Original Research: Improving Pain Assessment After Inpatient Orthopedic Surgery: A Comparison of Two Scales

In pain assessment, the commonly used Numeric Rating Scale (NRS) offers an incremental 0-to-10 range of response options. But this broad range often leads to discordant evaluations between nurses and their patients. This study aimed to compare the NRS to the three-category Interventional Pain Assessment (IPA) scale, validate the IPA scale in an inpatient setting, and determine RN and patient scale preferences.

This prospective study enrolled 122 postoperative orthopedic patients and their designated 104 RNs at a level 1 trauma center in the midwestern United States. Patients were asked to verbally rate their pain from 0 to 10 using the NRS and from 0 to 2 on the IPA scale. Patients were also asked which scale best conveyed their pain. The RNs were asked which scale best informed them of their patient's pain situation and which scale they preferred. To establish a correlation between the two scales, we considered NRS values of 0 to 7 (signifying no pain to moderate pain) to correspond to IPA scale values of 0 to 1 (signifying no pain to tolerable pain). NRS values of 8 to 10 (signifying severe pain) were considered to correspond to IPA scale values of 2 (signifying intolerable pain). Responses in which patients reported IPA scores indicating no pain to tolerable pain but NRS scores above 7 or IPA scale scores indicating intolerable pain but NRS scores of 7 or below were defined as discordant answers.

Data analysis revealed a strong significant correlation between the NRS and IPA scale (τ = 0.597), with an 82.7% concordance rate. Once an NRS score rose above 7, more discordance between the two scales became increasingly prevalent, as evidenced by the 45% of patients who also reported tolerable pain on the IPA scale. Significantly more patients (89.3%) preferred the IPA scale to communicate their pain level than the NRS (10.7%). Significantly more RNs (76%) felt the IPA scale best informed them of their patient's pain and was a better guide for treatment than felt the NRS did so (24%).

The IPA scale asks about pain tolerability and thus has a direct role in the management of pain medications. Both patients and nurses felt they were better able to convey and understand pain when using the IPA scale than when using the NRS. There was consensus regarding pain scale preference among patients and their RNs, with both groups preferring the IPA scale due to its simplicity and, among the RNs, its usefulness in guiding treatment. The IPA scale may be a much better tool for accurately assessing a patient's pain experience and needs, with the potential to change practice and improve pain management.