1. Department of Anesthesiology and Perioperative Medicine Mayo Clinic Jacksonville Florida USA
2. Department of Anesthesia University of Iowa Hospitals and Clinics Iowa City Iowa USA
3. Department of Gastroenterology University of Alabama at Birmingham Birmingham Alabama USA
4. Baptist Medical Center South Montgomery Alabama USA
5. Department of Anesthesiology University of Alabama at Birmingham Birmingham Alabama USA
6. School of Public Health University of Alabama at Birmingham Birmingham Alabama USA