Post-intensive care syndrome

Post-intensive care syndrome (PICS) describes a collection of health disorders that are common among patients who survive critical illness and intensive care. Generally, PICS is considered distinct from the impairments experienced by those who survive critical illness and intensive care following traumatic brain injury and stroke. The range of symptoms that PICS describes falls under three broad categories: physical impairment, cognitive impairment, and psychiatric impairment. A person with PICS may have symptoms from all three categories or just one. A video overview is available. Post-intensive care syndrome (PICS) describes a collection of health disorders that are common among patients who survive critical illness and intensive care. Generally, PICS is considered distinct from the impairments experienced by those who survive critical illness and intensive care following traumatic brain injury and stroke. The range of symptoms that PICS describes falls under three broad categories: physical impairment, cognitive impairment, and psychiatric impairment. A person with PICS may have symptoms from all three categories or just one. A video overview is available. Improvements in survival after a critical illness have led to research focused on long-term outcomes for these patients. This improved survival has also led to the discovery of significant functional disabilities that many survivors of critical illness suffer. Because the majority of literature in critical care medicine is focused on short-term outcomes (e.g. survival), current understanding of PICS is relatively limited. Recent research suggests that there is significant overlap among the three broad categories of symptoms. In addition, sedation and prolonged immobilization seem to be common themes among patients who suffer from PICS. The term PICS arose around 2010, at least in part, to raise awareness of the important long-term dysfunctions resulting from treatment in the intensive care unit (ICU). Awareness of these long-term functional disabilities is growing, and research is ongoing to further clarify the spectrum of disabilities and to find more effective ways to prevent these long-term complications and to more effectively treat functional recovery. Increased awareness in the medical community has also highlighted the need for more hospital and community-based resources to more effectively identify and treat patients with suffering from PICS after surviving a critical illness. The most recognized form of the syndrome is the physical dysfunction commonly known as ICU-acquired weakness. The other physical, cognitive, and mental health impairments are less well recognized and need further research to be better understood. ICU-acquired weakness (ICU-AW), sometimes called critical illness polyneuropathy, is the most common form of physical impairment, and is estimated to occur in 25 percent or more of ICU survivors. It is thought to be an effect of long-term immobility and deep sedation that many critically ill patients experience while in the ICU. In addition, severe infections and inflammation are significant risk factors for developing ICU-AW.ICU-AW often presents as difficulty performing activities of daily living (e.g. moving around the living environment, using the bathroom, ability to make meals or do laundry). Inability to effectively perform these tasks can be particularly distressing to patients. The deficits associated with ICU-AW have a direct and negative effect on a person’s independence. The natural course of ICU-AW is variable, but some patients recover within a year. Other physical impairments include joint contractures due to long periods of immobility while hospitalized. The elbow and ankle are the most commonly affected joints, followed by the hip and knee. Some physical weakness may result from malnutrition during critical illness. Though nutrition may be provided by tube-feeding or parenteral nutrition, the initiation of parenteral nutrition may be delayed, and interruptions in feeding often occur due to gastrointestinal intolerance or the performance of procedures that require an empty stomach. In people who experience acute respiratory distress syndrome and are treated with mechanical ventilation, lung function is often compromised for months to years. The most commonly impaired lung function is diffusing capacity for carbon monoxide, as well as reduced lung volumes and spirometry. Cognitive impairments include deficits in memory, attention, mental processing speed, and problem solving. These impairments affect up to 80% of individuals who survive a critical illness. Impairments in memory and executive function have the most profound effect in terms of prohibiting people from engaging in the tasks and behaviors needed to function effectively in daily life and carry out complex cognition. The effect of cognitive dysfunction is significant – unemployment is not uncommon because of difficulties with tasks of executive function (e.g. completing regular tasks like balancing a checkbook, and remembering facts or events). Among individuals with PICS-associated cognitive impairments, most patients improve or completely resolve over the first year. Major risk factors for cognitive impairment following ICU admission due to critical illness include delirium, prior cognitive deficit, sepsis, and acute respiratory distress syndrome (ARDS). It is currently believed that many factors can play a role in causing cognitive impairment following critical illness. Some possible mechanisms for include poor blood supply to the brain due to low blood pressure from sepsis, poor oxygen supply to the brain due to respiratory distress and impairment, inflammation of the brain, and disruption of the blood-brain barrier in the areas of the brain that are involved in executive function and memory Depression and anxiety are the two most common mental health disorders seen in individuals with PICS. The range of possible mental health problems, however, is far wider. Dementia, post-traumatic stress disorder (PTSD), and persistent delusional behavior are also manifestations of the syndrome. Although not completely understood, the anxiety and delusions seen in patients with PICS are likely linked to delusional memories that some individuals acquire during their stay in the ICU, rather than recall of factual memories. It is thought that medically-induced sedation may contribute to the formation delusional memories by raising the risk of delirium and hallucinations.