1. Center for Resuscitation Science, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden (G.R., M. Ringh, M.J., L.S., A.C., T.D., P.N., S.F., A.N., J. Hollenberg).
2. The Centre for Pre-hospital Research in Western Sweden, University of Borås, and Sahlgrenska University Hospital, Gothenburg (J. Herlitz).
3. Department of Anesthesiology and Intensive Care, Norrtälje Hospital, Sweden (S.F.).
4. Department of Surgical Sciences, Anesthesiology and Intensive Care Medicine, Uppsala University, Sweden (S.R.).
5. Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, Section of Cardiology, Stockholm, Sweden (M. Rosenqvist).