2.1. Objective:

• Primary Objective: To compare outcomes of patients with extremity injuries presenting with or without pre-hospital tourniquet placement.

2.2. Study Outcome Measures

• Primary Outcome: Incidence of arrival in shock (SBP <90)
• Secondary Outcomes: Demographics, comorbidities, mechanism of injury, cause of injury, diagnosis codes, procedure codes, Injury Severity Scale, Abbreviated Injury Scale, operative management vs. non-operative management, radiologic findings, pathologic findings, tourniquet effectiveness (as determined both subjectively by trauma surgeon and objectively by presence vs. absence of pulse below level of tourniquet application), total number of units of blood products transfused within first 24 hrs, total number of units of blood products for index admission, type of blood products or other fluid given, hospital length of stay, ICU length of stay, ventilator days, infectious complications, other complications, discharge disposition, 24 hr mortality, overall mortality.

This is a prospective, observational study. All patients who present to the participating ED's who meet inclusion/exclusion criteria will be identified by the treating trauma surgeons. Data collected will include basic patient demographics, data regarding the patient's injuries, data regarding tourniquet use, and data regarding outcomes. Please see the attached data collection tool for specifics (Appendix 12.1). Data will be collected prospectively in an observational manner using the data collection tool. Data collected on individual collection sheets will be de-identified. We plan to complete the data collection and analysis by 01\01\2021.

Inclusion Criteria:

≥ 18 y/o Patients with extremity injuries

• With a tourniquet in place OR
• Who the treating physician deems could have benefited from tourniquet placement

Exclusion Criteria:

• Children
• Prisoners
• Pregnant women
• Patients with non-traumatic bleeding requiring tourniquet use

All patients who present to the participating ED's who meet inclusion/exclusion criteria will be identified by the treating trauma surgeons.