Author: Dr. Catherine Buckley
It’s catchy. It rhymes for love’s sake! But is it necessary?
History
Let’s back-track a bit. It’s the summer of ‘74; two men create and release the Coma Index.
Math people (you know those people) made it better and decided to make the name better too – so it evolved into our beloved Glasgow Coma Scale (GCS.) Something we all know in our heart of hearts, but that we seem to forget was originally made for- and all the math was based around- trauma patients.
Then in the unusually hot summer of 1993 (seriously, the US had both significant floods and droughts) Gentlemen et al documented that patients with GCS < 8 after head trauma should be intubated to better prevent hypoxic injuries. And thus began the mantra!
But then…
We docs began to apply this rule to every patient, altered for any reason. We originally thought that GCS < 8 were at higher risk for aspiration or hypoxic injury as these patients are too altered to protect their airway- because they have lost their gag reflex. BUT as it turns out, GCS is a very poor predictor of the gag reflex. (Moulton et al.) People of all levels of consciousness can have poor gag reflexes. This has been shown across the board of etiologies: trauma, stroke, infection, etc. (Rotheray, et al.) To add infection to injury – studies have been showing that (specifically in poisoned patients) patients with GCS > 8 still accounted for about 15% of aspiration PNA! (Adnet and Baud)
So… What now?
This is not to say to ignore the rule. It’s a good rule.
Intubating patients with GCS <8 does not prevent all aspiration and does not protect every gag-less patient. But patients less that 8 DO have a higher proportion of gag-less-ness. (Rotheray et al) However, though it seems like the next logical replacement: I also don’t suggest that you test every patient’s gag reflex since that might actually make them vomit and then aspirate and then we would just be creating a self-fulfilling prophecy.
All said and done, as always, use your best clinical judgement. You got to do what is safest for the patient, especially as this is likely not occurring in an ER vacuum where you can sit and watch that one patient all night…just remember that intubation is not without its own risks and downstream outcomes. So if the GCS is low but the airway is intact and you have the means to adequately monitor the patient for dropping mental status or airway- then maybe consider holding off on the advanced airway.
Citations
- Adnet, F. Baud, F. Relation between Glascow Coma Scale and aspiration pneumonia. The Lancet. 1996; 348: 123-124
- Duncan, R. Thakore, S. Decreased Glasgow Coma Scale score does note mandate endotracheal intubation in the emergency department. Journal of Emergency Medicine. 2009; 37(4): 451-5
- Gentleman, D. Dearden, M. Midgely, S. Maclean, D. Guidelines for resuscitation and transfer of patients with serious head injury. BMJ. 1993; 307: 547-552
- Moulton, C. Pennycook, A. Makower, R. Relation between Glascow Coma Scale and the gag reflex.BMJ. 1991. 303(6812): 1240-1.
- Rotheray, K. Cheung, P. Cheung, C. Wai, A. Chan, D. Rainer, T. Graham, C. What is the relationship between Glascow coma scale and airway protective reflexes in the Chinese population? Resuscitation. 2012; 83: 86-89