The association between brain volumes, delirium duration, and cognitive outcomes in intensive care unit survivors: the VISIONS cohort magnetic resonance imaging study*.
OBJECTIVE
Delirium duration is predictive of long-term cognitive impairment in intensive care unit survivors. Hypothesizing that a neuroanatomical basis may exist for the relationship between delirium and long-term cognitive impairment, we conducted this exploratory investigation of the associations between delirium duration, brain volumes, and long-term cognitive impairment.


METHODS
A prospective cohort of medical and surgical intensive care unit survivors with respiratory failure or shock.


METHODS
Quantitative high resolution 3-Tesla brain magnetic resonance imaging was used to calculate brain volumes at discharge and 3-month follow-up. Delirium was evaluated using the confusion assessment method for the intensive care unit; cognitive outcomes were tested at 3- and 12-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 magnetic resonance imaging protocol. Patients with longer duration of delirium displayed greater brain atrophy as measured by a larger ventricle-to-brain ratio at hospital discharge (0.76, 95% confidence intervals [0.10, 1.41]; p = .03) and at 3-month follow-up (0.62 [0.02, 1.21], p = .05). Longer duration of delirium was associated with smaller superior frontal lobe (-2.11 cm(3) [-3.89, -0.32]; p = .03) and hippocampal volumes at discharge (-0.58 cm(3) [-0.85, -0.31], p < .001)--regions responsible for executive functioning and memory, respectively. Greater brain atrophy (higher ventricle-to-brain ratio) at 3 months was associated with worse cognitive performances at 12 months (lower Repeatable Battery for the Assessment of Neuropsychological Status score -11.17 [-21.12, -1.22], p = .04). Smaller superior frontal lobes, thalamus, and cerebellar volumes at 3 months were associated with worse executive functioning and visual attention at 12 months.


CONCLUSIONS
These preliminary data show that longer duration of delirium is associated with smaller brain volumes up to 3 months after discharge, and that smaller brain volumes are associated with long-term cognitive impairment up to 12 months. We cannot, however, rule out that smaller preexisting brain volumes explain these findings.
Department of Psychiatry, Vanderbilt University Medical Center, Vanderbilt University, Nashville, TN 37232-8300, USA
Max L
ML
Gunther
Alessandro
A
Morandi
Erin
E
Krauskopf
Pratik
P
Pandharipande
Timothy D
TD
Girard
James C
JC
Jackson
Jennifer
J
Thompson
Ayumi K
AK
Shintani
Sunil
S
Geevarghese
Russell R
RR
Miller
Angelo
A
Canonico
Kristen
K
Merkle
Christopher J
CJ
Cannistraci
Baxter P
BP
Rogers
J Chris
JC
Gatenby
Stephan
S
Heckers
John C
JC
Gore
Ramona O
RO
Hopkins
E Wesley
EW
Ely
D000367:Age Factors; D000368:Aged; D001284:Atrophy / Q000473:pathology; D001288:Attention; D001921:Brain / Q000473:pathology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D003693:Delirium / Q000453:epidemiology*; D038524:Diffusion Magnetic Resonance Imaging; D056344:Executive Function; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007362:Intensive Care Units; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011446:Prospective Studies; D018805:Sepsis / Q000453:epidemiology; D017741:Survivors; D013997:Time Factors