When Pain Management Leads to Medication Errors

Pain has been described as “the fifth vital sign” since the late 1990s.1 Unlike the traditional vital signs of temperature, pulse, blood pressure, and respiratory rate, pain is not a sign per se but rather a symptom; as such, it is entirely subjective.2 When clinicians make treatment decisions for patients, objective signs can be reliably monitored, they are typically reproducible, and the effects of interventions on such objective measures can be precisely observed. However, when the same approach is applied to an entirely subjective symptom like pain, hazards are bound to result if there is overreliance on the subjective measurement. Pain is most commonly measured on a 10-point Likert scale, ranging from zero to 10, with 10 being the worst pain the patient can conceive and zero being pain-free. Yet we have all seen patients who seem to be in little distress when they rate their pain as a 10, whereas others with obvious painful conditions seem to be more judicious in their ratings. Even obviously somnolent patients have been observed to call out a 10 through an oversedated haze. Actually, a subjective measurement through use of a Likert scale has inherent limitations.3,4 There is no simple way to deduce whether an intervention to reduce pain has “good” or “bad” effects. The patient’s subjective rating can assist a clinician only in determining what the effect has been. Many other variables must be considered, such as other sympathomimetic signs and the level of sedation or consciousness, for a complete assessment of pain and response to interventions to alleviate it. If clinicians rely too much on only the subjective numbers, the risk of overdosing or underdosing is increased.