E63 - Hyponatremia in Horses with Septic Lower Airway Disease Correlates with Severity of Inflammation

Abstract: < strong>Background: Hyponatremia is common in horses with bacterial pleuropneumonia, but no further characterization of this abnormality is reported.< br>< br> < br>< br>< strong>Objectives: To describe clinical variables and plasma sodium concentration [Na] at admission in horses with septic lower airway disease and to evaluate any association of plasma [Na] with markers of systemic inflammation.< br>< br> < br>< br>< strong>Animals: Medical records of horses that between 2008 and 2021 had a transtracheal aspirate performed, evidence of pulmonary disease on ultrasonography and/or radiography and plasma [Na] assessed by direct ion-selective-electrode. < br>< br> < br>< br>< strong>Methods: Clinical and clinicopathological variables between hypo- and normonatremic patients were compared. Correlation of plasma [Na] with variables of interest was evaluated. < br>< br> < br>< br>< strong>Results: 31/56 horses had hyponatremia, median and 95% confidence interval (CI) value 131.7mmol/L (130.1–132.7) (RR 134.2–138.39mmol/L). Hyponatremic patients had greater inflammatory responses than normonatremic patients: higher mean rectal temperature (38.7±0.7C°; P = 0.006), fibrinogen (445±143.1mg/dL; P < 0.001) and median triglyceride (79.5mg/dL; 95% CI 31–142; P = 0.04) concentrations. Negative correlations were found between plasma [Na], fibrinogen (ρ=-0.51; P < 0.001), and triglyceride (ρ=-0.59; P < 0.001) concentrations, and between plasma [Na] and neutrophil count in hyponatremic patients (ρ=-0.4; P = 0.02). Presence or absence of pleural effusion did not influence degree of hyponatremia. Median length of hospitalization was greater in hyponatremic patients (10 days; 95% CI 6 – 12; P = 0.05). < br>< br> < br>< br>< strong>Main limitations: Retrospective study without urine [Na] measurement.< br>< br> < br>< br>< strong>Conclusions and Clinical Relevance: Severity of inflammation during septic pneumopathy correlates with hyponatremia development. Characterization and treatment of hyponatremia in these cases should improve outcome.