Older adults in the intensive care unit (ICU) often experience sleep disturbances, which may stem from life-threatening illness, the ICU environment, medications/sedation, or psychological stress. Two complementary endocrinological responses occur as a result of compromised sleep and consequently could exacerbate ICU-acquired weakness: a decrease in anabolic hormones leading to decreased protein synthesis and an increase in catabolic hormones leading to increased protein degradation. Age-associated decreases in anabolic hormones, such as insulin-like growth factor 1, testosterone, and growth hormone, may inhibit protein synthesis. Likewise, age-associated increases in insulin resistance, glucocorticoids, and myostatin can stimulate muscle atrophy and further reduce protein synthesis. Thus, perhaps, sleep promotion in the ICU may attenuate muscle atrophy among critically ill older adults who are at risk for ICU-acquired weakness and subsequent functional decline.
The aim of this study was to discuss the hypothesized theoretical underpinnings of the relationship between sleep disturbances and ICU-acquired weakness among critically ill older adults.
A search of research literature published from 1970 to 2018 and indexed in MEDLINE, Embase, CINAHL, and Ovid was undertaken, and relevant sources were selected to build an informed discussion.
Nurses must be mindful of secondary sleep disturbances that occur throughout the acute phase of critical illness and their probable links to ICU-acquired weakness. Targeted interventions to promote functional outcomes in elderly patients should consider this relationship.
Improved sleep may have the potential to decrease the severity of muscle atrophy and ICU-acquired weakness. Future research must explore this hypothesis and the underlying mechanisms of the association between sleep disturbances and ICU-acquired weakness in critically ill older adults.
Maya N. Elías, PhD, MA, RN, is a postdoctoral research fellow at the School of Nursing & Health Studies at the University of Miami, Coral Gables, Florida.
Cindy L. Munro, PhD, ANP-BC, FAAAS, is dean and professor at the School of Nursing & Health Studies at the University of Miami, Coral Gables, Florida.
Zhan Liang, PhD, RN, is an assistant professor at the School of Nursing & Health Studies at the University of Miami, Coral Gables, Florida.
Karel Calero, MD, is an assistant professor at the College of Medicine, Department of Pulmonary, Critical Care, & Sleep Medicine at the University of South Florida, Tampa.
Ming Ji, PhD, is a professor at the College of Nursing at the University of South Florida, Tampa.
The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article.
Author contributions: All authors have agreed on the final version and meet at least 1 of the following criteria (recommended by the ICMJE, http://www.icmje.org/recommendations): substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; drafting the article or revising it critically for important intellectual content.
Address correspondence and reprint requests to: Maya N. Elías, PhD, MA, RN, School of Nursing & Health Studies, University of Miami, 5030 Brunson Dr, Coral Gables, FL 33146 (firstname.lastname@example.org).