Sleep quality and quantity determined by polysomnography in mechanically ventilated critically ill patients randomized to dexmedetomidine or placebo

Role of dexmedetomidine in postoperative cognitive dysfunction and sleep improvement in aged rats by regulating the PI3K/Akt signaling pathway and its mechanism

OBJECTIVE

This study aims to explore the mechanism of dexmedetomidine (Dex) in improving postoperative cognitive dysfunction (POCD) and postoperative sleep in aged rats through the PI3K/Akt signaling pathway.

METHODS

Splenectomy was used to establish a POCD model in aged rats. Open field test (OFT) and new object recognition test (NORT) were used to observe the cognitive function of rats The awakening and sleep times of rats were recorded. Hematoxylin-eosin, Nissl, and TUNEL staining were adopted to examine histopathological alterations, neuronal cell damage, and apoptosis, respectively; western blot to detect the activation of the PI3K/Akt signaling pathway and the protein level of apoptosis factors Bcl-2, Bax, and cleaved caspase-3; enzyme-linked immunosorbent assay to quantify the concentrations of inflammatory factors IL-6, IL-1β, and TNF-α.

RESULTS

On days 1, 7, and 14 post-splenectomy surgery, aged rats exhibited shortened moving distance in OFT, reduced discrimination rate in NORT, prolonged awakening time, and shortened sleep time, while such effect was reversed by further Dex treatment. In addition, neuronal damage, inflammatory response, and apoptosis occurred in the hippocampal CA1 area in aged rats but can be attenuated by Dex treatment. Dex triggered the activation of the PI3K/Akt signaling pathway in the hippocampus in aged rats after surgery, and inhibition of the PI3K/Akt signaling pathway can result in a partial reversal of the alleviating effects observed with Dex treatment.

CONCLUSION

Dex improves POCD and postoperative sleep in aged rats by activating the PI3K/Akt signaling pathway to reduce inflammatory response and apoptosis in the hippocampal CA1 area.

Pharmacological Management of Sleep-Wake Disturbances in Delirium

Delirium is a heterogeneous syndrome primarily characterized by fluctuations in attention and awareness. Sleep-wake disturbances are a common and significant feature of delirium and can manifest as circadian rhythm inversion, sleep fragmentation, and reduced rapid eye movement (REM) and slow-wave sleep. Some literature suggests that the relationship between sleep disruption and delirium is reciprocal wherein the two reinforce one another and may share an underlying etiology. As there are no FDA-approved medications for delirium or delirium-related sleep disturbances, management is primarily focused on addressing underlying medical concerns and promoting physiologic circadian patterns with non-pharmacological behavioral interventions. In practice, however, medications are often used, albeit with limited evidence to support their use. This literature review explores the pharmacology and pharmacokinetics of several medications with literature investigating their use in delirium: melatonin, ramelteon, dual orexin receptor antagonists (DORAs), and dexmedetomidine. Current evidence suggests a possible benefit of ramelteon or melatonin, dexmedetomidine for patients in the ICU setting, and DORAs as therapeutic options for the re-regulation of sleep-wake cycle disruption in delirium. We discuss pertinent pharmacokinetic and pharmacodynamic factors that may influence clinical decision-making regarding these interventions.

Novel applications of sleep pharmacology as delirium therapeutics

Sleep-wake and circadian disruption (SCD) is a core feature of delirium. It has been hypothesized that SCD contributes to delirium pathogenesis; therefore, interventions that prevent or reverse SCD represent an array of promising opportunities in relation to delirium. This review explores the relationship between sleep-wake/circadian physiology and delirium pathophysiology with a focus on neurotransmitter systems. Across potential targets aimed at preventing or treating delirium, three broad approaches are considered: 1. Pharmacological mechanisms that contribute to physiological sleep may preserve or restore next-day cognition in patients with or at risk for delirium (e.g., alpha 2 agonists, dopamine 2 antagonists, serotonin 2 A antagonists, dual orexin receptor antagonists, or GHB agonists); 2. Pharmacological mechanisms that promote wakefulness during the day may combat hypoactive delirium (e.g., adenosine 2 A antagonists, dopamine transporter antagonists, orexin agonists, histamine 3 antagonists); and 3. Melatonergic and other circadian interventions could strengthen the phase or amplitude of circadian rhythms and ensure appropriately entrained timing in patients with or at risk for delirium (e.g., as informed by a person's preexisting circadian phase).

