Near infrared spectroscopy monitoring during pediatric aortic coarctation repair

Background: Near infrared spectroscopy (NIRS) measures regional tissue oxygenation continuously and noninvasively and may allow assessment of changes in regional perfusion in real time. Methods: We used NIRS monitoring to track real-time changes in regional oxygenation (rSO₂) above and below the aortic cross-clamp in patients undergoing aortic coarctation repair and routinely stored these data in an operative electronic data base. This allowed us to analyze the changes in rSO₂ during aortic coarctation repair for three pediatric age groups (neonates, infants <1 year, and children >1 year).Two site [cerebral (rSO₂-C) and somatic thoracodorsal (rSO₂-S)] rSO₂ monitoring was performed in patients undergoing aortic coarctation repair. Data for rSO₂ were analyzed across sites and age groups before, during and after cross-clamp. Results: Twenty-six patients were available for analysis (11 neonates, 5 infants and 10 children). The regional oxygenation below the cross clamp (rSO₂-S) declined significantly in all three age groups, but the decrease in neonates and infants <1 year of age was significantly greater than in the older children. Conclusions: Monitoring rSO₂-S provides real-time trend information of regional oxygenation below the aortic cross-clamp. The decline in rSO ₂-S during aortic cross-clamp was rapid and large in most neonates and young infants <1 year which suggests impairment of regional perfusion presumably because of a lack of adequate collateral circulation to the monitored regional tissue. In contrast, the rSO₂-S changed only to a minor degree in most infants and children >1 year, possibly because they had time to develop a more adequate collateral circulation around incomplete aortic obstruction.