Bed rest after lung injury linked to muscle weakness, functional impairments

Duration of bed rest during acute lung injury was the most consistent predictor of muscle weakness among survivors 2 years later, according to a report in the April issue of Critical Care Medicine.

For every additional day of bed rest, survivors’ muscle strength was 3%-11% lower at 24-month follow-up, said Dr. Eddy Fan of the division of critical care medicine, University of Toronto.

The results underscore the importance of evidence-based methods to reduce bed rest during critical illness, including early physical and occupational therapy, wrote Dr. Fan and his colleagues (Crit. Care Med. 2014;42:849-59).

The prospective, multisite, longitudinal study comprised 520 patients with acute lung injury, of whom 222 underwent muscle strength evaluations. During follow-up visits at 3, 6, 12, and 24 months, investigators measured extremity, hand grip, and respiratory muscle strength; anthropometric variables; and the distance patients could walk in 6 minutes. Patients completed a short-form survey on health-related quality of life.

The researchers found that patients generally recovered muscle strength within 12 months after acute lung injury, but that muscle weakness was associated with significant limitations in physical function and quality of life that persisted for at least another 12 months. Only 36% of patients received any physical therapy while in the ICU, and while the average ICU stay was 13 days, patients who did receive PT went an average of 10 days before it began.

The researchers noted that they did not use nerve conduction studies, electromyography, or muscle and nerve biopsies, and did not control for factors such as outpatient rehabilitation or subsequent hospitalizations.

The National Institutes of Health partially funded the research. The authors did not disclose any conflicts of interest.