PACUPod is your trusted source for AI-infused evidence-based insights tailored to advanced clinical pharmacists and physicians. Each episode dives into the latest primary literature, covering medication-focused studies across emergency medicine and critical care. We break down study designs, highlight key findings, and objectively discuss clinical implications—without the hype—so you stay informed and ready to apply new evidence in practice. Whether you’re preparing for board certification or striving for excellence in patient care, PACUPod helps you make sense of the data, one study at a time.
Hey everyone, and welcome to this week's Emergency Medicine Pharmacy podcast! I'm diving into a timely article titled “Early intramuscular adrenaline administration is associated with improved survival from out-of-hospital cardiac arrest.” This was published in *Resuscitation* in August twenty-twenty-four, authored by Palatinus and colleagues, with a P. M. I. D. of three-eight-eight-five-seven-eight-four-seven.
So, what's this study about? It's a before-and-after study looking at the implementation of an early, first-dose intramuscular adrenaline E. M. S. protocol for adult out-of-hospital cardiac arrests. The pre-intervention phase ran from January twenty-ten to October twenty-nineteen, and the post-intervention period was from November twenty-nineteen to May twenty-twenty-four. It was conducted at a single urban, two-tiered E. M. S. agency. The participants were adult, non-traumatic out-of-hospital cardiac arrest patients who met the criteria for adrenaline use. The intervention was a single dose of five milligrams of intramuscular adrenaline given initially. All other care, including subsequent intravenous or intraosseous adrenaline, followed international guidelines. The primary outcome they measured was survival to hospital discharge. Secondary outcomes included time from E. M. S. arrival to first adrenaline dose, survival to hospital admission, and favorable neurologic function at discharge.
Out of one-thousand, four-hundred and five out-of-hospital cardiac arrests, four-hundred and twenty, or twenty-nine point nine percent, received intramuscular adrenaline, while nine-hundred and eighty-five, or seventy point one percent, received usual care. Fifty-two patients in the post-intervention period received their first dose via I. V. or I. O. and were included in the standard care group for analysis. An interesting note is that the intramuscular adrenaline group was younger and had higher rates of bystander C. P. R., but all other characteristics were similar. Crucially, the time to adrenaline administration was significantly faster for the intramuscular cohort: a median of four point three minutes versus seven point eight minutes in the standard care group. Compared with standard care, intramuscular adrenaline was associated with improved survival to hospital admission: thirty-seven point one percent versus thirty-one point six percent, with an adjusted odds ratio of one point three-seven. They also saw higher survival to hospital discharge: eleven point zero percent versus seven point zero percent, with an adjusted odds ratio of one point seven-three. And finally, there was increased favorable neurologic function at discharge: nine point eight percent versus six point two percent, with an adjusted odds ratio of one point seven-two.
You know, this study builds on existing research. For instance, a systematic review and meta-analysis by Ran and colleagues in twenty-twenty, P. M. I. D. three-two-four-four-one-one-eight-four, linked early pre-hospital adrenaline with increased survival to discharge and favorable neurological outcomes. Then there's the PARAMEDIC two randomized controlled trial, published by Nichol et al. in twenty-fifteen, P. M. I. D. two-seven-six-three-nine-nine-five-zero, which showed adrenaline improved survival rates in out-of-hospital cardiac arrest patients, though it did not significantly enhance neurological outcomes. There are also studies, like one by Aukland et al. in twenty-twenty-one, P. M. C. I. D. eight-two-four-four-four-three-one, demonstrating that intramuscular adrenaline can reduce time to drug delivery and potentially improve survival outcomes. However, it's important to mention that concerns about immortal time bias in before-and-after designs, as noted by Semple et al. in *Resuscitation Journal*, highlight the ongoing need for randomized controlled trials.
So, what does this mean for us as E. M. pharmacists? Well, these findings suggest that pharmacists should consider supporting protocols that enable earlier adrenaline administration via intramuscular injection in out-of-hospital cardiac arrest, especially in situations where intravenous or intraosseous access might be delayed. Advocacy for E. M. S. training in intramuscular adrenaline delivery and staying updated on resuscitation guidelines could be important roles for us. The potential for faster drug delivery and improved survival outcomes is a significant factor here.
Of course, like any study, this one has its limitations. It's a before-and-after design, which makes it susceptible to confounding and various biases, including that immortal time bias we just touched on. There was also an imbalance in age and bystander C. P. R. between the groups, which the authors attempted to adjust for, but it's still a point to consider. And being a single-center E. M. S. study, its generalizability to other regions or E. M. S. systems might be limited. However, it's worth noting its strengths: it included a large cohort of one-thousand, four-hundred and five patients with real-world E. M. S. implementation, it demonstrated rapid intramuscular adrenaline administration reducing time to first dose, and it looked at multiple relevant outcomes, including neurological function.
In conclusion, this single-center study found that an initial intramuscular adrenaline dose, as an adjunct to standard care, was associated with significantly improved survival to hospital admission, survival to hospital discharge, and favorable neurological function in out-of-hospital cardiac arrest. These results strongly support the need for further investigation through randomized controlled trials to fully assess the potential benefit of intramuscular adrenaline delivery in this critical patient population.