PREOXI Trial
Guest author (Leah Yuan).
This one’s for the PulmPEEPs and Critheads:
Noninvasive Ventilation for Preoxygenation during Emergency Intubation. KW Gibbs. JD Casey. NEJM. June 2024. (PREOXI Trial).
The bottom line: Pre-oxygenation with NIV (i.e. BIPAP) prior to intubation decreases rate of hypoxemia peri-intubation compared to pre-oxygenation with oxygen mask (e.g. non-rebreather)
Why does this matter?
Peri-intubation hypoxemia is associated with cardiac arrest and higher mortality aka bad things
How was it studied? This is a multicenter, randomized trial, focused on EDs and ICUs. The investigators measured whether there was hypoxemia (<85% in this study) between the induction of anesthesia and two minutes after intubation.
Hypoxemia occurred in 9.1% in the NIV group vs 18.5% in the oxygen mask group. This is an absolute risk reduction of 9.4% or a NNT of 10 (!!!)
What is the current standard of practice?
It’s not standardized. If a patient has really bad lung disease, they may get some BIPAP pre-intubation. However, NRB is easy and fast so that’s seems to be more common, at least at Rush and especially on floors. In the MICU, you may also see people use a bag-valve mask (ambu bag). If not squeezed, the ambu bag won’t provide any positive pressure, but it’ll theoretically give 100% FiO2 like an NRB.
Is there anyone too sick for NIV pre-intubation?
The initial inclusion and exclusion criteria were super broad (basically anyone who needed intubation in the ED or ICU). Apneic patients were of course excluded because you need to ventilate them.
4567 patients met inclusion criteria, BUT only 1301 patients were enrolled.
Of the 3266 that were excluded:
- 29% the intubation was deemed too urgent by primary team
- 12.3% had active hematemesis, hemoptysis, epistaxis or vomiting
- 7.8% had severe agitation precluding NIV
- just to name a few
So there was some degree of clinical decision making (common sense) required.
Is there anyone…too “healthy” for it?
Doesn’t seem like it at first glance! Even patients who were just on room air an hour before benefited from NIV pre-intubation. Same when stratifying by BMI or APACHE II score (see subgroup analyses in figure 2). There wasn’t enough data to show if they benefited more or less than their counterparts, but I think the conclusions are strong enough to advocate for all patients to get NIV pre-intubation.
Aren’t we worried about aspiration?
There were no significantly increased aspiration events between NIV and NRB groups. However, we also have to consider that many patients were not enrolled because they were actively spewing bodily fluids…these were decisions made by physician doing the intubation. And these studies are generally powered to detect primary outcome, not rare events. So, I think we can’t conclude anything about NIV benefit when there’s obvious aspiration risk, but as for patients with a low theoretical risk…
What are we doing at Rush?
Still not standardized, but there have been talks of implementing NIV preoxygenation protocols in the ICUs!
What are the barriers?
Seems pretty obvious - BIPAP is harder to set up than NRB. However, there are ventilators that can do both NIV and invasive ventilation - these are common in the ICU, but BIPAP might not be the first thing we grab in a staff assist. Habits and protocols can change though…and I think this trial is gonna kickstart a lot of changes.
The BIPAPs on the floors only have NIV capability. Now, this trial is not technically validated for GMF (only ED and ICU) and rarely do we need to intubate on the floors. Perhaps there will be a trend towards putting patients on BIPAP instead of NRB while wheeling them over to the ICU.
This trial is really well done and makes me excited. I’m curious to see if the PREOXI trial is enough for hospitals to implement new protocols…I guess we’ll find out!