1. Department of Mechanical Engineering, University of Canterbury, Dunedin, New Zealand.
2. Department of Intensive Care, Christchurch Hospital, Christchurch and Christchurch School of Medicine and Health Science, University of Otago, Dunedin, New Zealand.
3. Department of Mechanical Engineering, University of Canterbury; Dunedin, New Zealand.
4. Christchurch School of Medicine and Health Science, University of Otago, Dunedin, New Zealand.
5. Department of Mechanical Engineering, University of Canterbury and Christchurch School of Medicine and Health Science, University of Otago, Dunedin, New Zealand.