Epicardial radiofrequency ablation for stand-alone atrial fibrillation under total video-assisted thoracoscopy has gained popularity in recent years. However, severe cardiopulmonary disturbances during the surgery may affect cerebral perfusion and oxygenation. We therefore hypothesized that regional cerebral oxygen saturation (rSO 2) would decrease significantly during the surgery. In addition, the influencing factors of rSO 2 would be investigated.
A total of 60 patients scheduled for selective totally thoracoscopic ablation for stand-alone atrial fibrillation were enrolled in this prospective observational study. The rSO 2 was monitored at baseline (T0), 15 min after anesthesia induction (T1), 15 minute after 1-lung ventilation (T2), after right pulmonary vein ablation (T3), after left pulmonary vein ablation (T4) and 15 minute after 2-lung ventilation (T5) using a near-infrared reflectance spectroscopy -based cerebral oximeter. Arterial blood gas was analyzed using an ABL 825 hemoximeter. Associations between rSO 2 and hemodynamic or blood gas parameters were determined with univariate and multivariate linear regression analyses.
The rSO 2 decreased greatly from baseline 65.4% to 56.5% at T3 ( P < .001). Univariate analyses showed that rSO 2 correlated significantly with heart rate (r = -0.173, P = .186), mean arterial pressure (MAP, r = 0.306, P = .018), central venous pressure (r = 0.261, P = .044), arterial carbon dioxide tension (r = -0.336, P = .009), arterial oxygen pressure (PaO 2, r = 0.522, P < .001), and base excess (BE, r = 0.316, P = .014). Multivariate linear regression analyses further showed that it correlated positively with PaO 2 (β = 0.456, P < .001), MAP (β = 0.251, P = .020), and BE (β = 0.332, P = .003).