Baseline Values of Left Ventricular Systolic Function in Preterm Infants With Septic Shock: A Prospective Observational Study

Abstract

Background and Aim: Guidelines recommended that cardiac index (CI) of term infants with septic shock should reach the target level of 3.3–6.0L/(min⋅m2). However, there are still no standard values for preterm infants with septic shock. Herein, we investigated the functional echocardiographic baseline values of left ventricular (LV) systolic functional parameters at the onset of septic shock in preterm infants and possible correlations between baseline values and poor outcomes. Materials and Methods: This was a prospective, observational, and longitudinal single-center study. Eligible infants were monitored for LV systolic functional parameters using functional echocardiography at the onset of septic shock. The primary study outcome was the difference in the baseline value of LV systolic functional parameters in preterm infants with septic shock with different gestational age (GA) and birth weight (BW). The secondary outcome was septic shock-associated death or severe brain injury (including grade 3–4 intraventricular hemorrhage or periventricular leukomalacia). Results: In total, 43 subjects met the criteria, with a median GA of 321/7 weeks and BW of 1800 grams. No difference was observed in baseline values of LV systolic functional parameters among infants with different GA and BW. Infants were assigned to good and poor outcomes groups based on septic shock-associated death or severe brain injury. Out of 43 infants, 29 (67.4%) had good outcomes vs. 14 (32.6%) with poor outcomes. Stroke index (SI) [18.2 (11.1, 18.9) mL/m2 vs. 23.5 (18.9, 25.8) mL/m2, p = 0.017] and cardiac index (CI)[2.7 (1.6, 3.5) L/(min⋅m2) vs. 3.4 (3.0, 4.8) L/(min⋅m2), p = 0.015] in infants with poor outcomes were significantly lower (P < 0.05). Receiver operating characteristic (ROC) curve analysis showed that the cut-off values of SI and CI for predicting poor outcomes in preterm infants with septic shock were 19.5 mL/m2 (sensitivity, 73.9%; specificity, 81.8%) and 2.9L/(min⋅m2) (sensitivity, 78.3%; specificity, 72.7%), with area under the ROC curve (AUC) value of 0.755 and 0.759, respectively. Conclusion: There were no differences in baseline LV systolic functional values among preterm infants with septic shock with different GA and BW. However, preterm infants with SI<19.5mL/m2 and/or CI<2.9L/(min⋅m2) at the onset of septic shock were at high risk of having poor outcomes.