Accepted for Publication: January 11, 2015.
Published Online: June 17, 2015. doi:10.1001/jamasurg.2015.0306.
Study concept and design: Czarnetzki, Frossard, Giostra, Spahr, Waeber, Lysakowski, Tramèr.
Acquisition, analysis, or interpretation of data: Czarnetzki, Elia, Frossard, Giostra, Spahr, Waeber, Pavlovic, Tramèr.
Drafting of the manuscript: Czarnetzki, Elia, Frossard, Tramèr.
Critical revision of the manuscript for important intellectual content: Elia, Frossard, Giostra, Spahr, Waeber, Pavlovic, Lysakowski, Tramèr.
Statistical analysis: Elia.
Obtained funding: Czarnetzki, Tramèr.
Administrative, technical, or material support: Giostra, Spahr.
Study supervision: Frossard, Tramèr.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by institutional funds from the Division of Anesthesiology, Geneva University Hospitals.
Role of the Funder/Sponsor: The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Additional Contributions: Béatrice Gil-Wey, Claudine Carera, and Patrick Huwiler, Division of Anesthesiology, Geneva University Hospitals, served as research assistants and received no financial compensation outside of their usual salaries.