221 Impact of Balloon Atrial Septostomy on Cerebral Oxygen Saturation and Oxygen Extraction in Neonates with Transposition of the Great Arteries

Abstract

Background: Neonates with transposition of the great arteries (TGA) are at risk of hypoxic-ischemic brain-injury. Balloon atrial septostomy (BAS) improves mixing of oxygen-saturated and -desaturated blood. We determined the impact of BAS on regional cerebral tissue oxygen saturation (rcSO2) and fractional cerebral tissue oxygen extraction (FTOE) in neonates with TGA.Methods: Term neonates with TGA were included. RcSO2 was measured with near-infrared spectroscopy 2 hours (hrs) before, 2hrs after, and 24hrs after BAS for a two-hour period. Transcutaneous arterial oxygen saturation (tcSaO2) was measured simultaneously. FTOE was calculated: FTOE=(tcSaO2-rcSO2)/tcSaO2. In neonates who did not need BAS on clinical grounds, according to the attending cardiologist, tcSaO2 and rcSO2 were measured twice for a two-hour period: once within 24hrs after admission and once 24hrs later. Data were analysed by multi-level analysis and Mann-Whitney-U-test.Results: Nine neonates (median age: 1 day [range:0-18]) underwent BAS and four neonates (median age: 4 days [range:0-6]) did not. RcSO2 increased after BAS (from mean 37% to 49% to 64% [p=0.000]), as did tcSaO2 (from mean 68% to 81% to 84% [p=0.000]). FTOE decreased after BAS (from mean 0.46 to 0.40 to 0.25 [p=0.000]). Neonates who did not need BAS showed higher baseline rcSO2 and tcSaO2 compared to neonates who did (median 57% vs 35% [p=0.020] and 88% vs 77% [p=0.034], respectively). After BAS, there were no differences between both groups.Conclusion: In neonates with TGA in need of BAS, rcSO2 increased and FTOE decreased following BAS. This suggests improved cerebral oxygenation, which, possibly, protects against hypoxic-ischemic brain-injury.