Sleep and Intensive Care Unit-Acquired Weakness in Critically Ill Older Adults

Background 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. Objectives 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. Methods 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. Results 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. Discussion 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.