Enrollment challenges for critical care research are common. Contributing factors include short enrollment windows, the crisis nature of critical illness, lack of research staff, unavailable legal proxy, family dynamics, and language barriers.


To describe enrollment statistics for an ongoing critical care nursing trial, barriers to recruitment, and strategies to enhance enrollment.


Two years’ worth of recruitment and enrollment data from an oral care intervention trial in critically ill adults receiving mechanical ventilation at 1 hospital were analyzed. Recruitment logs include number of patients screened, eligible, enrolled, and declined and patients’ sex, race, and ethnicity.


Target enrollment (15.5 patients per month) was based on experience and historical data. Strategies implemented to promote enrollment included providing study personnel at least 18 hours per day for 7 days per week, regular rounds, communication with direct care staff, and Spanish consent processes. In 2 years, 6963 patients were screened; 1551 (22%) were eligible. Consent was sought from 366 (24% of eligible patients). Enrollment averaged 13.3 patients per month (86% of projected target). The main factor impeding enrollment was unavailability of a legal proxy to provide consent (88%). The refusal rates of white (11%), black (13%), and Hispanic (16%) patients did not differ significantly. However, those classified as Asian or as more than 1 race declined significantly more often (35%) than did white or black patients (P = .02).


Unavailability of a legal proxy within a short enrollment window was the major challenge to enrollment. Various factors influenced consent decisions. Clinical study design requires more conservative estimates.

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