Preoxygenation with noninvasive ventilation reduces hypoxemia during intubation

Key takeaways:

• Across several subgroups, preoxygenation with noninvasive ventilation lowered hypoxemia more than an oxygen mask during intubation.
• Fewer patients receiving noninvasive ventilation experienced cardiac arrest.

Fewer ICU/ED patients experienced hypoxemia during intubation with receipt of preoxygenation with noninvasive ventilation vs. an oxygen mask, according to research published in the New England Journal of Medicine.

Jonathan Casey

“The PREOXI trial shows that, for patients undergoing emergency tracheal intubation in the ED or ICU, preoxygenation with noninvasive ventilation reduces hypoxemia and may prevent cardiac arrest without increasing the risk of aspiration,” Jonathan Casey, MD, MSCI, assistant professor in the division of allergy, pulmonary and critical care medicine at Vanderbilt University Medical Center, told Healio.

“This simple intervention can be applied with the equipment already available at the bedside for invasive mechanical ventilation post-procedure, and we believe it should be the standard method of preoxygenation for critically ill adults,” he continued.

In the multicenter, randomized PREOXI trial, Casey and colleagues evaluated 1,301 adults (median age, 61 years) in the ICU (73.2%) or ED (26.8%) undergoing tracheal intubation to determine which delivery method of preoxygenation — noninvasive ventilation or oxygen mask — leads to fewer instances of hypoxemia during intubation.

Researchers classified hypoxemia as “an oxygen saturation of less than 85% during the interval between induction of anesthesia and 2 minutes after tracheal intubation.”

The group with the noninvasive ventilation method included 645 patients (median age, 61 years; 39.5% women; 59.5% non-Hispanic white), of whom 616 ended up receiving this preoxygenation method. The group with the oxygen mask method included 656 patients (median age, 61 years; 39.6% women; 60.8% non-Hispanic white), of whom 648 ended up receiving this preoxygenation method.

Notably, hypoxemia findings are reported out of 624 patients in the noninvasive ventilation group and 637 patients in the oxygen mask group.

A significantly greater proportion of patients receiving preoxygenation via oxygen mask vs. noninvasive ventilation experienced hypoxemia (18.5% vs. 9.1%; difference, –9.4 percentage points; 95% CI, –13.2 to –5.6; P < .001), according to researchers.

Noninvasive ventilation continued to be the method linked to a decreased likelihood for hypoxemia in several subgroups: location (ED and ICU), acute hypoxemic respiratory failure (with and without), BMI (< 30 kg/m² and ≥ 30 kg/m²), Acute Physiology and Chronic Health Evaluation II score (< 17 and ≥ 17) and fraction of inspired oxygen 1 hour before intubation (0.21, 0.22-0.4, 0.41-0.7 and > 0.7).

“We were surprised by the size and consistency of the benefit of preoxygenation with noninvasive ventilation, which significantly reduced hypoxemia for every patient population, including those expected to be at low risk of hypoxemia, such as those on room air prior to the procedure,” Casey said.

Among those who met the criteria for hypoxemia during intubation, researchers noted that a smaller proportion of patients receiving preoxygenation with noninvasive ventilation vs. an oxygen mask had an oxygen saturation below 80% (6.2% vs. 13.2%). This was also the case when evaluating those with an oxygen saturation below 70% (2.4% vs. 5.7%).

Another outcome that impacted fewer patients receiving preoxygenation with noninvasive ventilation vs. an oxygen mask was cardiac arrest (one patient [0.2%] vs. seven patients [1.1%]).

“While our hope had always been that preventing hypoxemia would prevent cardiac arrest, the trial was not designed to evaluate this rare but important complication,” Casey said. “We were encouraged to see that, while the numbers were small, preoxygenation with noninvasive ventilation significantly reduced the incidence of cardiac arrest, the most feared complication during emergency tracheal intubation.”

Additionally, aspiration was a less frequent outcome among those in the noninvasive ventilation group compared with the oxygen mask group (six patients [0.9%] vs. nine patients [1.4%]).

“There are more than a dozen decisions that need to be made during the brief 2-minute procedure to intubate a critically ill patient,” Casey said. “Our group is focused on evaluating every step of the procedure.

“In addition to preoxygenation with noninvasive ventilation, our prior trials have shown the benefit of using a video laryngoscope and providing ventilation after induction,” he added. “Our ongoing and future trials will focus on the sedatives and neuromuscular blockers used during the procedure and the type of video laryngoscope.”

Reference:

• Multicenter randomized trial identifies method of preoxygenation that prevents hypoxemia and cardiac arrest during emergency tracheal intubation. https://www.newswise.com/articles/multicenter-randomized-trial-identifies-method-of-preoxygenation-that-prevents-hypoxemia-and-cardiac-arrest-during-emergency-tracheal-intubation. Published June 13, 2024. Accessed June 13, 2024.