(E32) Echocardiography in Hypoxemic Neonatal Foals: Preliminary Results

Abstract:

Background: Hypoxemic newborn infants often show echocardiographic abnormalities. Regrettably, no echocardiographic data exists in hypoxemic neonatal foals (HYPO). Hypothesis/

Objectives: To compare selected echocardiographic parameters between HYPO, sick non-hypoxemic (SICK), and healthy neonatal foals (HEALTHY). Animals: 35 foals ≤5 days (12 HYPO, 8 SICK, and 15 HEALTHY).

Methods: Retrospective study on foals examined via transthoracic echocardiography within the first 5 days of life. A right parasternal short-axis view was used to measure left ventricular diameters horizontally (LVD1) and vertically (LVD2) in diastole (LVD1d, LVD2d) and systole (LVD1s, LVD2s). Diastolic and systolic eccentricity indices were calculated from these diameters. Aortic diameters at the Valsalva sinus (AoDsinus) and sinotubular junction (AoDSTJ) were measured in diastole from the left ventricular outflow tract view. Pulmonary artery systolic and diastolic diameters (PADd, PADs), pulmonary artery distensibility index, AoDsinus:PADd, and AoDSTJ:PADd ratios were also calculated. Presence of tricuspid regurgitation was noted. Parameters were compared using the Kruskal-Wallis test with Bonferroni correction.

Results: Age and body weight showed no significant differences between groups. HEALTHY had larger LVD1d than HYPO and SICK, and larger LVD2d than SICK. Additionally, SICK had smaller AoDsinus than HEALTHY. No other statistically significant differences were observed. Only two HEALTHY and one HYPO showed tricuspid regurgitation. Conclusions and clinical importance: Echocardiographic signs of left ventricular volume depletion were observed in SICK and HYPO, with no significant differences between these two groups. Further studies with larger sample sizes and additional echocardiographic parameters, including those assessing right heart dimensions and function, are needed to better characterize HYPO.