Real-time readings of the regional oxygen saturation (rSO(2)) using near-infrared spectroscopy (NIRS) during the aortic arch surgery can provide an early detection of perfusion or oxygenation abnormalities.
Background: Aortic arch repair techniques using low-flow antegrade selective cerebral perfusion have been standardized to a certain degree. However, some of the often-stated beneficial effects have never been proven. Especially, the existence of an adequate continuous flow in both cerebral hemispheres during the surgical procedure still remains unclear as the monitoring of an effective perfusion remains a nonstandardized technique.
Methods: Seventeen patients underwent surgical reconstruction of the aortic arch due to aortic aneurysm surgery (adult group n = 8 patients) or of the hypoplastic aortic arch due to hypoplastic left heart syndrome (HLHS) or aortic coarctation (infant group n = 9 patients) under general anesthesia and mild hypothermia (adult group 28 degrees C; infant group 25 degrees C). Mean weights were 92.75 +/- 14.00 kg and 4.29 +/- 1.32 kg, and mean ages were 58.25 +/- 10.19 years and 55.67 +/- 51.11 days in the adult group and the infant group, respectively. The cerebral O(2) saturation measurement was performed by continuous plotting of the somatic reflectance oximetry of the frontal regional tissue on both cerebral hemispheres (rSO(2), INVOS; Somanetics Corporation, Troy, MI, USA).
Results: During low-flow antegrade perfusion via innominate artery, continuous plots with similar values of O(2) saturation (rSO(2)) in both cerebral hemispheres were observed, whereas a decrease in the rSO(2) values below the desaturation threshold correlated with a displacement or an incorrect positioning of the arterial cannula in the right subclavian artery.
Conclusions: Continuous monitorization of the cerebral O(2) saturation during aortic arch surgery in adults and infants is a feasible technique to control an adequate cannula positioning and to optimize clinical outcomes avoiding neurological complications related to cerebral malperfusion.