Rural EM: PREOXI Trial Protocol In Rural Life

Authors: Ashley Weisman, MD (Rural emergency physician, University of Vermont Health Network); Cameron Upchurch, MD (Emergency Medicine and Critical Care Physician, University of Vermont Health Network); Skyler Lentz, MD (Emergency Medicine and Critical Care Physician, Medical Director of Respiratory Therapy, University of Vermont Health Network) // Reviewed by Brit Long, MD (@long_brit)

Introduction

Applying the findings of the PREOXI trial to your rural practice sounds like a great idea–see a sick patient, preoxygenate with bilevel positive airway pressure (BiPAP) ventilation,intubate and have fewer post-intubation cardiac arrests and less hypoxemia. But PREOXI also sounds daunting, especially if you are among the 30% of critical access hospitals with no respiratory therapist. There are a number of FOAM resources discussing how to apply PREOXI in tertiary centers where multiple physicians, nurses, technicians, and respiratory therapists can descend on a patient and add this to their resuscitation strategy. But can we make this happen in rural EDs staffed by one doctor and two nurses? More importantly, why should we? 

For starters, patients who received positive pressure for preoxygenation did better. They had significantly fewer cardiac arrests (0.2% vs 1.1%) and less hypoxemia (peripheral O2 saturation <85%) from induction to 2 minutes post-intubation (9.1% vs 18.5%), with no difference in the low rates of aspiration (0.9% vs 1.4%) in each group. Those with BMI ≥30 and those with preceding hypoxemia benefited the most but the intervention reduced the risk of hypoxemia in all groups. This benefit is clinically meaningful. But the protocol was NOT studied in a rural solo coverage setting. Are there unknown benefits or risks for the rural ED patient and solo coverage provider? 

Potential Benefits

 In addition to better preoxygenation, PREOXI may offer two additional benefits for rural teams — freeing up a pair of hands and more practice with your vent. Preoxygenation using a nasal cannula plus a bag valve mask (BVM) with a peep valve held over the patient’s face is labor-intensive. Someone needs to set that up, maintain a mask seal, and monitor the patient. You also need to have enough wall oxygen ports for the nasal cannula, the non-rebreather, and your vent. Since you need to set up your ventilator anyway, why not get the additional benefits of preoxygenating with it? Once your patient is on BiPAP, you can see their minute ventilation and oxygen saturation and can be confident that your patient is being oxygenated and ventilated while you prepare your equipment and meds for intubation. PREOXI also encourages increased repetitions using your ventilator, which we all need in small rural shops. 

Potential Risks

If your rural ED ventilator does not have a “non-invasive” setting or BiPAP mode or you need a different circuit for BiPAP, PREOXI may introduce more risk than benefit. Adding a separate BiPAP machine or swapping circuits in the middle of the resuscitation to follow PREOXI increases the complexity of your resuscitation, the risk of errors, and the number of hands you need. In this situation, The PreVent trial supports the use of BVM + PEEP valve of 5-10 cm H2O as an effective and safe option in preventing hypoxemia. Importantly, the study used optimal BVM technique with an oral airway, two handed mask seal, 10 breaths per minute and with the smallest volume that caused chest rise. Using this optimal technique, the risk of aspiration was similar to those not receiving BVM. We refer to this as BVM PEEP PLUS to help our teams remember all of the components. 

If you have the gear to do it, we think PREOXI is worth discussing, practicing, and implementing with your rural team.

How to Make it Happen:

1. Set up: Prepare your ventilator in advance with a circuit that can be used for both “non-invasive” settings (BiPAP) and “invasive” mechanical ventilation settings. Hang a bag on the ventilator with multiple sizes of BiPAP masks with appropriate connectors to link them to your circuit. Set the BVM with PEEP valve up as a back up. 
2. Practice: use a mannequin head and test lung or exam glove taped to the end of the circuit. Turn on your vent. Select BiPAP mode. Dial in your settings to inspiratory pressure  >=10 cm H20 and expiratory pressure  >= 5 cm H20, rate of >=10 (or higher if wish to match patients’ intrinsic high minute ventilation during the apneic period), at 100% Fi02. 
3. Prepare your intubation supplies, meds, end-tidal CO2, and nursing team.
4. Induce and paralyze the patient, perform jaw thrust to maintain a patent airway while the BiPAP continues to oxygenate/ventilate until the patient is sufficiently paralyzed, then remove the BiPAP mask, deliver 3 BVM breaths during the apneic period, and perform laryngoscopy. 
5. Intubate and confirm placement with ETCO2. 
6. Switch the ventilator from the “non-invasive” BiPAP mode to an “invasive” assist control mode and connect the ET tube to the ventilator circuit that is already set up and waiting for you.

If you cannot preoxygenate with BiPAP, consider the BVM PEEP PLUS method. 

1. Place a nasal cannula at flush flow rate on the patient. 
2. Add a BVM with a PEEP valve set to 5cm H20 with the oxygen at flush flow rate and hold in place with a good seal. Continue BVM 10 breath/min, enough volume for chest rise using an oral airway and 2 hand mask seal throughout induction and during apneic period preceding laryngoscopy. 
3. Go to step 3 above. 

Please see our preoxygenation video at https://youtu.be/8nOTerrXnHU

And our transition from preoxygenation to mechanical ventilation video at: https://youtu.be/3QtfqpVyeL4           

These videos use the Hamilton transport ventilators that we have in our health system. The general principles apply to all ventilators, but the circuit setup and ventilator knobology will vary. Talk to your intensivists, respiratory therapists, or ventilator vendor to make your own videos for your system.

References:

1. Gibbs KW et al. Noninvasive Ventilation for Preoxygenation During Emergency Intubation. NEJM 2024. PMID: 38869091
2. Casey M, Evenson A, Mosocovice I, Zhengtiana W. Availability of Respiratory Care Services in Critical Access and Rural Hospitals. Policy Brief. University of Minnesota Rural Health Research Center. June 2018. https://rhrc.umn.edu/wp-content/files_mf/1530149057UMNpolicybriefAvailabilityofRespiratoryCareServices.pdf.  
3. Scott Weingart, MD FCCM. EMCrit 377 – Breaking News – The PREOXI Trial changes everything about Preoxygenation for Intubations in the Critically Ill. EMCrit Blog. Published on June 13, 2024. Accessed on November 13th 2025. Available at [https://emcrit.org/emcrit/preoxi/ ].
4. Salim Rezaie, “The PREOXI Trial: Pre-Oxygenation with NIV vs Facemask”, REBEL EM blog, June 28, 2024. Accessed November 13th 2025. Available at: https://rebelem.com/the-preoxi-trial-pre-oxygenation-with-niv-vs-facemask/.
5. Roveri G, Camporesi A, Hofer A, Kahlen S, Breidt F, Rauch S. Preoxygenation With and Without Positive End-Expiratory Pressure in Lung-Healthy Volunteers: A Randomized Clinical Trial. JAMA Netw Open. 2025;8(5):e2511569. doi:10.1001/jamanetworkopen.2025.11569
6. Pitre, Tyler, Winnie Liu, Dena Zeraatkar, Jonathan D. Casey, Joanna C. Dionne, Kevin W. Gibbs, Adit A. Ginde, et al. “Preoxygenation Strategies for Intubation of Patients Who Are Critically Ill: A Systematic Review and Network Meta-Analysis of Randomised Trials.” The Lancet. Respiratory Medicine, March 20, 2025, S2213-2600(25)00029-3. https://doi.org/10.1016/S2213-2600(25)00029-3.
7. Casey JD, Janz DR, Russell DW, et al. Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults. N Engl J Med. 2019;380:811-821.