Diagnosis of Acute Pain

Benjamin W. Friedman, MD, MS: I want to move on to the topic of diagnosis and monitoring of acute pain. Maybe we could all discuss a little about subjective findings, diagnosis, and assessing the impact of pain on individuals—how we go about assessing pain among our patients, what findings we look for, and how we try to understand the patient’s experience. Paul, perhaps I could turn to you to talk about that.

Paul Arnstein, PhD, RN, FAAN: Thank you. It’s very much context specific. On the one hand, we want to identify some of the diagnostic variables associated with injury or illness that bring the patient in, because the words that the patient uses, whether the pains are sharp, stabbing, aching, gripping, or cramping, might lead us in a certain direction in terms of further imaging or testing that may be appropriate. But when we’re looking at the symptom of pain itself, it’s important that we look at the nature, intensity, and location of pain.

There are many acronyms that guide thinking about pain, but I prefer to use WILDA: words to describe pain, intensity, location, duration, and aggravating or alleviating factors. Let’s start with the words the patient uses. Some might lead me more toward somatic, visceral, or neuropathic pain. But some people might describe their pain as being excruciating or annoying, or say, “It’s killing me.” If I don’t assess their psychological status in terms of the anger, fear, or anxiety that they’re experiencing, I might miss an important component of that.

The intensity of pain is where a lot of people focus on pain. A lot of the pain scales home in on the intensity of pain, starting with the visual analog scale that was used for research purposes, which has a 10-cm line that the patient marks on. But that isn’t very useful clinically, so typically we use a numeric rating scale, which is on a scale of 0 to 10. You have to get those anchors right: 0 represents no pain, and 10 represents the worst pain you’ve experienced or the worst pain imaginable. A lot of people misuse that scale by saying “on a scale of 1 to 10.” Nobody knows what a 1 is, so it’s important to make sure you’re asking about the 0.

It’s also important to look at its location, when it started, how it has changed since it started, some of the exacerbating and alleviating factors, and its effect on activity, affect, and the ability to perform activities of daily living. Moving away from in the acute care setting, where we typically do pain assessments every 4 or 8 hours from the nursing perspective, more frequently with more critically ill patients or more invasive technologies that we’re using, looking at the intensity by itself tells only a partial picture and doesn’t guide treatment.

I’ve done some work on the functional pain scale, which basically determines whether there’s pain, to what extent it’s tolerable or intolerable, and to what extent it interferes with activities—activities that are active, that require exertion and effort, or that are ordered as a part of the treatment program—or interferes with even passive activities, such as watching TV, using a computer, or talking on the telephone.

Sometimes we get confused when a patient says that they don’t want to get out of bed and ambulate or participate in therapy, but they’re watching TV and laughing. That’s a virtue of the intensity of pain or the fact that pain gets exacerbated with movement. Looking at pain assessments while the patient is stagnant or stationary, but also when they move and how that affects their pain, tells us important clues regarding what’s going on with the patient as far as treating the underlying cause and things we need to put in place in our treatment of the pain that will help the patient think, feel, and do better.

Jeff Gudin, MD: Paul brings up a great point. We’ve thought about this in the chronic-pain world for quite some time. As a matter of fact, when you go for approval of any new chronic analgesic, one of the mandatory domains of assessment is function. The agency doesn’t care as much anymore about simply how much pain relief they got. They want to know: how did your function improve? That’s been morphing into the acute pain world as well. Postoperative therapies measure pain with movement, as Paul talks about. It’s critical when assessing your patients with pain. It isn’t just a static, onetime, unimodal, 0-to-10 measurement. It’s more of a functional assessment.

Francesca Beaudoin, MD, PhD, MS: That’s where we could do a better job in acute settings, in the emergency department and primary care offices, taking the time to ask those nuanced questions. You both raised good points. One area that these subjective assessments fall short is with children, nonverbal patients, and patients with dementia. We need to do a better job of assessing pain in populations that may be a little more challenging to figure out what’s going on. I’m not aware of the holy grail of some objective measure in children or older adults. Jeff, what do you do in your practice if you have somebody who has a hard time communicating?

Jeff Gudin, MD: My current population in southern Florida in Miami is mostly non-English speaking, and even with translators it’s very difficult. Often, I have to read the suffering on their face or try to interpret from language to language how impaired they are from a functional standpoint. Trying to do a substance abuse assessment or anything is very difficult. I always implore patients to bring a family member or friend who speaks their language and knows a bit about them to help us interpret what they’re feeling.

Paul Arnstein, PhD, RN, FAAN: You bring up a good point about facial expression, because the IASP [International Association for the Study of Pain] has a Faces Pain Scale freely available in 64 languages in terms of interpretation. But a lot of people don’t use the scale correctly. They’ll look at the face on the scale and look at the patient’s face and try to rate it that way, whereas that’s a self-reported measure of pain.

The real question that has been asked here is: in a patient who’s unable to self-report, how do you know what they’re experiencing? There are a number of validated scales for patients, all the way from preterm infants through older adults with dementia. There are the ICU [intensive care unit] scales, the critical care pain observation tools, the PAINAD [Pain Assessment in Advanced Dementia Scale] for those with advanced dementia, and even the Nociceptive Coma Scale for patients in a minimally conscious or comatose state. Basically, those scales look at the facial expression or behaviors like moans, groans, screams, and rubbing or certain positioning on these validated objective measures of pain and tell you the likelihood that the behaviors that you’re experiencing are pain.

With a numeric pain scale, we think that a 4 is twice as strong as a 2. But when you look at the CPOT [Critical Care Pain Observation Tool], for example, in a critical care population, a 4 is twice as likely as a 2 to indicate that the behaviors you’re seeing—the facial grimace, fighting the ventilator, some of the body positioning or stiffness—indicate that the patient is experiencing pain as opposed to agitation or delirium. It helps you with your differential diagnosis. To Jeff’s point, using surrogate reporting with family members or people who know the patient best and doing analgesic trials to see if those behaviors clear or get better when they’re exposed to an analgesic are some of the other ways that we know about the patient’s pain for patients who are unable to verbalize their pain.

Transcript Edited for Clarity