Sleep is vital for recovery from injury1. As well as the removal of metabolic waste, sleep is important for cellular responses in the body2,3. Sleep deprivation, therefore, can have significant adverse effects on normal physiological processes, including increased susceptibility to infection, overactivation of the sympathetic nervous system and increased risk of delirium4–6. Despite these risks, sleep deprivation is common in hospital, and particularly in the perioperative setting where environmental disturbances are common, pain and anxiety can affect sleep quantity and quality, and wards can be high-turnover and manage acute conditions and complications7.
Patients undergoing elective surgery experience a significant insult during major surgery and may take months to return to their functional and physiological baseline, if at all. During this time they are at risk of surgical complications that may delay their recovery and apply further systemic stress8. Enhanced Recovery After Surgery (ERAS) guidelines for postoperative care have been widely implemented across the world to improve mobility, diet, fluid status and analgesia, and reduce unnecessary interventions (for example routine nasogastric placement after colorectal resection)9. However, no ERAS guidelines currently include sleep quantity or quality. Given the negative effects of sleep deprivation, interventions to improve sleep after surgery have the potential to both moderate the surgical stress responses and mediate high compliance with other components of the ERAS pathway (for example by improving appetite and energy for mobilization).
Although other systematic reviews evaluating the effectiveness of sleep interventions for hospital inpatients exist, these have largely focused on critical care populations and drug therapies10,11. Pharmacological therapies typically have unattractive side-effect profiles that may hinder postoperative recovery12. Further research in non-pharmacological interventions (NPIs) for use in non-critical care areas including surgical wards is urgently needed13. In addition, traditional methods for sleep measurement such as highly controlled sleep studies are not feasible in a hospital environment. Future trials of NPIs in the surgical setting will have to adopt innovative, but validated methods for sleep measurement. The objectives of this systematic review were therefore three-fold: first, to identify and evaluate interventions tested out to improve sleep quality and quantity; second, to identify the approaches to measuring sleep in hospitalized adult patients; and third, to extract other sleep-associated health-related outcomes. The overall aim was to inform the co-development of a future randomized trial in patients undergoing surgery.
