Abstract 11063: Impaired Cerebral Autoregulation in Preoperative Newborn Infants with Congenital Heart Disease
Objectives: Our goal was to characterize cerebral autoregulation (CA) in preoperative newborn infants with congenital heart disease (CHD).
Methods: This is a prospective pilot study of full-term neonates with CHD requiring intensive care. Monitoring consisted of continuous mean arterial pressure (MAP) and cerebral near infrared spectroscopy (SctO2) for 24 hours starting the first day of life. Data were divided into 20 minute epochs for correlation analysis, with significant low frequency coherence between MAP and SctO2 defining impaired CA. Pressure passivity index (PPI) was calculated as percentage of epochs with abnormal CA per subject. Arterial oxygen saturation (SaO2), blood gases, hemoglobin (Hgb), end-tidal CO2, medications, and anthropometric data were collected. Cerebral fractional tissue oxygen extraction FTOE = (SaO2 - SctO2)/SaO2, was calculated. Spearman correlation coefficients were used to identify associations between PPI and patient data. Logistic linear models with repeated measures were used to identify associations with impaired CA.
Results: We evaluated 18 infants from October 2011 to May 2012. Mean gestational age was 38.5 ± 0.8 weeks. Support included prostaglandin (18), mechanical ventilation (10), inotropes (6), and sedatives (11). Subjects were studied for 23.3 ± 1.9 hours beginning 6.7 ± 3 hours from birth. Epochs with SaO2 variability >5% were excluded, leaving 65 ± 8 epochs per subject, 1167 total for analysis. All subjects demonstrated impaired CA, mean PPI 16 ± 14%, range 6-57%. PPI correlated with gestational age (r = -0.5, p =.03) but not birth weight or head circumference. Factors associated with impaired CA during an epoch included lower MAP (p = .001), lower Hgb (p < .001), higher FTOE (p < .001), and lack of sedation (p = .003).
Conclusion: Full-term newborns with severe forms of CHD display fluctuating pressure-passive cerebral perfusion in a spectrum similar to what has been described in premature newborns. The associations between abnormal CA and lower Hgb, higher FTOE, and lack of sedation suggest that impaired oxygen delivery and increased cerebral metabolic demand may overwhelm autoregulatory capacity in these infants. Further studies are needed to determine the significance of impaired CA in this population.
- Congenital heart disease
- Cerebrovascular circulation
- Pediatric cardiology
- Pediatric cardiac intensive care
- © 2012 by American Heart Association, Inc.