Abstract TMP61: Enrolling Stroke Patients in Prehospital Research During Late Night and Early Morning Times

Abstract

Background: Enrolling stroke patients into clinical research studies often necessitates having investigators available to field calls (from paramedics, potential subjects and ED personnel) as well as study nurses available at enrolment sites. Enrolment of patients overnight may thus not be cost effective if there are low numbers. Late night enrolment may have different characteristics such as more severe stroke or greater proportion of intracerebral hemorrhage. Methods: The Field Administration of Stroke Therapy-Magnesium (FAST-MAG) clinical trial enrolled patients 24 hours per day with designated on-call enrolling investigators and study nurses. We compared enrolment in the late night and early morning period defined as 10:00PM through 5:59AM compared to standard hours of 6:00AM through 9:59PM. We also considered implications of changing the late night/early morning definition to Midnight and 8:00AM. Results: Of 1700 enrolments, 171 (10%) occurred between 10PM-6AM. There was no significant differences in the late-night enrolments in stroke subtype (27% vs 22% ICH, p=0.268), age, ethnicity, race, vascular risk factors, prehospital stroke severity (LAMS) or hospital arrival stroke severity (NIHSS). Late night enrolments were less likely to be women (35% v 44%, p=0.035). There were 61 enrolments (3.4%) between midnight to 5:59AM. Expanding the early morning period from 6AM to 8AM would lead to 76 (4.4%) less enrollments. Conclusions: Late night/early morning enrolments are not clinically or demographically different from those during regular hours and accounted for 10% of overall enrolments. Less than 4% of enrolments occurred between midnight and 6:00AM. Future prehospital stroke trials can consider deferring enrolment in the late night/early morning period to help with resource allocation.