Airway Class is what you see looking in the mouth; Airway Grade is what you see with a laryngoscope. Class is determined looking in the mouth, Grade is what you see looking in the posterior pharynx.
Airway Class is a means of predicting difficult intubation; Grade is a more accurate measure of how much trouble you are going to have passing a tube.
If you ask the patient to open their mouth wide open and you see a lot of room and large dark space, that is a Mallampati Class 1. If you see some room but not a lot, that’s a 2. If you see little room, that’s a 3. If you don’t see anything but tongue, that’s a 4.
Mallampati is once again, for predicting how much trouble you might have intubating. If the patient is a Mallampati Class 4, get ready for a challenge.
Have all your equipment prepared before attempting including your back up airway devices. You might be well served to go straight to a video-laryngoscope on your first attempt if you have one. Don’t wait for a failure, prepare for it.
Cormack-Lehane Grading is done with a laryngoscope. It is what you see when performing direct laryngoscopy. It is a more accurate way of predicting the actual difficulty of putting a tube in. It is also used to document how tough the airway really is.
It too is easy to do. When you scope the patient if you see the entire glottis that is a Grade 1 Airway. If you have a partial view, that’s a 2. If you can only see the epiglottis, that’s a Grade 3. If you cannot see the epiglottis, that’s a grade 4 or very difficult.
In EMS most patients that we intubate are unconscious and/or non-breathing. That makes it tough to have them open their mouth for us. This translates into challenges getting a Mallampati Score before we attempt intubation in many situations.
There is one important exception and that’s when we do RSI. Medics should always assess Mallampati before pushing the syringe plunger. Take an extra few seconds to know what you are getting into before you jump off the deep end.
I hope that clears up confusion about what these two different scores really mean. They are not interchangeable or different ways of saying the same thing. Sometimes they don’t correlate.
A Mallampati Class 1 is not always a Cormack-Lehane Grade 1 airway. Neither is a Mallampati Class 4 always a nearly impossible intubation, it just flags you to consider the possibility early enough to be ready for it.