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 rSO2-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.