Author Contributions:Study concept and design: Jenkins, Sabel, Sarcone, Long, Morgan, Price, Mehler, and Burman. Acquisition of data: Jenkins, Sabel, Sarcone, and Steele. Analysis and interpretation of data: Jenkins, Knepper, Sabel, Long, Haukoos, Biffl, Steele, and Burman. Drafting of the manuscript: Jenkins. Critical revision of the manuscript for important intellectual content: Jenkins, Knepper, Sabel, Sarcone, Long, Haukoos, Morgan, Biffl, Steele, Price, Mehler, and Burman. Statistical analysis: Knepper and Sabel. Administrative, technical, and material support: Sarcone, Long, Haukoos, Steele, Price, and Mehler. Study supervision: Morgan and Burman.