Intensive care unit-acquired weakness

Abstract

Objective: Severe weakness is being recognized as a complication that impacts significantly on the pace and degree of recovery and return to former functional status of patients who survive the organ failures that mandate life-support therapies such as mechanical ventilation. Despite the apparent importance of this problem, much remains to be understood about its incidence, causes, prevention, and treatment.

Design: Review from literature and an expert round-table.

Setting: The Brussels Round Table Conference in 2009 convened more than 20 experts in the fields of intensive care, neurology, and muscle physiology to review current understandings of intensive care unit-acquired weakness and to improve clinical outcome.

Main results: Formal electrophysiological evaluation of patients with intensive care unit-acquired weakness can identify peripheral neuropathies, myopathies, and combinations of these disorders, although the correlation of these findings to weakness measurable at the bedside is not always precise. For routine clinical purposes, bedside assessment of neuromuscular function can be performed but is often confounded by complicating factors such as sedative and analgesic administration. Risk factors for development of intensive care unit-acquired weakness include bed rest itself, sepsis, and corticosteroid exposure. A strong association exists between weakness and long-term ventilator dependence; weakness is a major determinant of patient outcomes after surviving acute respiratory failure and may be present for months, or indefinitely, in the convalescence phase of critical illness.

Conclusion: Although much has been learned about the physiology and cell and molecular biology of skeletal and diaphragm dysfunction under conditions of aging, exercise, disuse, and sepsis, the application of these understandings to the bedside requires more study in both bench models and patients. Although a trend toward greater immobilization and sedation of patients has characterized the past several decades of intensive care unit care, recent studies have demonstrated that early physical and occupational therapy, including during the period of intubation and ventilator support, can be safely performed and will likely improve patient outcomes with regard to functional status.