Primary diagnosis for ECMO retrieval. Additional file 3 shows the numbers and frequencies of primary cause for ECMO retrieval within each age group and category. Diagnosis followed by number in italic expresses subdiagnosis within any of the primary diagnoses. In 199 of the 202 primary ECMO transports where treatment was commenced at our department, the primary diagnosis could be retrieved from our database. ECPR extracorporeal cardiopulmonary resuscitation; P/F ratio, ratio between partial pressure of oxygen in blood to fraction of inspired oxygen, calculated as PaO2 (mmHg)/FiO2 (%/100); OI Oxygenation index, calculated as [(FiO2 × Mean Airway Pressure (cmH2O)]/PaO2 (mmHg); BctPneu bacterial pneumonia; VirPneu viral pneumonia; ARF acute respiratory failure; ARDS acute respiratory distress syndrome; Bridge: bridge to lung transplant; PCPneu Pneumocystis jirovecii (Pneumocystis carinii) pneumonia; MAS meconium aspiration syndrome; CDH congenital diaphragmatic hernia; PPHN persistent pulmonary hypertension in the newborn; PFC persistent fetal circulation; CAD capillary alveolar dysplasia; AMI acute myocardial ischemia.