The relationship between delirium duration, white matter integrity, and cognitive impairment in intensive care unit survivors as determined by diffusion tensor imaging: The VISIONS prospective cohort magnetic resonance imaging study
ABSTRACT Evidence is emerging that delirium duration is a predictor of long-term cognitive impairment in intensive care unit survivors. Relationships between 1) delirium duration and brain white matter integrity, and 2) white matter integrity and long-term cognitive impairment are poorly understood and could be explored using magnetic resonance imaging.
A two-center, prospective cohort study incorporating delirium monitoring, neuroimaging, and cognitive testing in intensive care unit survivors.
Delirium was evaluated with the Confusion Assessment Method for the Intensive Care Unit and cognitive outcomes were tested at 3 and 12-month follow-up. Following the intensive care unit stay, fractional anisotropy, a measure of white matter integrity, was calculated quantitatively using diffusion tensor imaging with a 3-T magnetic resonance imaging scanner at hospital discharge and 3-month follow-up. We examined associations between 1) delirium duration and fractional anisotropy and 2) fractional anisotropy and cognitive outcomes using linear regression adjusted for age and sepsis.
A total of 47 patients with a median age of 50 yrs completed the diffusion tensor imaging-magnetic resonance imaging protocol. Greater duration of delirium (3 vs. 0 days) was associated with lower fractional anisotropy (i.e., reduced fractional anisotropy = white matter disruption) in the genu (-0.02; p = .04) and splenium (-0.01; p = .02) of the corpus callosum and anterior limb of the internal capsule (-0.02; p =.01) at hospital discharge. These associations persisted at 3 months for the genu (-0.02; p =.02) and splenium (-0.01; p = .004). Lower fractional anisotropy in the anterior limb of internal capsule at discharge and in genu of corpus callosum at three months was associated with worse cognitive scores at 3 and 12 months.
In this pilot investigation, delirium duration in the intensive care unit was associated with white matter disruption at both discharge and 3 months. Similarly, white matter disruption was associated with worse cognitive scores up to 12 months later. This hypothesis-generating investigation may help design future studies to explore these complex relationships in greater depth.
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ABSTRACT: Postoperative delirium is a common complication in older people and is associated with increased mortality, morbidity, institutionalization, and caregiver burden. Although delirium is an acute confusional state characterized by global impairments in attention and cognition, it has been implicated in permanent cognitive impairment and dementia. The pathogenesis of delirium and the mechanisms leading to these disabling consequences remain unclear. The present study is the first to address the potential predisposing role of brain morphologic changes toward postoperative delirium in a large prospective cohort of patients undergoing elective surgery using state-of-the-art magnetic resonance imaging (MRI) techniques conducted before admission. We investigated the association of MRI-derived quantitative measures of white-matter damage, global brain, and hippocampal volume with the incidence and severity of delirium. Presurgical white-matter hyperintensities (WMHs), whole brain, and hippocampal volume were measured in 146 consecutively enrolled subjects, ≥70 years old, without dementia who were undergoing elective surgery. These 3 presurgical MRI indices were tested as predictors of incidence and severity of subsequent delirium. Out of 146 subjects, 32 (22%) developed delirium. We found no statistically significant differences in WMH, whole brain, or hippocampal volume between subjects with and without delirium. Both unadjusted and adjusted (age, gender, vascular comorbidity, and general cognitive performance) regression analyses demonstrated no statistically significant association between any of the MRI measures with respect to delirium incidence or severity. In persons without dementia, preexisting cerebral WMHs, general and hippocampal atrophy may not predispose to postoperative delirium or worsen its severity. Copyright © 2015 Elsevier Inc. All rights reserved.Neurobiology of aging 02/2015; 36(6). DOI:10.1016/j.neurobiolaging.2015.02.024 · 4.85 Impact Factor
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ABSTRACT: Delirium is relatively common after lung transplantation, although its prevalence and prognostic significance have not been systematically studied. The purpose of the present study was to examine pretransplant predictors of delirium and the short-term impact of delirium on clinical outcomes among lung transplant recipients.Journal of Critical Care 09/2014; 30(1). DOI:10.1016/j.jcrc.2014.09.010 · 2.19 Impact Factor
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ABSTRACT: In the early 1990s, the in-hospital mortality rate of intensive care unit (ICU) patients dropped, and interest in the quality of life (QOL) of ICU survivors increased. In 1996, we published a study to investigate 1-year survival after hospital discharge and 6-month QOL after intensive care. Now, we compare our previous results with those reported in the recent literature to appraise any changes, and new knowledge in the area. The 1-year survival of ICU patients after hospital discharge is substantial, lower than in the general population, and different among subgroups. Some studies showed a reduction in QOL at 6 months, as in our study, while others showed an improvement. Different results seem to be related mainly to the case mix. Studies on different types of patients found long-term cognitive impairment in ICU survivors, possibly not disease specific. The proportions of patients with neuropsychological morbidities such as posttraumatic stress disorder, anxiety, and depression, described after our study, did not show any change over time. Differences between studies on long-term survival and QOL do not allow conclusions to be drawn about change over time. No change was found in neuropsychological morbidities. However, a lack of change may not be viewed negatively, because critically ill patients who survive ICU today may be at higher risk for poor long-term outcome than in the past due to the higher severity of their illness and the more aggressive treatments received. Future studies may provide understanding of the relationships between psychiatric symptoms, cognitive impairment, functional disability, and QOL.Intensive Care Medicine 01/2015; 41(4). DOI:10.1007/s00134-015-3654-z · 5.54 Impact Factor