Outcomes after intravenous opioids in emergency patients: a prospective cohort analysis.

Objectives: Pain management continues to be suboptimal in emergency departments (EDs). Several studies have documented failures in the processes of care, such as whether opioid analgesics were given. The objectives of this study were to measure the outcomes following administration of intravenous (IV) opioids and to identify clinical factors that may predict poor analgesic outcomes in these patients.

Methods: In this prospective cohort study, emergency patients were enrolled if they were prescribed IV morphine or hydromorphone (the most commonly used IV opioids in the study hospital) as their initial analgesic. Patients were surveyed at the time of opioid administration and 1 to 2 hours after the initial opioid dosage. They scored their pain using a verbal 0-10 pain scale. The following binary analgesic variables were primarily used to identify patients with poor analgesic outcomes: 1) a pain score reduction of less than 50%, 2) a postanalgesic pain score of 7 or greater (using the 0-10 numeric rating scale), and 3) the development of opioid-related side effects. Logistic regression analyses were used to study the effects of demographic, clinical, and treatment covariates on the outcome variables.

Results: A total of 2,414 were approached for enrollment, of whom 1,312 were ineligible (658 were identified more than 2 hours after IV opioid was administered and 341 received another analgesic before or with the IV opioid) and 369 declined to consent. A total of 691 patients with a median baseline pain score of 9 were included in the final analyses. Following treatment, 57% of the cohort failed to achieve a 50% pain score reduction, 36% had a pain score of 7 or greater, 48% wanted additional analgesics, and 23% developed opioid-related side effects. In the logistic regression analyses, the factors associated with poor analgesia (both <50% pain score reduction and postanalgesic pain score of >or=7) were the use of long-acting opioids at home, administration of additional analgesics, provider concern for drug-seeking behavior, and older age. An initial pain score of 10 was also strongly associated with a postanalgesic pain score of >or=7. African American patients who were not taking opioids at home were less likely to achieve a 50% pain score reduction than other patients, despite receiving similar initial and total equianalgesic dosages. None of the variables we assessed were significantly associated with the development of opioid-related side effects.

Conclusions: Poor analgesic outcomes were common in this cohort of ED patients prescribed IV opioids. Patients taking long-acting opioids, those thought to be drug-seeking, older patients, those with an initial pain score of 10, and possibly African American patients are at especially high risk of poor analgesia following IV opioid administration.