[1] School of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre
[2] Anaesthesia and Perioperative Medicine Service, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre
[3] Cardiology Service, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre
[4] Department of Statistics, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre
[5] Department of Surgery, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre
[6] Anaesthesia and Perioperative Medicine Service, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, RS, Porto Alegre