Intramuscular adrenaline for out-of-hospital cardiac arrest is associated with faster drug delivery: A feasibility study

Early intramuscular adrenaline administration is associated with improved survival from out-of-hospital cardiac arrest

BACKGROUND

Early administration of adrenaline is associated with improved survival after out-of-hospital cardiac arrest (OHCA). Delays in vascular access may impact the timely delivery of adrenaline. Novel methods for administering adrenaline before vascular access may enhance survival. The objective of this study was to determine whether an initial intramuscular (IM) adrenaline dose followed by standard IV/IO adrenaline is associated with improved survival after OHCA.

METHODS STUDY DESIGN

We conducted a before-and-after study of the implementation of an early, first-dose IM adrenaline EMS protocol for adult OHCAs. The pre-intervention period took place between January 2010 and October 2019. The post-intervention period was between November 2019 and May 2024.

SETTING

Single-center urban, two-tiered EMS agency.

PARTICIPANTS

Adult, nontraumatic OHCA meeting criteria for adrenaline use.

INTERVENTION

Single dose (5 mg) IM adrenaline. All other care, including subsequent IV or IO adrenaline, followed international guidelines.

MAIN OUTCOMES AND MEASURES

The primary outcome was survival to hospital discharge. Secondary outcomes were time from EMS arrival to the first dose of adrenaline, survival to hospital admission, and favorable neurologic function at discharge.

RESULTS

Among 1450 OHCAs, 372 (29.9%) received IM adrenaline and 985 (70.1%) received usual care. Fifty-two patients received the first dose of adrenaline through the IV or IO route within the post-intervention period and were included in the standard care group analysis. Age was younger and bystander CPR was higher in the IM adrenaline group. All other characteristics were similar between IM and standard care cohorts. Time to adrenaline administration was faster for the IM cohort [(median 4.3 min (IQR 3.0-6.0) vs. 7.8 min (IQR 5.8-10.4)]. Compared with standard care, IM adrenaline was associated with improved survival to hospital admission (37.1% vs. 31.6%; aOR 1.37, 95% CI 1.06-1.77), hospital survival (11.0% vs 7.0%; aOR 1.73, 95% CI 1.10-2.71) and favorable neurologic status at hospital discharge (9.8% vs 6.2%; aOR 1.72, 95% CI 1.07-2.76).

CONCLUSION

In this single-center before-and-after implementation study, an initial IM dose of adrenaline as an adjunct to standard care was associated with improved survival to hospital admission, survival to hospital discharge, and functional survival. A randomized controlled trial is needed to fully assess the potential benefit of IM adrenaline delivery in OHCA.

HOW SHOULD TRANEXAMIC ACID BE ADMINISTERED IN HEMORRHAGIC SHOCK? CONTINUOUS SERUM CONCENTRATION MEASUREMENTS IN A SWINE MODEL

ABSTRACT

Background : Tranexamic acid (TXA) reduces mortality in trauma patients. Intramuscular (IM) administration could be advantageous in low-resource and military settings. Achieving the same serum concentration as intravenous (IV) administration is important to achieve equal mortality reduction. Therefore, we aimed to investigate whether dividing an IM dose of TXA between two injection sites and whether an increase in dose would lead to serum concentrations comparable to those achieved by IV administration. Methods : Norwegian landrace pigs (n = 29) from a course in hemostatic emergency surgery were given TXA 1 h after start of surgery. Blood samples were drawn at 0, 5, 10, 15, 20, 25, 35, 45, 60, and 85 min. The samples were centrifuged and serum TXA concentrations quantified with liquid chromatography-tandem mass spectrometry. The use of two injection sites was compared with distributing the dose on one injection site, and a dose of 15 mg/kg was compared with a dose of 30 mg/kg. All IM groups were compared with IV administration. Results : The groups were in a similar degree of shock. Increasing the IM dose from the standard of 15 mg/kg to 30 mg/kg resulted in significantly higher serum concentrations of TXA, comparable to those achieved by IV administration. Distributing the IM dose on two injection sites did not affect drug uptake, as shown by equal serum concentrations. Conclusions : For IM administration of TXA, 30 mg/kg should be the standard dose. With a short delay, IM administration will provide equal serum concentrations as IV administration, above what is considered necessary to inhibit fibrinolysis.

