Characterisation of sleep in intensive care using 24-hour polysomnography: an observational study

Adding Insult to Injury: Sleep Deficiency in Hospitalized Patients

Sleep deficiency is a common problem in the hospital setting. Contributing factors include preexisting medical conditions, illness severity, the hospital environment, and treatment-related effects. Hospitalized patients are particularly vulnerable to the negative health effects of sleep deficiency that impact multiple organ systems. Objective sleep measurement is difficult to achieve in the hospital setting, posing a barrier to linking improvements in hospital outcomes with sleep promotion protocols. Key next steps in hospital sleep promotion include improvement in sleep measurement techniques and harmonization of study protocols and outcomes to strengthen existing evidence and facilitate data interpretation across studies.

Psychometric evaluation of the Chinese version of the hospital-acquired insomnia scale (HAIS) and analysis of influencing factors

BACKGROUND

Adequate sleep and rest are essential for patient recovery; however, lack of sleep has become a common problem faced by Chinese patients during hospital stays. Reduced sleep is often associated with a higher risk of disease progression and is strongly associated with increased hospital stay. However, there is no specific tool in China to assess short-term insomnia caused by hospitalization. This study aimed to translate the Hospital-acquired Insomnia Scale (HAIS) into Chinese, test its applicability to Chinese inpatients through reliability and validity indicators, and investigate the potential influencing factors of hospital-acquired insomnia.

METHODS

Psychometric analysis from a sample of 679 hospitalized patients to whom the HAIS questionnaire was applied. The structural validity was assessed by exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), and the content validity of the scale was assessed using the content validity index. Cronbach's alpha coefficient, split-half reliability and test-retest reliability were calculated to evaluate the internal consistency of the scale. Multiple stepwise linear regression analysis was conducted to determine the potential correlates of hospital-acquired insomnia.

RESULTS

EFA supported a four-factor structure with factor loadings for all dimensions greater than 0.40. CFA showed good indicators of model fit. The content validity index of the scale was 0.94. the Cronbach's alpha of the scale was 0.915, the split-half reliability coefficient was 0.819, and the retest reliability was 0.844. Gender, age, total hours of sleep during the night, medical insurance, length of hospital stay, perceived stress level, and perceptions about sleep explained 46.2% of the variance in hospital-acquired insomnia.

CONCLUSION

The Chinese version of HAIS has good psychometric characteristics and is an effective instrument for evaluating hospital-acquired insomnia. In addition, hospital-acquired insomnia is more common in women, of younger age, less than 5 h of sleep a night, without medical insurance, stressed, and patients with more misconceptions about sleep.

Impact of new lighting technology versus traditional fluorescent bulbs on sedation and delirium in the ICU

BACKGROUND

Critically ill patients frequently encounter disruptions in their circadian rhythms in the intensive care unit (ICU) environment. New lighting systems have been developed to enhance daytime light levels and to promote circadian alignment.

OBJECTIVES

To investigate the impact of implementing an innovative lighting technology that mimics natural light and reproduce the colour of the sky.

DESIGN

Prospective, observational, non-randomized comparative trial. ICU patients were exposed to either a cutting-edge lighting system based on new technology (intervention group) or a conventional lighting system using fluorescent bulbs (control group).

SETTING

An Italian intensive care unit with ten beds and five windowless rooms, thereby denying access to natural light. Three rooms had new lighting technology.

MAIN OUTCOME MEASURES

The two groups were compared to assess the prevalence or absence of delirium and the need for sedatives during ICU stay. The secondary aim was to assess the presence of anxiety, depression, and post-traumatic stress disorder in patients at 3, 6, and 12 months after ICU discharge.

RESULTS

86 patients were included: 52 (60 %) in the intervention group and 34 (40 %) in the control group. Seventy-nine patients (82 %) were alive at ICU discharge. Fourteen patients (16 %) developed delirium (intervention group: n = 8 [15 %] vs. control group: n = 6 [18 %] in the control group, (P=0.781). The use of sedative drugs and neuromuscular blocking agents was similar in both the groups. No differences in the incidence of anxiety, depression, or post-traumatic stress disorders were observed among patients who underwent follow-up visits.

CONCLUSIONS

Compared to traditional fluorescent tube lighting, the innovative lighting system did not provide any significant benefit in reducing the frequency of delirium or the necessity for sedative medications.

IMPLICATIONS FOR CLINICAL PRACTICE

A single intervention, the use of lights that mimic sunny light and the sky, did not result in a statistically significant reduction in the incidence of delirium. Delirium has a multifactorial aetiology, necessitating interventions that are multifaceted and address different domains.

A multicentre point prevalence study of nocturnal hours awake and enteral pharmacological sleep aids in patients admitted to Australian and New Zealand intensive care units

Objective

Critically ill patients suffer disrupted sleep. Hypnotic medications may improve sleep; however, local epidemiological data regarding the amount of nocturnal time awake and the use of such medications is needed.

Design

Point prevalence study.

Setting

Adult ICUs in Australia and New Zealand.

Participants

All adult patients admitted to participating Intensive Care Units (ICUs) on the study day.

Main outcome measures

Time awake overnight (22:00-06:00) was determined by structured nurse observation. The use of enterally administered sedative-hypnotic drugs prior to and during ICU admission was recorded, as was the use of a unit policy and non-pharmacological sleep promotion strategies.

Results

Data were available for 532 patients admitted to 40 ICUs (median age 60 years, 336 (63.2%) male, and 222 (41.7%) invasively ventilated). Forty-eight patients (9.0%) received an enteral pharmacological sleep aid, of which melatonin (28, 5.2%) was most frequently used. Patients not invasively ventilated were observed to be awake overnight for a median of 4.0 h (interquartile range (IQR): 2.5, 5.5), with no difference in those receiving an enteral hypnotic (p = 0.9). Non-pharmacological sleep aids were reportedly not offered or available for 52% (earplugs) and 63% of patients (eye masks). Only 7 (17.5%) participating ICUs had a policy informing sleep-optimising interventions.

Conclusions

Patients not receiving invasive ventilation appeared to spend many nocturnal hours awake. Pharmacological sleep aid administration was not associated with a greater observed time asleep. Most patients did not receive any non-pharmacological aid, and most ICUs did not have a local guideline or unit policy on sleep promotion.

Mitigating Intensive Care Unit Noise: Design-Led Modeling Solutions, Calculated Acoustic Outcomes, and Cost Implications

OBJECTIVES, PURPOSE, OR AIM

The study aimed to decrease noise levels in the ICU, anticipated to have adverse effects on both patients and staff, by implementing enhancements in acoustic design.

BACKGROUND

Recognizing ICU noise as a significant disruptor of sleep and a potential hindrance to patient recovery, this study was conducted at a 40-bed ICU in Fiona Stanley Hospital in Perth, Australia.

METHODS

A comprehensive mixed-methods approach was employed, encompassing surveys, site analysis, and acoustic measurements. Survey data highlighted the importance of patient sleep quality, emphasizing the negative impact of noise on work performance, patient connection, and job satisfaction. Room acoustics analysis revealed noise levels ranging from 60 to 90 dB(A) in the presence of patients, surpassing sleep disruption criteria.

RESULTS

Utilizing an iterative 3D design modeling process, the study simulated significant acoustic treatment upgrades. The design integrated effective acoustic treatments within patient rooms, aiming to reduce noise levels and minimize transmission to adjacent areas. Rigorous evaluation using industry-standard acoustic software highlights the design's efficacy in reducing noise transmission in particular. Additionally, cost implications were examined, comparing standard ICU construction with acoustically treated options for new construction and refurbishment projects.

CONCLUSIONS

This study provides valuable insights into design-based solutions for addressing noise-related challenges in the ICU. While the focus is on improving the acoustic environment by reducing noise levels and minimizing transmission to adjacent areas. It is important to clarify that direct measurements of patient outcomes were not conducted. The potential impact of these solutions on health outcomes, particularly sleep quality, remains a crucial aspect for consideration.

Effectiveness of Earplugs and Eye Masks on Sleep Quality and Fatigue Among Nonventilated Patients in an Intensive Care Unit

BACKGROUND

Sleep is a basic physiological need and is imperative for healing and rejuvenation. However, the environment of the intensive care unit (ICU), including loud sounds and bright lights, can undermine patients' sleep quality.

AIM

This study was designed to determine the effectiveness of overnight use of earplugs and eye masks to improve sleep quality and potentially influence hemodynamic parameters and mitigate fatigue among nonventilated patients in an ICU.

MATERIALS AND METHODS

This experimental study was conducted among 84 nonventilated patients in an ICU. The patients were evenly divided between an intervention group (n=42) and a control group (n=42). The intervention group patients received earplugs and eye masks for three consecutive nights from 10:30 pm to 6:30 am, while the control group patients received routine care. Clinical data, responses to the Richards-Campbell sleep questionnaire, and rankings on a numerical fatigue scale were collected before (pretest) and after the intervention each night and the next morning (posttests 1, 2, and 3).

RESULTS

The results revealed a significant reduction in fatigue. At pretest, fatigue scores in the study group were 4.19±1.64. The score was significantly reduced to 3.40±1.39 at posttest 1 and then to 2.21±1.00 at posttest 3 (p<0.0001). The sleep quality for the study group showed a significant improvement from the pretest score of 43.73±8.27 to 60.35±6.85 at posttest 3 (p<0.001), whereas the control group had slightly worse sleep quality, with 40.64±8.67 at pretest and 45.63±6.95 at posttest 3.

