Postoperative Mediastinitis in Pediatric Cardiac Surgery: Clinical Characteristics, Management and Risk Factors for Mortality.

Objectives: The aim is to describe the clinical features, management and outcomes of postoperative mediastinitis in children following cardiac surgery and to identify risk factors for mortality.

Methods: We retrospectively reviewed all cases of mediastinitis in children following congenital heart surgery over a 10-year period (2013-2023) at Necker Hospital, a tertiary care center.

Results: Cumulative incidence of mediastinitis was 0.74% [95% confidence interval (CI): 0.56-0.96] with 57 cases of 7665 interventions. Median age at surgery was 12 days (6-146), with 58% of patients younger than 1 month. Thirty-four patients (60%) had delayed sternal closure. The most frequent germs were Staphylococcus spp. (45%), Gram-negative bacteria (36%) and fungi (9%). All patients had surgical debridement: 46 (81%) in the operating room and 11 (19%) in the intensive care unit (ICU). Median length of stay was 21 days (13-30) in the ICU and 35 days (28-48) until hospital discharge. The mortality rate was 27%, with 12 of 15 deaths occurring in the ICU. In univariate analysis, mortality risk factors were surgical revision in the ICU compared with the operating room [odds ratio (OR): 4.9; 95% CI: 1.3-19.9], delayed sternal closure superior to 3 days (OR: 5.0; 95% CI: 1.3-16.5) and fungal mediastinitis (OR: 14.9; 95% CI: 2.0-185.4). In the multivariate analysis, only fungal infection remained a significant risk factor for mortality (OR: 25.4; 95% CI: 2.7-608).

Conclusion: Mediastinitis is a rare complication of neonatal cardiac surgery, with a low incidence (0.74%) in this tertiary referral center. However, mortality from this condition remains high, with fungal infections identified as the main mortality risk factor.