1. Department of Anaesthesia and Pain Management, Wellington Regional Hospital, Wellington, New Zealand
2. Institute of Fundamental Sciences, Massey University, Palmerston North, Manawatu, New Zealand
3. Specialist Anaesthetist, Department of Anaesthesia and Pain Management, Wellington Regional Hospital, Wellington, New Zealand
4. University of Auckland Medical School, University of Auckland, Auckland, New Zealand
5. Department of Anaesthesia and Intensive Care, Palmerston North Hospital, Palmerston North, Manawatu, New Zealand