CONCLUSIONS

Continuous patient monitoring is an essential nursing care activity in ICUs while ensuring good-quality sleep promotes healing and reduces fatigue. Sleep quality can be supported by devices such as earplugs and eye masks to limit undue disturbances in the ICU settings.

Pharmacologic Sleep Aids in the Intensive Care Unit: A Systematic Review

Background: Patients in the intensive care unit (ICU) often experience poor sleep quality. Pharmacologic sleep aids are frequently used as primary or adjunctive therapy to improve sleep, although their benefits in the ICU remain uncertain. This review aims to provide a comprehensive assessment of the objective and subjective effects of medications used for sleep in the ICU, as well as their adverse effects. Methods: PubMed, Web of Science, Scopus, Embase, and Cochrane Central Register of Controlled Trials were systematically searched from their inception until June 2023 for comparative studies assessing the effects of pharmacologic sleep aids on objective and subjective metrics of sleep. Results: Thirty-four studies with 3498 participants were included. Medications evaluated were melatonin, ramelteon, suvorexant, propofol, and dexmedetomidine. The majority of studies were randomized controlled trials. Melatonin and dexmedetomidine were the best studied agents. Objective sleep metrics included polysomnography (PSG), electroencephalography (EEG), bispectral index, and actigraphy. Subjective outcome measures included patient questionnaires and nursing observations. Evidence for melatonin as a sleep aid in the ICU was mixed but largely not supportive for improving sleep. Evidence for ramelteon, suvorexant, and propofol was too limited to offer definitive recommendations. Both objective and subjective data supported dexmedetomidine as an effective sleep aid in the ICU, with PSG/EEG in 303 ICU patients demonstrating increased sleep duration and efficiency, decreased arousal index, decreased percentage of stage N1 sleep, and increased absolute and percentage of stage N2 sleep. Mild bradycardia and hypotension were reported as side effects of dexmedetomidine, whereas the other medications were reported to be safe. Several ongoing studies have not yet been published, mostly on melatonin and dexmedetomidine. Conclusions: While definitive conclusions cannot be made for most medications, dexmedetomidine improved sleep quantity and quality in the ICU. These benefits need to be balanced with possible hemodynamic side effects.

Trajectory of Sleep, Depression, and Quality of Life in Pediatric HSCT Recipients

Disrupted sleep is commonly reported during hematopoietic stem cell transplant. In this study, we use actigraphy to measure sleep parameters, and qualitative measures of quality of life, depression, and sleep in pediatric and young adult transplant recipients to describe their time course through transplant. Eight patients had evaluable actigraphy data, and 10 patients completed the surveys. The median age of the 6 male and 7 female participants was 13.94 years old. Sleep duration and efficiency measured by actigraphy were suboptimal prior to transplant, then declined to a nadir between Day +7 to +14. Self-reported sleep quality, depression, and quality of life were worst at Day +14 to +30 but improved by Day +100. Findings support efforts to improve sleep, which may improve recovery, mental health and quality of life.

Sleep in the intensive and intermediate care units: Exploring related factors of delirium, benzodiazepine use and mortality

AIM OF THE STUDY

The primary purpose was to examine sleep difficulties and delirium in the Intensive and Intermediate Care Unit. Secondarily, factors impacting night-time sleep duration and quality, mortality, and the impact of benzodiazepine use on sleep outcomes were investigated.

MATERIALS AND METHODS

This retrospective study encompassed data from 323 intensive and intermediate care unit admissions collected in the Netherlands, spanning from November 2018 to May 2020. Sleep quality was measured using the Richards-Campbell Sleep Questionnaire. Night-time sleep duration was nurse-reported. We investigated associations of these sleep outcomes with age, sex, length-of-stay, natural daylight, disease severity, mechanical ventilation, benzodiazepine use, and delirium using Generalized Estimating Equations models. Associations with one-year post-discharge mortality were analyzed using Cox regression.

RESULTS

Night-time sleep duration was short (median 4.5 hours) and sleep quality poor (mean score 4.9/10). Benzodiazepine use was common (24 % of included nights) and was negatively associated with night-time sleep duration and quality (B = -0.558 and -0.533, p <.001). Delirium and overnight transfers were negatively associated with sleep quality (B = -0.716 and -1.831, p <.05). The day-to-night sleep ratio was higher in the three days before delirium onset than in non-delirious individuals (p <.05). Age, disease severity and female sex were associated with increased one-year mortality. Sleep quality was negatively, but not-significantly, associated with mortality (p =.070).

CONCLUSIONS

Night-time sleep in the critical care environment has a short duration and poor quality. Benzodiazepine use was not associated with improved sleep. Sleep patterns change ahead of delirium onset.

IMPLICATIONS FOR CLINICAL PRACTICE

Consistent sleep monitoring should be part of routine nursing practice, using a validated instrument like the Richards-Campbell Sleep Questionnaire. Given the lack of proven efficacy of benzodiazepines in promoting sleep in critical care settings, it is vital to develop more effective sleep treatments that include non-benzodiazepine medication and sleep hygiene strategies.

Patient-reported sleep and physical function during and after hospitalization

PURPOSE

Poor sleep is associated with morbidity and mortality in the community; however, the health impact of poor sleep during and after hospitalization is poorly characterized. Our purpose was to describe trends in patient-reported sleep and physical function during and after hospitalization and evaluate sleep as a predictor of function after discharge.

METHODS

This is a secondary analysis of trial data with 232 adults followed for 3months after hospital discharge. Main measures were patient-reported surveys on sleep (Pittsburgh Sleep Quality Index) and physical function (Katz Activities of Daily Living, Lawton Instrumental Activities of Daily Living, and Nagi Mobility Scale) were collected during hospitalization and at 1, 5, 9, and 13weeks postdischarge.

RESULTS

Patient-reported sleep declined significantly during hospitalization and remained worse for 3months postdischarge (median Pittsburgh Sleep Quality Index=8 vs. 6, p < .001). In parallel, mobility declined significantly from baseline and remained worse at each follow-up time (median Nagi score=2 vs. 0, p < .001). Instrumental activities of daily living similarly decreased during and after hospitalization, but basic activities of daily living were unaffected. In adjusted time-series logistic regression models, the odds of mobility impairment were 1.48 times higher for each 1-point increase in Pittsburgh Sleep Quality Index score over time (95% CI 1.27-1.71, p < .001).

CONCLUSIONS

Patient-reported sleep worsened during hospitalization, did not improve significantly for 3months after hospitalization, and poor sleep was a significant predictor of functional impairment over this time. Sleep dysfunction that begins with hospitalization may persist and prevent functional recovery after discharge.

TRIAL REGISTRATION

The primary study was registered at ClinicalTrials.gov NCT03321279.

S-Ketamine Improves Slow Wave Sleep and the Associated Changes in Serum Protein Among Gynecological Abdominal Surgery Patients: A Randomized Controlled Trial

Purpose

This study aims to evaluate the effect of S-ketamine on slow wave sleep (SWS) and the related changes in serum protein in gynecological patients after open abdomen surgery.

Methods

This was a randomized controlled trial. One hundred gynecological patients undergoing open abdomen surgery were randomized into an S-ketamine group (group S) or placebo group (0.9% saline; group C). During operation, patients in group S received adjuvant S-ketamine infusion (0.2 mg·kg-1·h-1) while those in group C received 0.9% saline. All patients were connected to patient-controlled intravenous analgesia (PCIA) pump in the end of the surgery and the patients in group S with an additional S-ketamine in PCIA pump. Polysomnogram (PSG) was monitored during the next night after surgery with PCIA pump. Blood samples were collected for proteomic analysis at 6:00 AM after PSG monitoring. The primary outcome was the percentage of SWS (also known as stage 3 non-rapid eye movement sleep, stage N3) on the next night after surgery, and the secondary outcome was subjective sleep quality, pain scores, and the changes in serum proteomics.

Results

Complete polysomnogram recordings were obtained from 64 study participants (31 in group C and 33 in group S). The administration of S-ketamine infusion resulted in a significant increase in the percentage of SWS/N3 compared to the control group (group C, median (IQR [range]), 8.9 (6.3, 12.5); group S, median (IQR [range]), 15.6 (12.4, 18.8), P<0.001). However, subjective evaluations of sleep quality revealed no significant variances between the two groups. The protein affected by S-ketamine was primarily associated with posttranslational modification, protein turnover, carbohydrate transport, and metabolism.

Conclusion

In patients undergoing open gynecological surgery, S-ketamine enhanced the percentage of objective sleep of SWS during the next night after surgery. Additionally, there were differences observed in serum protein levels between the two groups.

Trial Registration

ChiCTR2200055180. Registered on 02/01/2022.

