Background

Little is known regarding the effect of cardiopulmonary bypass (CPB) reoxygenation on cardiac function following tetralogy of Fallot repair. We hypothesized that hyperoxic reoxygenation would be more strongly associated with myocardial dysfunction in children with tetralogy of Fallot.

Methods

We investigated the association of perfusate oxygenation (PpO2) associated with myocardial dysfunction among children aged 6–72 months who underwent complete repair of tetralogy of Fallot in 2012–2018. Patients were divided into two groups: lower PpO2 group (≤ 250 mmHg) and higher PpO2 (> 250 mmHg) group based on the highest value of PpO2 during aortic occlusion. The odd ratio (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression models.

Results

This study included 163 patients perfused with lower PpO2 and 213 with higher PpO2, with median age at surgery 23.3 (interquartile range [IQR] 12.5–39.4) months, 164 female (43.6%), and median body mass index 15.59 (IQR 14.3–16.9) kg/m². After adjustment for baseline, clinical and procedural variables, patients with higher PpO2 were associated with higher risk of myocardial dysfunction than those with lower PpO2 (OR 1.770; 95% CI 1.040–3.012, P = 0.035). Higher PpO2, lower SpO2, lower pulmonary annular Z-score, and longer CPB time were independent risk factors for myocardial dysfunction.

Conclusions

Association exists between higher PpO2 and myocardial dysfunction risk in patients with tetralogy of Fallot, highlighting the modulation of reoxygenation during aortic occlusion to reduce cardiovascular damage following tetralogy of Fallot repair.