Combination of Vasopressin -Epinephrine as a Novel Candidate in Patients with Cardiac Arrest

Epinephrine in Out-of-Hospital Cardiac Arrest: A Network Meta-analysis and Subgroup Analyses of Shockable and Nonshockable Rhythms

BACKGROUND

Epinephrine is the most commonly used drug in out-of-hospital cardiac arrest (OHCA) resuscitation, but evidence supporting its efficacy is mixed.

RESEARCH QUESTION

What are the comparative efficacy and safety of standard dose epinephrine, high-dose epinephrine, epinephrine plus vasopressin, and placebo or no treatment in improving outcomes after OHCA?

STUDY DESIGN AND METHODS

In this systematic review and network meta-analysis of randomized controlled trials, we searched six databases from inception through June 2022 for randomized controlled trials evaluating epinephrine use during OHCA resuscitation. We performed frequentist random-effects network meta-analysis and present ORs and 95% CIs. We used the the Grading of Recommendations, Assessment, Development, and Evaluation approach to rate the certainty of evidence. Outcomes included return of spontaneous circulation (ROSC), survival to hospital admission, survival to discharge, and survival with good functional outcome.

RESULTS

We included 18 trials (21,594 patients). Compared with placebo or no treatment, high-dose epinephrine (OR, 4.27; 95% CI, 3.68-4.97), standard-dose epinephrine (OR, 3.69; 95% CI, 3.32-4.10), and epinephrine plus vasopressin (OR, 3.54; 95% CI, 2.94-4.26) all increased ROSC. High-dose epinephrine (OR, 3.53; 95% CI, 2.97-4.20), standard-dose epinephrine (OR, 3.00; 95% CI, 2.66-3.38), and epinephrine plus vasopressin (OR, 2.79; 95% CI, 2.27-3.44) all increased survival to hospital admission as compared with placebo or no treatment. However, none of these agents may increase survival to discharge or survival with good functional outcome as compared with placebo or no treatment. Compared with placebo or no treatment, standard-dose epinephrine improved survival to discharge among patients with nonshockable rhythm (OR, 2.10; 95% CI, 1.21-3.63), but not in those with shockable rhythm (OR, 0.85; 95% CI, 0.39-1.85).

INTERPRETATION

Use of standard-dose epinephrine, high-dose epinephrine, and epinephrine plus vasopressin increases ROSC and survival to hospital admission, but may not improve survival to discharge or functional outcome. Standard-dose epinephrine improved survival to discharge among patients with nonshockable rhythm, but not those with shockable rhythm.

TRIAL REGISTRY

Center for Open Science: https://osf.io/arxwq.

Therapeutic effects of vasopressin on cardiac arrest: a systematic review and meta-analysis

OBJECTIVE

To demonstrate the therapeutic effect of vasopressin as an alternative treatment for cardiac arrest.

DESIGN

Systematic review and meta-analysis.

METHODS

PubMed, EMBASE, the Cochrane Library and Web of Science were searched for randomised controlled trials. The intervention included administration of vasopressin alone or vasopressin combined with epinephrine or vasopressin, steroids and epinephrine (VSE) versus epinephrine combined with placebo as control group. The primary outcome was the return of spontaneous circulation (ROSC). The secondary outcomes included mid-term survival and mid-term good neurological outcome. We conducted subgroup analyses of the primary outcome based on different settings, different study drug strategies and different types of initial rhythm.

RESULTS

Twelve studies (n=6718) were included, of which eight trials (n=5638) reported the data on patients with out-of-hospital cardiac arrest and four trials (n=1080) on patients with in-hospital cardiac arrest (IHCA). There were no significant differences between intravenous vasopressin and placebo in the outcomes of ROSC (relative risk (RR): 1.11; 95% CI: 0.99 to 1.26), mid-term survival (RR: 1.23; 95% CI: 0.90 to 1.66) and mid-term good neurological outcome (RR: 1.20; 95% CI: 0.77 to 1.87). However, in the subgroup analysis, intravenous vasopressin as part of VSE can significantly improve the rate of ROSC (RR: 1.32; 95% CI: 1.18 to 1.47) but not the rate of mid-term survival (RR: 2.15; 95% CI: 0.75 to 6.16) and mid-term good neurological outcome (RR: 1.80; 95% CI: 0.81 to 4.01) for patients with IHCA.

