1. Glasgow Royal Infirmary Campus; School of Medicine; College of Medicine, Veterinary and Life Sciences; University of Glasgow; Glasgow UK
2. Department of Anaesthesia, Pain and Critical Care Medicine; Glasgow Royal Infirmary Infirmary and Stobhill Ambulatory Hospital; Glasgow UK
3. Queen Elizabeth University Hospital; Glasgow UK
4. Department of Anesthesiology; Foothills Medical Centre; Calgary Alberta Canada