Modeling the Impact of Inter-Rater Disagreement on Sleep Statistics Using Deep Generative Learning

Sleep staging is the process by which an overnight polysomnographic measurement is segmented into epochs of 30 seconds, each of which is annotated as belonging to one of five discrete sleep stages. The resulting scoring is graphically depicted as a hypnogram, and several overnight sleep statistics are derived, such as total sleep time and sleep onset latency. Gold standard sleep staging as performed by human technicians is time-consuming, costly, and comes with imperfect inter-scorer agreement, which also results in inter-scorer disagreement about the overnight statistics. Deep learning algorithms have shown promise in automating sleep scoring, but struggle to model inter-scorer disagreement in sleep statistics. To that end, we introduce a novel technique using conditional generative models based on Normalizing Flows that permits the modeling of the inter-rater disagreement of overnight sleep statistics, termed U-Flow. We compare U-Flow to other automatic scoring methods on a hold-out test set of 70 subjects, each scored by six independent scorers. The proposed method achieves similar sleep staging performance in terms of accuracy and Cohen's kappa on the majority-voted hypnograms. At the same time, U-Flow outperforms the other methods in terms of modeling the inter-rater disagreement of overnight sleep statistics. The consequences of inter-rater disagreement about overnight sleep statistics may be great, and the disagreement potentially carries diagnostic and scientifically relevant information about sleep structure. U-Flow is able to model this disagreement efficiently and can support further investigations into the impact inter-rater disagreement has on sleep medicine and basic sleep research.

Diagnostic Value of the Bispectral Index to Assess Sleep Quality after Elective Surgery in Intensive Care Unit

Purpose

Monitoring and improving sleep quality may help recovery from major illness. Polysomnography is a gold standard for measuring sleep quality, but routine use is not practical. The goal of this study is to investigate the diagnostic accuracy of an alternative monitor, the Bispectral Index (BIS), for evaluating the quality of sleep-in postoperative patients in the intensive care unit (ICU).

Study design

An observational study.

Materials and methods

Patients admitted to postoperative ICU after elective major noncardiac surgery were monitored with both BIS and PSG during the first night. The temporally synchronized data from both monitors were obtained for measurement of the association. Clinical outcomes were compared between patients with different postoperative sleep quality.

Results

Thirty-three patients were enrolled in this study. For determining the average BIS index associated with good postoperative sleep quality, receiver operating characteristics (ROC) curve was generated. Area under the ROC curve (AUC) was 0.65. The cutoff with best discriminability was 75 with a sensitivity of 68% and a specificity of 56%. Compared with those with good and poor postoperative sleep quality, there were no differences in main postoperative outcomes including duration of mechanical ventilation and ICU stay. Although the quality of sleep after surgery of all subjects with postoperative delirium was poor, the incidence of delirium between the groups did not significantly differ (0% vs 10.3%; p = 0.184).

Conclusion

The monitoring of BIS is a viable tool for evaluating sleep quality in mechanically ventilated patients in the postoperative ICU with acceptable precision.

Trial registration

www.clinicaltrials.in.th, TCTR20200310005.

How to cite this article

Sirilaksanamanon P, Thawitsri T, Charuluxananan S, Chirakalwasan N. Diagnostic Value of the Bispectral Index to Assess Sleep Quality after Elective Surgery in Intensive Care Unit. Indian J Crit Care Med 2023;27(11):795-800.

Sleep and critical illness: a review

Critical illness and stays in the Intensive Care Unit (ICU) have significant impact on sleep. Poor sleep is common in this setting, can persist beyond acute critical illness, and is associated with increased morbidity and mortality. In the past 5 years, intensive care clinical practice guidelines have directed more focus on sleep and circadian disruption, spurring new initiatives to study and improve sleep complications in the critically ill. The global SARS-COV-2 (COVID-19) pandemic and dramatic spikes in patients requiring ICU level care also brought augmented levels of sleep disruption, the understanding of which continues to evolve. This review aims to summarize existing literature on sleep and critical illness and briefly discuss future directions in the field.

Effects of non-pharmacologic prevention on delirium in critically ill patients: A network meta-analysis

BACKGROUND

Delirium is a common complication among patients in the intensive care unit (ICU). It is important to prevent the occurrence of delirium in critically ill patients.

AIM

This review aimed to evaluate the efficacy of non-pharmacological interventions and determine what combination of these is effective in preventing delirium among Intensive Care Unit patients.

STUDY DESIGN

A systematic review and meta-analysis. This review follows the guidelines of the Preferred Reporting Items for Systematic reviews and Meta Analysis statements for Network Meta-Analysis (PRISMA-NMA). Data sources included the Cumulative Index to Nursing & Allied Health Literature., MEDLINE, and Cochrane library databases. The integrated data were investigated with odds ratio (OR) and 95% confidence interval (95% CI), using the random-effects Mantel-Haenszel model. Data were considered significant when p < 0.05. Furthermore, to reveal what combination of care is effective, we performed a network meta-analysis estimated OR, 95% CI.

RESULTS

We identified three randomized controlled trials and eight controlled before-after trials (11 in total, with 2549 participants). The pooled data from 11 trials of multicomponent intervention had a significant effect on delirium prevention (OR 0.58, 95% CI 0.44-0.76, p < 0.001). As a result of network meta-analysis, two bundles were effective compared to the control group in reducing the incidence of delirium: a) the combination of sleep promotion (SP), cognitive stimulation (CS), early mobilization (EM), pain control (PC), and assessment (AS) (OR 0.47, 95% CI 0.35-0.64, p < 0.002), and b) the combination of SP and CS (OR 0.46, 95% CI 0.28-0.75, p < 0.001).

CONCLUSION

This study revealed that non-pharmacological interventions, particularly multicomponent interventions, helped to prevent delirium in critically ill patients. In the network meta-analysis, the most effective care combination for reducing incidence of delirium was found to be multicomponent intervention, which comprises SP-CS-EM-PC-AS, and SP-CS.

RELEVANCE TO CLINICAL PRACTICE

These findings reveal an efficient combination of multicomponent interventions for preventing delirium, which may be a very important prerequisite in planning care programs in the future.

Sleep during and following critical illness: A narrative review

Sleep is a complex process influenced by biological and environmental factors. Disturbances of sleep quantity and quality occur frequently in the critically ill and remain prevalent in survivors for at least 12 mo. Sleep disturbances are associated with adverse outcomes across multiple organ systems but are most strongly linked to delirium and cognitive impairment. This review will outline the predisposing and precipitating factors for sleep disturbance, categorised into patient, environmental and treatment-related factors. The objective and subjective methodologies used to quantify sleep during critical illness will be reviewed. While polysomnography remains the gold-standard, its use in the critical care setting still presents many barriers. Other methodologies are needed to better understand the pathophysiology, epidemiology and treatment of sleep disturbance in this population. Subjective outcome measures, including the Richards-Campbell Sleep Questionnaire, are still required for trials involving a greater number of patients and provide valuable insight into patients’ experiences of disturbed sleep. Finally, sleep optimisation strategies are reviewed, including intervention bundles, ambient noise and light reduction, quiet time, and the use of ear plugs and eye masks. While drugs to improve sleep are frequently prescribed to patients in the ICU, evidence supporting their effectiveness is lacking.

Dexmedetomidine Improved Sleep Quality in the Intensive Care Unit After Laryngectomy

Purpose

To examine whether nighttime dexmedetomidine infusion improved sleep quality in patients after laryngectomy.

Patients and Methods

Thirty-five post-laryngectomy patients admitted to the intensive care unit (ICU) were randomly assigned to a 9-h (from 2100 h on surgery day to 0600 h the morning after laryngectomy) dexmedetomidine (0.3 μg/kg/h continuous infusion) or placebo group. Polysomnography results were monitored during the dexmedetomidine infusion period. The percentage of stage 2 non-rapid eye movement (stage N2) sleep was the primary outcome measure.

Results

Thirty-five patients (18 placebo group; 17 dexmedetomidine group) had complete polysomnogram recordings. The percentage of stage N3 sleep was significantly increased in the dexmedetomidine infusion group (from median 0% (0 to 0) in placebo group to 0% (interquartile range, 0 to 4) in dexmedetomidine group (difference, -2.32%; 95% CI, -4.19 to -0.443; P = 0.0167)). Infusion had no effect on total sleep time, stage N1 or N2 sleep percentages, or sleep efficiency. It decreased muscle tensity and snore non-rapid eye movement. Subjective sleep quality improved. Hypotension incidence increased in the dexmedetomidine group, but significant intervention was not required.

Conclusion

Dexmedetomidine infusion improved overall patient sleep quality in the ICU after laryngectomy.

Causes, Consequences, and Treatments of Sleep and Circadian Disruption in the ICU: An Official American Thoracic Society Research Statement

Background: Sleep and circadian disruption (SCD) is common and severe in the ICU. On the basis of rigorous evidence in non-ICU populations and emerging evidence in ICU populations, SCD is likely to have a profound negative impact on patient outcomes. Thus, it is urgent that we establish research priorities to advance understanding of ICU SCD. Methods: We convened a multidisciplinary group with relevant expertise to participate in an American Thoracic Society Workshop. Workshop objectives included identifying ICU SCD subtopics of interest, key knowledge gaps, and research priorities. Members attended remote sessions from March to November 2021. Recorded presentations were prepared and viewed by members before Workshop sessions. Workshop discussion focused on key gaps and related research priorities. The priorities listed herein were selected on the basis of rank as established by a series of anonymous surveys. Results: We identified the following research priorities: establish an ICU SCD definition, further develop rigorous and feasible ICU SCD measures, test associations between ICU SCD domains and outcomes, promote the inclusion of mechanistic and patient-centered outcomes within large clinical studies, leverage implementation science strategies to maximize intervention fidelity and sustainability, and collaborate among investigators to harmonize methods and promote multisite investigation. Conclusions: ICU SCD is a complex and compelling potential target for improving ICU outcomes. Given the influence on all other research priorities, further development of rigorous, feasible ICU SCD measurement is a key next step in advancing the field.

