] vs 35[21-51%]; P< 0.0001); Total protein pre- and post-fluids (5.2[3.1-11.0] vs 4.9[2.9-10.6 g/dL]; P< 0.0001); Lactate, pre- and post-fluids (3.4[0.8-25] vs 2.6[0.6-16 mmol/L] P< 0.0001); AG, pre- and post-fluids (10.9[-1.4-37.1] vs 10.5[-3.3-28.4] P=0.002). The following had significant increases after fluids: Sodium, pre- and post-fluids (137[109-161] vs 137[112-158 mEq/L] P=0.007); Bicarbonate, pre- and post-fluids (28.0[10.6-34.3] vs 28.3[11.2-37.7 mEq/L] P< 0.0001); Base excess [BE] pre- and post-fluids (2.9[-18.6-9.5] vs 3.5[-20.7-11.7] P< 0.0001); abbreviated strong ion difference (SID), pre- and post-fluids (35[14-53] vs 36[16-52] P=0.0003); Glucose, pre- and post-fluids (122[4-336] vs 137[16-438 mg/dL] P=0.0004). Conclusions and clinical importance: Markers of hydration (PCV, TP) and metabolic acidosis (BE, bicarbonate, anion gap, SID, and lactate) improved with fluid therapy in ill neonatal foals.
