Hemodynamic disturbances in premature infants born after chorioamnionitis: association with cord blood cytokine concentrations

Abstract

Chorioamnionitis and elevated cord blood inflammatory cytokine concentrations are associated with detectable disturbances of systemic and cerebral hemodynamics in premature newborns. Fifty-five infants (25-31 wk gestation) were enrolled. Chorioamnionitis was defined by placental histology. IL-6, IL-1beta, and tumor necrosis factor-alpha were quantified by ELISA. Blood pressure, heart rate, cardiac output, stroke volume, fractional shortening, and middle cerebral artery blood flow velocities were measured at 3 +/- 1 h after birth. Chorioamnionitis was evident in 22 placentas and was associated with increased IL-6 (p < 0.001), IL-1beta (p = 0.035), and heart rate (p = 0.027); and with decreased mean and diastolic blood pressure (p = 0.026 and p = 0.019, respectively). IL-6 concentration correlated inversely with systolic, mean, and diastolic blood pressures. Right ventricular cardiac output was elevated (p = 0.028) in infants with fetal vessel inflammation. Maternal temperature >or=38.0 degrees C and newborn immature-to-total white blood cell ratio >or=0.4 were associated with significant decreases in left ventricular fractional shortening (p = 0.001 and p = 0.005, respectively). Neither chorioamnionitis nor elevated cytokine concentrations were associated with changes in middle cerebral artery Doppler blood flow velocities. Chorioamnionitis and elevated cord blood IL-6 concentrations are associated with decreased blood pressure in premature newborns. Inflammation of the fetal vessels and nonspecific indicators of infection are associated with disturbances in cardiac function. Infants with chorioamnionitis and elevated cytokine concentrations do not manifest changes in cerebral Doppler indices within the first few postnatal hours. We speculate that cytokine-associated systemic hemodynamic disturbances in premature infants born after chorioamnionitis predispose such infants to perinatal brain injury.