CONCLUSIONS

Our study failed to demonstrate increased benefit from vasopressin with or without epinephrine compared with the standard of care. However, vasopressin as a part of VSE is associated with the improvement of ROSC in patients with IHCA, and the benefit on mid-term survival or mid-term good neurological outcome is uncertain. Larger trials should be conducted in the future to address the effect of vasopressin only, vasopressin plus epinephrine or VSE on cardiac arrest.

PROSPERO REGISTRATION NUMBER

CRD42021293347.

Pharmacological Approach for Neuroprotection After Cardiac Arrest-A Narrative Review of Current Therapies and Future Neuroprotective Cocktail

Cardiac arrest (CA) results in global ischemia-reperfusion injury damaging tissues in the whole body. The landscape of therapeutic interventions in resuscitation medicine has evolved from focusing solely on achieving return of circulation to now exploring options to mitigate brain injury and preserve brain function after CA. CA pathology includes mitochondrial damage and endoplasmic reticulum stress response, increased generation of reactive oxygen species, neuroinflammation, and neuronal excitotoxic death. Current non-pharmacologic therapies, such as therapeutic hypothermia and extracorporeal cardiopulmonary resuscitation, have shown benefits in protecting against ischemic brain injury and improving neurological outcomes post-CA, yet their application is difficult to institute ubiquitously. The current preclinical pharmacopeia to address CA and the resulting brain injury utilizes drugs that often target singular pathways and have been difficult to translate from the bench to the clinic. Furthermore, the limited combination therapies that have been attempted have shown mixed effects in conferring neuroprotection and improving survival post-CA. The global scale of CA damage and its resultant brain injury necessitates the future of CA interventions to simultaneously target multiple pathways and alleviate the hemodynamic, mitochondrial, metabolic, oxidative, and inflammatory processes in the brain. This narrative review seeks to highlight the current field of post-CA neuroprotective pharmaceutical therapies, both singular and combination, and discuss the use of an extensive multi-drug cocktail therapy as a novel approach to treat CA-mediated dysregulation of multiple pathways, enhancing survival, and neuroprotection.

Translation from animal studies of novel pharmacological therapies to clinical trials in cardiac arrest: A systematic review

BACKGROUND

There is a lack of new promising therapies to improve the dismal outcomes from cardiac arrest. The objectives of this study were: (1) To identify novel pharmacological therapies investigated in experimental animal studies and (2) to identify pharmacological therapies translated from experimental animal studies to clinical trials.

METHODS

PubMed was searched to first identify relevant experimental cardiac arrest animal models published within the last 20 years. Based on this, a list of interventions was created and a second search was performed to identify clinical trials testing one of these interventions. Data extraction was performed using standardised data extraction forms.

RESULTS

We identified 415 animal studies testing 190 different pharmacological interventions. The most commonly tested interventions were classified as vasopressors, anaesthetics/gases, or interventions aimed at molecular targets. We found 43 clinical trials testing 26 different interventions identified in the animal studies. Of these, 13 trials reported positive findings and 30 trials reported neutral findings with regards to the primary endpoint. No study showed harm of the intervention. Some interventions tested in human clinical trials, had previously been tested in animal studies without a positive effect on outcomes. A large number of animal studies was performed after publication of a clinical trial.

CONCLUSION

Numerous different pharmacological interventions have been tested in experimental animal models. Despite this only a limited number of these interventions have advanced to clinical trials, however several of the clinical trials tested interventions that were first tested in experimental animal models.

Epinephrine for Out-of-Hospital Cardiac Arrest: An Updated Systematic Review and Meta-Analysis

OBJECTIVES

To perform an updated systematic review and meta-analysis of clinical trials evaluating epinephrine for adult out-of-hospital cardiac arrest resuscitation.

DATA SOURCES

The search included MEDLINE, EMBASE, and Ovid Evidence-Based Medicine, clinical trial registries, and bibliographies.

STUDY SELECTION

Randomized and quasi-randomized controlled trials that compared the current standard dose of epinephrine to placebo, high or low dose epinephrine, any other vasopressor alone or in combination were screened by three independent reviewers.