A pharmacist's guide to mitigating sleep dysfunction and promoting good sleep in the intensive care unit

PURPOSE

To review causes, risk factors, and consequences of sleep disruption in critically ill patients; evaluate the role of nonpharmacological and pharmacological therapies for management of sleep in the intensive care unit (ICU); and discuss the role of pharmacists in implementation of sleep bundles.

SUMMARY

Critically ill patients often have disrupted sleep and circadian rhythm alterations that cause anxiety, stress, and traumatic memories. This can be caused by factors such as critical illness, environmental factors, mechanical ventilation, and medications. Methods to evaluate sleep, including polysomnography and questionnaires, have limitations that should be considered. Multicomponent sleep bundles with a focus on nonpharmacological therapy aiming to reduce nocturnal noise, light, and unnecessary patient care may improve sleep disorders in critically ill patients. While pharmacological agents are often used to facilitate sleep in critically ill patients, evidence supporting their use is often of low quality, which limits use to patients who have sleep disruption refractory to nonpharmacological therapy. Dedicated interprofessional teams are needed for implementation of sleep bundles in the ICU. Extensive pharmacotherapeutic training and participation in daily patient care rounds make pharmacists vital members of the team who can help with all components of the bundle. This narrative review discusses evidence for elements of the multicomponent sleep bundle and provides guidance on how pharmacists can help with implementation of nonpharmacological therapies and management of neuroactive medications to facilitate sleep.

CONCLUSION

Sleep bundles are necessary for patients in the ICU, and dedicated interprofessional teams that include pharmacists are vital for successful creation and implementation.

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.

Effect of sleep quality on weaning from mechanical ventilation: A scoping review

Introduction

Mechanically ventilated patients have disturbed sleep.

Aim of the study

To explore whether there is a relationship between successful or unsuccessful weaning of patients and their sleep quality and circadian rhythm.

Materials and Methods

A scoping review. The search process involved four online databases: CINAHL, MEDLINE, ProQuest, and ScienceDirect. Original studies published between January 2020 and October 2022 were included in the review.

Results

Six studies met the inclusion criteria. These studies showed that patients with difficult weaning were more likely to have atypical sleep, shorter REM sleep, and reduced melatonin metabolite excretion. Muscle weakness was an independent factor associated with prolonged weaning from mechanical ventilation and was significantly more frequent in patients with atypical sleep. Heterogeneous patient samples and the methodology of the studies hamper a clear interpretation of the results.

Conclusions

A relationship was found between abnormal sleep patterns, reduced melatonin metabolite (6-sulfa-toxymelatonin) excretion, and unsuccessful weaning. However, the causality is not clear from the existing research.

Comparing the effect of sedation with dexmedetomidine and propofol on sleep quality of patients after cardiac surgery: A randomized clinical trial

Introduction

Sleep quality is the main concern of patients after cardiac surgery. We compared the effect of two routinely used sedatives on the sleep quality of patients admitted to the intensive care unit (ICU) after cardiovascular surgery.

Methods

It is a prospective, controlled, randomized clinical trial. A total of 120 patients, after cardiac surgery were enrolled. During extubating, patients were randomized into two groups: 60 patients received an infusion of dexmedetomidine (precede; 0.5 μg/kg/h), and 60 patients received 50 μg/kg/min propofol for 6 hours. Baseline characteristics were compared between the groups. The patients completed the St. Mary's Hospital Sleep Questionnaire, and the scores were compared between the groups.

Results

The groups were not different in terms of demographics, underlying diseases, smoking/drug abuse/alcohol, number of vessels involved, history of non-cardiac surgery, and mean levels of serum parameters (P>0.05). Most of the medications used were similar between the groups (P>0.05), except calcium channel blockers (more frequently used in the propofol group [P=0.027). The details of surgery were not statistically significant different (P>0.05); but, the mean volume of platelet received after the surgery was higher in propofol group (P=0.03). The propofol group had less problems with last night's sleep (0 vs 0.1±0.66), felt more clear-headed (4.9±0.6 vs 4.68±0.58, were more satisfied with their last night's sleep (52.1% vs 47.9%), but spent more time getting into sleep (0.38±1.67 vs 0 ) (P<0.5).

Conclusion

The sleep quality of patients under the influence of propofol seemed to be better than dexmedetomidine after cardiac surgery.

Intensive care unit interventions to promote sleep and circadian biology in reducing incident delirium: a scoping review

RATIONALE/OBJECTIVES

Despite plausible pathophysiological mechanisms, research is needed to confirm the relationship between sleep, circadian rhythm and delirium in patients admitted to the intensive care unit (ICU). The objective of this review is to summarise existing studies promoting, in whole or in part, the normalisation of sleep and circadian biology and their impact on the incidence, prevalence, duration and/or severity of delirium in ICU.

