Relationship of intraoperative cerebral oxygen saturation to neurodevelopmental outcome and brain magnetic resonance imaging at 1 year of age in infants undergoing biventricular repair

Abstract

Background: Near-infrared spectroscopy monitoring of cerebral oxygen saturation (rSo(2)) has become routine in many centers, but no studies have reported the relationship of intraoperative near-infrared spectroscopy to long-term neurodevelopmental outcomes after cardiac surgery.

Methods and results: Of 104 infants undergoing biventricular repair without aortic arch reconstruction, 89 (86%) returned for neurodevelopmental testing at 1 year of age. The primary near-infrared spectroscopy variable was the integrated rSo(2) (area under the curve) for rSo(2) <or=45%; secondary variables were the average and minimum rSo(2) by perfusion phase and at specific time points. Psychomotor and mental development indexes of the Bayley scales, head circumference, neurological examination, and abnormalities on brain magnetic resonance imaging did not differ between subjects according to a threshold level for rSo(2) of 45%. Lower Psychomotor Development Index scores were modestly associated with lower average (r=0.23, P=0.03) and minimum (r=0.22, P=0.04) rSo(2) during the 60-minute period after cardiopulmonary bypass but not with other perfusion phases. Hemosiderin foci on brain magnetic resonance imaging were associated with lower average rSo(2) from postinduction to 60 minutes post cardiopulmonary bypass (71+/-10% versus 78+/-6%, P=0.01) and with lower average rSO(2) during the rewarming phase (72+/-12% versus 83+/-9%, P=.003) and during the 60-minute period following cardiopulmonary bypass (65+/-11% versus 75+/-10%, P=0.009). In regression analyses that adjusted for age <or=30 days, Psychomotor Development Index score (P=0.02) and brain hemosiderin (P=0.04) remained significantly associated with rSo(2) during the 60-minute period following cardiopulmonary bypass.

Conclusions: Perioperative periods of diminished cerebral oxygen delivery, as indicated by rSo(2), are associated with 1-year Psychomotor Development Index and brain magnetic resonance imaging abnormalities among infants undergoing reparative heart surgery. Clinical Trial Registration- URL: http://clinicaltrials.gov. Unique identifier: NCT00006183.

Figure 1

Psychomotor Development Index (PDI) as a function of average rSO₂ from off-CPB to 60 minutes post-CPB by scatter plot. The solid line was derived by unadjusted linear regression of the data, and the dashed lines delimit the 95% confidence interval. The linear regression P value shown is for the effect of average rSO₂ from off-CPB to 60 minutes post-CPB on PDI, adjusting for social class.

Figure 2

Box plots of average rSO₂ from off-CPB to 60 minutes post-CPB by hemosiderin status. A solid bar within the box represents the median value, the upper boundary of the box represents the 75^th percentile, and the lower boundary of the box represents the 25^th percentile. The vertical lines extend to the 10^th and 90^th percentiles, with more extreme observations plotted as filled circles. The logistic regression P value shown is for the effect of average rSO₂ from off-CPB to 60 minutes post-CPB on hemosiderin.