Early predictors of bacterial pneumonia infection in children with congenital heart disease after cardiopulmonary bypass: a single-centre retrospective study

Abstract

Objectives The objective of this study was to evaluate the early predictors of bacterial pneumonia infection in children with congenital heart disease (CHD) after cardiopulmonary bypass (CPB).Design Retrospective study.Setting A freestanding tertiary paediatric hospital in China.Participants Patients admitted to the hospital due to CHD who underwent open-heart surgery.Outcome measures We retrospectively reviewed and analysed data from 1622 patients with CHD after CPB from June 2018 to December 2020 at the Children’s Hospital of Nanjing Medical University. Enrolled patients were assigned to an infection group or a non-infection group according to the presence of postoperative bacterial pneumonia infection, and the differences in clinical indicators were compared. Potential predictors were analysed by multivariate logistic regression analysis and area under the curve (AUC) analysis.Results Among the 376 patients (23.2%) in the infection group, the three most common bacteria were Streptococcus pneumoniae in 67 patients (17.8%), Escherichia coli in 63 patients (16.8%) and Haemophilus influenzae in 53 patients (14.1%). The infection group exhibited a lower weight (8.0 (6.0–11.5) kg vs 11.0 (7.5–14.5) kg, p<0.001). In the infection group, procalcitonin (PCT) (ng/mL: 4.72 (1.38–9.52) vs 1.28 (0.47–3.74), p<0.001) and C reactive protein (CRP) (mg/L: 21.0 (12.1–32.0) vs 17.0 (10.0–27.0), p<0.001) levels were significantly greater than those in the non-infection group. Binary logistic regression analysis revealed that weight, PCT and CRP were independent risk factors for pulmonary bacterial infection after CPB. The AUCs of weight, PCT, CRP and PCT+CRP for predicting pulmonary bacterial infection after CPB were 0.632 (95% CI 0.600 to 0.664), 0.697 (95% CI 0.667 to 0.727), 0.586 (95% CI 0.554 to 0.618) and 0.694 (95% CI 0.664 to 0.724), respectively, and the cut-off values were ≤10.25 kg, ≥4.25 ng/mL, ≥6.50 mg/L and ≥0.20, respectively. The sensitivities were 69.7%, 54.0%, 93.9% and 70.2%, and the specificities were 53.5%, 77.7%, 19.4% and 59.1%, respectively.Conclusions In our study, weight, PCT and CRP were found to be independent predictors of pulmonary bacterial infection after CPB. Moreover, PCT was the most specific predictor, and CRP was the most sensitive independent predictor that might be beneficial for the early diagnosis of pulmonary bacterial infection after CPB in patients with CHD.