METHODS

A sensitive search of electronic databases and conference proceedings was completed in March 2023. Inclusion criteria were English-language studies of any design that evaluated in-ICU non-pharmacological, pharmacological or mixed intervention strategies for promoting sleep or circadian biology and their association with delirium, as assessed at least daily. Data were extracted and independently verified.

RESULTS

Of 7886 citations, we included 50 articles. Commonly evaluated interventions include care bundles (n=20), regulation or administration of light therapy (n=5), eye masks and/or earplugs (n=5), one nursing care-focused intervention and pharmacological intervention (eg, melatonin and ramelteon; n=19). The association between these interventions and incident delirium or severity of delirium was mixed. As multiple interventions were incorporated in included studies of care bundles and given that there was variable reporting of compliance with individual elements, identifying which components might have an impact on delirium is challenging.

CONCLUSIONS

This scoping review summarises the existing literature as it relates to ICU sleep and circadian disruption (SCD) and delirium in ICU. Further studies are needed to better understand the role of ICU SCD promotion interventions in delirium mitigation.

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.

Effect of prolonged sedation with dexmedetomidine, midazolam, propofol, and sevoflurane on sleep homeostasis in rats

BACKGROUND

Sleep disruption is a common occurrence during medical care and is detrimental to patient recovery. Long-term sedation in the critical care setting is a modifiable factor that affects sleep, but the impact of different sedative-hypnotics on sleep homeostasis is not clear.

METHODS

We conducted a systematic comparison of the effects of prolonged sedation (8 h) with i.v. and inhalational agents on sleep homeostasis. Adult Sprague-Dawley rats (n=10) received dexmedetomidine or midazolam on separate days. Another group (n=9) received propofol or sevoflurane on separate days. A third group (n=12) received coadministration of dexmedetomidine and sevoflurane. Wakefulness (wake), slow-wave sleep (SWS), and rapid eye movement (REM) sleep were quantified during the 48-h post-sedation period, during which we also assessed wake-associated neural dynamics using two electroencephalographic measures: theta-high gamma phase-amplitude coupling and high gamma weighted phase-lag index.

RESULTS

Dexmedetomidine-, midazolam-, or propofol-induced sedation increased wake and decreased SWS and REM sleep (P<0.0001) during the 48-h post-sedation period. Sevoflurane produced no change in SWS, decreased wake for 3 h, and increased REM sleep for 6 h (P<0.02) post-sedation. Coadministration of dexmedetomidine and sevoflurane induced no change in wake (P>0.05), increased SWS for 3 h, and decreased REM sleep for 9 h (P<0.02) post-sedation. Dexmedetomidine, midazolam, and coadministration of dexmedetomidine with sevoflurane reduced wake-associated phase-amplitude coupling (P≤0.01). All sedatives except sevoflurane decreased wake-associated high gamma weighted phase-lag index (P<0.01).

CONCLUSIONS

In contrast to i.v. drugs, prolonged sevoflurane sedation produced minimal changes in sleep homeostasis and neural dynamics. Further studies are warranted to assess inhalational agents for long-term sedation and sleep homeostasis.

Sedation for Patients with Sepsis: Towards a Personalised Approach

This article looks at the challenges of sedoanalgesia for sepsis patients, and argues for a personalised approach. Sedation is a necessary part of treatment for patients in intensive care to reduce stress and anxiety and improve long-term prognoses. Sepsis patients present particular difficulties as they are at increased risk of a wide range of complications, such as multiple organ failure, neurological dysfunction, septic shock, ARDS, abdominal compartment syndrome, vasoplegic syndrome, and myocardial dysfunction. The development of any one of these complications can cause the patient's rapid deterioration, and each has distinct implications in terms of appropriate and safe forms of sedation. In this way, the present article reviews the sedative and analgesic drugs commonly used in the ICU and, placing special emphasis on their strategic administration in sepsis patients, develops a set of proposals for sedoanalgesia aimed at improving outcomes for this group of patients. These proposals represent a move away from simplistic approaches like avoiding benzodiazepines to more "objective-guided sedation" that accounts for a patient's principal pathology, as well as any comorbidities, and takes full advantage of the therapeutic arsenal currently available to achieve personalised, patient-centred treatment goals.

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.

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.

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.