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Abstract

Introduction: Myocardial dysfunction has not been evaluated in children with septic shock despite the assumption that it is a significant determinant of outcome when compared to adults. Hypothesis: Its prevalence in adults with septic shock is 40-60%, but its prevalence in children is not known. Methods: Thirty patients with fluid refractory septic shock were prospectively studied by echo <24 hours after admission to the pediatric intensive care unit (PICU). Evaluation included measures of left ventricular (LV) size and function, mitral valve (MV) inflow velocities in early (E) and late (A) diastole, MV annular velocities in systole (s’) and early (e’) and late (a’) diastole, and MV annular acceleration during isovolumic contraction (IVA). LV myocardial performance index (MPI) to assess combined systolic/diastolic function was calculated as the sum of isovolumic contraction and relaxation times divided by ejection time. All data were compared to normal children using Z scores. LV systolic dysfunction was defined as ejection fraction or shortening fraction Z score <-2. LV diastolic dysfunction was defined as E/e’ Z score >2. Measured secondary outcomes included vasoactive inotropic score (VIS), troponin, acute kidney injury (pediatric RIFLE score), and 28-day mechanical ventilation free duration. Results: Mortality for the 30 patients (mean 9.5 ± 7 yrs; range 10 days-21 yrs) was 7%. The prevalence of LV systolic and/or diastolic dysfunction was 53% (16/30). Eleven (37%) had systolic dysfunction; 10 (33%) had diastolic dysfunction; 5 (17%) had both. Systolic dysfunction was significantly associated with IVA (P = 0.05), s’ Z score <-2 (P= 0.005), and MPI Z score >2 (P= 0.03). Systolic and/or diastolic dysfunction was also significantly associated with VIS (P=0.006), troponin (P=0.007), and RIFLE score (P=0.02) but not with ventilation free duration (P= 0.12). Kaplan Meier analysis for duration of PICU and hospital stay was not different between those with and without dysfunction. Conclusions: The prevalence of myocardial dysfunction is similar in children and adults with septic shock. Although myocardial dysfunction is associated with some measures of poor clinical outcome, it does not affect PICU and hospital length of stay.