Bag-Mask Ventilation Fails to Improve on Intubation for OHCA

Debra L. Beck

March 05, 2018

In a randomized trial of patients with out-of-hospital cardiac arrest (OHCA), bag-mask ventilation (BMV) was associated with the same rate of 28-day functional survival as  seen with endotracheal intubation (ETI) during cardiopulmonary resuscitation (CPR) but failed to meet the statistical criteria necessary to demonstrate noninferiority.

The findings of the prospective, multicenter CAAM trial were first presented last August at the European Society of Cardiology (ESC) 2017 meeting and were published February 27 in JAMA.

"Our trial was inconclusive regarding the demonstration of noninferiority of bag-mask ventilation compared with endotracheal intubation for airway management during CPR for out-of-hospital cardiac arrest patients," concluded Frédéric Adnet, MD, PhD during an ESC hot line session in Barcelona.

However, the study also did not confirm the superiority of BMV that has been reported in observational studies. Adnet, who is an emergency physician at Avicenne Hospital in Bobigny, France, said that more research is needed to determine equivalence or superiority between the two airway options.

Commenting for theheart.org | Medscape Cardiology, Roger J. Lewis, MD, PhD, said, "The study provides no evidence that one of the treatment strategies is better than the other strategy." However, he added that the trial was likely underpowered, complicating interpretation of the findings.

Lewis and Marianne Gausche-Hill, MD, both from Harbor-UCLA Medical Center in Torrance, California, wrote an editorial accompanying the trial's publication.  

CAAM enrolled 2043 patients with OHCA from 20 emergency medical service centers in France and Belgium. Participants were randomly assigned to receive BMV or ETI during CPR.

For the primary endpoint, survival with good neurologic function at 28 days based a score on the Glasgow-Pittsburgh Cerebral Performance Categories of 2 or less, the rates were nearly identical for BMV and ETI (4.2% and 4.3%, respectively), but this failed to meet the prespecified noninferiority margin of 1% (P = .11 for noninferiority).

Survival to hospital admission and survival at 28 days did not differ between groups, but technique failure was more common in the BMV group (6.7% vs 2.1% for ETI; P < .0001), as were airway management difficulties (18.1% vs 13.4% for ETI; P = .004).

Regurgitation or aspiration of gastric content was seen in 15.2% of patients in the BMV group compared with 7.5% of those in the ETI group (P < .001).

"BMV appears less safe than ETI as a means of ventilation during cardiopulmonary resuscitation in out-of-hospital cardiac arrest," said Adnet.

In France and Belgium, emergency medical service systems have physicians on ambulance crews, while in the United States, out-of-hospital rescue personnel are overwhelmingly paramedics, supported by emergency medical technicians.

"The major finding is that bag-mask-valve ventilation as the sole strategy and endotracheal intubation as the intended strategy give extremely similar results in terms of neurologically intact survival, and this is true even in a setting in which the practitioners are likely more skilled in ETI than those in the US," said Lewis.

Most emergency services agencies in the United States recommend ETI for adults, and often for children too, as the intended method of airway management for OHCA, said Lewis.

"There are many people who, because ETI is the standard technique in the hospital, have a strong feeling that it should be the preferred technique in the prehospital setting as well, so the fact that the outcomes were virtually indistinguishable between the two techniques reopens the question of whether or not there is really any evidence that ETI is superior in terms of patient outcomes and therefore the training and equipment costs and burden are justified."

Lewis noted that the CAAM trial will inform the design and implementation of additional research in this area.

"There may have been situations where people were reluctant to do research with BMV as one of the acceptable arms, and I think this study strongly supports the interpretation that we should continue to accept BMV as an acceptable strategy for OHCA," he said.

The study was supported by the French Ministry of Health. Adnet and Lewis reported no conflicts of interest relevant to the contents of this paper.

JAMA. 2018;319:779-787, 771-772. Abstract, Editorial

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