SGEM#361: Under My Umbrella, Ella, Ella – Review of Meta-Analyses in Emergency Medicine

Date: February 24th, 2022

Reference: Parish et al. An umbrella review of effect size, bias, and power across meta-analyses in emergency medicine. AEM 2021

Guest Skeptic: Professor Daniel Fatovich is an emergency physician and clinical researcher based at Royal Perth Hospital, Western Australia. He is Head of the Centre for Clinical Research in Emergency Medicine, Harry Perkins Institute of Medical Research; Professor of Emergency Medicine, University of Western Australia; and Director of Research for East Metropolitan Health Service.

Case: A resident has been following the literature over their four years of training. They have already seen several things come into fashion and go out of fashion during this short time. This includes therapeutic hypothermia for out-of-hospital cardiac arrest (OHCA), tranexamic acid (TXA) for epistaxis and electrolyte solutions for mild pediatric gastroenteritis. They wonder how strong the evidence is for much of what we do in emergency medicine.

Background: There are many things in medicine that could be considered myth or dogma. We have covered some of these over the 10 years.

* Topical anesthetic uses of 24-48 hours for mild cornea abrasions will cause blindness- No (SGEM# 315)

* Epinephrine for adult out-of-hospital cardiac arrests (OHCAs) results in better neurologic outcomes – No (SGEM#238)

* TXA for intracranial hemorrhage, isolated traumatic brain injury, post-partum hemorrhage or gastrointestinal bleed results in better primary outcomes – No (SGEM#236, SGEM#270, SGEM#214, and SGEM#301)

* Therapeutic hypothermia in adult OHCA saves lives – No (SGEM#336)

* Electrolyte solutions are needed in mild pediatric gastroenteritis – No (SGEM#158)

A lot of medical practice is based on low quality research. Tricoci et al. JAMA Feb 2009 looked at the ACC/AHA guidelines from 1984 to 2008. They found 53 guidelines with 7,196 recommendations. The results were only 11% of recommendations were considered Level A, 39% were Level B and 50% were Level C.

The definitions used for each level of evidence are as follows:

An update was published by Fanaroff et al in JAMA 2019. The level of high-quality evidence had not changed much when looking at the ACC/AHA guidelines from 2008-2018. There were 26 guidelines with 2,930 recommendations. Now Level A recommendations were down to 9%, Level B 50% and Level C 41%.

This lack of evidence is not isolated to cardiology. A recent study looked at the top ten elective orthopaedic procedures. It was an umbrella review of meta-analyses of randomized control trials (RTCs) or other study designs if no RCTs existed (Blom et al BMJ 2021). The comparison was the clinical efficacy of the most common orthopaedic procedures with no treatment, placebo, or non-operative care. The primary outcome was the quality of the evidence for each procedure. Only two out of ten common procedures,