Bag-Mask Ventilation Improves Tracheal Intubation Outcomes

A study involving 401 patients in seven ICUs across the nation found higher oxygen saturation using the bag-mask ventilation, and lower risk of vomiting stomach contents into the lungs.

Using bag-mask ventilation to force air into the lungs during tracheal intubation improves outcomes and has the potential to save lives, new research shows.

"When you place a breathing tube, you have to give patients medications to make them relaxed and sleepy. And those medications take about a minute to kick in," said Jonathan D. Casey, MD, a pulmonary and critical care fellow at Vanderbilt University Medical Center.

"After you give those medications, there is a big divide among doctors about whether to just wait and watch while their breathing slows and stops, or to provide ventilation (breath for the patient) with a bag-mask device," Casey said in comments accompanying the study.

"We found that providing ventilation with a bag-mask device is safe and very effective. Most importantly, it cut the rate of severely low oxygen levels in half," he said.

More than 1.5 million patients undergo tracheal intubation each year in the United States, during which 40% of patients with illness suffer low oxygen levels, which may damage the brain and heart. Two percent of people undergoing a tracheal suffer cardiac arrest, which is frequently fatal.

Vanderbilt's PreVent trial (Preventing Hypoxemia with Manual Ventilation during Endotracheal Intubation) study, published this week in the New England Journal of Medicine has the potential to fundamentally change the practice.  

For the study, the multicenter trial was used in seven ICUs across the nation, with adult patients undergoing the procedure receiving either ventilation with a bag-mask device or no ventilation between induction and laryngoscopy.

Among the findings:

• 401 patients enrolled, the lowest median oxygen saturation was 96% in the bag-mask ventilation group as compared to 93% in the no-ventilation group.
   
• A total of 21 patients in the bag-mask ventilation group had severely low oxygen levels, as compared with 45 patients in the no-ventilation group.
   
• Vomiting stomach contents into the lungs occurred during 2.5% of intubations in the bag-mask ventilation group and during 4% of the group without bag-mask ventilation.

"Some doctors believe that when you squeeze the bag and force air into the lungs that will also put air into the stomach and put the patient at risk for vomiting of stomach contents into the lungs," Casey said.

"That is not what we found. Our study found that bag-mask ventilation didn't cause the vomiting that people were worried about, and it was very effective at preventing low oxygen levels," he said. 

Based on the study findings, VUMC's ICU now uses bag-mask ventilation during placement of a breathing tube.

"It is important to act on what we learn," said study senior author Matthew W. Semler, MD, VUMC's ICU medical director.

"Not only did we immediately apply these important results to our practice, but we have started follow-up trials of other ways to improve the safety of tracheal intubation – and those new trials require that bag-mask ventilation be provided for every patient receiving a breathing tube," he said.

Study co-author David R. Janz, MD, added that "the best thing about this intervention is that it is free."

"This is a device that is already always available when you are placing a breathing tube," said Janz, assistant professor of Medicine at Louisiana State University.

"In the past, we only used the bag-mask device to assist patients' breathing if we had difficulty placing a breathing tube. Now we know that it should be used in every procedure even before we make our first attempt to place a breathing tube," he said.