When the first edition of this book was published in 1994, the standard metric of outcome after critical illness was 28-day all-cause mortality. Since that time, there has been a revolution in the way we view critical illness, its treatment, and its lasting effects both for the patient and the family caregiver. The dramatic rise in the number of longer-term outcomes reports published over the past 5 to 10 years clearly reflects this point. It is now apparent that most patients who have survived an episode of severe critical illness requiring mechanical ventilation will sustain some compromise in physical function related to intensive care unit (ICU) acquired weakness and a myriad of other physical disabilities.1–5 This acquired disability may be permanent.5 Patients may also sustain an important new or incremental decline in neuropsychological function, including neurocognitive impairments, and neuropsychiatric or mood disorders.6–8 The constellation of muscle, nerve, and brain dysfunction3,9–13 may permanently alter disposition for those who were previously independent and who, post-ICU, now require assisted living or comprehensive care.1 ICU-acquired morbidity may result in an additional cost burden in health care utilization that is similar to patients with chronic disease,1,5,13–14 and this traumatic life event may completely erode the reserve of family members and they may also acquire new mood disorders.15–18
This chapter reviews the literature on physical and neuropsychological outcomes after critical illness and highlights important emerging data that link patient characteristics, burden of comorbid disease, and ICU practice patterns to acquisition of new morbidity. In addition, newer data on psychological disability in family caregivers and models of rehabilitation and intervention after critical illness are discussed. To date, the outcomes literature has been dominated by reports on survivors of acute respiratory distress syndrome (ARDS), but there are emerging data on other vulnerable patient subgroups, such as the frail elderly and the chronically critically ill. Outcomes in these populations add insight to the current understanding of the diversity in post-ICU disability and also are discussed. The chapter concludes with a commentary on a proposed framework for a continuum of rehabilitation for patients and families after critical illness.
The current state of the outcomes literature suggests that the greatest short-term morbidity after critical illness is diminished physical health-related quality of life as a consequence of ICU-acquired weakness.3,5,9,10,13,19–22 Reports from long-term follow-up studies suggest that by 5 years, patients complain less of physical disability and more of a decline in general health, diminished vitality, and mood disorders.5 The finding of compromised physical quality of life has been robust across many studies since the early 1990s, as discussed in detail below. An understanding, however, of the specific determinants of this reported decrease in physical function was not well known until more than a decade later.