Contributor: Travis Barlock MD

Educational Pearls:

When might you need to apply a painful stimulus in a medical setting?

The main reason is to assess the patient's level of consciousness, such as when they are waking up from anesthesia or have potentially suffered a brain injury.
It can be part of the Glasgow Coma Scale (GCS) if patients are not responding to auditory stimuli.
Possible levels of consciousness include Alert, Lethargic, Obtunded, and Comatose (ALOC)

What are the approved ways to apply a painful stimulus to assess central nervous system function?

Trapezius squeeze. Grab the trapezius muscle and twist (contraindicated in clavicle fractures).
Supraorbital rim pressure. Find the notch in the supraorbital rim of the patient and push hard with your thumb (contraindicated in facial fractures).
Mandibular pressure (not mentioned). Press hard at the angle of the jaw on the mandibular nerve (contraindicated in mandible fractures).
Sternal rub. Push down with your knuckles into the patient’s sternum and rub vigorously (contraindicated in chest injury/surgery).
Each technique should be done for between 15 and 30 seconds.
If skin damage is observed in one location, move to a different location. This is especially true of the sternal rub.

Important note: Peripheral techniques such as nail tip pressure should only be used to evaluate spinal nerve reflexes and not as a method of assessing the level of consciousness.

References

Lower J. Using pain to assess neurologic response. Nursing. 2003 Jun;33(6):56-7. doi: 10.1097/00152193-200306000-00047. PMID: 12799591.
Middleton PM. Practical use of the Glasgow Coma Scale; a comprehensive narrative review of GCS methodology. Australas Emerg Nurs J. 2012 Aug;15(3):170-83. doi: 10.1016/j.aenj.2012.06.002. Epub 2012 Aug 3. PMID: 22947690.
Mistovich JJ, Krost W, Limmer DD. Beyond the basics: patient assessment. Emerg Med Serv. 2006 Jul;35(7):72-7; quiz 78-9. PMID: 16878751.
Naalla R, Chitirala P, Chittaluru P, Atreyapurapu V. Sternal rub causing presternal abrasion in a patient with capsuloganglionic haemorrhage. BMJ Case Rep. 2014 Apr 7;2014:bcr2014204028. doi: 10.1136/bcr-2014-204028. PMID: 24711478; PMCID: PMC3987201.

Summarized by Jeffrey Olson, MS2 | Edited by Jorge Chalit, OMSII

Podcast 862: How to Apply a Painful Stimulus

Emergency Medical Minute