Critical care : the official journal of the Critical Care Forum
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Editorial Comment
The brain after critical illness: effect of illness and aging on cognitive function.
Large numbers of patients who survive critical illness are left with significant new cognitive impairments that are often severe and remain years after hospital discharge. In the previous issue of Critical Care, Guerra and colleagues assessed risk factors for the development of dementia after an intensive care unit (ICU) admission in a sample of older beneficiaries of Medicare. Older age was strongly associated with a diagnosis of dementia. ⋯ This study has several limitations - including use of ICD-9-CM codes that identified primarily neurodegenerative types of dementia, the lack of a control group, and a high mortality rate during the first 6 months after hospital discharge - which the authors acknowledge. An important additional limitation of the study by Guerra and colleagues and all previous post-ICU cognitive outcome studies is the inability to determine what role, if any, cognitive impairments that existed before the critical illness contribute to the diagnosis of new post-ICU dementia and whether such cognitive impairments are stable over time or are progressive like those observed in neurodegenerative diseases. Research is needed to answer questions regarding mechanisms of injury, medical and personal risk factors, and importantly the effect of interventions administered either during or after ICU treatment that may prevent or ameliorate such impairments.
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Urinary indices are classically believed to allow differentiation of transient (or pre-renal) acute kidney injury (AKI) from persistent (or acute tubular necrosis) AKI. However, the data validating urinalysis in critically ill patients are weak. ⋯ This study confirms the limited diagnostic and prognostic ability of urine testing. Together with other studies, this study raises more fundamental questions about the value, meaning and pathophysiologic validity of the pre-renal AKI paradigm and suggests that AKI (like all other forms of organ injury) is a continuum of injury that cannot be neatly divided into functional (pre-renal or transient) or structural (acute tubular necrosis or persistent).
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Editorial Comment
Over-distension of the airways by mechanical ventilation in the elderly: adding insult to injury.
Setzer and colleagues demonstrate that older animals are more susceptible to ventilator-induced lung injury than young animals and develop a more pronounced local and systemic cytokine response to high tidal volumes. These data have significant implications for older patients receiving mechanical ventilation if these findings can be translated to human critical care medicine.