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44 MARCH 2015 | EMSWORLD.com shock, and 1,239 patients with traumatic brain injury who presented to level I and II trauma centers from 81 different EMS sys- tems. They compared the patients' 28-day mortality and 6-month Glasgow Outcome Scale-extended score (for patients with trau- matic brain injury). The researchers found no suggestion that arriving at a trauma center greater than 60 minutes following injury impacted long-term outcomes. This paper supports a 2010 Annals of Emergency Medicine paper that reviewed over 3,600 trauma patients in shock—22% of whom died—and found shortened out-of-hospital times did not reduce a patient's risk for in- hospital death. They found increased EMS response, scene, transport or total EMS time did not increase mortality. 20 One subgroup proved the exception in Newgard, et al. Patients who presented in hemorrhagic shock during prehospital care and required emergent trauma center intervention did have better 28-day mor- tality when they arrived at a trauma cen- ter within 60 minutes. The same outcome improvement was not noted in head-injured patients. 20 These two papers have come out chal- lenging the golden hour since a 2001 lit- erature review could find no clinical evi- dence for the instruction of the concept. 21 Acknowledging the golden hour doesn't exist doesn't mean there is no time sen- sitivity to trauma center care. But it does mean there is not a definitive 60-minute threshold for decreasing morbidity or mor- tality. Challenging this myth helps push the notion that there are patients who only have minutes for EMS to bring lifesaving trauma care to their side. Rather than thinking about a mythical 60-minute benchmark, focus on determin- ing whether or not you have the tools to stabilize a patient, and if you do not then emergently transporting the patient directly to a trauma center that can provide such stabilization may outweigh the risks of emergency transport, which include pro- vider and further patient injury in the event of a motor vehicle collision. The Bottom Line Delivery of patients suffering from a traumatic injury to a trauma center within 60 minutes of their incident does not improve their out- comes, unless they present in hemorrhagic shock. Safe transport to a trauma center is more important than rapid transport. Myth #9: MAST Improves Outcomes The myth explained: First introduced dur- ing the Vietnam War, military anti-shock trousers (MAST) and pneumatic anti-shock garments (PASG) continue to be used in many EMS systems for the acute manage- ment of severe hemorrhagic shock and the stabilization of suspected pelvic fractures. Since their war-driven introduction, MAST have been popular, albeit poorly studied pre- hospital interventions. The theory behind MAST is that their compression of the distal and then proximal lower extremities—and abdomen, if necessary—increases venous return to central circulation, which increas- es cardiac output. The Evidence When all compartments of MAST are inflated to 90 mmHg, cardiac output does rise. 21 However, with time, cardiac output, systemic vascular resistance and venous return once again lower. No benefit is seen when MAST are inflated with less than 40 mmHg, and at most there is a 5% increase in central blood volume with full inflation. 22 While some studies have demonstrated MAST application does provide some ability to control otherwise uncontrolled hemorrhage within the MAST applica- tion region—in the legs or abdomen—the opposite effect is seen when the hemor- rhage location is not within the areas MAST compress. In these animal models survival time decreased from 60 to 10–18 minutes following MAST application. 22 The correla- tion to a human would be that if a patient is experiencing shock from a hemothorax, the MAST could worsen their hemorrhage. Only a few human patient studies have evaluated the use of MAST in the prehos- pital or emergency department settings for patients experiencing decompensated hemorrhagic shock. Two of these studies demonstrated no increased survival with MAST application, and one prospective ran- domized trial demonstrated a 6% increase in mortality with application. 22 Overall, while there are select instances where MAST can provide hemorrhage control and increase the odds of a patient being admitted to the hospital, there is little to no data suggest- ing they improve patient outcomes. This is because MAST have no impact on blood flow proximal to the renal arteries. 23 Finally, a Cochrane review determined MAST do not decrease a patient's hospital or ICU stay, and they have no impact on patient morbid - ity or mortality. 24 The Bottom Line MAST likely have no benefit for trauma patients, although there is limited infor- mation about patients with long transport times and lower extremity trauma and pelvic fractures. Given the paucity of evi- dence for any additional benefit, traction splints and pelvic binders appear to be bet- ter focused interventions for these injuries. Summary Evidence-based medicine will continually change the paradigm in which emergency medicine is practiced. Fifteen years ago tourniquets were a last resort and often considered a guaranteed way to lose a limb; today they are a gold standard in hemor- rhage control. Believing in, and having prac- ticed, medicine we later learn to be false doesn't make someone a bad provider, nor does it make them wrong. It simply means emergency medicine and EMS will continue to develop as a profession, and our body of evidence will continue to grow as we learn more about prehospital care. As we prepare to retire MAST, back- boards and lidocaine, and realize the gold- CONTINUING EDUCATION FOCUS ON DETERMINING WHETHER OR NOT YOU HAVE THE TOOLS TO STABILIZE A PATIENT.