DATA EXTRACTION

Randomized and quasi-randomized controlled trials that compared the current standard dose of epinephrine to placebo, high or low dose epinephrine, any other vasopressor alone or in combination were screened by three independent reviewers.

DATA SYNTHESIS

A total of 17 trials (21,510 patients) were included; seven were judged to be at high risk of bias. Compared to placebo, pooled results from two trials showed that standard dose of epinephrine increased return of spontaneous circulation (risk ratio, 3.09; 95% CI, 2.82-3.89), survival to hospital admission (risk ratio, 2.50; 95% CI, 1.68-3.72), and survival to discharge (risk ratio, 1.44; 95% CI, 1.11-1.86). The largest placebo-controlled trial showed that standard dose of epinephrine also improved survival at 30 days and 3 months but not neurologic outcomes, standard dose of epinephrine decreased return of spontaneous circulation (risk ratio, 0.87; 95% CI, 0.77-0.98) and survival to admission (risk ratio, 0.88; 95% CI, 0.78-0.99) when compared with high dose epinephrine. There were no differences in outcomes between standard dose of epinephrine and vasopressin alone or in combination with epinephrine.

CONCLUSIONS

Largely based on one randomized controlled trial, standard dose of epinephrine improved overall survival but not neurologic outcomes in out-of-hospital cardiac arrest patients compared with placebo. There is a paucity of trials with meaningful patient outcomes; future epinephrine trials should evaluate dose and method of delivery on long-term survival, neurologic function, and quality of life after cardiac arrest.

Vasopressors During Cardiopulmonary Resuscitation. A Network Meta-Analysis of Randomized Trials

OBJECTIVES

Several randomized controlled trials have compared adrenaline (epinephrine) with alternative therapies in patients with cardiac arrest with conflicting results. Recent observational studies suggest that adrenaline might increase return of spontaneous circulation but worsen neurologic outcome. We systematically compared all the vasopressors tested in randomized controlled trials in adult cardiac arrest patients in order to identify the treatment associated with the highest rate of return of spontaneous circulation, survival, and good neurologic outcome.

DESIGN

Network meta-analysis.

PATIENTS

Adult patients undergoing cardiopulmonary resuscitation.

INTERVENTIONS

PubMed, Embase, BioMed Central, and the Cochrane Central register were searched (up to April 1, 2017). We included all the randomized controlled trials comparing a vasopressor with any other therapy. A network meta-analysis with a frequentist approach was performed to identify the treatment associated with the highest likelihood of survival.

MEASUREMENTS AND MAIN RESULTS

Twenty-eight studies randomizing 14,848 patients in 12 treatment groups were included. Only a combined treatment with adrenaline, vasopressin, and methylprednisolone was associated with increased likelihood of return of spontaneous circulation and survival with a good neurologic outcome compared with several other comparators, including adrenaline. Adrenaline alone was not associated with any significant difference in mortality and good neurologic outcome compared with any other comparator.

CONCLUSIONS

In randomized controlled trials assessing vasopressors in adults with cardiac arrest, only a combination of adrenaline, vasopressin, and methylprednisolone was associated with improved survival with a good neurologic outcome compared with any other drug or placebo, particularly in in-hospital cardiac arrest. There was no significant randomized evidence to support neither discourage the use of adrenaline during cardiac arrest.

Adrenaline and vasopressin for cardiac arrest

BACKGROUND

Adrenaline and vasopressin are widely used to treat people with cardiac arrest, but there is uncertainty about the safety, effectiveness and the optimal dose.

OBJECTIVES

To determine whether adrenaline or vasopressin, or both, administered during cardiac arrest, afford any survival benefit.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase and DARE from their inception to 8 May 2018, and the International Liaison Committee on Resuscitation 2015 Advanced Life Support Consensus on Science and Treatment Recommendations. We also searched four trial registers on 5 September 2018 and checked the reference lists of the included studies and review papers to identify potential papers for review.

