Is there a lot of evidence for it?
No- there is very little, but we will see the evidence coming out soon. The current evidence is mostly anecdotal.
What is it?
It is really procedural sedation, where the procedure is improved oxygenation. What you say? Thinks of it this way, you have a patient that will need intubation, but they are not obtunded and you are having a difficult time pre-oxygenating them, to allow you to give paralysis and intubate. They can be difficult to pre-oxygenate because they are cerebrally agitated, or simply because they can’t tolerate CPAP or BiPAP.
Is it for everyone?
No. Its not suitable for your obtunded patients. They just need the tube. It’s probably not needed for those with Oxygen saturations >95%, although can be used in those patients. I use it for those patients that have oxygen sats of <95% and in whom I have difficulty pre-oxygenating.
How do I actually do it?
The key is apnoeic oxygenation and Ketamine.
Use Ketamine at a dose of 1-2mg/kg. I wouldn’t use more than 2mg/kg. Ketamine results in dissociative anaesthesia, but maintains airway reflexes and doesn’t affect respiratory drive at these doses. This means your patient is breathing, maintaining their airway and now calm and tolerating pre-oxygenation.
Unless it’s a trauma, I have the patient head-up 20 degrees.
I use the apneic oxygenation technique, of nasal prongs at 15L/min and then I add either CPAP or I use a bag valve mask on the patient with a PEEP valve set at 5-10cm H2O. I don’t actively bag the patient, but let them breathe through the mask. The sats should rise in a couple of minutes.
Then, whilst still maintaining apneic oxygenation, give the paralysing agent and intubate.
It may get us out of trouble, but remember it doesn’t always work. It’s something else to have in your bag of tricks.