Variable Patterns of Continuous Morphine Infusions at End of Life

Continuous morphine infusions (CMIs) treat pain and dyspnea at the end of life (EOL). CMIs may be initiated at an empiric rate and/or are rapidly escalated without proper titration.

The study objective was to evaluate CMI patterns at the EOL.

This single-center, retrospective chart review evaluated adult patients who died while receiving CMI at EOL. Patient demographics and opioid dosing information were extracted from an electronic medical record. Twenty-four hour IV morphine equivalent was calculated prior to CMI initiation and at the time of death.

Of the 190 patient charts, 63.2% (n=120) received no bolus doses prior to CMI initiation. Mean 24-hour IV morphine equivalent prior to CMI initiation was 49.3 mg (range: 0-1200 mg, SD 384.9) and at time of death was 267.1 mg (12.0-5193.2 mg, SD 442.2), representing an increase of +442%. Mean CMI starting rate was 3.3 mg/hour (0.4-30.0 mg/hour, SD 3.6) with titration at time of death to a mean of 7.7 mg/hour (0.4-70.0 mg/hour, SD 9.4), representing an increase of +130%. Mean number of CMI rate adjustments was 2.5 (0-5, SD 3.3); and number of bolus doses administered between titrations was 4.2 (0-27, SD 4.8). Mean time from CMI initiation to death was 15.5 hours (0.05-126.9 hours, SD 21.7). There was a negative association between rate of infusion increase per hour and total number of hours on CMI (r=-0.2, p=0.0062).

Hospitalized patients at EOL had a much higher 24-hour IV morphine equivalents and CMI rates at time of death compared to CMI initiation. Variability was observed in the number of CMI rate adjustments and the number of bolus doses administered.