SELECTION CRITERIA

Any randomised controlled trial comparing: standard-dose adrenaline versus placebo; standard-dose adrenaline versus high-dose adrenaline; and adrenaline versus vasopressin, in any setting, due to any cause of cardiac arrest, in adults and children. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified trials for review, assessed risks of bias and extracted data, resolving disagreements through re-examination of the trial reports and by discussion. We used risk ratios (RRs) with 95% confidence intervals (CIs) to compare dichotomous outcomes for clinical events. There were no continuous outcomes reported. We examined groups of trials for heterogeneity. We report the quality of evidence for each outcome, using the GRADE approach.

MAIN RESULTS

We included 26 studies (21,704 participants).Moderate-quality evidence found that adrenaline increased survival to hospital discharge compared to placebo (RR 1.44, 95% CI 1.11 to 1.86; 2 studies, 8538 participants; an increase from 23 to 32 per 1000, 95% CI 25 to 42). We are uncertain about survival to hospital discharge for high-dose compared to standard-dose adrenaline (RR 1.10, 95% CI 0.75 to 1.62; participants = 6274; studies = 10); an increase from 33 to 36 per 1000, 95% CI 24 to 53); standard-dose adrenaline versus vasopressin (RR 1.25, 95% CI 0.84 to 1.85; 6 studies; 2511 participants; an increase from 72 to 90 per 1000, 95% CI 60 to 133); and standard-dose adrenaline versus vasopressin plus adrenaline (RR 0.76, 95% CI 0.47 to 1.22; 3 studies; 3242 participants; a possible decrease from 24 to 18 per 1000, 95% CI 11 to 29), due to very low-quality evidence.Moderate-quality evidence found that adrenaline compared with placebo increased survival to hospital admission (RR 2.51, 95% CI 1.67 to 3.76; 2 studies, 8489 participants; an increase from 83 to 209 per 1000, 95% CI 139 to 313). We are uncertain about survival to hospital admission when comparing standard-dose with high-dose adrenaline, due to very low-quality evidence. Vasopressin may improve survival to hospital admission when compared with standard-dose adrenaline (RR 1.27, 95% CI 1.04 to 1.54; 3 studies, 1953 participants; low-quality evidence; an increase from 260 to 330 per 1000, 95% CI 270 to 400), and may make little or no difference when compared to standard-dose adrenaline plus vasopressin (RR 0.95, 95% CI 0.83 to 1.08; 3 studies; 3249 participants; low-quality evidence; a decrease from 218 to 207 per 1000 (95% CI 181 to 236).There was no evidence that adrenaline (any dose) or vasopressin improved neurological outcomes.The rate of return of spontaneous circulation (ROSC) was higher for standard-dose adrenaline versus placebo (RR 2.86, 95% CI 2.21 to 3.71; participants = 8663; studies = 3); moderate-quality evidence; an increase from 115 to 329 per 1000, 95% CI 254 to 427). We are uncertain about the effect on ROSC for the comparison of standard-dose versus high-dose adrenaline and standard-does adrenaline compared to vasopressin, due to very low-quality evidence. Standard-dose adrenaline may make little or no difference to ROSC when compared to standard-dose adrenaline plus vasopressin (RR 0.97, 95% CI 0.87 to 1.08; 3 studies, 3249 participants; low-quality evidence; a possible decrease from 299 to 290 per 1000, 95% CI 260 to 323).The source of funding was not stated in 11 of the 26 studies. The study drugs were provided by the manufacturer in four of the 26 studies, but neither drug represents a profitable commercial option. The other 11 studies were funded by organisations such as research foundations and government funding bodies.

AUTHORS' CONCLUSIONS

This review provides moderate-quality evidence that standard-dose adrenaline compared to placebo improves return of spontaneous circulation, survival to hospital admission and survival to hospital discharge, but low-quality evidence that it did not affect survival with a favourable neurological outcome. Very low -quality evidence found that high-dose adrenaline compared to standard-dose adrenaline improved return of spontaneous circulation and survival to admission. Vasopressin compared to standard dose adrenaline improved survival to admission but not return of spontaneous circulation, whilst the combination of adrenaline and vasopressin compared with adrenaline alone had no effect on these outcomes. Neither standard dose adrenaline, high-dose adrenaline,vasopressin nor a combination of adrenaline and vasopressin improved survival with a favourable neurological outcome. Many of these studies were conducted more than 20 years ago. Treatment has changed in recent years, so the findings from older studies may not reflect current practice.