BARCELONA – Bag-mask ventilation for airway management during resuscitation of patients with out-of-hospital cardiac arrest was considerably less safe and yet no more effective than endotracheal intubation in a large randomized trial, Frederic Adnet, MD, reported at the annual congress of the European Society of Cardiology.
This was an unexpected result.
Several large, well-respected observational registry studies had strongly suggested that bag-mask ventilation is associated with a superior survival rate with good neurologic outcome. As a result, many in the resuscitation science field have been moving closer to replacing endotracheal intubation as the standard of care in favor of bag-mask ventilation. But this first-of-its-kind, large, randomized trial to formally address the issue showed virtually identical rates of day-28 survival with good neurologic outcome in the two study arms. Plus, bag-mask ventilation had a significantly higher complication rate.
“So, at this time, we will not yet change our technique,” according to coinvestigator, of Fernand Widal Hospital in Paris.
This major prospective randomized trial included 2,043 patients with out-of-hospital cardiac arrest at 20 centers in France and Belgium. The primary endpoint – day-28 survival with good neurologic status as defined by a Glasgow-Pittsburgh Cerebral Performance Scale score of 2 or less – occurred in 4.2% of the bag-mask ventilation group and 4.1% of the endotracheal intubation group.
However, the rate of aspiration or regurgitation of gastric contents was significantly higher in the bag-mask ventilation group by a margin of 14.9% to 7.7%. Moreover, the bag-mask ventilation technique failed in 6.3% of patients, compared with a 2.5% endotracheal intubation failure rate.
Discussant, praised the study as a high-quality, well-conducted randomized trial, adding that it’s just the sort of study that the field of resuscitation science had needed for a long time. Indeed, most guidelines in the field are based on faint supporting evidence. That may be one reason why good outcomes of out-of-hospital cardiac arrest are so disappointingly low: The worldwide average is roughly 7%, with huge differences between countries.
“It is really very depressing sometimes when one looks at the percentage of patients who actually return to normal life and normal functional neurologic status and, indeed, whose relatives get back to work,” commented Dr. Price, a cardiologist and intensivist at Royal Brompton Hospital in London.
“This is a huge study for resuscitation science,” she continued. “Prehospital airway management is currently a very hot topic. Bear in mind that in the United States, roughly 88% of cardiac arrests happen in the home.”
“This trial does challenge the current feeling that bag-mask ventilation is definitely superior to advanced airway interventions,” Dr. Price added.
For her, the study contained three surprises, she continued. One was the high bag-mask failure rate in the hands of very experienced operators. Another was the high complication rate associated with the device, again even in expert hands. Also, contrary to numerous published reports, the chest compression rate in this RCT was not better with bag mask ventilation.
“The study did not demonstrate that endotracheal intubation interrupts chest compressions. In fact, chest compression pauses were actually significantly more frequent in the bag-mask ventilation group than with endotracheal intubation,” she observed.
It’s worth noting that in the French EMS system, a physician experienced in cardiopulmonary resuscitation is typically on board for ambulance runs. This creates an element of uncertainty as to the generalizability of the study findings to EMS systems where paramedics who may be less proficient in endotracheal intubation are the first responders. Indeed, whether endotracheal intubation will stack up as favorably as it did against bag-mask ventilation in this randomized trial when tested in other settings where airway management is left in the hands of paramedics is an open question that’s the topic of ongoing studies, Dr. Price noted.
Dr. Adnet and Dr. Vicaut reported having no financial conflicts regarding their study, which was funded by the French Ministry of Health.