Improving vasopressor use in cardiac arrest

The Chain of Survival highlights the effectiveness of early recognition of cardiac arrest and call for help, early cardiopulmonary resuscitation and early defibrillation. Most patients, however, remain in cardiac arrest despite these interventions. Drug treatments, particularly the use of vasopressors, have been included in resuscitation algorithms since their inception. This narrative review describes the current evidence base for vasopressors and reports that adrenaline (1 mg) is highly effective at achieving return of spontaneous circulation (number needed to treat 4) but is less effective on long-term outcomes (survival to 30 days, number needed to treat 111) with uncertain effects on survival with a favourable neurological outcome. Randomised trials evaluating vasopressin, either as an alternative to or in addition to adrenaline, and high-dose adrenaline have failed to find evidence of improved long-term outcomes. There is a need for future trials to evaluate the interaction between steroids and vasopressin. Evidence for other vasopressors (e.g. noradrenaline, phenylephedrine) is insufficient to support or refute their use. The use of intravenous calcium chloride as a routine intervention in out of hospital cardiac arrest is not associated with benefit and may cause harm. The optimal route for vascular access between peripheral intravenous versus intraosseous routes is currently the subject of two large randomised trials. Intracardiac, endobronchial, and intramuscular routes are not recommended. Central venous administration should be limited to patients where an existing central venous catheter is in situ and patent.

A prospective observational study on impact of epinephrine administration route on acute myocardial infarction patients with cardiac arrest in the catheterization laboratory (iCPR study)

BACKGROUND

Epinephrine is routinely utilized in cardiac arrest; however, it is unclear if the route of administration affects outcomes in acute myocardial infarction patients with cardiac arrest.

OBJECTIVES

To compare the efficacy of epinephrine administered via the peripheral intravenous (IV), central IV, and intracoronary (IC) routes.

METHODS

Prospective two-center pilot cohort study of acute myocardial infarction patients who suffered cardiac arrest in the cardiac catheterization laboratory during percutaneous coronary intervention. We compared the outcomes of patients who received epinephrine via peripheral IV, central IV, or IC.

RESULTS

158 participants were enrolled, 48 (30.4%), 50 (31.6%), and 60 (38.0%) in the central IV, IC, and peripheral IV arms, respectively. Peripheral IV epinephrine administration route was associated with lower odds of achieving return of spontaneous circulation (ROSC, odds ratio = 0.14, 95% confidence interval = 0.05-0.36, p < 0.0001) compared with central IV and IC administration. (There was no difference between central IV and IC routes; p = 0.9343.) The odds of stent thrombosis were significantly higher with the IC route (IC vs. peripheral IV OR = 4.6, 95% CI = 1.5-14.3, p = 0.0094; IC vs. central IV OR = 6.0, 95% CI = 1.9-19.2, p = 0.0025). Post-ROSC neurologic outcomes were better for central IV and IC routes when compared with peripheral IV.

CONCLUSION

Epinephrine administration via central IV and IC routes was associated with a higher rate of ROSC and better neurologic outcomes compared with peripheral IV administration. IC administration was associated with a higher risk of stent thrombosis. Trial registration This trial is registered at NCT05253937 .

Drug routes in out-of-hospital cardiac arrest: A summary of current evidence

Recent evidence showing the clinical effectiveness of drug therapy in cardiac arrest has led to renewed interest in the optimal route for drug administration in adult out-of-hospital cardiac arrest. Current resuscitation guidelines support use of the intravenous route for intra-arrest drug delivery, with the intraosseous route reserved for patients in whom intravenous access cannot be established. We sought to evaluate current evidence on drug route for administration of cardiac arrest drugs, with a specific focus on the intravenous and intraosseous route. We identified relevant animal, manikin, and human studies through targeted searches of MEDLINE in June 2022. Across pre-hospital systems, there is wide variation in use of the intraosseous route. Early administration of cardiac arrest drugs is associated with improved patient outcomes. Challenges in obtaining intravenous access mean that the intraosseous access may facilitate earlier drug administration. However, time from administration to the central circulation is unclear with pharmacokinetic data limited mainly to animal studies. Observational studies comparing the effect of intravenous and intraosseous drug administration on patient outcomes are challenging to interpret because of resuscitation time bias and other confounders. To date, no randomised controlled trial has directly compared the effect on patient outcomes of intraosseous compared with intravenous drug administration in cardiac arrest. The International Liaison Committee on Resuscitation has described the urgent need for randomised controlled trials comparing the intravenous and intraosseous route in adult out-of-hospital cardiac arrest. Ongoing clinical trials will directly address this knowledge gap.