Complications after surgery/interventions: None

confirmed infection = any evidence of infection requiring antibiotic therapy which is confirmed on microbiological culture (despite perioerative antibiotic prophylaxis)

wound infection = any evidence of infection requiring antibiotic therapy which is confirmed on a positive wound swap (despite perioperative prophylaxis)

respiratory = pleural effusions(drainage required), pneumothorax, haematothorax

cardiogenic NEC = Bell stage 2 or 3, infants with abdominal distension, blood in stool together with abdominal x-ray or ultrasound showing bowel oedema, pneumastosis or pneumoperitoneum

Stroke = clinical or MRI

LCO syndrome = combination of:

• mean blood pressure lower than 5th percentile of age-related normal values and/or increased inotropics/vasopressors required to achieve this blood pressure goal
• difference between the arterial oxygen saturation (SaO2) and central venous oxygen saturation (ScvO2) value of >35% or Scv=2<60% for non cyanotoc patients
• urine output <1ml/kg/hr
• peripheral temperature <32°C in the absence of the use of target temperature management
• serum lactate >2mmol/L