1. The Respiratory Division, Vancouver General Hospital, Vancouver, British Columbia, Canada
2. Misericordia Hospital, University of Alberta, Edmonton, Alberta, Canada
3. the Medical Department, Astra Pharma Inc, Toronto, Ontario, Canada
4. The Respiratory Division, St Paul’s Hospital, Vancouver, Canada
5. the Emergency Department, St Paul’s Hospital, Vancouver, Canada
6. Department of Emergency Medicine, Vancouver General Hospital, Vancouver, British Columbia, Canada