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Melissa Orman, MD
By Melissa Orman, MD on June 13, 2024

Revolutionizing Preoxygenation: Insights from the PREOXI Trial

Is there anything more bread and butter in emergency medicine than intubating patients in high-stress situations? With five million adults needing emergency intubation annually, staying updated on intubation best practices is crucial. The PRagmatic trial Examining OXygenation prior to Intubation (PREOXI), just published in the NEJM and discussed on ERcast in this free segment, could revolutionize our approach to preoxygenation and, most importantly, improve patient safety.

The Challenge of Hypoxemia During Intubation

Intubation, while life-saving, carries significant risks. Up to 40% of patients experience complications, with hypoxemia being one of the most common and dangerous. Occurring in about 25% of cases, hypoxemia during intubation increases the risk of cardiac arrest and death by 3 to 4 times. Historically, the standard practice has been to preoxygenate patients using an oxygen mask, such as a non-rebreather or bag-valve device. This method, supported by current guidelines, is employed in 80% of intubations worldwide.

The PREOXI Trial: A New Paradigm in Preoxygenation

The PREOXI trial compared the effectiveness of preoxygenation with noninvasive ventilation (NIV) versus the traditional oxygen mask. Conducted across 24 emergency departments (EDs) and intensive care units (ICUs) in the US, the trial enrolled 1,301 critically ill adults undergoing tracheal intubation.

Study Design and Methodology

Patients were randomly assigned to receive preoxygenation with either NIV or an oxygen mask:

  • NIV Group: Ventilator or BiPAP with 100% FiO2, an expiratory pressure of at least 5 cm H2O, an inspiratory pressure of at least 10 cm H2O, and a respiratory rate of 10.
  • Oxygen Mask Group: Non-rebreather or bag-valve-mask without bagging, delivering ≥ 15 L/min.

Both groups received preoxygenation for three minutes before induction.

Key Findings and Outcomes

The primary outcome was the incidence of hypoxemia (oxygen saturation <85%) between induction and two minutes post-intubation. The results were compelling:

  • NIV Group: 9.1% incidence of hypoxemia.
  • Oxygen Mask Group: 18.5% incidence of hypoxemia (95% CI, -13.2 to -5.6; P<0.001).

Secondary outcomes included the lowest oxygen saturation, cardiac arrest, and aspiration rates. Notably, the NIV group experienced fewer cases of cardiac arrest and aspiration.

Implications for Emergency Medicine Practice

The PREOXI trial’s findings suggest that preoxygenation with NIV significantly reduces hypoxemia and associated risks during intubation. This new paradigm challenges the traditional reliance on oxygen masks.

Implementing NIV in Your Practice

Transitioning to NIV for preoxygenation may require additional training for therapists and clinical staff to set up ventilators in BiPAP mode. Most ventilators can switch to noninvasive mode, though some may need adapters to fit face masks.


For patients requiring intubation, preoxygenate with NIV for ideally three minutes before the procedure. The PREOXI trial demonstrates that embracing NIV for preoxygenation can enhance patient outcomes, reduce complications, and ultimately save lives.

Stay informed, stay prepared, and let's continue to push the boundaries of emergency medicine for better patient care.

Published by Melissa Orman, MD June 13, 2024
Melissa Orman, MD