Pain in Trauma Patients: Measurement and Predisposing Factors.

Introduction: Acute pain is common after injury. This study intended to evaluate the feasibility of quantifying pain experience over an entire admission using "area under the pain curve" and to identify factors associated with increased pain.

Methods: This retrospective single-center study included all trauma patients admitted from 2013 to 2020. Maximum pain scores were extracted for each day. Pain was defined as area under the curve (AUC) of maximum pain scores/day plotted against time. Injury patterns were analyzed by dichotomizing Abbreviated Injury Scale (AIS) scores (AIS < 3 versus AIS ≥ 3) for each body region. Urinary drug screen results were collected from admission data. A general linear model was used to determine which injury patterns, mechanisms, and age groups were predictive of increased AUC in all patients together and separate by operative and nonoperative groups.

Results: We identified 21,640 patients, of which 70% were male and 83% had suffered blunt injury. Overall injury severity was associated with increased pain experience. Serious head injury, younger age, and older age (compared to 45-49 y) were associated with decreased pain. Spinal injuries, thoraco-abdominal injuries, and combined thoracic and lower extremity injuries were predictive of increased pain. Compared to patients with no positive test for illicit substances or documentation of prehospital narcotic medications, the pain experience was greater for both, those who had been administered a narcotic in the prehospital setting and those who tested positive for illicit substances.

Conclusions: This study extends the concept of total pain experience using AUC methodology. Our results demonstrate associations between increased pain and certain patterns of injury, ages, and presence of drugs on admission. Measuring total pain experience could assist in comparing pain-management strategies. Future research should focus on validating pain experience against quality-of-life measurements.