Journal Feed Weekly Wrap-up

Spoon Feed
For new onset atrial fibrillation (a-fib), an electrical-first approach reduced ED length of stay compared to a chemical-first approach.

Why does this matter?
With RACE 7, one might ask if there is need to cardiovert anyone with new onset a-fib or rather take a wait-and-see approach, as most spontaneously convert to NSR. But, many patients are profoundly symptomatic with a-fib, and restoration of NSR is a reasonable goal. As such, is it faster to chemically or electrically provide rhythm control?

Get into the rhythm
This was a multi-center RCT comparing chemical first to electrical first management of new onset a-fib. In all, 84 patients were randomized. The electrical first group was discharged home in under 4 hours 67% of the time, compared to the chemical first (procainamide) group at 32%. Procainamide converted 54% (22 of 41), and all failures crossed over and were then successfully converted electrically. Electrical cardioversion converted 88% (38 of 43), with 4 of the 5 failures crossing over and converting with procainamide. Adverse events were the same in each group, as were 3 and 30-day outcomes.

Source
A Multicenter Randomized Trial to Evaluate a Chemical-first or Electrical-first Cardioversion Strategy for Patients With Uncomplicated Acute Atrial Fibrillation. Acad Emerg Med. 2019 Aug 19. doi: 10.1111/acem.13669. [Epub ahead of print]

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Spoon Feed
The evidence does not support routine use of cricoid pressure (CP) to prevent pulmonary aspiration during intubation.

Why does this matter?
Sellick proposed CP in a case series of 26 patients considered at risk for aspiration but had no control group. In fact, CP may be biomechanically impossible. There is also little compelling evidence that it is effective. IRIS found that sham vs real cricoid pressure was identical in terms of pulmonary aspiration (0.5% without; 0.6% with) and slightly increased time to intubation. In light of this controversy being reignited, the authors set out to compile the known evidence.

Under pressure…

Anatomy controversy

• In 2003, an MRI study showed cricoid pressure often laterally displaced the esophagus.

• But in 2009, a new study showed that it was the hypopharynx that lies behind the cricoid ring at the C5 level which is fixed, immobile, and consistently compressed by cricoid pressure. Therefore, esophageal position was irrelevant.

Aspiration is bad

• Aspiration of gastric contents may be lethal.

• The authors argue it should be defined as, “bilious secretions or particulate material in the tracheobronchial tree or a new infiltrate on a chest roentgenogram,” producing clinical effects, such as hypoxia rather than defined as micro-aspiration by pepsin-A measurement.

Airway management effects

• It makes supraglottic device placement, videolaryngoscopy (multiple studies), and tube passage harder.

• Although, it may make direct laryngoscopy easier.

Appropriate application

• If done, it should be posterior pressure on the anterior cricoid with two fingers, 30N of force. It may be biomechanically impossible, as laryngoscopy provides direct counterforce.

• Most agree it should be performed in pregnant women. Most agree it should not be used in known unstable c-spine fracture.

Alternative?

• A 30N left paratracheal force reduced gastric insufflation of air with bag-valve mask.

International views

• British guidelines say it may be appropriate.

• Scandanavian guidelines leave it up to the individual.

• CP is much more common in the U.S., likely due to malpractice fears based on closed claims’ analysis.

Summary

• There is little solid evidence for using CP. The RCT we have indicates it does not reduce aspiration.

• “Using the best currently available techniques, the incidence of pulmonary aspiration is not zero. This fact should be universal knowledge and should be well explained in medico-legal situations.”

• In my practice, I have largely abandoned use of CP. It doesn’t reduce aspiration and makes a difficult airway even more difficult. Why would I want to do that?

Another Spoonful
Don’t miss Dr. John Hinds delivering a brilliant demolition of cricoid pressure in airway management, at smaccGOLD. Thanks, Aaron!

Source
The Clinical Use of Cricoid Pressure: First, Do No Harm. Anesth Analg. 2019 Aug 6. doi: 10.1213/ANE.0000000000004360. [Epub ahead of print]

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