1. Department of Anesthesiology; Centro Hospitalar São João; Oporto Portugal
2. Department of Health Information and Decision Sciences & Center for Health Technology and Services Research; Faculty of Medicine of the University of Porto; Oporto Portugal
3. Department of Surgery; Faculty of Medicine of the University of Porto; Oporto Portugal
4. Department of Experimental Biology; Faculty of Medicine of the University of Porto; Oporto Portugal