Cognitive changes in older adults following intensive care unit stays

Implementation

History. Deficits seen in patients with PICS cognitive impairment include executive function (planning and sequencing tasks), short-term memory, attention or concentration, and mental processing speed.¹⁶

The impact of cognitive changes on a patient’s day-to-day life may be difficult to assess in ICU survivors, as they may also have PICS-related physical impairment causing limitations in basic or instrumental activities of daily living. To explore cognitive effects on function, ask questions such as, “Are there things you (or the person you are caring for) are no longer able to do because of the way you (they) think? For example, playing cards, completing crossword puzzles, or participating in another hobby?”

Objective testing. We suggest screening for cognitive impairment by evaluating commonly affected domains as part of a comprehensive assessment that includes patient and caregiver reports of cognitive changes related to ICU admission. Various cognitive testing options exist that can be selected based on your practice situation and patients’ needs.¹⁷

Confounding causes. Rule out other potential factors in cognitive impairment. Consider effects of new medications—including benzodiazepines, antipsychotics, opioids, or anticholinergics—started in hospital. Mood disorders may present with cognitive changes. Obstructive sleep apnea is missed easily and may impair executive function, which overlaps with the presentation of PICS cognitive impairment.

Basic laboratory test screening may be considered. If brain imaging has not been done since discharge from the ICU, it is reasonable to obtain a noncontrast computed tomography or magnetic resonance imaging scan, if available. Neuroimaging helps assess for causes of cognitive changes such as ischemia and may help with prognosis by showing patterns of atrophy suggestive of primary neuro-cognitive disorders such as Alzheimer disease.

Patients admitted to ICUs with diagnoses of traumatic brain injury or stroke are typically excluded from studies of PICS cognitive impairment. Pre-existing dementia, however, is not an exclusion criterion and patients with pre-existing dementia who experience declines in cognition after ICU admission should be considered as having PICS cognitive impairment.

Prognosis. It is hypothesized that prognosis variability relates to the underlying critical illness, such as septic shock, acute respiratory distress syndrome, or trauma.³ Factors such as delirium or unmasking of dementia may affect individual prognoses in older adults. Pragmatically, prognoses can be divided into the following:

Improvement, if PICS cognitive impairment is primarily due to resolving delirium: Symptoms of delirium can persist 6 months or longer after hospital discharge in older adults not admitted to ICU, but most improve over time.¹⁸ Given that the prevalence of delirium among ICU patients may be as high as 80%, patients presenting with PICS cognitive impairment may have similar potential to improve in the months following ICU discharge.¹⁸

Stability, if PICS cognitive impairment is primarily due to acquired brain injury (ABI): If the patient’s PICS cognitive impairment is primarily attributable to ABI from hypoxia, hypotension, glucose dysregulation, or inflammatory and cytokine response during critical illness, deficits may be more persistent but are not expected to worsen if no new insult is experienced. With rehabilitation such patients may improve, as with other populations of patients with ABI.^7,16

Progression, if PICS cognitive impairment is primarily due to a pre-existing or unmasked neurodegenerative disorder: Cognitively intact older adults may be found to have neuropathologic changes of Alzheimer disease on autopsy without having had clinical symptoms.¹⁹ Features of dementia can appear when additional stressors on the brain, such as delirium or ischemic events, overcome an individual’s cognitive reserve. In these circumstances, cognitive decline may progress over time in keeping with dementia syndromes.

Serial assessments at 3, 6, and 12 months after hospital discharge may clarify a patient’s cognitive trajectory, which may help with counselling related to prognosis.⁶ Referral to geriatric medicine or geriatric psychiatry may be considered, depending on circumstances and availability.

There are currently no pharmacologic options for management of PICS cognitive impairment; nonpharmacologic management is the mainstay of treatment. Individualized treatment plans should be created through shared decision making between the clinician, patient, and caregivers.