Dynamic prevalence of sleep disturbance among critically ill patients in intensive care units and after hospitalisation: A systematic review and meta-analysis

BACKGROUND

Sleep disturbance is a common complaint among critically ill patients in intensive care units and after hospitalisation. However, the prevalence of sleep disturbance among critically ill patients varies widely.

OBJECTIVE

To estimate the prevalence of sleep disturbance among critically ill patients in the intensive care unit and after hospitalisation.

METHODS

Electronic databases were searched from their inception until 15 August 2022. Only observational studies with cross-sectional, prospective, and retrospective designs investigating sleep disturbance prevalence among critically ill adults (aged ≥ 18 years) during intensive care unit stay and after hospitalisation were included.

RESULTS

We found 13 studies investigating sleep disturbance prevalence in intensive care units and 14 investigating sleep disturbance prevalence after hospitalisation, with 1,228 and 3,065 participants, respectively. The prevalence of sleep disturbance during an ICU stay was 66 %, and at two, three, six and ≥ 12 months after hospitalisation was 64 %, 49 %, 40 %, and 28 %, respectively. Studies using the Richards-Campbell Sleep Questionnaire detected a higher prevalence of sleep disturbance among patients in intensive care units than non-intensive care unit specific questionnaires; studies reported comparable sleep disturbance prevalence during intensive care stays for patients with and without mechanical ventilation.

CONCLUSION

Sleep disturbance is prevalent in critically ill patients admitted to an intensive care unit and persists for up to one year after hospitalisation, with prevalence ranging from 28 % to 66 %. The study results highlight the importance of implementing effective interventions as early as possible to improve intensive care unit sleep quality.

Society of Anesthesia and Sleep Medicine Position Paper on Patient Sleep During Hospitalization

This article addresses the issue of patient sleep during hospitalization, which the Society of Anesthesia and Sleep Medicine believes merits wider consideration by health authorities than it has received to date. Adequate sleep is fundamental to health and well-being, and insufficiencies in its duration, quality, or timing have adverse effects that are acutely evident. These include cardiovascular dysfunction, impaired ventilatory function, cognitive impairment, increased pain perception, psychomotor disturbance (including increased fall risk), psychological disturbance (including anxiety and depression), metabolic dysfunction (including increased insulin resistance and catabolic propensity), and immune dysfunction and proinflammatory effects (increasing infection risk and pain generation). All these changes negatively impact health status and are counterproductive to recovery from illness and operation. Hospitalization challenges sleep in a variety of ways. These challenges include environmental factors such as noise, bright light, and overnight awakenings for observations, interventions, and transfers; physiological factors such as pain, dyspnea, bowel or urinary dysfunction, or discomfort from therapeutic devices; psychological factors such as stress and anxiety; care-related factors including medications or medication withdrawal; and preexisting sleep disorders that may not be recognized or adequately managed. Many of these challenges appear readily addressable. The key to doing so is to give sleep greater priority, with attention directed at ensuring that patients' sleep needs are recognized and met, both within the hospital and beyond. Requirements include staff education, creation of protocols to enhance the prospect of sleep needs being addressed, and improvement in hospital design to mitigate environmental disturbances. Hospitals and health care providers have a duty to provide, to the greatest extent possible, appropriate preconditions for healing. Accumulating evidence suggests that these preconditions include adequate patient sleep duration and quality. The Society of Anesthesia and Sleep Medicine calls for systematic changes in the approach of hospital leadership and staff to this issue. Measures required include incorporation of optimization of patient sleep into the objectives of perioperative and general patient care guidelines. These steps should be complemented by further research into the impact of hospitalization on sleep, the effects of poor sleep on health outcomes after hospitalization, and assessment of interventions to improve it.

Delirium in the intensive care unit and its importance in the post-operative context: A review

The burden of delirium in the intensive care setting is a global priority. Delirium affects up to 80% of patients in intensive care units; an episode of delirium is often distressing to patients and their families, and delirium in patients within, or outside of, the intensive care unit (ICU) setting is associated with poor outcomes. In the short term, such poor outcomes include longer stay in intensive care, longer hospital stay, increased risk of other hospital-acquired complications, and increased risk of hospital mortality. Longer term sequelae include cognitive impairment and functional dependency. While medical category of admission may be a risk factor for poor outcomes in critical care populations, outcomes for surgical ICU admissions are also poor, with dependency at hospital discharge exceeding 30% and increased risk of in-hospital mortality, particularly in vulnerable groups, with high-risk procedures, and resource-scarce settings. A practical approach to delirium prevention and management in the ICU setting is likely to require a multi-faceted approach. Given the good evidence for the prevention of delirium among older post-operative outside of the intensive care setting, simple non-pharmacological interventions should be effective among older adults post-operatively who are cared for in the intensive care setting. In response to this, the future ICU environment will have a range of organizational and distinct environmental characteristics that are directly targeted at preventing delirium.

Effects of dexmedetomidine on postoperative sleep quality: a systematic review and meta-analysis of randomized controlled trials

STUDY OBJECTIVES

To assess the effect of dexmedetomidine (DEX) on postoperative sleep quality using polysomnography (PSG) to identify possible interventions for postoperative sleep disturbances.

METHODS

An electronic search of PubMed/MEDLINE, EMBASE, Cochrane Library and Web of Science was conducted from database inception to November 20, 2022. Randomized controlled trials (RCTs) on the effect of DEX administration on postoperative sleep quality using PSG or its derivatives were included. No language restrictions were applied. The sleep efficiency index (SEI), arousal index (AI), percentages of stage N1, N2 and N3 of non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep were measured in our meta-analysis.

RESULTS

Five studies, involving 381 participants were included. Administration of DEX significantly improved SEI, lowered AI, decreased the duration of stage N1 sleep and increased the duration of stage N2 sleep compared to placebo groups. There were no significant differences in the duration of stage N3 sleep and REM sleep. DEX administration lowered the postoperative Visual Analogue Scale (VAS) score and improved the Ramsay sedation score with no adverse effect on postoperative delirium (POD). However, high heterogeneity was observed in most of the primary and secondary outcomes.

CONCLUSIONS

Our study provides support for the perioperative administration of DEX to improve postoperative sleep quality. The optimal dosage and overall effect of DEX on postoperative sleep quality require further investigation using large-scale randomized controlled trials.

Is obstructive sleep apnea a circadian rhythm disorder?

Obstructive sleep apnea is the most common sleep-related breathing disorder worldwide and remains underdiagnosed. Its multiple associated comorbidities contribute to a decreased quality of life and work performance as well as an increased risk of death. Standard treatment seems to have limited effects on cardiovascular and metabolic aspects of the disease, emphasising the need for early diagnosis and additional therapeutic approaches. Recent evidence suggests that the dysregulation of circadian rhythms, processes with endogenous rhythmicity that are adjusted to the environment through various cues, is involved in the pathogenesis of comorbidities. In patients with obstructive sleep apnea, altered circadian gene expression patterns have been demonstrated. Obstructive respiratory events may promote circadian dysregulation through the effects of sleep disturbance and intermittent hypoxia, with subsequent inflammation and disruption of neural and hormonal homeostasis. In this review, current knowledge on obstructive sleep apnea, circadian rhythm regulation, and circadian rhythm sleep disorders is summarised. Studies that connect obstructive sleep apnea to circadian rhythm abnormalities are critically evaluated. Furthermore, pathogenetic mechanisms that may underlie this association, most notably hypoxia signalling, are presented. A bidirectional relationship between obstructive sleep apnea and circadian rhythm dysregulation is proposed. Approaching obstructive sleep apnea as a circadian rhythm disorder may prove beneficial for the development of new, personalised diagnostic, therapeutic and prognostic tools. However, further studies are needed before the clinical approach to obstructive sleep apnea includes targeting the circadian system.

Sleep staging in the ICU with heart rate variability and breathing signals. An exploratory cross-sectional study using deep neural networks

Introduction: To measure sleep in the intensive care unit (ICU), full polysomnography is impractical, while activity monitoring and subjective assessments are severely confounded. However, sleep is an intensely networked state, and reflected in numerous signals. Here, we explore the feasibility of estimating conventional sleep indices in the ICU with heart rate variability (HRV) and respiration signals using artificial intelligence methods Methods: We used deep learning models to stage sleep with HRV (through electrocardiogram) and respiratory effort (through a wearable belt) signals in critically ill adult patients admitted to surgical and medical ICUs, and in age and sex-matched sleep laboratory patients Results: We studied 102 adult patients in the ICU across multiple days and nights, and 220 patients in a clinical sleep laboratory. We found that sleep stages predicted by HRV- and breathing-based models showed agreement in 60% of the ICU data and in 81% of the sleep laboratory data. In the ICU, deep NREM (N2 + N3) proportion of total sleep duration was reduced (ICU 39%, sleep laboratory 57%, p < 0.01), REM proportion showed heavy-tailed distribution, and the number of wake transitions per hour of sleep (median 3.6) was comparable to sleep laboratory patients with sleep-disordered breathing (median 3.9). Sleep in the ICU was also fragmented, with 38% of sleep occurring during daytime hours. Finally, patients in the ICU showed faster and less variable breathing patterns compared to sleep laboratory patients Conclusion: The cardiovascular and respiratory networks encode sleep state information, which, together with artificial intelligence methods, can be utilized to measure sleep state in the ICU.

