[1] Univ Colorado, Hlth Sci Ctr, Dept Anesthesiol, Denver, CO 80262 USA
[2] Univ Penn, Dept Anesthesiol, Philadelphia, PA 19104 USA
[3] Univ Penn, Dept Surg, Philadelphia, PA 19104 USA
[4] St James Hosp, Dept Anesthesia, Leeds LS9 7TF, W Yorkshire, England
[5] Azienda Osped Univ Pisa, Post Surg & Transplant Intens Care Unit, Pisa, Italy
[6] Univ Calif San Francisco, Dept Anesthesia & Perioperat Care, San Francisco, CA 94143 USA
[7] Univ Calif San Francisco, Dept Surg, San Francisco, CA 94143 USA
[8] Vanderbilt Univ, Dept Anesthesiol, Nashville, TN USA
[9] Univ Washington, Dept Anesthesiol, Seattle, WA 98195 USA
[10] Univ Colorado, Hlth Sci Ctr, Dept Prevent Med & Biometr, Denver, CO USA
[11] Univ Colorado, Hlth Sci Ctr, Dept Surg, Denver, CO 80262 USA