1. Department of AnesthesiologyUniversity Hospital of Gran Canaria Dr. Negrín Las Palmas de Gran Canaria Spain
2. Department of Medical and Surgical Science, University of Las Palmas de Gran Canaria Las Palmas de Gran Canaria Spain
3. Department of General and Digestive SurgeryUniversity Hospital of Gran Canaria Dr. Negrín Las Palmas de Gran Canaria Spain