Prophylactic Use of Ramelteon for Delirium in Hospitalized Patients: A Systematic Review and Meta-Analyses

BACKGROUND

Small prospective studies, case reports, as well as some randomized placebo-controlled trials and previous meta-analyses have shown that ramelteon, a melatonin agonist, may reduce the risk of developing delirium.

OBJECTIVE

The goal of this systemic review and meta-analyses was to assess the current evidence supporting the use of ramelteon in delirium prevention by including data from larger (>100 subjects) and more recent trials since the most recent meta-analyses were published in 2019. There were no exclusions for trial size, age, ramelteon dose, length of treatment, or hospital setting.

METHODS

Medline, Embase, PsycINFO, EBM Reviews, Scopus, and Web of Science databases were queried using the search terms delirium (with subterms including prevention and control), ramelteon, Rozerem, or melatonin receptor agonists, for English-language publications until March 16, 2021. Randomized placebo-controlled trials of hospitalized subjects receiving ramelteon for delirium prevention were included. The primary outcome of interest was delirium incidence. Odds ratios of the risk of developing incident delirium and 95% confidence intervals were calculated using a random effects model.

RESULTS

A total of 177 articles were identified by the literature search. Five studies (n = 443, 53.7% male) met criteria for inclusion in the final meta-analyses. The meta-analyses of the randomized placebo-controlled trials revealed that ramelteon did not result in a reduction in the risk of incident delirium (n = 443; odds ratio = 0.49; 95% confidence interval = 0.13-1.85). A moderate degree of heterogeneity was noted among the studies (I² = 53%).

CONCLUSIONS

Current evidence suggests that ramelteon is ineffective as a prophylactic drug in reducing the incidence of delirium in hospitalized patients.

What are the sleep characteristics among early kidney transplant recipients? An objective and subjective measurement from China

OBJECTIVE

To evaluate the sleep quality by self-reported questionnaires and polysomnography (PSG) among early kidney transplant recipients (KTRs) and to further explore their correlation.

DESIGN

This was a prospective and cross-sectional analysis of the sleep characteristics among early kidney transplant recipients through an objective and subjective measurement.

PARTICIPANTS

Patients with end stage renal disease on the transplant waiting list and after kidney transplantation were from a major organ transplantation center in Southern China (n = 83).

PRIMARY AND SECONDARY OUTCOME MEASUREMENTS

Objective outcomes: PSG, noise and light. Subjective outcomes: demographic and clinical questionnaires, self-reported pain and Richards Campbell sleep questionnaire (RCSQ). After agreement with the informed consent, participants first completed demographic and clinical questionnaires, then worn the PSG within 5-10 days after kidney transplantation. Both noise, light and self-reported pain were monitored during sleep. After completion of PSG, the RCSQs were filled out next morning.

RESULTS

A total of 298 patients were recruited and 83 participants were finally analyzed. The total RCSQ mean score was 51.0±18.9mm. The prevalence of poor sleep quality among early KTRs was 45.1%. Most of PSG characteristics were significantly correlated with their corresponding RCSQ items. And the total RCSQ scores were significantly correlated with the number of awakenings, the N2 percentage and the total sleep time (r = 0.79, 0.47 and 0.40, P<0.05) respectively. Noise was a statistically significant factor affecting the subjective sleep quality.

CONCLUSIONS

The sleep quality in early KTRs measured by both PSG and RCSQ exhibits consistency with each other. Sleep disruption always remains a substantial problem and is affected by self-reported noise among early KTRs. The RCSQ is easily applicable and interpretable so that it can be used for future daily clinical practice.

Sleep of Intensive Care Patients: A Qualitative Study Based on Experiences of Nurses

BACKGROUND

Intensive care patients experience a high rate of poor sleep quality. As the sleep quality is improved with nursing practices, patients' recovery and the length of stay in the intensive care unit (ICU) may be positively influenced, and patients may benefit from treatment and care at the highest level. Therefore, it is important to explore the experiences and evaluation of nurses working in ICUs.

OBJECTIVES

This study was carried out to explore the experiences and evaluations of ICU nurses about patients' sleep.

METHODS

The study is a qualitative study conducted in a descriptive phenomenological design. The data were collected using the individual in-depth interview method with the semistructured interview form. Thematic analysis was performed to analyze the data. The Consolidated Criteria for Reporting Qualitative Research (COREQ) checklist was used.

RESULTS

The analysis revealed 4 main themes, which are (1) importance of sleep, (2) evaluation of sleep, (3) reasons for poor sleep, and (4) sleep promotion interventions.

CONCLUSIONS

This study revealed that nurses are aware of the importance of sleep; however, they do not evaluate sleep and try to improve sleep quality only based on their own knowledge and experience rather than on evidence-based approaches. However, their interventions are not sufficient and they are restricted because of physical conditions and intensive care procedures.

Monitoring of nighttime EEG slow-wave activity during dexmedetomidine infusion in patients with hyperactive ICU delirium: An observational pilot study

BACKGROUND

The disturbance of sleep has been associated with intensive care unit (ICU) delirium. Monitoring of EEG slow-wave activity (SWA) has potential in measuring sleep quality and quantity. We investigated the quantitative monitoring of nighttime SWA and its association with the clinical evaluation of sleep in patients with hyperactive ICU delirium treated with dexmedetomidine.

METHODS

We performed overnight EEG recordings in 15 patients diagnosed with hyperactive delirium during moderate dexmedetomidine sedation. SWA was evaluated by offline calculation of the C-Trend Index, describing SWA in one parameter ranging 0 to 100 in values. Average and percentage of SWA values <50 were categorized as poor. The sleep quality and depth was clinically evaluated by the bedside nurse using the Richards-Campbell Sleep Questionnaire (RCSQ) with scores <70 categorized as poor.

RESULTS

Nighttime SWA revealed individual sleep structures and fundamental variation between patients. SWA was poor in 67%, sleep quality (RCSQ) in 67%, and sleep depth (RCSQ) in 60% of the patients. The category of SWA aligned with that of RCSQ-based sleep quality in 87% and RCSQ-based sleep depth in 67% of the patients.

CONCLUSION

Both, SWA and clinical evaluation suggested that the quality and depth of nighttime sleep were poor in most patients with hyperactive delirium despite dexmedetomidine infusion. Furthermore, the SWA and clinical evaluation classifications were not uniformly in agreement. An objective mode such as practical EEG-based solution for sleep evaluation and individual drug dosing in the ICU setting could offer potential in improving sleep for patients with delirium.

The role of light pollution in mammalian metabolic homeostasis and its potential interventions: A critical review

Irregular or unnatural artificial light causes severe environmental stress on the survival and health of organisms, which is rapidly becoming a widespread new type of environmental pollution. A series of disruptive behaviors to body homeostasis brought about by light pollution, including metabolic abnormalities, are likely to be the result of circadian rhythm disturbances. Recently, the proposed role of light pollution in metabolic dysregulation has accelerated it into an emerging field. Hence, the regulatory role of light pollution in mammalian metabolic homeostasis is reviewed in this contribution. Light at night is the most widely affected type of light pollution, which disrupts metabolic homeostasis largely due to its disruption of daily food intake patterns, alterations of hormone levels such as melatonin and glucocorticoids, and changes in the rhythm of inflammatory factor production. Besides, light pollution impairs mammalian metabolic processes in an intensity-, photoperiod-, and wavelength-dependent manner, and is also affected by species, gender, and diets. Nevertheless, metabolic disorders triggered by light pollution are not irreversible to some extent. Potential interventions such as melatonin supplementation, recovery to the LD cycle, time-restricted feeding, voluntary exercise, wearing blue light-shied goggles, and bright morning light therapy open a bright avenue to prevent light pollution. This work will help strengthen the relationship between light information and metabolic homeostasis and provide new insights for the better prevention of metabolic disorders and light pollution.

Psychometric properties of a Thai version of the Richards-Campbell sleep questionnaire

BACKGROUND

In critically ill patients, a poor sleep quality can escalate mortality and the length of hospital stays. Albeit being the gold standard for sleep assessment, polysomnography (PSG) is expensive and complicated. The Richards-Campbell sleep questionnaire (RCSQ) is another tool with proof of good correlation with PSG. RCSQ was translated into many languages. However, the Thai version (T-RCSQ) has not been developed.

AIMS AND OBJECTIVES

Our study aimed to translate the original RCSQ into Thai, to test the content validity and reliability, and to introduce the questionnaire into clinical practice at the surgical intensive care unit (SICU).

DESIGN

Prospective cross-sectional study METHODS: This study enrolled 92 patients from the SICU between August 2019 and January 2020. The content validity of T-RCSQ was determined by the index of item-objective congruence (IOC). The reliability was tested by test-retest reliability at 7 am and 9 am after intensive care unit (ICU) admission. The internal consistency was expressed by Cronbach's alpha. Patients' demography was reported as percentage, mean and standard deviation, and median and interquartile range.

RESULTS

The content validity and test-retest reliability of the T-RCSQ were 0.8 and 0.97, respectively. The internal consistency was 0.964. Most patients were female with American Society of Anesthesiologist physical status III. The mean RCSQ scores at 7 am and 9 am were 5.82 ± 2.15 cm and 5.61 ± 2.18 cm, respectively.

CONCLUSIONS

The T-RCSQ is reliable and could be used as an alternative to PSG for sleep assessment of ICU patients. Further research is required to validate the T-RCSQ against PSG and to assess its impact on improving sleep quality and patients' clinical outcomes.

