Study identifies preoxygenation method that reduces hypoxemia and cardiac arrest risk

Posted by Nancy Humphrey on Wednesday, March 5, 2025 in Around the Medical Center, Spring 2025 .

For critically ill adults undergoing emergency tracheal intubation, hypoxemia (low levels of oxygen in the blood) increases the risk of cardiac arrest and death. In current clinical care most critically ill adults receive preoxygenation using an oxygen mask.

The Pragmatic Trial Examining Oxygenation Prior to Intubation clinical trial was led nationally by Vanderbilt University Medical Center and involved researchers at the University of Wisconsin School of Medicine and Public Health. The study compared the two most commonly used methods to preoxygenate patients prior to tracheal intubation: preoxygenation with noninvasive ventilation and preoxygenation with an oxygen mask.

The study, published in the New England Journal of Medicine, showed that the noninvasive ventilation method using a tight-fitting respiratory mask connected to a BPAP — bilevel positive airway pressure — machine reduced the risks associated with the intubation.

“More than 1.5 million critically ill adults undergo emergency tracheal intubation each year in the United States,” said Jonathan Casey, MD, MSCI, assistant professor of Medicine in the Division of Allergy, Pulmonary and Critical Care Medicine at VUMC and a senior principal investigator in the trial.

“Hypoxemia occurs during 10% to 20% of those tracheal intubations in the emergency department or intensive care unit and may lead to cardiac arrest and death. Our study found that among critically ill adults undergoing tracheal intubation, preoxygenation with noninvasive ventilation decreases the incidence of hypoxemia during intubation compared to preoxygenation with an oxygen mask.”

The investigators hoped that preoxygenation with noninvasive ventilation would prevent hypoxemia during intubation, defined as an oxygen saturation less than 85% during the interval between induction and two minutes after tracheal intubation.

In the 1,301 patients enrolled, hypoxemia occurred in 57 of the 624 patients (9.1%) in the noninvasive ventilation group and 118 of the 637 patients (18.5%) in the oxygen mask group.

Further, it appeared that by preventing hypoxemia during tracheal intubation, preoxygenation with noninvasive ventilation also prevented cardiac arrest, the most feared complication of tracheal intubation. Cardiac arrest occurred in one patient (0.2%) in the noninvasive ventilation group and seven patients (1.1%) in the oxygen mask group.

Prior to this trial, international guidelines stated that preoxygenation with either noninvasive ventilation or an oxygen mask is acceptable — guidance that results of this trial are likely to change.