Objective: Impact of the decrease of regional cerebral oxygen saturation (rSO2) on postoperative delayed awakening after total aortic arch replacement (TAR) was validated.
Methods: From 2008 to 2013, 143 consecutive patients underwent TAR using selective antegrade cerebral perfusion. rSO2 was monitored using near-infrared spectroscopy. We calculated a percent decrease of rSO2 (%-D) immediately after rewarming according to the following formula: %-D=rSO2 (X1)-rSO2 (X2)/rSO2 (X1)×100 (%), where rSO2 (X1) was measured at the beginning of rewarming, and rSO2 (X2) was measured 10 min later. Delayed awakening was defined as patients not waking up for more than 6 h after the termination of anaesthesia.
Results: The average time to wake up was 3.6±2.0 h. Fourteen patients showed delayed awakening. %-D showed a positive linear relationship to awakening time (y=0.67x-0.7, r=0.23, P=0.007) and receiver operating characteristic analysis showed %-D had a good predictive value for delayed awakening (area under the curve=0.84). %-D was significantly different between the delayed awakening and the normal group (7.1±5.1 vs 1.3±6.6%, P=0.002). Two patients (1.4%) who had multicomorbidity with higher %-D died in the hospital due to colon necrosis and sepsis. There were significant differences between patients with normal and delayed awakening in hospital mortality (P=0.04) and transient neurological deficit (TND, P=0.007).
Conclusion: The maintenance of rSO2 at the early phase of rewarming may be important to avoid delayed awakening or TND after TAR.
Keywords: %-decrease of rSO2; Delayed awakening; Near-infrared spectroscopy; Regional cerebral oxygen saturation; Total arch replacement.
© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.