The PREOXI Trial
Noninvasive Ventilation for Preoxygenation during Emergency Intubation
My Guests
Authors of PREOXI:
Kevin Gibbs
Adit Ginde
What is PREOXI? Bundle Therapy of…
- High FiO2 preox
- PEEP Preox
- Augmented Insp Pressure Preox
- Apneic Breaths
- Apneic PEEP
PICO of the Trial
Multicenter RCT in 7 EDs and 17 ICUS in the USA. Intention to treat analysis
Patients
Adults
Not apneic or being bagged, not crash intubations
48% hypoxemic respiratory failure
73% in the ICU and 27% in the ED
Intevention
Pragmatic trial
asked to use NIPPV mask and BIPAP with NIPPV machine or Ventilator
Jaw thrust during apnea
FiO2 100%, EPAP >=5, IPAP >=10, RR >=10
95.5% got the intervention (0.6% couldn't tolerate)
3% got some form of NC
Comparator
asked to use NRB at flush rate, >=15 lpm
98.8% got the intervention
30% bvm with ventilations, 11.3% bvm without ventilations during apneic period
16% got some form of NC
Outcome
- Hypoxemia < 85% during/2 min after: 9.1% vs. 18.5%
- Hypoxemia < 80% during/2 min after: 6.3% vs. 13.2%
- Cardiac Arrest: 0.2% vs. 1.1%
- Aspiration: No sig. difference (point estimate worse in NRB group)
Key Points
- Even room air patients benefited
- Especially necessary in obese patients
- Doubters will say it is all fiO2, but this is not consistent with the authors' experience during the trial
- Full, full stomachs excluded at the discretion of the clinicians
EMCrit Preox Page
Post-PREOXI Preoxygenation Options
- Start with NIPPV mask, CPAP, and then transition to mandatory breath mode at induction
- Start with BIPAP with a rate right up front
- Oxylator with a PEEP valve
- BVM + PEEP Valve + NC with positive pressure breaths after induction
Additional New Information
More on EMCrit
- EMCrit Preox Page
- EMCrit 173 – LaMW – Oxygenation Kills Part I
- EMCrit 174 – LaMW – Oxygenation Kills Part II
- EMCrit 206 – ApOx, ENDAO, & PreOx Update(Opens in a new browser tab)
- EMCrit – When it comes to Preintubation Terminology we stink like POO(Opens in a new browser tab)
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Professor
Nassau University Medical Center
No conflicts of interest (coi).
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I’ve not read the paper yet….but it seems like bag valve mask without ventilation, peep valve, nasal prongs is not a proper way of preoxygenate patients and could worsen outcomes of the arm in question…..don’t you think?
as long as it has a proper exhalation valve, it is actually the gold standard for pure preoxygenation up until this point.
Even without nasal prongs and peep valve?
yes, before this trial this was the gold standard
I generally preoxgyenate and ventilate if necessary with a mapleson C circiut set to give a little peep instead of a BVM, I much prefer this over a BVM in a spontaneously breathing patient simply which seems to help by giving some extra recuritment and also much more pleasant for a patient to breathe on than a BVM
it is touch to compare pt comfort unless you have controlled for the same level of PEEP and the same amount of FGF between the two devices. When I have done the experiment on myself, they feel the same. The problem with the mapleson circuits is the rebreathing in pts with high minute ventilation and the lack of any measurement of how much PEEP you are giving.
Hi Scott
The decrease in cardiac arrest is most important.
I suspect that the standard practice of drugs and then onto PPV is the double-whammy that results in post intubation crashes
The beauty of the PREOXI (and your DsI) protocol is that we temporarily separate the insults to cardiac output allowing intervention and Resus in between events.
That 3 -5 minutes on NIV can give a lot of information and make for a smoother transition?
In Uk we use a mapelson C with 15 L flow rate as ventilation, how does this differ from a BVM with your USA flow rates of 50-60l/min?
The problem with the mapleson circuits is the rebreathing in pts with high minute ventilation and the lack of any measurement of how much PEEP you are giving. At 15 lpm many patients will be rebreathing. In order to avoid rebreathing, you generally need 2.5x the patients minute ventilation.
Scott, Fantastic podcast and interview! Great job asking the key questions to the authors. Overall this is a strong pragmatic trial. Finally solid evidence validating the powerful impact of routine pre-oxygenation via non-invasive facemask with the addition of positive pressure. A few of my thoughts: Several reasons here to explain why this method of pre-ox resulted in less hypoxemia, critical hypoxemia, and even cardiac arrest. On one hand, we have the perfect pre-oxygenation. A tight-fitting NIV mask with 100% FIO2 and PEEP of ≥ 5 cm H2O—which importantly was sustained after induction and during apnea. I personally do not believe… Read more »
Thanks for the great episode Scott I tend to agree with everything you say, although I worry that our mostly shared prior beliefs on this topic could easily bias our reading of the paper. 2 points: 1) Minor quibble, but I think the language you use in the conclusion might be a touch too strong. I think it was something like “beyond a shadow of a doubt”, but as great a trial as this is, it is an unblinded trial, which always has the potential to create significant bias. I think being overly dogmatic after a single unblinded trial could… Read more »
Scott if you were a medical director for an EMS agency how would you write the preoxygenation process for the RSI protocol? We currently use standard preoxygenation procedures, but we now have Hamilton T1 ventilators on all our ambulances. We performed 128 RSIs last year with 26% incidences of hypoxia and would love to reduce our adverse reactions. Would you place every patient on NIV-ST with a backup rate during the preoxygenation procedure in addition to a nasal cannula at flush flow rates? Just curious on your thoughts. Thanks in advance.
Is there any added benefit to having the NC underneath if you are using BiPAP or the vent for preox/ apneic period?
It’s a good question. As I know Scott will agree, I think it can only help in terms of apneic oxygenation during the actual laryngoscopy attempt. And more importantly, if you are going to re-oxygenate after a failed first pass with the BVM and not the vent, then you will want it on there to compensate for any potentially imperfect seal and also to power your PEEP valve.
This very much feels like we’re treating a number that seemingly had no benefit on patient oriented benefit. The fragility index on cardiac arrest was zero, and the in hospital death was no different between groups. this feels like the peds RSV trials on pulse ox targets where number didn’t matter much. Sure NIV seems safe, just doesn’t seem to make much of a difference and we should choose a different hill to die on. Again- there was no difference in in-hospital death and the fragility index was zero for peri-intubation cardiac arrest. We should water down the rhetoric on… Read more »
Hi Scott. We have been running through the setup for the PREOXI strategy in our ED. I have 2 questions that I would love to hear your thoughts upon: 1.) the use of a NPA adjunct – this does make maintaining an open airway for the induction phase and also in the event of the need for rescue ventilations. Should this be encouraged as part of the PREOXI setup as it seems like a simple, low risk addition? 2.) what to do if the first (or second) intubation fails.. I imagine that following the traditional algorithm is what the trialists… Read more »
Important topic and great discussion. Tend to agree with Patrick Bufama’s comment. The study background is that hypoxaemia during intubation increases the risk of cardiac arrest and death. There was no mortality benefit, and a marginal decrease in cardiac arrest. Should we focus on using NIV prior to intubation on subgroups more likely to benefit as shown in Fig 2 (acute hypoxemic respiratory failure and BMI > 30), and then do clinical trials to clarify if that is the case.
Is there any concern about NIV causing hypotension as the thoracic cavity is pressurized decreasing venous return? Certainly see that in patients on a ventilator, have to say do not recall seeing that in my patients with BiPAP.