Delirium and its motoric subtypes: a study of 614 critically ill patients.
OBJECTIVE
To describe the motoric subtypes of delirium in critically ill patients and compare patients aged 65 and older with a younger cohort.


METHODS
Prospective cohort study.


METHODS
The medical intensive care unit (MICU) of a tertiary care academic medical center.


METHODS
Six hundred fourteen MICU patients admitted during a process improvement initiative to monitor levels of sedation and delirium.


METHODS
MICU nursing staff assessed delirium and level of consciousness in all MICU patients at least once per 12-hour shift using the Confusion Assessment Method for the Intensive Care Unit and the Richmond Agitation-Sedation Scale. Delirium episodes were categorized as hypoactive, hyperactive, and mixed type.


RESULTS
Delirium was detected in 112 of 156 (71.8%) subjects aged 65 and older and 263 of 458 (57.4%) subjects younger than 65. Mixed type was most common (54.9%), followed by hypoactive delirium (43.5%) and purely hyperactive delirium (1.6%). Patients aged 65 and older experienced hypoactive delirium at a greater rate than younger patients (41.0% vs 21.6%, P<.001) and never experienced hyperactive delirium. Older age was strongly and independently associated with hypoactive delirium (adjusted odds ratio=3.0, 95% confidence interval=1.7-5.3), compared with no delirium in a model that adjusted for other important determinants of delirium including severity of illness, sedative medication use, and ventilation status.


CONCLUSIONS
Older age is a strong predictor of hypoactive delirium in MICU patients, and this motoric subtype of delirium may be missed in the absence of active monitoring.
Peterson
Josh F
JF
Division of General Internal Medicine, Center for Health Services Research, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA. josh.peterson@vanderbilt.edu
Pun
Brenda T
BT
Dittus
Robert S
RS
Thomason
Jason W W
JW
Jackson
James C
JC
Shintani
Ayumi K
AK
Ely
E Wesley
EW
D000367:Age Factors; D000368:Aged; D003422:Critical Care / Q000379:methods*; D016638:Critical Illness / Q000628:therapy*; D003693:Delirium / Q000145:classification* / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D009043:Motor Activity; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D012720:Severity of Illness Index