Sleep-wake rhythm during stay in an intensive care unit: a week's long-term recording of skin potentials

Evaluating adult patients' sleep: an integrative literature review in critical care

BACKGROUND

Patients in a critical care unit sleep quite poorly even when they appear to be sleeping. Sleep is light and fragmented. Acute lack of sleep causes patients suffering in the form of fatigue, irritability, disorientation and hallucinations. It may also affect their recovery and immune defence. To promote sleep, nurses must be able to evaluate patients' sleep reliably.

AIM AND OBJECTIVES

Our aim was to form a comprehensive overview of the sleep evaluation methods in critical care. Our objectives were to determine the content and the quality of the methods as reported by the researchers. This overview hopefully improves the use of the sleep evaluation methods as part of sleep promoting nursing interventions and practices.

METHOD

The literature search was performed from the Ovid MEDLINE, CINAHL, an 'All EBM Reviews', and PsycINFO databases. The search terms sleep, evaluating sleep and critical care were used. An integrative review method was used to analyse the data.

RESULTS

According to the 52 articles of this review, there is a wide variety of methods to evaluate patients' sleep in critical care by observation, by asking for patient's own perception and by objective measures. Most instruments evaluate only total sleep time or the quality of sleep in general. The validity and reliability of the instruments has been insufficiently reported. Some questionnaires for patients' perception have been tested and used in several studies.

CONCLUSION

Sleep evaluation instruments do not cover all dimensions of sleep since they mostly measure total sleep time or estimate the overall quality of sleep. The quality of the sleep evaluation instruments varies from scientifically tested tools to untested instruments. This review will allow nurses to recognise the strengths and limitations of sleep evaluation instruments when selecting one to be used in critical care. Valid information about patients' sleep enables nurses to facilitate it.

Nonrespiratory sleep disorders found in ICU patients

Intensive care subjects the critically ill patient to a multitude of stressors caused by the severity of illness and the use of invasive treatment modalities and medications. The ICU environment contributes significant stress of its own related to noise, light, 24-hour patient care, and other factors that disturb sleep. Consequently, various sleep pathologies may emerge or worsen in the ICU patient. Some sleep disorder symptomatology may be confused with serious neurologic complications of critical illness and lead to inappropriate testing or treatment, particularly in the patient who has narcolepsy. Given the high prevalence of sleep disorders in the general population, it is essential that the ICU practitioner attain an adequate knowledge of sleep and its disorders.

Influence of bright light therapy on postoperative patients: A pilot study

Bright light therapy is a method of maintaining or restoring the natural circadian rhythm by assisting daytime awakening using bright lights. Postoperative delirium is one of the potential complications encountered by patients receiving postoperative care in the intensive care unit (ICU), but there have been no studies on the use of light for the prevention of postoperative delirium. The objective of this study was to examine whether the circadian rhythms of patients after surgery for oesophageal cancer can be adjusted and whether the postoperative delirium crisis rate can be reduced by bright light therapy. The subjects were 11 patients operated on for oesophageal cancer in Osaka University Hospital. After informed consent was obtained, they were divided into a study group and a control group by a random sampling method. After removal of the endotracheal tube, the study group was exposed to light. The light intensity was about 5000lx immediately before the eyes, and the distance from the light source was about 100 cm. The control group was placed in a natural lighting environment after extubation. In both groups, the rhythms of physical activities and autonomic activities were monitored after surgery, and delirium was evaluated. A significant difference was observed in the delirium score between the study group and control group on the morning of day 3 of bright light therapy by the Mann-Whitney U-test (P=0.014). The study group could begin ambulation about 2 days earlier than the control group. Bright light therapy may reduce the rate of postoperative delirium and make early ambulation possible. However, our study involved a very small sample size. We want to increase the sample in the future after having reviewed clinical application methods.

Sleep in acute care units

Patients in the acute care units (ACU) are usually critically ill, making them more susceptible to the unfavorable atmosphere in the hospital. One of these unfavorable factors is sleep disruption and deprivation. Many factors may affect sleep in the ACU, including therapeutic interventions, diagnostic procedures, medications, the underlying disease process, and noise generated in the ACU environment. Many detrimental physiological effects can occur secondary to noise and sleep deprivation, including cardiovascular stimulation, increased gastric secretion, pituitary and adrenal stimulation, suppression of the immune system and wound healing, and possible contribution to delirium. Over the past few years, many studies have endeavored to objectively assess sleep in the ACUs, as well as the effect of mechanical ventilation and circadian rhythm changes critically ill patients. At this time, therefore, it is important to review published data regarding sleep in ACUs, in order to improve the knowledge and recognition of this problem by health care professionals. We have therefore reviewed the methods used to assess sleep in ACUs, factors that may affect sleep in the ACU environment, and the clinical implications of sleep disruption in the ACU.

Use of ambulatory skin conductance recording for monitoring psychophysiological arousal in the elderly staying in care facilities

To monitor the psychophysiological arousal level in the elderly, 24 h recordings of skin conductance change (SCC) were done during their stay in care facilities. The mean and maximum SCC levels in 17 awake elderly subjects were significantly lower than those of levels in 20 healthy, young control subjects (P < 0.05 and P < 0.001, respectively). The mean SCC levels during sleep did not differ between groups. The SCC trend graph reflected a degree of daily activity. The daytime SCC profile of elderly individuals who could walk independently was comparable to that of healthy young subjects. In contrast, the SCC profile of the bedridden elderly were generally flattened with poor SCC responses that were evoked only by nursing procedures.