Long-term cognitive and psychological outcomes in the awakening and breathing controlled trial

Abstract

Rationale: Studies have shown that reducing sedation of critically ill patients shortens time on the ventilator and in the intensive care unit (ICU). Little is known, however, of how such strategies affect long-term cognitive, psychological, and functional outcomes.

Objectives: To determine the long-term effects of a wake up and breathe protocol that interrupts and reduces sedative exposure in the ICU.

Methods: In this a priori planned substudy conducted at one tertiary care hospital during the Awakening and Breathing Controlled Trial, a multicenter randomized controlled trial, we assessed cognitive, psychological, and functional/quality-of-life outcomes 3 and 12 months postdischarge among 180 medical ICU patients randomized to paired daily spontaneous awakening trials with spontaneous breathing trials (SBTs) or to sedation per usual care plus daily SBTs.

Measurements and main results: Cognitive impairment was less common in the intervention group at 3-month follow-up (absolute risk reduction, 20.2%; 95% confidence interval, 1.5-36.1%; P = 0.03) but not at 12-month follow-up (absolute risk reduction, -1.9%; 95% CI, -21.3 to 27.1%; P = 0.89). Composite cognitive scores, alternatively, were similar in the two groups at 3-month and 12-month follow-up (P = 0.80 and 0.61, respectively), as were symptoms of depression (P = 0.59 and 0.82) and posttraumatic stress disorder (P = 0.59 and 0.97). Activities of daily living, functional status, and mental and physical quality of life were similar between groups throughout follow-up.

Conclusions: In this trial, management of mechanically ventilated medical ICU patients with a wake up and breathe protocol resulted in similar cognitive, psychological, and functional outcomes among patients tested 3 and 12 months post-ICU. The proven benefits of this protocol, including improved 1-year survival, were not offset by adverse long-term outcomes. Clinical trial registered with www.clinicaltrials.gov (NCT 00097630).

Trial registration: ClinicalTrials.gov NCT00097630.

Figure 1.

Enrollment, randomization, and follow-up. Patients were assessed 3 and 12 months after discharge. From screening to the completion of follow-up, horizontal arrows indicate those patients who were not evaluated during the remainder of follow-up due to exclusion, death, study withdrawal, or loss to follow-up. Vertical arrows indicate patients (even if they were not assessed at one time point) for whom follow-up at a later time point was achieved. SAT = spontaneous awakening trial; SBT = spontaneous breathing trial.

Figure 2.

Cognitive outcomes and mortality at 3-month and 12-month follow-up according to treatment group. At each period of follow-up, every patient who was able to undergo cognitive testing is represented by a single symbol, which displays their cognitive outcome in two ways: (1) A plus symbol indicates the patient had cognitive impairment according to a priori criteria (see text), and a circle symbol indicates the patient did not have cognitive impairment. (2) Position along the Y-axis shows the patient's mean composite T-score, which is an average of their T-scores on nine individual cognitive tests. Normal performance on one of the nine individual tests would be a T-score between 40 and 60, with higher scores reflecting better performance. Medians of the composite T-scores according to treatment group are displayed as horizontal lines beside each scatter plot. Because the scatterplots (and lines representing medians) do not account for potential confounding due to death, bar graphs show the percentages of patients who had died or were too ill to undergo testing (only two patients at 3 months and no patients at 12 months). This graph shows that composite cognitive scores among those tested (summarized by horizontal lines) were similar between treatment groups at 3- and 12-month follow-up, but more patients in the intervention group survived without cognitive impairment (shown as circles vs. plus symbols) than in the control group.