David Crippen1, Mitchell Levy2, Robert Truog3, Leslie Whetstine4 and John Luce5
1University of Pittsburgh Medical Center, and Department of Emergency and Critical Care Medicine, St Francis Medical Center, Pittsburgh, Pennsylvania, USA
2Department of Critical Care, Rhode Island Hospital, Providence, Rhode Island, USA
3Multidisciplinary Intensive Care Unit, Children's Hospital, Farley, Boston, Massachusetts, USA
4Medical Ethics, Duquesne University, Pittsburgh, Pennsylvania, USA
5Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, San Francisco, USA