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Long-term cognitive impairment and delirium in intensive care: A prospective cohort study

Mitchell, M. L., Shum, D. H. K., Mihala, G. , Murfield, J. E. & Aitken, L. M. (2018). Long-term cognitive impairment and delirium in intensive care: A prospective cohort study. Australian Critical Care, 31(4), pp. 204-211. doi: 10.1016/j.aucc.2017.07.002


Background: Whilst there is a growing body of research exploring the effect of delirium in intensive care unit (ICU) patients, the relationship between patient delirium and long-term cognitive impairment has not been investigated in settings where low rates of delirium have been reported.

Objectives: To assess the association between the incidence of delirium, duration of mechanical ventilation and long term cognitive impairment in general ICU patients.

Methods: Prospective cohort study conducted in a tertiary level ICU in Queensland, Australia. Adult medical and surgical ICU patients receiving ≥12. h mechanical ventilation were assessed for delirium on at least one day. Cognitive impairment was assessed at three and/or six-months using the: Repeatable Battery for the Assessment of Neuropsychological Status (RBANS); Trail Making Test (TMT) Part A and B; and Mini-Mental State Examination (MMSE).

Results: Of 148 enrollees, 91 (61%) completed assessment at three and/or six months. Incidence of delirium was 19%, with 41% cognitively impaired at three months and 24% remaining impaired at six months. Delirium was associated with impaired cognition at six-months: mean TMT Part A scores (information processing speed) were 7.86. s longer than those with no delirium (p = 0.03), and mean TMT Part B scores (executive functioning) 24.0. s longer (p = 0.04).

Conclusions: ICU delirium was positively associated with impaired information processing speed and executive functioning at six-months post-discharge for this cohort. Testing for cognitive impairment with RBANS and TMT should be considered due to its greater sensitivity in comparison to the MMSE.

Publication Type: Article
Additional Information: © 2017 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Publisher Keywords: Cognition, Critical illness, Delirium, Intensive care units, Long-term effects, Patient outcome assessment
Departments: School of Health & Psychological Sciences > Nursing
SWORD Depositor:
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