ABSTRACT
Objectives: To compare regional cerebral tissue oxygen saturation (rScO2) changes during cardiac surgery in children with ventricular septal defect (VSD) and tetralogy of Fallot (TOF). Methods: A total of 60 children aged 3~36 months were enrolled (28 in VSD group 32 in TOF group). rScO2was monitored by Fore-Sight near-infrared spectroscopy device. rScO2, pulse oxygen saturation (SpO2), systolic pressure, diastolic pressure, heart rate, stroke volume index, cardiac index, systemic vascular reststance index the maximal slope of systolic upstroke (dp/dt max) were obtained at following time points: after anesthesia induction (t0), pericardium opening (t1), 5 min after cardiopulmonary bypass (CPB) initiation (t2), 5 min before separation from CPB (t3), separation from CPB (t4), post-modified ultrafiltration (t5), end of surgery (t6). Results: (1) The lowest rScO2value was observed at separation from CPB (t4), and which was significantly lower than that at t0(P<0.05) for both groups; rScO2, stoke volume index, cardiac index, and dp/dt max at t5were significantly higher than at t4(all P<0.001) for both groups. (2) rScO2and SpO2were significantly higher at t5and t6than at t0(both P<0.05) in TOF group. rScO2at t0-t2was significantly lower in TOF group than in VSD group (both P<0.05). rScO2increased more significantly after modified ultrafiltration and rScO2was positively correlated with SpO2at t0and t1(r=0.35, P<0.05 and r=0.64,P<0.01) in TOF group. (3) In the total cohort, rScO2was positively correlated with age, weight at t0, t1, t3, t4, t5, t6(all P<0.01). After modified ultrafiltration, the increase in cardiac index was positively correlated with increase in rScO2(r=0.41, P<0.05), and the amount of cardiac index and rScO2increases were negatively correlated with age (r=-0.30;r=-0.34, both P<0.05). Conclusions: rScO2is closely related with age and weight. Cerebral oxygen delivery before biventricular surgical correction is lower in TOF group than in VSD group, and the cerebral oxygenation improves significantly after surgical repair. Modified ultrafiltration could significantly improve systemic hemodynamics and rScO2, and TOF children and younger children benefit more from modified ultrafiltration. Pre- and post-separation from CPB period is vulnerable to cerebral desaturation, it is therefore of importance to maintain the cerebral oxygen delivery-consumption balance at these periods for children with TOF and VSD undergoing surgical repair.