Again, I realize this is an EMS forum, and I would agree that in the crisis setting, management of moderate to severe acute pain is in most cases best done by medicating (typically with opioids) based on the patient's reported pain level. In the field we are limited to this strategy because of numerous practical limitations.
We aren't debating whether we should take seriously an individual's complaint of pain. And we aren't talking about the "pain thermometer" that the OP posted about. We are talking about why an objective measure of pain intensity might be useful. And the answer to that is this:
- Pain management can be quite complex (that's why there are medical subspecialties devoted to it)
- Optimum pain management depends first and foremost on a good pain assessment
- A good pain assessment (or any assessment) is as objective as possible.
There's plenty of research that indicates that patients are highly inconsistent with self-reported pain scores. And there are numerous reasons for it.
We have all seen people report 10/10 pain as they are literally giggling to the person next to them them and taking silly-face selfies. I have had people in no apparent distress at all tell me with a straight face that their pain is "20/10", and when questioned further, say that their pain has been like that every day for years. I've also seen people in a post-anesthetic stupor with large amounts of pain meds already on board wake up only when the PACU nurse aroused them, and then just long enough to tell me that they are having 10/10 pain, only to immediately doze off and start snoring again. I've had people with nerve blocks that were obviously working well do the same thing.
In these examples, are we really doing what is in the best interest of the patient by blasting them unnecessarily with large doses of opioids, just because they say they are having 10/10 pain? Clearly not. Clearly, pain is not
always what the patient says it is.
What about the older person with chronic or acute cognitive deficits? Or the stoic who appears very uncomfortable but says they are "fine" when you try to talk to them about their pain? Should their pain go untreated because pain is always what the patient says it is? There are consequences to untreated pain, just like there are consequences to unnecessary opioids.
We can take a complaint of pain seriously without formulating an entire treatment plan based on the answer to a single question. I can't think of many other examples of where we are expected to form management decisions on a single data point.
There are many types of pain and some don't respond well to opioids - some can even potentially be worsened by large doses of opioids. Many pain syndromes respond best to well-defined pharmacologic strategies. Dosing people with lots of fentanyl or dilaudid is often not the best strategy for a good outcome. It all depends on the history and assessment. This is why objective assessment tools are desirable.