RELEVANCE TO CLINICAL PRACTICE

T-RCSQ is a useful tool for sleep assessment in ICU. According to cost-effectiveness, convenience, and good reliability, it could be applied to determine proper sleep to minimize patient morbidity and mortality.

Psychometric properties of the Turkish version of modified Freedman questionnaire for sleep quality

To investigate the psychometric characteristics of the modified Freedman Sleep Quality Questionnaire (mFSQQ) to assess sleep in Turkish intensive care unit (ICU) patients. This prospective cross-sectional study was conducted between December 2020 and August 2021 with patients older than 18 years, who stayed in the ICU for ≥ 24 h and were cooperative with a Glasgow Coma Scale score ≥ 10 in medical and surgical ICUs of a university hospital. During the adaptation of the items of the mFSQQ, language, content, and construct validity were examined, and the test-retest method and internal consistency were used to examine its reliability. The content validity index of the questionnaire was 0.82. The Kaiser-Meyer-Olkin measure of sampling adequacy was 0.71, which indicates adequate sampling; Bartlett's test of sphericity was χ2 = 2868.97, p < 0.001. The Turkish version had three subscales. The factor loadings of the items were above 0.30, and the factors explained 60.59% of the total variance. The test-retest reliability coefficient was 0.85, indicating high consistency. The Cronbach α reliability coefficient was 0.80, indicating high reliability. The item-total correlations were found to be sufficient (between 0.25 and 0.78). The Turkish version of the mFSQQ showed good psychometric characteristics and can be used as a routine evaluation instrument to determine sleep quality by the ICU team and to promote sleep.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41105-022-00389-2.

A nurse-led intervention to reduce the incidence and duration of delirium among adults admitted to intensive care: A stepped-wedge cluster randomised trial

BACKGROUND

Delirium is an acute change in behaviour, characterised by a fluctuating course, inattention, and disorganised thinking. For critically ill adults in the intensive care, the incidence of delirium has been reported to be at least 30% and is associated with both short-term and long-term complications, longer hospital stay, increased risk of mortality, and long-term cognitive problems.

AIM

The objective of this study was to determine the effectiveness of a nurse-led delirium-prevention protocol in reducing the incidence and duration of delirium among adults admitted to intensive care.

METHODS

A hybrid stepped-wedge cluster randomised controlled trial was conducted to assess the effectiveness of the implementation and dissemination of the nurse-led intervention to reduce the incidence and duration of delirium among adults admitted to the four adults intensive care units in the southwest of Sydney, Australia.

RESULTS

Between May 2019 and February 2020, over a 10-month period, 2618 admissions, among 2566 patients, were included in the study. After an initial 3-month baseline period, each month there was a random crossover to the nurse-led intervention in one of the four intensive care units, and by the 7th month of the trial, all units were exposed to the intervention for at least 3 months. The incidence of acute delirium was observed to be 10.7% (95% confidence interval [CI] = 9.1-12.4%), compared to 14.1% (95% CI = 12.2-16.2%) during the preintervention (baseline) period (adjusted rate ratio [adjRR] = 0.78, 95% CI = 0.57-1.08, p = 0.134). The average delirium-free-days for these preintervention and postintervention periods were 4.1 days (95% CI = 3.9-4.3) and 4.4 days (95% CI = 4.2-4.5), respectively (adjusted difference = 0.24 days [95% CI = -0.12 to 0.60], p = 0.199).

CONCLUSION

Following the introduction of a nurse-led, nonpharmacological intervention to reduce the burden of delirium, among adults admitted to intensive care, we observed no statistically significant decrease in the incidence of delirium or the duration of delirium.

An Automated Algorithm for Determining Sleep Using Single-Channel Electroencephalography to Detect Delirium: A Prospective Observational Study in Intensive Care Units

The relationship between polysomnography-based objective sleep and delirium in the intensive care unit (ICU) is inconsistent across studies, suggesting limitations in manually determining the sleep stage of critically ill patients. We objectively measured 24-h sleep using a single-channel electroencephalogram (SleepScope [SS]) and an under-mattress sleep monitor (Nemuri SCAN [NSCAN]), both of which have independent algorithms that automatically determine sleep and wakefulness. Eighteen patients (median age, 68 years) admitted to the ICU after valvular surgery or coronary artery bypass grafting were included, and their sleep time was measured one day after extubation. The median total sleep times (TSTs) measured by SS (TST-SS) and NSCAN were 548 (48−1050) and 1024 (462−1257) min, respectively. Two patients with delirium during the 24-h sleep measurement had very short TST-SS of 48 and 125 min, and the percentage of daytime sleep accounted for >80% in both SS and NSCAN. This preliminary case series showed marked sleep deprivation and increased rates of daytime sleeping in ICU patients with delirium. Although data accuracy from under-mattress sleep monitors is contentious, automated algorithmic sleep/wakefulness determination using a single-channel electroencephalogram may be useful in detecting delirium in ICU patients and could even be superior to polysomnography.

GOODNIGHT, SLEEP TIGHT, DON'T LET THE MICROBES BITE: A REVIEW OF SLEEP AND ITS EFFECTS ON SEPSIS AND INFLAMMATION

ABSTRACT

Sleep is a restorative biological process that is crucial for health and homeostasis. However, patient sleep is frequently interrupted in the hospital environment, particularly within the intensive care unit. Suboptimal sleep may alter the immune response and make patients more vulnerable to infection and sepsis. In addition, hospitalized patients with sepsis experience altered sleep relative to patients without infectious disease, suggesting a bidirectional interplay. Preclinical studies have generated complementary findings, and together, these studies have expanded our mechanistic understanding. This review article summarizes clinical and preclinical studies describing how sleep affects inflammation and the host's susceptibility to infection. We also highlight potential strategies to reverse the detrimental effects of sleep interruption in the intensive care unit.

Effect of low-dose dexmedetomidine on sleep quality in postoperative patients with mechanical ventilation in the intensive care unit: A pilot randomized trial

Background

Sleep disturbances are prevalent in patients requiring invasive mechanical ventilation in the intensive care unit (ICU) and are associated with worse outcomes. Sedative-dose dexmedetomidine may improve sleep quality in this patient population but is associated with adverse events. Herein, we tested the effect of low-dose dexmedetomidine infusion on nighttime sleep quality in postoperative ICU patients with invasive ventilation.

Methods

In this pilot randomized trial, 80 adult patients who were admitted to the ICU after non-cardiac surgery and required invasive mechanical ventilation were randomized to receive either low-dose dexmedetomidine (0.1 to 0.2 μg/kg/h, n = 40) or placebo (n = 40) for up to 72 h. The primary endpoint was overall subjective sleep quality measured using the Richards–Campbell Sleep Questionnaire (score ranges from 0 to 100, with a higher score indicating better quality) in the night of surgery. Secondary outcomes included sleep structure parameters monitored with polysomnography from 9:00 PM on the day of surgery to the next 6:00 AM.

Results

All 80 patients were included in the intention-to-treat analysis. The overall subjective sleep quality was median 52 (interquartile 20, 66) with placebo vs. 61 (27, 79) with dexmedetomidine, and the difference was not statistically significant (median difference 8; 95% CI: −2, 22; P = 0.120). Among 68 patients included in sleep structure analysis, those in the dexmedetomidine group tended to have longer total sleep time [median difference 54 min (95% CI: −4, 120); P = 0.061], higher sleep efficiency [median difference 10.0% (95% CI: −0.8%, 22.3%); P = 0.060], lower percentage of stage N1 sleep [median difference −3.9% (95% CI: −11.8%, 0.5%); P = 0.090], higher percentage of stage N3 sleep [median difference 0.0% (95% CI: 0.0%, 0.4%); P = 0.057], and lower arousal index [median difference −0.9 (95% CI −2.2, 0.1); P = 0.091] but not statistically significant. There were no differences between the two groups regarding the incidence of adverse events.

Conclusion

Among patients admitted to the ICU after surgery with intubation and mechanical ventilation, low-dose dexmedetomidine infusion did not significantly improve the sleep quality pattern, although there were trends of improvement. Our findings support the conduct of a large randomized trial to investigate the effect of low-dose dexmedetomidine in this patient population.

Clinical trial registration

ClinicalTrial.gov, identifier: NCT03335527.

A Review of Equine Sleep: Implications for Equine Welfare

Sleep is a significant biological requirement for all living mammals due to its restorative properties and its cognitive role in memory consolidation. Sleep is ubiquitous amongst all mammals but sleep profiles differ between species dependent upon a range of biological and environmental factors. Given the functional importance of sleep, it is important to understand these differences in order to ensure good physical and psychological wellbeing for domesticated animals. This review focuses specifically on the domestic horse and aims to consolidate current information on equine sleep, in relation to other species, in order to (a) identify both quantitatively and qualitatively what constitutes normal sleep in the horse, (b) identify optimal methods to measure equine sleep (logistically and in terms of accuracy), (c) determine whether changes in equine sleep quantity and quality reflect changes in the animal's welfare, and (d) recognize the primary factors that affect the quantity and quality of equine sleep. The review then discusses gaps in current knowledge and uses this information to identify and set the direction of future equine sleep research with the ultimate aim of improving equine performance and welfare. The conclusions from this review are also contextualized within the current discussions around the “social license” of horse use from a welfare perspective.

