PICS: Post-Intensive Care Syndrome

Do you know anyone (family, friend, or neighbor) who had a life-threatening illness or major surgery and has never really been the same since? It may be because they are suffering from “Post‐intensive care syndrome (PICS)." PICS refers to an intensive care unit (ICU) survivor who has either a new impairment or a pre-existing impairment that got worse in at least one of these three areas (each explained in detail in the sections below):

• Cognitive impairment—acquired dementia
• Mental health—depression and PTSD
• Physical impairment—muscle and nerve disease

These impairments include day-to-day struggles with memory and attention, depression, anxiety, post-traumatic stress disorder (PTSD), muscle weakness and nerve problems. These problems can happen following even short ICU stays – for example, a few days or a week of lying sedated and immobilized in an ICU bed while on a breathing machine. PICS becomes a form of chronic illness that leaves patients, caregivers, and entire families injured and struggling with a new normal. 

Cognitive Impairment—Acquired Dementia

Cognitive impairment - which refers to problems with thinking and memory that are significant enough that they interfere with day to day living - is experienced by 30% to 50% of all ICU survivors. Mild changes in a person’s brain functioning can create problems with daily living in areas like cooking, driving, managing money, interacting with technology, using healthcare devices, and understanding social situations. Unfortunately, among many people with PICS, cognitive impairment becomes a fact of life. For some people this is temporary and for others it is more permanent. These impairments begin in the hospital and can last for years after leaving the hospital. 

While no one is necessarily completely protected from the risk of impairment, it is especially likely to happen in people of older age, in people who have already faced cognitive challenges (for example those who have dementia), and those who have prolonged delirium (or acute confusion) while hospitalized.  Even people who are young and healthy before admission can develop cognitive deficits, although the likelihood that these will be severe and lasting is relatively low.  

There are many different cognitive symptoms people with PICS may experience. These symptoms may be part of a progressive decline that resembles dementia or the symptoms can be more stable, meaning they don't change much over time. Below are some of the common domains that may be impaired in an individual with PICS:

• Executive functioning: Deficits in executive functioning can cause problems with planning and prioritizing, organization, getting started on tasks, and time management. People with executive dysfunction tend to have problems at work. Often they perform tasks much more slowly than they used to and sometimes they use ineffective strategies—meaning that even though they are working harder than ever, they have little to nothing to show for it.  
• Attention: Attention deficits can lead to difficulty completing tasks, trouble with detail orientated tasks, and forgetfulness.
• Aspects of memory: Memory problems may lead to a wide-range of disruptions and can contribute to problems functioning in employment or in social settings.
• Processing speed: Delayed processing speed can make it harder to learn new information. It can also impact communication ability as it may take someone longer to respond if they have a slower processing speed.   
• Visual/spatial: Trouble with visual and/or spatial ability can affect many aspects of everyday life. It can make it difficult to drive (especially unfamiliar routes) or to find where things are at, such as where your car is parked.   

Cognitive impairment from PICS can affect an individual's day-to-day life. It can limit a person’s ability to work and hold a full-time job. It can put a strain on the family members of the ICU survivor and impact their relationships. 

Causes and Risk Factors

What causes cognitive impairment in PICS? There are a number of risk factors – potential contributors that can result in an injured and, often, inflamed brain. These risk factors include: 

• Delirium in the ICU (especially longer duration of delirium)
• Prolonged mechanical ventilation
• Older age
• Preexisting cognitive impairments 

The most significant risk factor for cognitive impairment with PICS is delirium. Reducing delirium in the ICU is key to preventing these cognitive challenges from happening after a patient is discharged. 

What can I do?

Cognitive deficits due to PICS are responsive to cognitive rehabilitation. This type of therapy can help alleviate some of the issues. Seeking help from a post-ICU clinic can help improve symptoms from PICS. Attending an ICU survivor support group can help survivors feel less alone in their struggles and provide a safe space to discuss their concerns. 

Mental Health Outcomes

Many patients with PICS experience mental health issues. This can be due to the direct effects of their critical illness or as a result of the consequences of being ill. For example if a worker on the assembly line at a General Motors plant is too debilitated to do his job, he loses parts of his identity and his income in the process, and - as a result - becomes depressed. 

These mental health outcomes involved in PICS generally fall into 3 "buckets:" depression, anxiety, and post-traumatic stress disorder (PTSD).  The severity of these conditions differs between patients - from very mild to disabling and severe, with most people experiencing symptoms that are moderate in severity.  In general, depression and anxiety impact up to 1 in 3 survivors of the ICU.  PTSD, on the other hand, has been reported to impact as few as 10% of ICU survivors and as many as half.  Of the outcomes discussed here, PTSD is the one that most consistently catches patients "off guard."  Why?  Because many people don't fully appreciate the extent to which critical illness is "traumatic." Most people associate trauma with things like combat or assault, but fail to realize that being in the intensive care unit, fighting through delirium, and facing potentially imminent death can be very traumatic in its own right.  Ironically, "medical" trauma may be among the most common forms of trauma and we need to continue our efforts to help people understand and recognize the symptoms that often emerge after being exposed to it.

Risk Factors

Risk factors for developing mental health issues after the ICU have been widely studied.  The most consistently identified risk factor is previous psychological challenges or conditions.  If someone had depression and/or anxiety before the ICU experience, they are more vulnerable to developing new or worsening mental health struggles. The stress of being critically ill can make existing problems worse.  While the role of risk factors cannot be overlooked or ignored, the truth is that mental health concerns can emerge in virtually anyone - even in people with pristine psychiatric histories.  No one is immune.

Physical Impairments

In addition to the cognitive and mental health deficits experienced with PICS, there are physical impairments that emerge and range in severity and duration following intensive care. The most prevalent condition is intensive care unit-acquired weakness (ICU-AW) which is a group of conditions related to muscle weakness, primarily in the arms and legs. This weakness can be the result of critical illness myopathy (CIM) (muscle weakness), polyneuropathy (CIP) (nerve disease resulting in weakness, numbness, and burning pain), or a combination of the two. Other physical impairments ICU survivors may experience are fatigue, sleep disturbances and possible weight loss. Physical impairments affect ICU survivors in their daily activities related to caring for themselves (for example: showering and getting dressed) and to mobility.

Risk Factors

Though the incidence of physical impairment has varied across studies, these known risk factors can increase the likelihood of patients experiencing physical impairment:

• Older age
• Duration of mechanical ventilation
• Immobility in the hospital
• Medications
• Severity of illness

Recovery also varies depending on the severity and type of impairment, be it muscular or neurological, ranging from months to years after discharge. In addition, ICU-AW can lead to prolonged mechanical ventilation and longer hospital stays, two conditions that increase the risk of impairment.

One of the best ways to combat these impairments is intensive physical rehabilitation during an ICU stay as well as nutritional therapy to maintain adequate energy for muscle strength.

Original draft by Natalie Wright, Vanderbilt