The association between brain volumes, delirium duration, and cognitive outcomes in intensive care unit survivors

Abstract

Objective Delirium duration is predictive of long-term cognitive impairment (LTCI) in Intensive Care Unit (ICU) survivors. Hypothesizing that a neuroanatomical basis may exist for the relationship between delirium and LTCI, we conducted this exploratory investigation of the associations between delirium duration, brain volumes and LTCI. Design, Setting, and Patients A prospective cohort of medical and surgical ICU survivors with respiratory failure or shock. Measurements Quantitative high resolution 3-Tesla brain magnetic resonance imaging was used to calculate brain volumes at discharge and three-month follow-up. Delirium was evaluated using the Confusion Assessment Method for the ICU; cognitive outcomes were tested at three- and twelve-month follow-up. Linear regression was used to examine associations between delirium duration and brain volumes, and between brain volumes and cognitive outcomes. Results A total of 47 patients completed the MRI protocol. Patients with longer duration of delirium displayed greater brain atrophy as measured by a larger ventricle-to-brain ratio (VBR) at hospital discharge [0.76, 95% confidence intervals (CI) (0.10, 1.41); p=0.03] and at 3-month follow-up [0.62 (0.02, 1.21), p=0.05]. Longer duration of delirium was associated with smaller superior frontal lobe [−2.11 cm3 (−3.89, −0.32); p=0.03] and hippocampal volumes at discharge [−0.58 cm3 (−0.85, −0.31), p<0.001] – regions responsible for executive functioning and memory, respectively. Greater brain atrophy (higher VBR) at three months was associated with worse cognitive performances at twelve months [lower RBANS battery score −11.17 (−21.12, −1.22), p=0.04]. Smaller superior frontal lobes, thalamus, and cerebellar volumes at three months were associated with worse executive functioning and visual attention at twelve months. Conclusions These preliminary data show that longer duration of delirium is associated with smaller brain volumes up to three months after discharge, and that smaller brain volumes are associated with LTCI up to 12 months. We cannot, however, rule out that smaller preexisting brain volumes explain these findings.

Severity of delirium in the ICU is associated with short term cognitive impairment. A prospective cohort study

“…Additionally, the present study demonstrates that the duration of delirium, as assessed by ICDSC, is associated with cognitive impairment at the time of hospital discharge, i.e., the longer the duration of delirium, the stronger the association with cognitive impairment. These data are consistent with earlier reports that also demonstrated that delirium is associated with cognitive impairment in ICU survivors (Girard et al, 2010;Gunther et al, 2012;Jackson et al, 2004;Pandharipande et al, 2013;van den Boogaard et al, 2012).…”

“…Although a number of previous studies have demonstrated a positive association between duration of delirium and cognitive impairment (Girard et al, 2010;Jackson et al, 2004;Pandharipande et al, 2013), to date, no single study has examined the association between severity of delirium and cognitive impairment. Longer durations of delirium are particularly closely associated with smaller brain volumes, which, in turn, are associated with long term cognitive impairment (Gunther et al, 2012).…”

Encefalopatia septyczna a majaczenie stanu ciężkiego

“…Przedłużający się czas trwania majaczenia jest niezależnym czynnikiem ryzyka dla zaburzeń poznawczych oraz funkcji wykonawczych po 3 i 12 miesiącach od rozpoznania [5,21]. Dodatkowo dłuższy czas trwania majaczenia jest związany ze zmniejszeniem objętości mózgowia 3 miesiące po wypisie z OIT, a to z kolei związane jest z długoterminowymi zaburzeniami poznawczymi aż do 12 miesięcy po wypisie [22].…”

Functional brain imaging in survivors of critical illness: A prospective feasibility study and exploration of the association between delirium and brain activation patterns

“…Several small studies of critically ill cohorts retrospectively examined results of clinical neuroimaging and found a variety of abnormalities including heterogeneous lesions, white matter hyperintensities and diffuse atrophy [5–7]. More recently, prospective investigations using quantitative magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) identified a robust association between delirium duration and generalized brain atrophy and loss of white matter integrity measured by fractional anisotropy in the corpus callosum and internal capsule in survivors of critical illness [8,9]. …”