A randomized controlled trial comparing two vaso-occlusive episode (VOE) protocols in sickle cell disease (SCD)

Abstract

Limited evidence guides opioid dosing strategies for acute Sickle Cell (SCD) pain. We compared two National Heart, Lung and Blood (NHBLI) recommended opioid dosing strategies (weight-based vs. patient-specific) for ED treatment of acute vaso-occlusive episodes (VOE). A prospective randomized controlled trial (RCT) was conducted in two ED's. Adults ≥ 21 years of age with SCD disease were eligible. Among the 155 eligible patients, 106 consented and 52 had eligible visits. Patients were pre-enrolled in the outpatient setting and randomized to one of two opioid dosing strategies for a future ED visit. ED providers accessed protocols through the electronic medical record. Change in pain score (0-100 mm VAS) from arrival to ED disposition, as well as side effects were assessed. 52 patients (median age was 27 years, 42% were female, and 89% black) had one or more ED visits for a VOE (total of 126 ED study visits, up to 5 visits/patient were included). Participants randomized to the patient-specific protocol experienced a mean reduction in pain score that was 16.6 points greater than patients randomized to the weight-based group (mean difference 95% CI = 11.3 to 21.9, P = 0.03). Naloxone was not required for either protocol and nausea and/or vomiting was observed less often in the patient-specific protocol (25.8% vs 59.4%, P = 0.0001). The hospital admission rate for VOE was lower for patients in the patient-specific protocol (40.3% vs 57.8% P = 0.05). NHLBI guideline-based analgesia with patient-specific opioid dosing resulted in greater improvements in the pain experience compared to a weight-based strategy, without increased side effects.

Keywords: emergency; pain; sickle cell disease; vaso-occlusive crisis.

Figure 1

Study Sample and Randomization

Figure 2

Trajectory of Change in Pain Scores During ED Visits A hierarchical mixed-effects model for longitudinal data, adjusting for nested patient and site effects, was conducted on the pain scores collected at the above six time points to evaluate the trajectory of change in pain scores over this interval. After two hours, patients began to complete the protocol and meet the discharge criteria. The protocols did not differ on rate of change in pain scores from arrival to 120-minutes. However, the patient-specific protocol had a significantly lower mean adjusted pain score at discharge than the standard protocol (F=7.53, df=1,118, p=0.007).