High-frequency oscillatory ventilation for respiratory failure after congenital heart surgery: a retrospective analysis

Background: Pulmonary complications such as acute respiratory distress syndrome and refractory respiratory failure have been major causes of morbidity and mortality after cardiac surgery in children. Patients are usually transitioned to either high-frequency oscillatory ventilation (HFOV) or extracorporeal membrane oxygenation (ECMO) as "salvage therapy" when the maximal medical management and controlled mechanical ventilation (CMV) become ineffective. Methods: A retrospective review of paediatric patients who underwent congenital heart surgery and developed cardiorespiratory failure during their stay in a paediatric cardiac ICU, refractory to maximal CMV, was performed in the study. The outcomes as-sessed were respiratory variables such as SpO2, RR, oxygenation index (OI), P/F ratio, and ABG parameters in CMV and HFOV as predictors of survival. Results: Twenty-four children with cardiorespiratory failure were candidates for a tran-sition to either HFOV (n = 15) or VA ECMO (n = 9) for refractory hypoxaemia; of these 24 patients, 13 (54.16%) survived. PaO2 showed a significant improvement in the survi-vors (P = 0.03). Improvement in the PaO2/FiO2 (P/F ratio) after initiation of HFOV was as-sociated with survival (P < 0.001). pH, PaCO2, HCO3, FiO2, Paw, RR/Amp, SpO2, and OI also showed improvements in survivors but these were not statistically significant. The HFOV survivors had longer mechanical ventilation and ICU stay than non-survivors (P = 0.13). Conclusions: HFOV was associated with improved gas exchange for paediatric patients who developed post-cardiac surgery refractory respiratory failure. HFOV can be consid-ered as rescue therapy where ECMO has major financial implications.