173 - Cerebral And Renal Saturations Progressively Decrease In Neonates With Congenital Heart Defects And Diastolic Steal Prior To Intervention Period: A Prospective Study

Poster Number: 173
Publication Number: 173.2919

Background: Limited data exists on the trends of cerebral (CSat) and renal (RSat) saturations measured by near infrared spectroscopy (NIRS) of neonates with a congenital heart defect (CHD) during the first days of life in the pre-interventional setting. Fractional tissue oxygen extraction (FTOE) measured by NIRS and peripheral oximetry (SpO2) reflects the relationship between oxygen delivery (DO2) and consumption (VO2). We hypothesized that retrograde aortic flow in aorta would be associated with adverse CSat/Rsat profiles and altered FTOE.

Objective: Describe CSat/RSat trends in the first week of life in neonates with CHD.

Design/Methods: Single-center prospective observational study recruiting newborns admitted to the intensive care for a CHD, born at >34 weeks. CSat/RSat were monitored until day 7 and averaged hourly. Daily echocardiograms were performed. Presence/absence of retrograde flow in post-ductal aorta was assessed on last day of monitoring. FTOE was calculated with the formula: [SpO2-(CSat or RSat)]/ SpO2. Pre-ductal SpO2 was used for the cerebral FTOE, and post-ductal for the renal FTOE. Random mixed effect models were constructed to evaluate the association between NIRS/FTOE trends and retrograde flow.

Results: Out of 135 infants screened, we recruited 49 newborns that met inclusion/exclusion criteria, out of which 27 (55%) had retrograde flow. Mean gestational age (GA) was 38.5 and was similar between groups. Birth weight (BW), Apgar at 5 minutes, sex and C-section frequency was similar between groups. Prostaglandins infusion (PGE) was more common in the retrograde group (p < 0.001). Patients were monitored up to a median of 82 and 76 hours of life for retrograde and non-retrograde group, respectively (p=NS). Mean CSat and RSat decreased progressively in the preoperative period in both groups. The decrease was more profound in RSat of babies with ductal steal phenomenon (Table Panel A and B, Figure). Trends of cerebral and renal FTOE are outlined in the Figure. Random mixed effect models outlined that retrograde flow was significantly associated with lower Csat and Rsat, and higher cerebral FTOE (Table Panel C).

Conclusion(s): Ductal steal may exacerbate end-organ injury in neonates with CHD. Our cohort of CHD with aortic retrograde flow demonstrated significantly lower Csat and Rsat through time. Furthermore, in the retrograde group, the relationship between cerebral oxygen delivery and consumption was altered, possibly due to altered blood flow distribution. Future studies should evaluate if this may be contributive to the increased burden of cerebral injury within this population of infants.