There are a lot of rumblings within critical care at the moment regarding the usage of high flow oxygen. We sometimes forget how efficacious it can be.
The FLORALI trial looked at 4777 admissions within 20 french and Belgian ICU’s. They had a well-defined study protocol with sealed randomisation….clearly not blinded! They wanted to ascertain whether 3 different approaches to hypoxia would decrease intubation rate at 28 days.
- Patients with hypoxic respiratory failure (Pa/FiO2 <39.9 KPa) almost entirely due to pneumonia) with no COPD. CO2 had to be within normal limits.
- those with pulmonary oedema
- shock GCS<12
- hypercapnia or neutropoenia
- those needing emergent intubation were also excluded.
randomised 312 to receive:
- face mask oxygen at 10l/min
- high-flow (warm humidified) nasal oxygen (starting at 50l/min)
- NIV (for at least 8hr/day, PEEP 2-10, Vt 7-10ml/kg, high-flow nasal oxygen when not on NIV)
What they found:
- No significant difference in the 28 day intubation rate primary between the 3 groups.
- Overall trend towards superiority of high-flow nasal oxygen, but the subgroup with more severe hypoxia (PaO2:FiO2 ratio of <26.7KPa) showed most benefit.
- 90 day mortality was a lower in the high-flow nasal oxygen group.
- High flow O2 was more comfortable
What amazes me is that they had ethical approval to utilise a fairly tame approach to the hypoxic patient in usage of mere face mask O2 (but at 10l/min), V.s the other 2 that could be considered more ‘proactive’. They may have under-powered the study in assuming a fairly high intubation rate with the lesser of the 3 interventions (the face mask O2 alone). Our old friend ‘high Vt ventilation’, may have reared it’s ugly head here. Those on NIV had a higher mortality, perhaps due to the relatively high tidal volumes used (around 9ml/Kg).
This changes things…I will certainly consider this therapy before jumping in with NIV. It is simple, comfortable and may make a difference by avoiding high Vt NIV.