BACKGROUND: Refractory ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) refers to cases that do not respond to traditional Advanced Cardiac Life Support measures and are associated with significantly lower survival rates. Beta-blockade may improve outcomes by protecting against the deleterious effects associated with epinephrine's beta-receptor effect.
OBJECTIVE: This systematic review and meta-analysis aimed to evaluate whether beta-blockade compared with control improved outcomes among patients in cardiac arrest due to refractory VF/VT.
METHODS: PubMed, Scopus, CINAHL, LILACS, the Cochrane databases, Google Scholar, and bibliographies of selected articles were assessed on September 2nd, 2019 for all studies evaluating beta-blockade versus control groups in patients with cardiac arrest due to refractory VF/VT. PRISMA guidelines were followed. Data were dual extracted into a predefined worksheet and quality analysis was performed with the Cochrane Risk of Bias in Non-randomised Studies of Interventions tool. Data were summarized and a meta-analysis was performed assessing temporary and sustained return of spontaneous circulation (ROSC), survival-to-admission, survival-to-discharge, and survival with a favorable neurologic outcome.
RESULTS: Three studies (n?=?115 patients) were selected for final inclusion. Beta-blockade was associated with an increased rate of temporary ROSC (OR 14.46; 95% CI 3.63-57.57), sustained ROSC (OR 5.76; 95% CI 1.79-18.52), survival-to-admission (OR 5.76; 95% CI 1.79-18.52), survival-to-discharge (OR 7.92; 95% CI 1.85-33.89), and survival with a favorable neurologic outcome (OR 4.42; 95% CI 1.05-18.56). Overall risk of bias ranged from moderate-to-severe, which was primarily influenced by selection of participants and potential confounding. This study was registered with PROSPERO (CRD42019126902).
CONCLUSIONS: The data suggest that beta-blockade may be associated with improved outcomes ranging from ROSC to survival with a favorable neurologic outcome. Future randomized controlled trials are needed to further evaluate this intervention in refractory VF/VT.
This is a useful meta-analysis for those of us involved in teaching or performing ACLS; the present publication is only hypothesis-generating, and a call for formal trials. However, it also defensibly justifies an on-site attempt to beta-blockade in an ACLS scenario when standard measures have failed to achieve ROSC.
I've witnessed end-organ hazard of high-dose epinephrine therapy too many times in my career. Although this is a small meta-analysis (n=115), how wonderful that it suggests that beta blocker therapy is associated with survival and improved neurologic outcome. I hope there will be a randomized trial.
This meta-analysis looks at only three observational studies, and the two included esmolol studies have a retrospective observational designs. This is not exactly the highest grade of evidence, nor is there an abundant amount of it, to be slapping them together to build a systematic review. This analysis is interesting, but likely doesn't add anything beyond the buzz already generated by the original papers themselves.
Hardly practice-changing with 3 significantly flawed observational studies totaling 115 patients, but large effect size favoring beta-blocker gives pause. Therefore, potentially newsworthy to clinicians, although higher-quality evidence should precede incorporation into practice.
This is a small meta-analysis of some very small-scale and flawed observational studies. It is insufficient on its own to warrant practice change, but suggests a worthy target for future research.
Although potentially intriguing, this review is based on observational data and rated very low-certainty (according to GRADE) for outcomes of interest. The results are hypothesis-generating at best, and the findings are not yet at the point of informing clinical care. RCTs are needed (even small ones).
Interesting topic. Every clinician who deals with cardiac arrest situations where advanced life support is required should read this paper.