Take Home Messages:

• Neurocognitive impairments are a major determinant of the ability to return to work, work productivity, and life satisfaction following critical illness.
• More research is needed to understand the prevalence, nature, risk factors and nuances of neurocognitive impairments. 
•  The education of clinical care providers regarding patient impairments prior to ICU discharge may help to increase identification rates, thereby benefiting patients through raising physician awareness and potentially leading to increased referrals to rehabilitation specialists or speech and language therapists.

Why the research matters:

A person’s ability to process information, think and plan are known as neurocognitive abilities.

Neurocognitive function impacts on a patient’s ability to think or remember clearly, to live a normal life and go to work.

It is believed the incidence of long term neurocognitive dysfunction has been underestimated and underreported in critically ill patients.

What the research involved:

Researchers from the US with specialist knowledge of Intensive Care patients looked for all studies that assessed cognitive function after intensive care stays and found ten relevant studies.  They summarised the findings of those studies

Summary of research findings:

The authors pointed out the original research articles were difficult to compare because of differences between the different studies. However the following findings were noted:

Testing:

• Most critically ill patients were not evaluated for neurocognitive impairments and the issues about neurocognitive abilities appear to be unrecognized by both ICU and rehabilitation providers.
• In non-ICU clinical settings many physicians failed to recognize or assess neurocognitive impairment.

Cause:

• There appeared to be no single cause, but a number of factors were found to affect long-term neurocognitive function after critical Illness. Some possible mechanisms included lack of oxygen, the use of sedatives or analgesic, low blood pressure, delirium and hyperglycemia.

Level of impairment:

• In ICU survivors, approximately one third of patients or more developed long term neurocognitive impairment.
• Within a survey of 87 lung problem survivors, 20pc rated their memory as poor 18 months after ICU on such tasks as filling in a cheque book, following written directions and complying with complex medication instructions.
• The overall results showed general memory was the most frequently observed deficit, followed by executive function and attention deficit.

Long term outcomes:

• Many critically ill patients had improvement of significant neurocognitive impairments during the first six to 12 months post discharge.
• The neurocognitive impairments in survivors of critical illness were often long-lasting and likely to be permanent, often persisting for months or years.
• Even mild neurocognitive impairments can lead to significant deficits in completing daily tasks such as driving and money management.
• The financial impact of critical illness on patients and their families was great, with 20pc of patients reporting a family member had to quit work, 29pc had lost a major source of income and 31pc lost the majority of the family savings.
• Neuropsychological function experienced by ICU survivors could not be explained simply in terms of the degree of acute illness severity.
• Neurocognitive impairments in critically ill patients were not associated with the following factors: ICU length of stay, acute physiology and chronic health evaluation, duration of mechanical ventilation, number of days receiving sedatives, narcotic and paralytic medications.
• An investigation which focused on one year outcomes reported 51pc of lung problem survivors were not working. Although a significant number of the patients had not re-entered the workforce, most of these individuals reported physical as opposed to neurocognitive-related reasons for the failure to return to work.
• Lung problem patients with neurocognitive impairments had a lower quality of life compared to patients with no impairments. Similarly, survivors of acute lung injury with neurocognitive impairments had a worse quality of life compared to those without neurocognitive impairments. Both groups had a lower quality of life compared to age-matched and gender-matched healthy control.

Original Research:

Long-Term Neurocognitive Function After Critical Illness.

Ramona O. Hopkins and James C. Jackson

CHEST, 2006,130:869-878.

Link to PubMed abstract