The effect of early, prehospital norepinephrine use in patients with traumatic shock on mortality is unknown. Recent existing observational evidence from single system data (US, France, Japan) are conflicting. The investigators hypothesize that prehospital norepinephrine is associated with decreased mortality when used in patients with traumatic shock.

Prehospital hypotension is associated with worse clinical outcomes in patients who sustain traumatic injuries. Administration of vasoactive medications, including norepinephrine, is not advocated in North American trauma systems due to the belief that vasopressors will worsen clinical outcomes and increase mortality. However, in European trauma systems prehospital vasopressor administration is included as part of the guidelines for the management of hypotension and hemorrhagic shock. There are multiple physiologic explanations for why prehospital vasopressor administration may be useful in patients with traumatic shock, such as providing adequate blood pressure to maintain vital signs until arrival at the trauma center, allowing adequate organ perfusion in the setting of low blood flow, and supplementing decreased hormone production in the later stages of hemorrhagic shock.

The purpose of this retrospective study is to investigate if prehospital norepinephrine administration is associated with decreased mortality in patients with traumatic shock. The investigators will collect patient data from previously collected sources of information and trauma databases from three separate locations: the TRAUMABase consortium in Paris, France; TRENAU trauma database from Grenoble, France; and the R Adams Cowley Shock Trauma Center in Baltimore, MD, USA. The investigators will perform statistical modeling to propensity score match patients that received prehospital vasopressors with patients that did not receive prehospital vasopressors and assess the association with 24-hour and 28-day mortality.

Inclusion Criteria:

• Age 18-90 years
• Blunt traumatic mechanism of injury
• Admitted to the trauma center from the scene of injury
• Systolic blood pressure during prehospital transport or at admission to the trauma center <100 mmHg

Exclusion Criteria:

• Penetrating mechanism of injury
• No vital signs at the scene of injury
• Prehospital cardiac arrest
• Transferred to the trauma center from another hospital

The study population will be collected from the previously collected trauma database at three separate locations, as previously described. These databases are collected, maintained, and managed by professional medical staff.