Written by Alex Chen, MD
Spoon Feed
Patients intubated in the Emergency Department with usual care (no oxygen delivered after induction) vs apneic oxygenation (AO) via nasal cannula did not have significant differences in lowest mean oxygen saturation.
Why does this matter?
The FELLOW trial looked at AO vs usual care in the ICU setting and it showed that AO does not appear to increase the lowest mean oxygen saturation during endotracheal intubation of critically ill patients. There were some questions about whether this was applicable to our patients in the Emergency Department. Now we have the ENDAO trial, which is the first RCT looking at patients receiving AO vs usual care during RSI in the ED.
The END of Apneic Oxygenation?
This took place in a single academic ED in New York City. Patients were randomized to either AO with flush flow rates (≥15LPM) of nasal cannula vs no supplemental oxygen during laryngoscopy. They enrolled 206 patients to achieve a power of 80% to detect a 5% difference in oxygen saturation. A strength of this study is that they had a good mix of pulmonary, trauma, and neurologic patients, which is more representative of patients that we may encounter in the ED. Also, observers were not involved in the intubation and were also blinded to outcomes. All patients received a minimum of 3 minutes of pre-oxygenation via NRB, BVM, or BiPAP. It is interesting that the mean time of pre-oxygenation was 13 minutes. An important note from this study is that patients who were unable to receive a full 3 minutes of pre-oxygenation were excluded from this study. In the FELLOW study, patients who were unable to be randomized due to need for emergent intubation were excluded. This may create some selection bias with the sickest “crashing” patients being excluded from both of these studies. It is possible that there may be some benefit to apneic oxygenation in patients who are unable to receive a full 3 minutes of pre-oxygenation. I will continue to utilize it on my sickest patients because it does not seem to cause harm and it is easy to set-up. There is a great post on the utility of lowest mean oxygen saturation as an outcome measure by Rory Spiegel on EM Nerd (see Another Spoonful below).
Source
Caputo N et al. EmergeNcy Department use of Apneic Oxygenation Versus Usual Care During Rapid Sequence Intubation: A Randomized Controlled Trial (the ENDAO Trial). Acad Emerg Med 2017.
Another Spoonful
- Salim Rezaie on R.E.B.E.L. EM – http://rebelem.com/endao-trial-apneic-oxygenation-futile-intervention-ed-rsi/
- Rory Speigel on EM Nerd – https://emcrit.org/emnerd/em-nerd-case-elemental-truancy/
- Simon Carley on St. Emlyn’s Blog – http://stemlynsblog.org/jc-apnoeic-oxygenation-again-st-emlyns/
- Ryan Radecki on EMLitOfNote – http://www.emlitofnote.com/?p=3992
Peer reviewed by Clay Smith, MD and Thomas Davis, MD.
We wonder if it would benefit patients with a difficult airway who take longer to intubate (90% were intubated by 100 seconds). Also, would true high-flow NC 50L/min, as has been done in some studies, have made a difference?
Interesting study, but it seems to prove that pre-oxygenation works more so than it does that AO doesn’t work. What would mean more to my practice would be seeing a randomized larger cohort / one that includes the sickest of the sick, and compares the n that falls below 90% sat in each group. Average O2 sats will be skewed by the large percentage that we are able to intubate successfully and quickly. The only ones that really stand to benefit from AO are the ones that can’t be preoxygenated appropriately, desat quickly, or have really prolonged apnic periods.
Couldn’t have said it better. I think it may still have a role in our sickest patients. And I wonder about 50-60 L/min.