1. Anesthesiology Department, Hospital de Santa Marta, Centro Hospitalar Universitário Lisboa Central, Rua de Santa Marta, 50, 1169-024 Lisbon, Portugal
2. Epidemiology and Statistics Unit, Research Centre, Centro Hospitalar Universitário Lisboa Central, Rua Jacinta Marto, 1169-045 Lisbon, Portugal
3. Centre of Statistics and Its Applications (CEAUL), Faculty of Sciences, University of Lisbon, 1749-016 Lisbon, Portugal
4. Independent Researcher, Lisbon 1400, Portugal
5. Cardiothoracic University Clinic and Department, Hospital de Santa Marta, Centro Hospitalar Universitário Lisboa Central, Rua de Santa Marta, 50, 1169-024 Lisbon, Portugal