Pre-hospital Hypoxemia in Trauma Patients

Trauma patients in the United States frequently receive high-flow high-concentration supplemental oxygen in the pre-hospital setting, yet their physiologic need is rarely known. Providing oxygen to everyone regardless of need may seem straightforward, but the practice has extensive implications in logistically challenging areas such as a combat arena or mass casualty event, and is not supported by care guidelines. Indeed, too much oxygen can be harmful for some patients.1, 2 If it is the case, that not all trauma patients require oxygen, this would decrease the logistical burden of providing oxygen in the pre-hospital environment. No study has yet been performed that describes the proportion of patients requiring oxygen, the amount of oxygen they require, and whether or not oxygen is beneficial to outcomes. This prospective observational cohort investigation aims to bridge the knowledge gap surrounding the need and possible benefits or harms arising from oxygen therapy. In our Emergency Medical Services (EMS) systems, the written standard of care is to provide oxygen only to maintain oxygen saturation at 95% or when hemorrhagic shock or traumatic brain injury are suspected.3 We will observe patterns of oxygen treatment and outcome for patients treated according to this written standard of care, and compare this to the treatment and outcomes for patients transported by EMS units who continue their usual practice pattern.

Specifically, we aim to:

1. Identify the proportion of trauma patients who are hypoxemic or who have traumatic brain injury or hemorrhagic shock at the time of initial EMS contact
2. Identify the proportion of trauma patients who develop hypoxemia or hemorrhagic shock while in the pre-hospital setting
3. Identify differences in clinically important outcomes associated with treatments driven by written standard of care compared with the usual practice pattern of EMS units. These outcomes include requirement for advanced airway management, hospital and intensive care unit lengths of stay, and disposition (including in-hospital and 30-day mortality)
4. Determine the amount of oxygen (Liters per minute) required to reverse hypoxemia