Prevalence and Risk Factors for Iatrogenic Opioid Withdrawal in Medical Critical Care Patients.

Opioids are the mainstay of pain management and sedation in critically ill patients, which can lead to the development of physiologic tolerance and dependency. The prevalence of iatrogenic opioid withdrawal syndrome (IWS) is reported as 17-32% in the ICU; however, limited evidence exists for the medical ICU patient population.

Objectives: To identify the and risk factors for IWS in adult patients admitted to critical care medicine services who received greater than or equal to 24 hours of continuous opioid infusion therapy.

Design setting and participants: A prospective, observational study was conducted in a tertiary care hospital in adult medical ICU patients. Ninety-two patients who received greater than or equal to 24 hours of continuous opioid infusions were included in the study.

Main outcomes and measurements: Patients were assessed daily after opioid infusion discontinuation using the Clinical Opiate Withdrawal Scale (COWS) and the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) opioid withdrawal criteria for a maximum of 5 days. The primary outcome was the prevalence of IWS of moderate severity or greater using COWS. Secondary outcomes included the prevalence of IWS diagnosis of any severity based on COWS, the prevalence of IWS diagnosis based on a positive DSM-V score, and the identification of potential risk factors for developing IWS of any severity.

Results: Four hundred forty-seven patients received greater than or equal to 24 hours of continuous opioid therapy. Of these, 385 were excluded, leaving 92 patients included in the final analysis. Except for a higher prevalence of psychiatric history in the IWS-positive group, baseline characteristics were similar. Overall, 11 patients (12%) developed IWS of moderate severity or greater, based on COWS. The IWS-positive group also had longer durations of opioid infusions, higher cumulative opioid infusion doses, higher mean daily doses, and higher infusion rates at any given time. The concomitant use of dexmedetomidine (38.3 vs 15.6%, p = 0.014) and benzodiazepines (63.8 vs 37.8%, p = 0.021) during or after the opioid infusion were significantly higher in the IWS-positive group compared with the IWS-negative group. No significant differences were found between the two groups for scheduled or as needed opioids after cessation of the opioid infusion. Continuous opioid infusions greater than or equal to 72 hours and total daily dose greater than or equal to 1,200 μg were found to be independent predictors for the development of iatrogenic opioid withdrawal via logistic regression.

Conclusions and relevance: Approximately one in every eight patients receiving continuous infusion opioid for greater than 24 hours while mechanically ventilated in the medical ICU will develop IWS of moderate severity or greater; this increases to one in three patients diagnosed with DSM-V criteria or any level of IWS severity. Patients receiving opioid infusions greater than or equal to 72 hours, or a total daily fentanyl dose of greater than or equal to 1,200 μg (~ 50 μg/hr) are at a higher risk for developing IWS and should be monitored as part of clinical practice when opioid infusions are discontinued.