EMS World

DEC 2018

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EMSWORLD.com | DECEMBER 2018 55 A s you wait not-so-patiently for your relief to show up and send you home, you consider two calls you had today: a cardiac arrest and an MVC that resulted in a severely injured patient. You wonder if there is any- thing new in the literature that suggests potential changes to your management of these patients. As it happens, your relief shows up with four papers in her hands, eager to talk about their implications for your practice. The s e four pap er s—t wo on air way management in cardiac arrest, one on the use of epinephrine in cardiac arrest, and one on the effect of EMS-adminis- tered plasma in hemorrhaging trauma patients—are all well done and impor- tant to EMS medicine. As a paramedic, EMS physician, and data nerd, I'd like to describe these trial s and share some thoughts about what they mean. Airway Management in Cardiac Arrest: PART Results of the Pragmatic Air way Resus- citation Trial (PART), led by Dr. Henr y Wang, were published in JAMA this year. 1 This was a U.S.-based multicenter, pro- spective, pragmatic randomized trial of adult patient s with all- cause cardiac arrest. It compared the 72-hour sur vival of patients who had either endotracheal intubation (ETI) or a SGA (supraglottic air way; the King LT in this study) used as their first approach to air way man- agement. The trial involved 27 EMS a gencies across the U.S., including large urban providers and smaller suburban agencies that see only a few thousand patients a year. Each agency was randomized to use either the King or ETI for its initial air way attempts for several months, then switched to the opposite strategy. The vast majorit y (almost 99%) of intuba- tions were performed with direct lar yn- goscopy. Providers were given no addi- tional training in air way mana gement other than what their agency t ypically provided. Other than the initial air way strategy, they would treat all patients the way they normally would. In this fash- ion, the outcome would likely be similar if other, similar agencies adopted this strategy. This lack of additional training reflec ted the pra gmatic approach of the trial; this is actually a strength and makes it easier to extrapolate the results to other EMS systems. There were 3,004 patients with out- of-hospital cardiac arrest of any etiol- ogy (1,499 patients in the ETI-first group, and 1,505 in the LT-first group). The two groups were well matched in the areas likely to af fect sur vival. More patients were alive at 72 hours in the LT group (18.3%) than the ETI group (15.4%). This 2.9% improved sur vival was statistically significant (95% CI, 0.2%–5.6%). The authors' conclusion was that an initial strategy of a lar yngeal tube was supe- rior to endotracheal intubation in cardiac arrest. While some agencies are taking these results and changing their practice to use King LTs for cardiac arrest, there are some caveats to this study that will prevent me from doing so (for now) in my agen- cies. There are some methodologic nits to pick, but the most important issue here is the ETI per formance: First-pass suc- cess was only 51% with ETI. This is sub- stantially lower than the FPS rate in our system. Although there was no evidence in this study to suggest this, I suspect a large par t of the reason for worse out- comes with intubation can be attributed to poor performance. A g ai n , b e c au s e o f th e p r a g m ati c aspect of this study, these results are likely to be seen with many s ystems. Perhaps better intubation performance would erase the outcome difference seen in this study. Better performance, how- ever, isn't easy or cheap. If my agency is any indication, it takes a large investment in resources and training to build a QI and training s ys tem suf ficient to improve endotracheal intubation. Video lar yngos- copy will likely make this improvement easier for medics who do not intubate often. EMS agencies and medical direc- tors must take a hard look and decide if their resources are best spent on improv- ing intubation or using an SGA in cardiac arrest and focusing instead on optimizing other areas of care. One other aspect of this trial is worth m e n ti o n i n g : T h e r e w a s a g r o u p o f patients who had no advanced air way placed. Because of the analysis meth- odology, these patients were included in the analysis of the group to which they were randomized. This means if a patient was supposed to get an ETI but didn't get any air way, they would be analyzed along with all the patients who got ETIs. This is called an intention-to-treat analysis and is entirely appropriate. The challenge, though, is that more of the patients who had no advanced air way attempted but were analyzed in the LT group had char- acteristics favorable to a good outcome than did those in the ETI group (things like witnessed arrests, shor t response times, shockable rhy thms, or awaking prior to air way management). This may have biased the results in favor of the King LT. An additional analysis was per- formed to help understand the impact of this dif ference. It looked at sur vival b a s ed on the s trateg y ac tually us ed after eliminating those patients with no advanced air way attempted. This sen- sitivit y analysis showed no statistical dif ference in sur vival (LT 16.0% vs. ETI 13.5%, difference of 2.5% with a 95% CI, [-0.2%]–5.2%), erasing the benefit found in the primar y analysis. It is h elpf ul to think of w hy th e s e results might be. The theoretic benefit of the King LT is that medics do not have to interrupt compressions, while endo- tracheal intubation has frequently been EVIDENCE-BASED MEDICINE An initial strategy of a laryngeal tube was superior to endotracheal intubation in cardiac arrest.

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