EBM Review Series: Noninvasive Ventilation for Preoxygenation During Emergency Intubation
VACEP Evidence-Based Medicine for General Emergency Physicians Series
Authors: Morgan Webb, MD PGY-3 and Carrie Maupin, MD | VCU Health
Reviewer: Gabriella Dean, MD PGY-2 and Winston Wu, MD | UVA Health
The VACEP Evidence-Based Medicine Review Series allows Virginia emergency medicine residents and attendings to share and analyze a recent peer-reviewed clinical study. You can also read the full article, “Noninvasive Ventilation for Preoxygenation during Emergency Intubation” from the New England Journal of Medicine, Volume 390 Number 23.
THE CASE
A 65-year old male reports to the ED with respiratory distress. His past medical history includes CHF (EF 30-35%) and COPD, not on home oxygen. He has had cough, fever, and decreased PO intake for several days. No relief with home nebulizers. On exam, he is tachypneic with increased work of breathing and is becoming lethargic. You decided to intubate for airway protection.
What is your preoxygenation plan?
STUDY SUMMARY
A multi-center randomized trial across 24 sites – including EDs and ICUs in the United States – evaluated the use of non-invasive ventilation (NIV) versus oxygen mask for preoxygenation prior to rapid sequence intubation (RSI). After patient selection and 1:1 randomization, the operators were instructed to administer oxygen via NIV (FiO2 100%, IPAP/EPAP 10/5, RR 10) or via facemask (non-rebreather or bag-valve mask) for at least 3 minutes before the induction of anesthesia and until the initiation of largyngoscopy.
Primary outcome: hypoxemia (SpO2 <85%) during the interval between induction of anesthesia and 2 minutes post intubation.
Secondary and exploratory outcomes: lowest oxygen saturation during the same interval, aspiration, hypotension, use of vasopressors, and cardiac arrest.
Exclusion Criteria: <18 years old, pregnant patients, prisoners, patients already receiving PPV, apnea/hypopnea, clinician-determined contraindication or necessity for positive-pressure ventilation, or immediate need for. tracheal intubation that precluded randomization and study protocols.
RESULTS:
Patients in the NIV group had a significantly lower incidence of hypoxemia compared to those receiving standard oxygen masks (9.1% vs 18.5%; 95% confidence interval [CI], -13.2 to -5.6; P<0.001). Cardiac arrest during the interval between anesthesia and 2 minutes post-intubation was reporting in 0.2% of patients in the NIV group compared to 1.1% in the oxygen mask group (difference, -0.9 percentage points; 95% CI, -1.8 to 0.1). Operator reported aspiration events were not significantly different between the two groups (0.9% in the NIV group and 1.4% in the oxygen mask group; 95% CI, -1.6 to 0.7). Additionally, the incidence of new opacity on chest x-ray and baseline oxygen saturation at 24 hours were similar between the two groups.
About the EBM Review Series
This is a literature review series started by the University of Virginia’s Josh Easter, MD, MSc, a VACEP board member working to connect the academic community in Virginia. We invite each residency in Virginia (and D.C.) to create a faculty/resident team to submit and review articles. Sign up to submit one.
Goals
Provide a brief monthly synopsis of a high yield article germane to the practice of emergency medicine for distribution to all VACEP members
Provide an opportunity for a peer reviewed publication and invited presentation for faculty and trainees
Foster an academic community focused on evidenced based medicine for emergency medicine residency programs in the region
STRENGTHS and LIMITATIONS:
Strengths:
Large study enrollment with broad range of underlying medical conditions (1301 patients across ED and ICU setting).
Randomization minimizes selection bias.
Data collection and interpretation performed by independent observer.
Limitations:
Patients already receiving PPV were excluded, which limits applicability to this population which may benefit the most from this intervention.
Patients perceived at high risk for aspiration were excluded, which limits interpretation of aspiration as an exploratory outcome.
Not a blinded study.
BOTTOM LINE:
NIV appears to be a superior preoxygenation strategy compared to standard oxygen masks in emergency intubation, reducing the incidence of hypoxemia without introducing significant complications in appropriately selected patients. Emergency physicians should consider NIV patients at high risk of desaturation, particularly in those with comorbidities that may benefit from PPV including COPD or pulmonary edema. However, practical limitations such as equipment availability, setup time, patient tolerance, vomiting, and altered mental status/agitation must be considered when selecting appropriate preoxygenation method.
DISCUSSION
First off, thank you to Dr. Webb & Dr. Maupin for choosing such a salient article to the practice of emergency medicine for our review series. Our follow-up conversation with our colleagues at VCU raised several thoughtful points that we believe could add valuable context to this review.
One key consideration was that the majority of intubations in the study took place in the ICU rather than the ED (73.2% vs 26.8%). Together, we discussed how this might impact the applicability of these findings to emergency department settings, where resource constraints such as staffing, respiratory therapist availability, and equipment access may vary. Our colleagues noted that since most ventilators are capable of providing NIV, the equipment itself is typically available in both settings. We appreciated this perspective and agreed that while equipment may be accessible, site-specific operational realities still play an important role in determining whether NIV is a practical option in the ED.
We also discussed the finding that intubation timing and success rates were similar between groups, which supports the idea that using NIV does not introduce delays or impact procedural success. Our colleagues highlighted the practical benefit of using the same ventilator for both preoxygenation and post-intubation care, which may help streamline workflow. We found this to be a helpful operational insight worth emphasizing, as it reinforces that NIV can be implemented efficiently as long at the team is prepared to use the equipment appropriately.
We do feel there is an important aspect of this study that remains under-addressed but particularly relevant to emergency medicine practice.
While the study highlights the physiological benefits of NIV for preoxygenation, it does not fully explore the real-world challenges of patient cooperation and tolerance. As Drs. Webb and Maupin mention in their summary, many patients we encounter are agitated, delirious, hypoxic, or significantly altered. These patients may be unable or unwilling to tolerate the tight-fitting mask required for NIV. In our opinion, during these situations attempting NIV may actually increase distress, delay intubation, or pose additional risks compared to preoxygenation with a nonrebreather mask.
Similarly, the exclusion of patients at high risk of aspiration, while understandable from a study design perspective, also limits the applicability of the findings to a broader population, many of whom make up a large proportion of those we intubate in the ED. This reinforces an important takeaway: clinical context matters, and there is no one-size-fits-all solution to airway management. NIV can be an excellent preoxygenation strategy for selected patients, but it is not appropriate or feasible for every clinical scenario.
We’re grateful to our colleagues at VCU for highlighting this important article and giving us the opportunity to think more deeply about the nuances of preoxygenation strategies. These discussions help us better prepare for managing some of the most emergent and high-stakes scenarios we face in emergency medicine.
REFERENCES:
Gibbs KW, Semler MW, Driver BE, et al. Noninvasive Ventilation for Preoxygenation during Emergency Intubation. N Engl J Med. 2024;390(23):2165-2177. doi:10.1056/NEJMoa2313680
