[1] Indiana Univ Sch Med, Dept Anesthesia, Indianapolis, IN 46202 USA
[2] Indiana Univ Sch Med, Dept Surg, Indianapolis, IN 46202 USA
[3] Indiana Univ Sch Med, Dept Biostat, Indianapolis, IN 46202 USA
[4] Richard M Fairbanks Sch Publ Hlth, Indianapolis, IN 46202 USA