Dr. Wang is Assistant Professor of Clinical Psychiatry, Indiana University School of Medicine, IU Health Neuroscience Center, Indianapolis, IN; Dr. Kheir is a Resident, Department of Psychiatry, Indiana University School of Medicine, IU Health Neuroscience Center; Dr. Allen is Resident, Department of Internal Medicine, Indiana University School of Medicine; Dr. Khan is Associate Professor of Medicine, Division of Pulmonary, Critical Care, Sleep and Occupational Medicine, Department of Internal Medicine, Indiana University School of Medicine.
Post-intensive care syndrome (PICS) is a rapidly growing phenomenon in older adults. As survival rates from ICU hospitalizations have increased over the past few decades, the long-term cognitive, psychological, and physical sequelae of the illness have become a major challenge in critical care medicine. More than half of all ICU survivors suffer from at least one PICS-related impairment, and these effects can persist as long as 5 or more years.
PICS has become an increasingly important phenomenon in older adults for several reasons. First, the number of older adults with critical illness is rapidly increasing as the population ages and now accounts for about 50% of ICU admissions.1 Second, more than 70% of older adults hospitalized in the ICU develop delirium, which is a major risk factor for ICU-acquired cognitive impairments.2 Third, cognitive and functional impairment before an ICU hospitalization increases the likelihood of cognitive and functional decline afterward.
Paul, a 76-year-old widower, was found lying on the floor of his home. When the emergency medical technicians arrived, he was having trouble breathing and was not oriented to place or time. In the emergency department, the diagnosis was sepsis secondary to pneumonia. He was intubated and placed on mechanical ventilation. In the ICU he was treated with intravenous fluids, vasopressors, and antibiotics for overwhelming infection and septic shock. After 1 week, he was extubated and transferred to the regular floor. For the first few days on the regular floor, he remained confused and only sometimes recognized his surroundings. Eventually, he improved physically and was fully oriented to person, place, and time upon discharge.
Two months later, Paul’s neighbor brought him to his primary care physician. Paul was having difficulties paying his bills and keeping track of his medication regimen. He was still able to drive a few blocks to the grocery store but became tired if he drove more than 30 minutes. He was also less willing to drive to unfamiliar places because he had difficulty following the GPS. The neighbor noted that Paul was frequently repeating himself and misplacing items. Paul seemed withdrawn and depressed.
ICU-acquired long-term cognitive impairments (LTCIs) affect 30% to 80% of survivors. LTCIs appear to affect multiple domains, including executive functioning, memory, and attention. For many, LTCIs improve within the first year, although they can persist for many years in some people. Risk factors for LTCIs in older adults include neurological dysfunction, infection or severe sepsis, and acute dialysis. Duration of delirium is also a risk factor for LTCIs.
Current theories suggest that LTCIs from delirium may be distinct from Alzheimer disease (AD). While beta-amyloid deposition appears to be a key factor in the development of AD, long-term cognitive impairment from delirium appears to be caused by hypoxia and pro-inflammatory cytokines.3 This theory is consistent with the observation that the onset of LTCIs from delirium may depend on the duration of exposure to the pathophysiologic processes of delirium.
1. Mullins PM, Goyal M, Pines JM. National growth in intensive care unit admissions from emergency departments in the United States from 2002 to 2009. Acad Emerg Med. 2013;20:479-486.
2. McNicoll L, Pisani MA, Zhang Y, et al. Delirium in the intensive care unit: occurrence and clinical course in older patients. J Am Geriatr Soc. 2003;51:591-598.
3. Jutte JE, Erb CT, Jackson JC. Physical, cognitive, and psychological disability following critical illness: what is the risk? Semin Respir Crit Care Med. 2015;36:943-958.
4. Duggan MC, Wang L, Wilson JE, et al. The relationship between executive dysfunction, depression, and mental health-related quality of life in survivors of critical illness: results from the BRAIN-ICU investigation. J Crit Care. 2017;37:72-79.
5. Gunther ML, Morandi A, Krauskopf E, et al. The association between brain volumes, delirium duration, and cognitive outcomes in intensive care unit survivors: the VISIONS cohort magnetic resonance imaging study. Crit Care Med. 2012;40:2022-2032.
6. Rabiee A, Nikayin S, Hashem MD, et al. Depressive symptoms after critical illness: a systematic review and meta-analysis. Crit Care Med. 2016;44:1744-1753.
7. Nikayin S, Rabiee A, Hashem MD, et al. Anxiety symptoms in survivors of critical illness: a systematic review and meta-analysis. Gen Hosp Psychiatry. 2016;43:23-29.
8. Jackson JC, Pandharipande PP, Girard TD, et al. Depression, posttraumatic stress disorder, and functional disability in survivors of critical illness: results from the BRAIN ICU investigation: a longitudinal cohort study. Lancet Respir Med. 2014;2:369-379.
9. Wang S, Mosher C, Perkins AJ, et al. Post-intensive care unit (ICU) psychiatric comorbidity and quality of life (QoL). J Hosp Med. 2017;12:831-835.
10. Wunsch H, Christiansen CF, Johansen MB, et al. Psychiatric diagnoses and psychoactive medication use among nonsurgical critically ill patients receiving mechanical ventilation. JAMA. 2014;311:1133-1142.
11. Khan BA, Lasiter S, Boustani MA. Critical care recovery center: an innovative collaborative care model for ICU survivors. Am J Nurs. 2015;115: 24-31.