Project Summary/Abstract
Almost 25% of intensive care unit (ICU) survivors experience post-ICU cognitive impairment
comparable to that of mild Alzheimer’s disease; about 33% suffer from cognitive impairment equivalent to
moderate traumatic brain injury. Critically ill older adults (ages 65 and older) have the highest incidence of
mechanical ventilation and are at most risk for post-ICU cognitive impairment. Mechanically ventilated ICU
patients experience worse sleep than those who are not ventilated. The proposed research focuses on older
adult ICU survivors who required mechanical ventilation for survival. The scientific premises are: 1) sleep
deficiency may be associated with post-ICU syndrome and cognitive impairment, and 2) sleep may be a
modifiable risk factor to prevent post-ICU cognitive impairment. Understanding sleep deficiency is essential to
design personalized symptom management interventions to prevent post-ICU cognitive decline. This is the first
study to evaluate the longitudinal effect of sleep deficiency on post-ICU cognitive impairment among older
adult ICU survivors. Specific Aim 1 is to determine the daytime and nighttime sleep quality (sleep architecture
and sleep environment) of older adult ICU survivors who required mechanical ventilation while in ICU. Sleep
(i.e., polysomnography and actigraphy) will be measured at time of transfer out of ICU, and again at 1 and 3
months post-hospital discharge. Polysomnography will describe sleep architecture (sleep duration, efficiency,
fragmentation, and latency; N1, N2, N3, and REM stages; and cortical and sympathetic arousals). Actigraphy
will describe sleep environment (ambient light/dark levels and motion/inactivity). Specific Aim 2 is to determine
the effect size of the longitudinal relationship between sleep deficiency and post-ICU cognitive impairment.
Cognitive function (i.e., executive function and working memory) will be assessed at time of transfer out of ICU,
and again at 1 and 3 months post-hospital discharge, using selected measures from the NIH Toolbox
Cognition Battery. Additional related data (biological variables including age, sex, race/ethnicity, and clinical
history such as obstructive sleep apnea) will be collected to explore risk factors for sleep deficiency and post-
ICU cognitive impairment. Data will provide direction on development of nursing interventions (e.g., promoting
sleep consolidation, restructuring sleep environment, reestablishing circadian rhythm, decreasing daytime
sleepiness) to best target and prevent post-ICU cognitive impairment. The proposed research will take place in
one of the largest “minority-majority” metropolitan areas in the United States—65% of Miami’s population is
Hispanic/Latino. The proposed project will support the applicant in her career goal to develop her professional
identity as a nurse scientist, with an individualized, rigorous training program of symptom science research and
longitudinal data analysis centered on geriatrics, sleep, cognitive neuropsychology, and critical care. The
proposed training plan integrates the scientific and analytic expertise of an interdisciplinary mentorship team.