Giving oxygen via BiPAP before emergency intubation decreases the risk of dangerously low oxygen levels, cardiac arrest

by Hennepin Healthcare

Hennepin Healthcare part of Department of the Defense-funded Pragmatic Trial Examining Oxygenation Prior to Intubation (PREOXI)

In current clinical care, most critically ill adults receive preoxygenation using an oxygen mask. Preoxygenation is the administration of supplemental oxygen prior to the start of a procedure to increase the content of oxygen in the lung and decrease the risk of hypoxemia (low levels of oxygen in the blood) during the tracheal intubation procedure.

In critically ill adults undergoing emergency tracheal intubation, hypoxemia increases the risk of cardiac arrest and death.

Hennepin Healthcare was part of the Department of the Defense-funded Pragmatic Trial Examining Oxygenation Prior to Intubation (PREOXI) trial comparing the two most commonly used methods used to preoxygenate patients prior to tracheal intubation: preoxygenation with noninvasive ventilation and preoxygenation with an oxygen mask. The study showed that the noninvasive ventilation method (a way to support breathing by using a tight-fitting respiratory mask connected to a BPAP – bilevel positive airway pressure – machine) reduced the risks associated with the intubation procedure.

“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 Vanderbilt University Medical Center 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 multicenter, randomized trial was conducted in 24 emergency departments and intensive care units in the United States. Critically ill adults undergoing tracheal intubation were randomly assigned to two groups: preoxygenation using noninvasive ventilation or preoxygenation using an oxygen mask.

The investigators hoped that preoxygenation with non-invasive ventilation would prevent hypoxemia during intubation, defined as an oxygen saturation of less than 85% during the interval between induction and 2 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 non-invasive ventilation also prevented cardiac arrest, the most feared complication of tracheal intubation, which occurred in one patient (0.2%) in the noninvasive ventilation group and seven patients (1.1%) in the oxygen mask group.

Matthew Prekker, MD, MPH, who co-led the trial locally for Hennepin Healthcare with Brian Driver, MD, reported that these findings were important because noninvasive ventilation is an existing tool in the care of critically ill adults, but it has been underutilized for emergency preoxygenation before intubation. Dr. Driver added that some physicians in our region and nationwide will be surprised at how effective it was in improving outcomes.

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.

Kevin Gibbs, MD, the first author on the study and a critical care medicine physician at Wake Forest School of Medicine, said, “Applying these results to clinical care by routinely using noninvasive ventilation for preoxygenation before tracheal intubation has the potential to prevent tens of thousands of patients each year from experiencing hypoxemia and cardiac arrest.”

The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the U.S. Government.

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Hennepin Healthcare is a nationally recognized system of care that includes HCMC, a Level I Adult Trauma Center and Level 1 Pediatric Trauma Center with the largest emergency department in Minnesota. The comprehensive academic medical center and public teaching hospital includes a 484-bed acute care hospital as well as primary care and specialty clinics located in downtown Minneapolis its surrounding communities.


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