Journal Feed Weekly Wrap-Up

We always work hard, but we may not have time to read through a bunch of journals. It’s time to learn smarter. 

Originally published at JournalFeed, a site that provides daily or weekly literature updates. 

Follow Dr. Clay Smith at @spoonfedEM, and sign up for email updates here.

#1: Prehospital Cardiac Arrest – Is Advanced Airway or BVM Best?

Spoon Feed
Endotracheal tube (ETT) or supraglottic airway (SGA) vs bag-valve mask (BVM) airway management in prehospital cardiac arrest made no difference in neurologically favorable survival at 30-days when controlled for clinical differences.

Why does this matter?
The chain of survival begins with the call to 911, with lasting impacts with each step in management. One of the key early links in this chain is EMS care, in particular, airway management by them. Prehospital airway management has been studied in the literature and covered on JournalFeed extensively but with mixed results. Where does this study fit into the current landscape, and what does it mean for you?

Just in case the water wasn’t murky enough…

This paper

  • This was a retrospective review of 9,616 adult cardiac arrests of medical etiology (i.e. non trauma/burn) from a Korean database.
  • After controlling for clinical differences in three separate ways (propensity score matching (PSM), inverse probability of treatment weight (IPTW), and LASSO), there was no difference between advanced airway management (AAM = ETT or SGA; n = 6,232; 5,410; and 822, respectively) and BVM (n=3,354) on neurological favorable survival at 30 days (PSM 9.6% vs 10.0%; HR=0.98, 95% CI=0.93 to 1.03, p >0.05).
  • A subgroup analysis comparing ETT-alone vs BVM and SGA-alone vs BVM showed improved 30-day neurologically favorable survival with ETT placement (IPTW 0.88, 95% CI 0.78 to 0.98, p = 0.023) but not SGA management (IPTW 1.00, 95% CI 0.95 to 1.05, p = 0.99) compared to BVM.
  • Another subgroup analysis showed more favorable neurological outcome with ETT over SGA management (p = 0.005).

Prior Literature

  • There are studies showing worse, equivocal, and better outcomes comparing BVM to other management in out-of-hospital cardiac arrest, with this one being equivocal.
  • There are studies showing worse, equivocal, and better outcomes comparing SGA placement to other management in out-of-hospital cardiac arrest, with this one being equivocal.
  • There are studies showing worse, equivocal, and better outcomes comparing ETT vs other management in out-of-hospital cardiac arrest, with this one showing improvement.
  • These are 9 separate papers and conclusions out of a litany of research on the topic. The point is, this subject is murky.

What can we take away from this study?

  • The authors of this paper acknowledge that even in their own database over time there have been differences in outcomes comparing different airway management strategies.
  • This study is unique because it worked diligently to correct for clinical differences between patients.
  • In the end, most of the higher quality literature supports that a SGA or BVM technique is equivocal or better than ETT during out-of-hospital cardiac arrest. Placement of an ETT in out-of-hospital cardiac arrest should be done by those with adequate training and with equipment that will maximize success in select circumstances. Defining those specific circumstances is the difficult part.

Prehospital airway management for out-of-hospital cardiac arrest: A nationwide multicenter study from the KoCARC registry. Acad Emerg Med. 2022 Jan 22. doi: 10.1111/acem.14443. Online ahead of print.

#2: Should We Use Atropine to Prevent Bradycardia in Pediatric Airways?

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Atropine pretreatment was not associated with a reduction in the incidence of bradycardia in this tiny, single center study of pediatric intubations.

Why does this matter?
PALS guidelines from 2015 state, “The available evidence does not support the routine use of atropine preintubation of critically ill infants and children. It may be reasonable for practitioners to use atropine as a premedication in specific emergency intubations when there is higher risk of bradycardia (eg, when giving succinylcholine as a neuromuscular blocker to facilitate intubation).” So, should we give it or not?

How slow can you go?
This was a small, single-center retrospective study with 62 children undergoing endotracheal intubation. Just 3 patients (4.8%) had bradycardia (according to age-based norms) at the time of RSI or within 5 minutes. Pre-treatment with atropine was up to the physician, and 15 (24.2%) were pretreated. There was no difference in the incidence of bradycardia in the treatment vs non-treatment cohorts: 6.6% vs 4.3%, respectively. Bradycardia was rare in this study. Patients treated with atropine were younger than those who did not, and there were undoubtedly other differences that physicians may have seen in the moment that could have confounded these results. Personally, I use atropine for intubations in children <12 months. I don’t see much downside risk and would like to think this could prevent conversion of a peri-arrest child to full arrest requiring compressions if the heart rate drops. Maybe atropine isn’t doing any good. But this study is so small, it’s really hard to tell. A large database or RCT would be helpful to clarify.

Incidence of Bradycardia and the Use of Atropine in Pediatric Rapid Sequence Intubation in the Emergency Department. Pediatr Emerg Care. 2022 Feb 1;38(2):e540-e543. doi: 10.1097/PEC.0000000000002382.

Spoon Feed
Accelerated diagnostic protocols using delta high-sensitivity cardiac troponin (hs-cTn) assays had high diagnostic accuracy.

Why does this matter?
There have been several studies that led to the European Cardiology Society guidelines for ultra-rapid rule out of acute MI using hs-cTn T or I. How accurate are these 0/1, 0/2, or 0/3 hour accelerated diagnostic protocols?

Rapid rule-outs
This is a brief “Brass Tacks” from Annals of EM and covering this big systematic review. In total, they found 32 studies with 30,066 patients. There was no major difference in accuracy among the different assays by Roche, Abbott, and Siemens. Diagnostic accuracy was as follows.

0/1-hour algorithm

  • sensitivity 99% (95%CI 98.5% to 99.5%); negative likelihood ratio (LR-): 0.01 (95% CI 0.01 to 0.02)
  • specificity 94.0% (95%CI 90.7 to 96.2%); positive likelihood ratio (LR+) 14 (95%CI 9 to 20)
  • 17% ruled in; 54% ruled out; 29% undifferentiated

0/2-hour algorithm

  • sensitivity 98.6% (95%CI 97.2 to 99.3%); LR- 0.02 (95%CI 0.01 to 0.04)
  • specificity 96% (95%CI 92.9 to 97.9%); LR+ 21 (95%CI 13 to 35)
  • 15% ruled in; 61% ruled out; 24% undifferentiated

0/3-hour algorithm

  • sensitivity 93.7% (95%CI 87.4 to 97.0%); LR- 0.09 (95%CI 0.05 to 0.15)
  • specificity 93% (95%CI 86.9 to 96.6%); LR+ 13 (95%CI 6.7 to 24)
  • 19% ruled in; 66% ruled out; 15% undifferentiated

Limitations: There was heterogeneity among the studies. Some used clinical criteria plus hs-cTn; some did not. Prevalence of MI varied widely, from 4% to 37%. Authors noted that studies with very high MI prevalence also likely included a larger proportion of patients with conditions that elevated hs-cTn unrelated to AMI. Sometimes the timing of lab draws were way off the 1, 2, or 3-hour mark.

Accuracy of the European Society of Cardiology 0/1-, 0/2-, and 0/3-hour algorithms for diagnosing acute myocardial infarction. Acad Emerg Med. 2022 Jan 22. doi: 10.1111/acem.14444. Online ahead of print.

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