Predictors of Response in Emergency Department Patients Receiving Intravenous Opioids for Severe Pain.

The primary objective of this study was to identify significant environmental and patient characteristics of emergency department (ED) patients who responded to intravenous (IV) hydromorphone and IV morphine for severe pain. Secondary objectives were to investigate the individual effect of the significant environmental and patient characteristics of responders, and to assess the nature and strength of the correlation of initial dose and change in pain score from arrival to pre-administration. A retrospective chart review was performed in patients who received IV hydromorphone or morphine in the ED for severe pain. Key evaluated patient characteristics included patient demographics, recent opioid use, history of drug or alcohol abuse, and pain location, among others. Key evaluated environmental characteristics included initial opioid administered, time to first dose, initial pain score, and initial dose of opioid administered, among others. Environmental and patient characteristics associated with response to pain management were first identified using bivariate analyses and then entered into a multiple stepwise logistic regression mode. Patients were excluded if they were younger than 18 years, did not have a follow-up pain score within 2 hours of drug administration, or if they were discharged from the ED within 1 hour of administration. Patients meeting the inclusion criteria were grouped into two cohorts based on response and lack of response to treatment. A total of 200 patients were included. A decrease in pain score from arrival until pre-administration pain score and an inactive tobacco history had a positive association with response (odds ratio [OR] 1.488, 95% confidence interval [CI] 1.088-2.036, p=0.013, and OR 1.835, 95% CI 0.801-4.200, overall p=0.022, respectively). A higher initial dose and an active tobacco history had a negative association with response (OR 0.715, 95% CI 0.580-0.881, p=0.002, and OR 0.582, 95% CI 0.296-1.144, overall p=0.022, respectively). Two characteristics were associated with response to IV opioid pain management in the ED, inactive tobacco history and an increase in pain score from arrival until pre-administration, and two characteristics were associated with nonresponse to IV opioid pain management in the ED, active tobacco history and a higher initial dose. Previous literature supports both characteristics identified as risk factors but does not support either characteristic identified as protective factors, prompting the need for further research.