Sleep assessment in critically ill adults: A systematic review and meta-analysis

PURPOSE

To systematically review sleep evaluation, characterize sleep disruption, and explore effects of sleepdisruption on outcomes in adult ICU patients.

MATERIALS AND METHODS

We systematically searched databases from May 1969 to June 2021 (PROSPERO protocol number: CRD42020175581). Prospective and retrospective studies were included studying sleep in critically ill adults, excluding patients with sleep or psychiatric disorders. Meta-regression methods were applied when feasible.

RESULTS

132 studies (8797 patients) were included. Fifteen sleep assessment methods were identified, with only two validated. Patients had significant sleep disruption, with low sleep time, and low proportion of restorative rapid eye movement (REM). Sedation was associated with higher sleep efficiency and sleep time. Surgical versus medical patients had lower sleep quality. Patients on ventilation had a higher amount of light sleep. Meta-regression only suggested an association between total sleep time and occurrence of delirium (p < 0.001, 15 studies, 519 patients). Scarce data precluded further analyses. Sleep characterized with polysomnography (PSG) correlated well with actigraphy and Richards Campbell Sleep Questionnaire (RCSQ).

CONCLUSIONS

Sleep in critically ill patients is severely disturbed, and actigraphy and RCSQ seem reliable alternatives to PSG. Future studies should evaluate impact of sleep disruption on outcomes.

Sleep Spindles and K-Complexes Are Favorable Prognostic Biomarkers in Critically Ill Patients

SUMMARY

In this narrative review, we summarize recent research on the prognostic significance of biomarkers of sleep in continuous EEG and polysomnographic recordings in intensive care unit patients. Recent studies show the EEG biosignatures of non-rapid eye movement 2 sleep (sleep spindles and K-complexes) on continuous EEG in critically ill patients better predict functional outcomes and mortality than the ictal-interictal continuum patterns. Emergence of more complex and better organized sleep architecture has been shown to parallel neurocognitive recovery and correlate with functional outcomes in traumatic brain injury and strokes. Particularly interesting are studies which suggest intravenous dexmedetomidine may induce a more biomimetic non-rapid eye movement sleep state than intravenous propofol, potentially providing more restorative sleep and lessening delirium. Protocols to improve intensive care unit sleep and neurophysiological studies evaluating the effect of these on sleep and sleep architecture are here reviewed.

The effect of evening light on circadian-related outcomes: A systematic review

Bright light exposure at night can help workers adapt to their shift schedules, but there has been relatively little research on evening light. We conducted a systematic review of studies that manipulated light exposure in the evening (broadly defined as 16:00-22:00) before real or simulated night shifts. Across the five eligible studies, evening light produced phase delays in melatonin, body temperature, and sleep propensity; it also improved sleep quality, sleep duration, memory, and work performance. There were mixed effects for mood, no changes in sleepiness, and no negative effects. The confidence in these results ranged from moderate for physiological markers of circadian phase delays to very low for mood. Future studies should compare the relative effectiveness and safety of evening versus night-time light exposure. Overall, the benefits of evening light for shift workers are tentative yet promising.

Efforts to improve sleep quality in a medical intensive care unit: effect of a protocol of non-pharmacological interventions

PURPOSE

This study aimed to evaluate the effect of a protocol of nonpharmacological interventions to improve sleep quality in the intensive care unit (ICU). Due to its close relationship with sleep quality, the effects of the same interventions on noise levels and delirium rates were also evaluated in this study.

METHODS

This pretest-posttest design with a control group was carried out in a medical ICU over 8 months. Data were collected using Acute Physiology and Chronic Health Evaluation II, the Glasgow Coma Scale, the Richmond Agitation-Sedation Scale, the Richards-Campbell Sleep Questionnaire (RCSQ), the Confusion Assessment Method for the Intensive Care Unit, and noise measurement devices. In the first phase of the study, patients receiving standard care in the ICU were followed. After the first stage, a training session was held for nurses to raise awareness and information. Then, the sleep-promoting protocol created by the researchers was applied. The ambient noise level was measured continuously.

RESULTS

A total of 78 patients with a mean age of 70.0 ± 13.2 years were followed in the ICU for an average of 7.3 ± 3.8 days. With protocol implementation, the ambient noise level in the ICU was reduced from 70.9 ± 3.8 dB(A) to 62.7 ± 3.5 dB(A) (p < 0.01); the RCSQ scores of the patients increased from 48.3 ± 1.4 to 62.1 ± 1.8 (p < 0.01). Although statistically nonsignificant, efforts to improve sleep quality also reduced the development of delirium by 15%.

CONCLUSION

It is possible to improve sleep quality and reduce noise levels in an ICU with a protocol consisting of multicomponent nonpharmacological interventions.

Adding Insult to Injury: Sleep Deficiency in Hospitalized Patients

Sleep deficiency is a common problem in the hospital setting. Contributing factors include preexisting medical conditions, illness severity, the hospital environment, and treatment-related effects. Hospitalized patients are particularly vulnerable to the negative health effects of sleep deficiency that impact multiple organ systems. Objective sleep measurement is difficult to achieve in the hospital setting, posing a barrier to linking improvements in hospital outcomes with sleep promotion protocols. Key next steps in hospital sleep promotion include improvement in sleep measurement techniques and harmonization of study protocols and outcomes to strengthen existing evidence and facilitate data interpretation across studies.

The use of melatonin in Danish intensive care departments-A nationwide observational study

BACKGROUND

Melatonin is widely employed as a hypnotic in various patient groups. In intensive care patients, melatonin seems to be increasingly used due to potential clinical effects and a favourable safety profile.

OBJECTIVES

We aimed to investigate the extend of usage and clinical practice of melatonin therapy in intensive care departments in Denmark.

DESIGN

Data from regional hospital pharmacies and the Danish Intensive Care Database were used to estimate defined daily dose and defined daily dose per 1000 ICU admission days. Also, related expenses in the period 2015-2019. Finally, a questionnaire describing the clinical practice of melatonin therapy was provided to all Danish intensive care departments.

PRINCIPAL OBSERVATIONS

The usage of melatonin in intensive care departments in Denmark increased from 21,300 DDD (200.0 DDD per 1000 ICU admission days) in 2015 to 52,170 DDD (560.7 DDD per 1000 ICU admission days) in 2019. A total of 32 ICU departments participated in the study (97% of all Danish ICU departments). All included ICU departments employed melatonin as a hypnotic. Nineteen percent of included departments administered melatonin to all admitted patients, whereas 25% of departments rarely administered melatonin. Magistral melatonin 3-mg tablets was the most employed drug dose/formulation. Increased doses of melatonin were administered in selected patients. Melatonin was considered safe by prescribing clinicians.

CONCLUSIONS

Melatonin is widely and increasingly used in Danish intensive care departments. The more than doubled usage of melatonin in the study period advocates for further studies employing validated outcomes of sleep and other patient-relevant outcomes.

EDITORIAL COMMENT

This study documents that melatonin is frequently used as a hypnotic in Danish intensive care units during recent years despite a shortage of reliable evidence to support a recommendation to treat with melatonin in this context. These results support a need for conducting clinical trials to determine whether or not there is a beneficial effect of melatonin treatment in critically ill patients.

Potentials and Challenges of Pervasive Sensing in the Intensive Care Unit

Patients in critical care settings often require continuous and multifaceted monitoring. However, current clinical monitoring practices fail to capture important functional and behavioral indices such as mobility or agitation. Recent advances in non-invasive sensing technology, high throughput computing, and deep learning techniques are expected to transform the existing patient monitoring paradigm by enabling and streamlining granular and continuous monitoring of these crucial critical care measures. In this review, we highlight current approaches to pervasive sensing in critical care and identify limitations, future challenges, and opportunities in this emerging field.

Sensitivity and specificity of proposed Richards‐Campbell Sleep Questionnaire cut‐off scores for good quality sleep during an ICU stay

BACKGROUND

The 5-visual analogue scale Richards-Campbell Sleep Questionnaire subjective sleep measure is widely used in intensive care. A cut-off score indicative of good quality sleep has not been established and is required to guide the categorisation of individual patient and unit wide sleep quality.

DESIGN AND METHODS

The aim was to determine the global Richards-Campbell Sleep Questionnaire cut-off score for good to very good sleep during an intensive care unit stay in non-ventilated patients. The study was a secondary (cohort) retrospective analysis of patient self-report data (n = 32) from an interventional study testing a sleep promotion bundle. The Standards for Reporting Diagnostic Accuracy studies statement were used to report the study. The study was conducted in two mixed adult 12 and 20-bed ICUs of a tertiary referral hospital in a metropolitan area. In the morning, eligible patients were administered the Richards-Campbell Sleep Questionnaire together with a 5-category item Likert scale in which patients rated their nocturnal sleep quality as 'very poor', 'poor', 'fair', 'good' and 'very good'. Receiver Operator Curve analysis was performed.

RESULTS

Thirty-seven per cent (n = 32) of the total sample of 84 adult intensive care patients were females. The median age was 61.5 (51, 72) years. Self-reported median global Richards-Campbell Sleep Questionnaire score was 54.4 (30.1, 77.1) mm. A global score of ≥63.4 mm was the optimal cut-off for self-reported 'good sleep' (sensitivity: 87%, specificity: 81% and area under the curve: 0.896).

CONCLUSIONS

Although the study requires replication in ventilated patients and other ICU settings, the cut-off score (63 mm) could be used to guide the categorisation of individual patient and unit wide sleep quality.

