Drugs during cardiopulmonary resuscitation:

Sodium Bicarbonate and Calcium Chloride for the Treatment of Hyperkalemia-Induced Cardiac Arrest: A Randomized, Blinded, Placebo-Controlled Animal Study

OBJECTIVES

Current international guidelines recommend administrating calcium chloride and sodium bicarbonate to patients with hyperkalemia-induced cardiac arrest, despite limited evidence. The aim of this study was to evaluate the efficacy of calcium chloride and sodium bicarbonate on return of spontaneous circulation (ROSC) in a pig model of hyperkalemia-induced cardiac arrest.

DESIGN

A randomized, blinded, placebo-controlled experimental pig study. Hyperkalemia was induced by continuous infusion of potassium chloride over 45 minutes followed by a bolus. After a no flow period of 7 minutes, pigs first received 2 minutes of basic cardiopulmonary resuscitation and subsequently advanced life support. The first intervention dose was administered after the fifth rhythm analysis, followed by a defibrillation attempt at the sixth rhythm analysis. A second dose of the intervention was administered after the seventh rhythm analysis if ROSC was not achieved. In case of successful resuscitation, pigs received intensive care for 1 hour before termination of the study.

SETTING

University hospital laboratory.

SUBJECTS

Fifty-four female Landrace/Yorkshire/Duroc pigs (38-42 kg).

INTERVENTIONS

The study used a 2 × 2 factorial design, with calcium chloride (0.1 mmol/kg) and sodium bicarbonate (1 mmol/kg) as the interventions.

MEASUREMENTS AND MAIN RESULTS

Fifty-two pigs were included in the study. Sodium bicarbonate significantly increased the number of animals achieving ROSC (24/26 [92%] vs. 13/26 [50%]; odds ratio [OR], 12.0; 95% CI, 2.3-61.5; p = 0.003) and reduced time to ROSC (hazard ratio [HR] 3.6; 95% CI, 1.8-7.5; p < 0.001). There was no effect of calcium chloride on the number of animals achieving ROSC (19/26 [73%] vs. 18/26 [69%]; OR, 1.2; 95% CI, 0.4-4.0; p = 0.76) or time to ROSC (HR, 1.5; 95% CI, 0.8-2.9; p = 0.23).

CONCLUSIONS

Administration of sodium bicarbonate significantly increased the number of animals achieving ROSC and decreased time to ROSC. There was no effect of calcium chloride on the number of animals achieving ROSC or time to ROSC.

Efficacy and safety of corticosteroid therapy in patients with cardiac arrest: A meta-analysis of randomized controlled trials

BACKGROUND

The clinical benefits of steroid therapy during cardiac arrest (CA) are unclear. Several recent clinical trials have shown that administering corticosteroid therapy during CA may improve patient outcomes. The purpose of the present study was to determine whether providing corticosteroids improves outcomes for patients following CA.

METHODS

We searched the PubMed, Embase, Cochrane Library, Web of Science and CNKI databases for randomized controlled trials comparing corticosteroid therapy to placebo during CA.

RESULTS

Eleven relevant studies involving a total of 2273 patients were included in the meta-analysis. The statistical analysis showed that corticosteroid treatment during CA was significantly associated with an increased rate of sustained return of spontaneous circulation (ROSC) (OR: 2.05, 95% CI: 1.24 to 3.37, P < 0.01). Corticosteroid treatment during CA did not show a significant benefit in favorable neurological outcomes (OR: 1.13, 95% CI: 0.81 to 1.58, P = 0.49) or overall survival rate at hospital discharge (OR: 1.29, 95% CI: 0.74 to 2.26, P = 0.38). However, in the subgroup analysis, we found that patients had a significantly increased survival rate and ROSC if the dose of corticosteroid therapy above 100 mg methylprednisolone. The statistical analysis revealed no significant differences in adverse events.

CONCLUSION

High-dose corticosteroid treatment (above 100 mg methylprednisolone) is associated with better overall survival rate at hospital discharge and ROSC outcomes. However, there is uncertainty regarding whether this treatment results in a benefit or harm to the favorable neurological outcomes at hospital discharge.

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.

Vasopressin and glucocorticoids for in-hospital cardiac arrest: A systematic review and meta-analysis of individual participant data

AIM

To perform a systematic review and individual participant data meta-analysis of vasopressin and glucocorticoids for the treatment of cardiac arrest.

METHODS

The PRISMA-IPD guidelines were followed. We searched Medline, Embase, and the Cochrane Library for randomized trials comparing vasopressin and glucocorticoids to placebo during cardiac arrest. The population included adults with cardiac arrest in any setting. Pairs of investigators reviewed studies for relevance, extracted data, and assessed risk of bias. Meta-analyses were conducted using individual participant data. A Bayesian framework was used to estimate posterior treatment effects assuming various prior beliefs. The certainty of evidence was evaluated using GRADE.

RESULTS

Three trials were identified including adult in-hospital cardiac arrests only. Individual participant data were obtained from all trials yielding a total of 869 patients. There was some heterogeneity in post-cardiac arrest interventions between the trials. The results favored vasopressin and glucocorticoids for return of spontaneous circulation (odds ratio: 2.09, 95%CI: 1.54 to 2.84, moderate certainty). Estimates for survival at discharge (odds ratio: 1.39, 95%CI: 0.90 to 2.14, low certainty) and favorable neurological outcome (odds ratio: 1.64, 95%CI, 0.99 to 2.72, low certainty) were more uncertain. The Bayesian estimates for return of spontaneous circulation were consistent with the primary analyses, whereas the estimates for survival at discharge and favorable neurological outcome were more dependent on the prior belief.

CONCLUSIONS

Among adults with in-hospital cardiac arrest, vasopressin and glucocorticoids compared to placebo, improved return of spontaneous circulation. Larger trials are needed to determine whether there is an effect on longer-term outcomes.

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.