Contextual factors related to ventilator mode during an embedded randomized trial: a longitudinal survey of...

Pragmatic trials can efficiently generate comparative effectiveness evidence by embedding delivery of interventions assigned by the trial with the people and systems of clinical care. Delivering assigned treatments with high fidelity is essential to generating informative trial results, but which factors affect clinicians' adherence to assigned treatments in pragmatic trials is not known.

Observational study assessing clinician perceptions of trial rationale, conduct, and interventions during a pragmatic, randomized trial of three ventilator modes (volume control vs. pressure control vs. adaptive pressure control) in a single intensive care unit. Clinicians were surveyed before and monthly during the 9-month trial. Survey instruments assessed readiness for the trial using the Hospital Change Readiness Questionnaire (scored from 7 to 49), Proctor's Implementation Outcomes, and comfort with each mode on a Likert scale of 1-7. We hypothesized that perceptions would differ by ventilator mode, clinician type (respiratory therapists, advanced practice providers, fellow physicians, attending physicians) and over time. Comparisons between groups were performed by chi-squared and ANOVA tests, and tests for change over time were performed by generalized estimating equations.

Overall, 82 of 120 clinicians (68%) responded to at least one survey, with a median response rate of 51% (IQR 48%-56%) per survey. Pre-trial readiness scores differed by clinician type and were lowest among fellows (median 43 [IQR 39-45]) and highest among respiratory therapists (49 [48-49]) (P < 0.01). During the trial, comfort differed by ventilator mode with a median of 7.0 (6.6-7.0) for volume control, 6.3 (6.0-7.0) for pressure control, and 6.6 (6.0-7.0) for adaptive pressure control (P < 0.01). Comfort with using each mode also differed by clinician type and over time. Perceptions of appropriateness (6.8 [6.3-7.0]), acceptability (6.3 [5.8-7.0]), and feasibility (6.5 [6.0-7.0]) for conducting the trial were high, similar between clinician types, and consistent over time.

For a pragmatic trial of ventilator modes, clinician perceptions of readiness, appropriateness, acceptability, feasibility, and comfort with trial interventions were high, and differences between modes and clinician types were small. To optimize trials embedded in healthcare systems, future work should survey across multiple sites and use interviews to attain a broader perspective on contextual factors affecting fidelity.