Sleep Assessment in Critically Ill Adults: Established Methods and Emerging Strategies

Sleep is a biological mandate with an integral role in optimizing functions that maintain psychological and physical health. During critical illness, however, sleep may be disrupted at best and elusive at worst. Sleep improvement efforts and research endeavors evaluating interventions to improve sleep in critically ill adults are hampered by limited methods available to measure sleep in this setting. This narrative review summarizes available modalities for sleep assessment in the ICU, describes new ICU sleep assessment methods under development, and highlights features of the ideal ICU sleep measurement tool.

DATA SOURCES

The most relevant literature and author experiences were assessed for inclusion from PubMed and textbooks.

STUDY SELECTION

The authors selected studies for inclusion by consensus.

DATA EXTRACTION

The authors reviewed each study and selected appropriate data for inclusion by consensus.

DATA SYNTHESIS

Currently available tools to measure sleep in critically ill adults have important flaws. Subjective measurements are limited by recall bias, the inability of many patients to communicate, and poorly correlate with objective measures when completed by surrogates. Actigraphy does not consider the effects of sedating medications or myopathy leading to an over estimation of sleep time. Polysomnography, the gold standard for sleep assessment, is limited by interpretation issues and practical application concerns. Single and multiple channel electroencephalogram devices offer real-time physiologic data and are more practical to use than polysomnography but are limited by the scope of sleep-specific information they can measure and poorly characterize the circadian system.

CONCLUSIONS

A measurement tool that offers real-time sleep and circadian assessment and is practical for broad application in the ICU does not exist. Newer sleep assessment devices have shown promise in measuring physiologic data in real time; when used in combination with other assessment modalities, and analyzed by computational techniques, they may revolutionize sleep monitoring in the ICU.

Impact of sound levels on physiological and consciousness state of cardiovascular patients

BACKGROUND

Patients treated in intensive care units (ICUs) experience life-threatening medical conditions but some external factors in ICUs do not help or even adversely affect and complicate their evolution. Among others, such factors include noise pollution due to alarms and medical clinical equipment, as well as the activities of the health care personnel themselves.

AIM

This study aimed to evaluate the influence of elevated sound levels on physiological variables and the consciousness state of patients treated in a cardiovascular area in an ICU.

DESIGN

A longitudinal study with several observations was carried out during 1 month in the cardiovascular area of an ICU of a third-level hospital in southern Spain.

METHODS

Sound levels were monitored in different work shifts and patients' physiological data and consciousness status were recorded. Generalized additive mixed models (GAMMs) were developed to detect the variability of the sound levels together with the vital parameters of the patients in the ICU.

RESULTS

Thirty-eight patients were included. The mean sound level was 54.09 dBA. The GAMM sound levels analysis showed a significant increase in sound levels from 4:30 p.m. to 8:00 p.m. (1.83 dBA; P < .001) and 8:00 p.m. to 11:30 p.m. (3.06 dBA; P < .001). An increase in heart rate (3.66 bpm; P < .001), respiratory rate (2.62 rpm; P < .001) and the Glasgow Coma Scale (0.50 units; P = .002) was detected during the 4:30 p.m.-8:30 p.m.

PERIOD

CONCLUSIONS

Elevated sound levels in cardiovascular ICUs seem to influence positively the physiological and consciousness status of patients. Given the importance of the findings for patient safety, future intervention studies are recommended.

RELEVANCE TO CLINICAL PRACTICE

The finding of this study could translate into structural changes in ICU facilities, as well as the development of clinical practice guidelines that influence the behaviour of health care professionals.

Effect of earplug/eye mask on sleep and delirium in intensive care patients

BACKGROUND

Environmental factors such as loud sounds and bright lights in intensive care units can cause sleep disorders and delirium.

AIM

The present study aims to investigate the effects of the overnight use of earplugs and eye masks by intensive care patients on their sleep quality and the degree of delirium.

STUDY DESIGN

This randomized controlled experimental study was conducted on the patients admitted to a coronary intensive care unit.

METHODS

The patients in the experimental group used earplugs and eye masks during the night, while those in the control group received only routine care. Data were collected using an information form, the Richards-Campbell sleep questionnaire (RCSQ), and the intensive care delirium screening checklist (ICDSC).

RESULTS

The study included a total of 84 patients, 42 in the experimental group and 42 in the control group. The baseline average score of the patients in the experiment group on the RCSQ was 40.11 ± 16.55, with a Time 1 average score of 64.09 ± 14.07 and a Time 2 average score of 72.07 ± 11.75; their baseline average score on the ICDSC was 0.47 ± 0.50, with a Time 1 average score of 0.33 ± 065 and a Time 2 average score of 0.19 ± 039. The baseline average score of the patients in the control group on the RCSQ was 44.07 ± 7.30, with a Time 1 average score of 46.97 ± 9.22 and a Time 2 average score of 47.04 ± 11.53; the baseline average score of the control group on the ICDSC was 0.42 ± 0.50, with a Time 1 average score of 0.50 ± 0.70 and a Time 2 average score of 0.57 ± 0.66. A statistically significant difference was found between the Time 1 and Time 2 average scores of the experimental and control groups on the RCSQ and between the Time 2 average scores of the experimental and control groups on the ICDSC (U = 198.00, P < .001; U = 70.000, P < .001; U = 614.000, P = ·004 respectively).

CONCLUSIONS

The earplugs and eye masks used by the intensive care patients overnight were associated with an increase in sleep quality and a decrease in the degree of delirium.

RELEVANCE TO CLINICAL PRACTICE

The use of earplugs and eye masks is recommended for intensive care units in supporting sleep quality and preventing delirium.

Dexmedetomidine Improves Non-rapid Eye Movement Stage 2 Sleep in Children in the Intensive Care Unit on the First Night After Laparoscopic Surgery

BACKGROUND

Previous studies have reported that children who were admitted to the ICU experienced a significant decrease in sleep quality compared to home. We investigated the effects of dexmedetomidine as an adjunct to sufentanil on the sleep in children admitted to the ICU on the first night after major surgery.

METHODS

This is a prospective study From January to February 2022. Clinical trial number: ChiCTR2200055768, http://www.chictr.org.cn. Fifty-four children aged 1-10 years old children undergoing major laparoscopic surgery were recruited and randomly assigned to either the DEX group, in which intravenous dexmedetomidine (0.3 ug/kg/h) and sufentanil (0.04 ug/kg/h) were continuously infused intravenously for post-operative analgesia; or the SUF group, in which only sufentanil (0.04 ug/kg/h) was continuously infused. Patients were monitored with polysomnography (PSG) on the first night after surgery for 12 h. PSG, sleep architecture, physiologic variables and any types of side effects related to anesthesia and analgesia were recorded. The differences between the two groups were assessed using the chi-square and Wilcoxon rank-sum tests.

RESULTS

Fifty-four children completed data collection, of which thirty-four were 1-6 years old and twenty were aged >6 years. Compared to the SUF group, subjects in the DEX group aged 1-6 years displayed increased stage 2 sleep duration (P = 0.02) and light sleep duration (P = 0.02). Subjects aged >6 years in the DEX group also displayed increased stage 2 sleep duration (P = 0.035) and light sleep duration (P = 0.018), but decreased REM sleep percentage (P = 0). Additionally, the heart rate and blood pressure results differed between age groups, with the heart rates of subjects aged >6 years in DEX group decreasing at most time points compared to SUF group (P < 0.05).

CONCLUSION

Dexmedetomidine prolonged N2 sleep and light sleep duration in the pediatric ICU after surgery but had different effects on the heart rate and blood pressure of subjects in different age groups.

Interrater reliability of sleep stage scoring: a meta-analysis

STUDY OBJECTIVES

We evaluated the interrater reliabilities of manual polysomnography sleep stage scoring. We included all studies that employed Rechtschaffen and Kales rules or American Academy of Sleep Medicine standards. We sought the overall degree of agreement and those for each stage.

METHODS

The keywords were "Polysomnography (PSG)," "sleep staging," "Rechtschaffen and Kales (R&K)," "American Academy of Sleep Medicine (AASM)," "interrater (interscorer) reliability," and "Cohen's kappa." We searched PubMed, OVID Medline, EMBASE, the Cochrane library, KoreaMed, KISS, and the MedRIC. The exclusion criteria included automatic scoring and pediatric patients. We collected data on scorer histories, scoring rules, numbers of epochs scored, and the underlying diseases of the patients.

RESULTS

A total of 101 publications were retrieved; 11 satisfied the selection criteria. The Cohen's kappa for manual, overall sleep scoring was 0.76, indicating substantial agreement (95% confidence interval, 0.71-0.81; P < .001). By sleep stage, the figures were 0.70, 0.24, 0.57, 0.57, and 0.69 for the W, N1, N2, N3, and R stages, respectively. The interrater reliabilities for stage N2 and N3 sleep were moderate, and that for stage N1 sleep was only fair.

CONCLUSIONS

We conducted a meta-analysis to generalize the variation in manual scoring of polysomnography and provide reference data for automatic sleep stage scoring systems. The reliability of manual scorers of polysomnography sleep stages was substantial. However, for certain stages, the results were poor; validity requires improvement.

CITATION

Lee YJ, Lee JY, Cho JH, Choi JH. Interrater reliability of sleep stage scoring: a meta-analysis. J Clin Sleep Med. 2022;18(1):193-202.