Objective: The purpose of this study was to determine if emergency tourniquet use saved lives. Summary Background Data: Tourniquets have been proposed as lifesaving devices in the current war and are now issued to all soldiers. Few studies, however, describe their actual use in combat casualties. Methods: A prospective survey of injured who required tourniquets was performed over 7 months in 2006 (NCT00517166 at ClinicalTrials.gov). Follow-up averaged 28 days. The study was at a combat support hospital in Baghdad. Among 2838 injured and admitted civilian and military casualties with major limb trauma, 232 (8%) had 428 tourniquets applied on 309 injured limbs. We looked at emergency tourniquet use, and casualties were evaluated for shock (weak or absent radial pulse) and prehospital versus emergency department (ED) tourniquet use. We also looked at those casualties indicated for tourniquets but had none used. We assessed survival rates and limb outcome. Results: There were 31 deaths (13%). Tourniquet use when shock was absent was strongly associated with survival (90% vs. 10%; P Ͻ 0.001). Prehospital tourniquets were applied in 194 patients of which 22 died (11% mortality), whereas 38 patients had ED application of which 9 died (24% mortality; P ϭ 0.05). The 5 casualties indicated for tourniquets but had none used had a survival rate of 0% versus 87% for those casualties with tourniquets used (P Ͻ 0.001). H emorrhage from injured extremities continues to be one of the leading sources of preventable death on the battlefield. 1-4 Data from recent conflicts involving US military personnel confirmed the continued importance of improving prehospital hemorrhage control. 3,[5][6][7] In response, the US Army implemented a design, testing, training, and fielding program for battlefield tourniquets, 8 -11 resulting in policy that all military personnel in theater carry tourniquets. As a result of this effort, tourniquets are now common on the battlefields of Iraq and Afghanistan, both in the hands of medical and nonmedical personnel.With the Tactical Combat Casualty Care initiative, the US military is not alone in establishing procedures and equipment for use of tourniquets in the prehospital environment by both medical and nonmedical personnel. 12,13 However, this renewed emphasis on tourniquets for prehospital hemorrhage control of extremity injuries is not agreed upon by all authors 14 -16 with some authors discouraging prehospital use of tourniquets altogether. [17][18][19][20] showed that tourniquet use is indicated in civilian trauma, albeit in a very small percentage of patients. However, the lifesaving capability of tourniquets has been unproven. Most of the controversy regarding the capacity of tourniquets to save lives versus tissue damage has been based more on speculation rather than actual data, as research in the human use of emergency tourniquets is limited. Clearly, the discussion would be better informed with actual data regarding these critical concerns. In 2003, we initiated data collection regarding e...