The Dirty Adrenaline (Epi) drip.

Background

This week we are looking at a paper from Central Australia on the use of a dirty adrenaline/epi drip. In their retrieval practice they often have to deal with patients in remote clinics that may be hours away from critical care facilities. Those patients are often seriously unwell with hypotension/shock which is a major problem when awaiting aeromedical retrieval. It’s different to Virchester, but even here there are certainly situations in prehospital/emergency care where there is a requirement for ongoing vasopressor support in settings where kit/people/pharmacy support is unavailable. One such situation is in the post cardiac arrest patient who requires ongoing inotropic support. In such scenarios, some clinicians have adopted a technique known as “dirty adrenaline,” a peripheral dilute adrenaline infusion. This treatment, though widely used and popular on social media platforms, lacks significant supporting literature.

Dirty adrenaline/epi refers to a rapidly prepared infusion of 1 mg adrenaline in 1 litre of 0.9% saline (1 mcg/mL), administered intravenously.

What kind of study is this?

This is a descriptive case series study that retrospectively examines patients who received peripheral dilute adrenaline infusions in remote clinics between January 2017 and October 2023. Data were collected from the Central Australian Retrieval Service’s database, focusing on patients receiving adrenaline infusions before patients were retrieved by an aeromedical service.

As an observational study, there is no control group, as it is designed to describe the characteristics, outcomes, and potential adverse effects associated with the use of dirty adrenaline in this specific pre-hospital setting. We must always be cautious with observational studies as they can be prone to bias, but they can tell us about current practice and may be useful to pick up any major hazards, which in this case is really important.

Tell me about the patients

57 patients were included in the study. The median age of the patients was 50 years, with an age range 2 to 96 years. The majority of the cohort were female (75%) and Indigenous Australians (87%), reflecting the demographics of Central Australia’s rural population.

Many patients had co-morbidities that heightened their risk for fluid overload. This was one of the main reasons for the use of vasopressors. Among the cohort:

• 28% had chronic kidney disease.
• 7% had heart failure.
• Several patients had both conditions, and some also suffered from rheumatic heart disease (much more common in this population but rare in Virchester).

The primary clinical indication for adrenaline infusions was septic shock, accounting for 70% of cases. Other diagnoses included cardiogenic shock, refractory anaphylaxis, status asthmaticus, haemorrhagic shock, and post-ROSC hypotension.

Hypotensive patients were discussed with a retrieval physician who directed the use of a dirty epi drip according to a predetermined protocol (see supplementary data as well worth a read). Changes to rate to titrate to effect were also directed by the retrieval physician. The dose range was untitled 1‐10microg/kg/hr (though highest in the study was 6microg/Kg/Hr). They were typically aiming for an SBP of 100mmHg. Whilst not explicit I think they controlled the rate with a pump of some sort. That would make sense and be the most appropriate method to control the rate, but for many prehospital teams there may be an issue as they may not carry ‘that’ sort of infusion pump. Less of a problem in the ED>

What were the measured outcomes in this study?

The primary measured outcomes were:

• Changes in systolic blood pressure (BP) from the start of the infusion until patient retrieval.
• Overall survival to hospital discharge.
• Duration of adrenaline infusion and total volume of crystalloid fluid administered during pre-hospital care.
• Adverse events potentially linked to the adrenaline infusion.
• Mortality, both pre- and post-hospitalisation.

Secondary outcomes included ICU length of stay, total hospital length of stay, and any subsequent use of vasopressors or inotropes after the initial adrenaline infusion.

What are the main results?

The study’s findings demonstrated that the treatment was effective in improving blood pressure and survival in critically ill patients.

• Systolic blood pressure: The median systolic BP rose from 75.5 mmHg at the start of the adrenaline infusion to 91 mmHg by the time patients were retrieved.
• Infusion duration: The median duration of the adrenaline infusion was 155 minutes.
• Survival: Of the 57 patients, 86% survived to hospital discharge. Of the six patients who died, three deaths were attributed to septic shock, and one to cardiogenic shock. Two patients had non-survivable illness episodes, including prolonged cardiac arrest.
• Adverse events: No major adverse events directly linked to the dirty adrenaline infusions were reported. Minor events included one case of cold fingers that resolved without complication, a case of tachycardia that was managed by reducing the infusion rate, and one instance of hypertension that resolved once the infusion was stopped.

