Medical Director's Corner

Welcome to the first edition of the Medical Director’s Corner. This is a new feature we are adding to the AirWaves newsletter. The goal is to provide education and updates to our prehospital and hospital colleagues that coincides with our in house education each quarter. This quarter we are talking TRAUMA!

As many of you are aware, most EMS providers in the region are now carrying Tranexamic Acid (TXA). This has been shown to be beneficial in trauma patients who require massive transfusion protocols (MTP) when given within three hours of the onset of injury. But how can you predict who may need MTP? The answer … the shock index (SI). The shock index is simply a ratio of the heart rate (HR) to the systolic blood pressure (SBP). A SI >0.8 has been shown to indicate a significantly higher likelihood of needing MTP (25% vs 3%)¹. To keep it simple, if the HR is equal to or greater than the SBP, there is a much higher chance your patient will need MTP and would likely benefit from TXA. These patients will also likely be receiving fluid resuscitation initially. But what fluid is best and how much?

Current ATLS recommendations suggest limiting fluid resuscitation to one liter of crystalloid solution but do not give recommendations regarding maintaining any blood pressure. A recent review showed evidence that limiting fluid resuscitation with crystalloid decreased mortality². Limiting crystalloids is thought to decrease coagulopathy, decrease development of hypothermia, and decrease acidosis associated with high volume saline resuscitation, all of which contribute to the “lethal triad” in trauma³. There has been more recent data suggesting that initial volume resuscitation with plasma decreases mortality. This has led the FDA to give our military access to freeze dried plasma in an emergency use authorization prior to FDA approval for civilian use⁴. A recent study also showed that prehospital administration of plasma as initial fluid resuscitation decreased mortality by 10% (23% vs 33%) in patients that were transported to trauma centers via air ambulance⁵. Based on this research and in collaboration with local trauma teams, West Michigan Air Care has started to carry two units of liquid plasma on every flight. This is in addition to the two units of (packed red blood cells) PRBCs which we had previously carried. Our goal is to bring the most up to date care to our patients in the region.

I hope you have liked this first edition and found it informative. Check back next quarter when we talk about adult critical care. Have a happy and safe summer!

By Chris Milligan, DO
Medical Director
West Michigan Air Care

References:

1. El-Menyar, Ayman, et al. “Shock Index: A Simple Predictor of Exploratory Laparotomy and Massive Blood Transfusion Protocol in Patients with Abdominal Trauma.” Journal of the American College of Surgeons, vol. 227, no. 4, 2018, doi:10.1016/j.jamcollsurg.2018.08.179.
2. Albreiki, Mohammed, and David Voegeli. “Permissive Hypotensive Resuscitation in Adult Patients with Traumatic Haemorrhagic Shock: a Systematic Review.” European Journal of Trauma and Emergency Surgery, vol. 44, no. 2, 2017, pp. 191–202., doi:10.1007/s00068-017-0862-y.
3. “Evidence-Based EMS: Permissive Hypotension in Trauma.” EMS World, 29 Jan. 2016, www.emsworld.com/article/12163910/evidence-based-ems-permissive-hypotension-in-trauma.
4. Commissioner, Office of the. “FDA Takes Action to Support American Military Personnel by Granting an Authorization for Freeze-Dried Plasma Product to Enable Broader Access While the Agency Works toward Approval of the Product.” U.S. Food and Drug Administration, FDA, www.fda.gov/news-events/press-announcements/fda-takes-action-support-american-military-personnel-granting-authorization-freeze-dried-plasma.
5. Sperry, Jason L., et al. “Prehospital Plasma during Air Medical Transport in Trauma Patients at Risk for Hemorrhagic Shock.” New England Journal of Medicine, vol. 379, no. 4, 2018, pp. 315–326., doi:10.1056/nejmoa1802345.