Effect of intensive care unit sedation strategy on patient-reported experience: secondary mediation analysis of the A2B randomised controlled trial

Introduction

The optimal ICU sedation strategy to improve patient-reported experience is unknown. In a planned secondary analysis of the A2B randomised trial, we evaluated the effect of sedation strategy (dexmedetomidine, clonidine or propofol) on recalled patient experience at 90 days post-randomisation. Using mediation analyses, we explored plausible mediators of the relationship between sedation strategy and patient experience.

Methods

We analysed data for all patients from A2B who completed the Intensive Care Experience Questionnaire (ICE-Q) at 90 days. The primary outcome was patient-recalled experience, measured by the four ICE-Q domain scores (awareness, frightening memories, recall, satisfaction). Sedation strategy effect was evaluated using linear regression, adjusting for potential confounders. Mediation analyses were conducted for duration of mechanical ventilation; ICU stay; and days with pain behaviour, agitation and coma/delirium.

Results

Of 1404 patients included in the primary trial analysis, 1009 (71.9%) were alive at 90 days post-randomisation with ICE-Qs completed by 289/1009 (28.6%). Compared with propofol, dexmedetomidine sedation was associated with higher awareness of surroundings (median score 32 vs. 28, adjusted mean difference 3.6, 95%CI 1.0–6.2, p = 0.01), but clonidine sedation had no association (difference 2.4, 95%CI -0.2–5.0, p = 0.07). No associations were found with other ICE-Q domains. The contribution of the five potential mediators on the dexmedetomidine–awareness relationship was small.

Discussion

Dexmedetomidine compared with propofol sedation strategy may be associated with increased recalled awareness of surroundings, which is considered a favourable indicator of ICU experience. Together with the primary A2B trial results, which showed no effect on ventilation duration, these hypothesis-generating findings in a subgroup of the A2B cohort do not support the use of dexmedetomidine over propofol based on patient-reported experience. Based on our findings, we advocate that a personalised approach to sedation strategies should continue to be used.