While two patients experienced fluid overload, the study did not conclusively attribute this to the adrenaline infusions.

Critically appraise the methodology and findings

Here at St Emlyn’s we like real world studies (with the caveat about methodology above) as they reflect real-world practice, in this case that’s a remote and resource-limited environment. This is also quite a large cohort for this setting, although absolute numbers to change practice should be considered small. Notably when we are looking at potential harm 57 is a pretty low number as it’s the sample size is not powered to do that.

As mentioned previously this is observational data, there is no control or comparison group and therefore we need to be really careful about causality as we simply do not know what would have happened if adrenaline had not been used (they may have done even better – though I doubt it). There were also a significant number of documentation gaps such as missing data on cannula size and location which would be useful to know.

Should we change practice based on this study?

Based on this case series, the adrenaline drip appears to be reasonably safe and a viable option for managing fluid-resistant shock in remote, resource-poor settings like Central Australia. However, this study alone is not sufficient to recommend a widespread change in clinical practice. Its retrospective, descriptive nature limits the strength of its conclusions, and further research, ideally in the form of a controlled trial with a comparator arm, would be necessary before implementing dirty adrenaline as a standard pre-hospital treatment in other regions.

That said, in settings where patients face long delays to advanced care, or where there is insufficient kit/expertise/people this study supports the continued use of dirty adrenaline as a stopgap measure. Though I do think it’s a pretty advanced intervention and should be guided by a critical care trained physician. For remote healthcare systems with limited resources, this treatment may remain an important tool. The current alternative in my prehsopital practice is to make up a 1:100,000 adrenaline syringe and give boluses of that. It can work reasonably well but I often find I need a reasonable quantity of this and it is intermittent which is not exactly great for getting a nice smooth and stable BP. With that in mind I also find that having an arterial line helps a lot in the titration of resus vasopressors, so I would really recommend getting an a-line in if you can.

You should also think carefully about labelling and who has access to the drip, and how it will be titrated. It would be very easy for someone unfamiliar with the technique to change flow rates, give a bolus or turn off. Clear labelling and a lot of vigilance is needed. The paper contains the SOP for use. It’s really worth a read as there are a lot of caveats and cautions in there that need addressing before you think about doing this. For instance they used specialised giving sets (darkened and with no side ports), they avoided more than one cannula in the same arm dedicated to the adrenaline infusion. The rate of infusion was directed by the retrieval physician remotely until they arrived.

So it’s more complicated than just the cardiovascular effects. There is a whole lot of human factors that can cause issues here too.

Summary

This case series provides important observational evidence regarding the use of dirty adrenaline infusions in pre-hospital care in remote areas of Central Australia. The study demonstrates that dirty adrenaline is probably safe, with few adverse events, and appears to improve survival in patients with fluid-resistant shock, particularly those suffering from septic shock. However, it’s small numbers and observational data so the level of certainty for safety etc is low.

I suspect that it will not, and probably should not, become routine practice in Virchester, but as a potential option in a tight spot it may have a role. It’s also good to see an emerging evidence base to support its use.

References

1. Braham, D., Adams, D. W. S., & Johnson, R. (2024). Pre‐hospital ‘dirty adrenaline’: A descriptive case series of patients receiving peripheral dilute adrenaline infusions in Central Australian remote nurse‐led clinics prior to aeromedical retrieval. Emergency Medicine Australasia. doi: 10.1111/1742-6723.14496
2. Albert, E. (2022). Dirty Adrenaline: Thinking Outside the Box in Wilderness Emergency Care. Adventure Medic. Retrieved from https://www.theadventuremedic.com/coreskills/dirty-adrenaline-thinking-outside-the-box-in-wilderness-emergency-care/
3. Ernst, R., Guest, B., & Herbert, M. (2023). Bedside Epinephrine Drip (“Dirty Epi Drip”). EM:RAP. Retrieved from https://www.emrap.org/corependium/chapter/recJCKsNuvUC7XNDn/
4. Owen, V. S., Rosgen, B. K., & Cherak, S. J. (2021). Adverse events associated with administration of vasopressor medications through a peripheral intravenous catheter: A systematic review and meta-analysis. Critical Care, 25(146).
5. The Dirty Epi Drip: IV Epinephrine When You Need It. https://www.aliem.com/dirtyepi/