Rapid eye movement sleep debt accrues in mice exposed to volatile anesthetics

Parafacial GABAergic neurone ablation induces behavioural resistance to volatile anaesthetic-induced hypnosis without reducing sleep

BACKGROUND

It is hypothesised that general anaesthetics co-opt the neural circuits regulating endogenous sleep and wakefulness to produce hypnosis. To further probe this association, we focused on the GABAergic neurones of the parafacial zone (PZGABA), a brainstem site capable of promoting non-rapid eye movement sleep.

METHODS

To determine whether PZ neurones are activated by a hypnotic dose of anaesthetics, c-Fos immunohistochemistry was performed. The behavioural and physiological contributions of PZGABA neurones to anaesthetic sensitivity were assessed in mice transfected with an adeno-associated virus (AAV)-driving expression of an mCherry fluorescent control or a caspase that irreversibly eliminates PZGABA neurones. EEG-defined sleep was measured in PZGABA-ablated and mCherry control mice, as was the homeostatic drive to sleep after sleep deprivation.

RESULTS

Consistent with anaesthetic-induced depolarisation, hypnotic doses of isoflurane significantly increased c-Fos expression three-fold in PZGABA neurones compared with oxygen-exposed mice. PZGABA-ablated mice developed significant and durable behavioural resistance to both isoflurane- and sevoflurane-induced hypnosis, with roughly 50% higher likelihood of intact righting than controls. PZGABA-ablated mice emerged from isoflurane significantly faster than mCherry controls with purposeful movements. The degree of anaesthetic resistance was inversely correlated with the number of surviving PZGABA neurones. Despite confirming that PZGABA ablation reduced the potency of two distinct volatile anaesthetics behaviourally, ablation did not alter the amount of endogenous sleep or wakefulness, nor did it affect the homeostatic sleep drive after sleep deprivation, and it did not produce EEG signatures of anaesthetic resistance during isoflurane exposure.

CONCLUSIONS

There was an unexpected dissociation in which destruction of up to 70-80% of PZGABA neurones was sufficient to alter anaesthetic susceptibility behaviourally without causing insomnia or altering sleep pressure. These findings suggest that PZGABA neurones are more critical to drug-induced hypnosis than to the regulation of natural sleep and arousal.

Incidence of psychiatric disorders after total knee or hip arthroplasty by anesthesia type: A nationwide cohort study

BACKGROUND

Evidence is lacking of an association between anesthetic choice and the risk of psychiatric disorders. Therefore, this study aimed to examine the impact of regional anesthesia (R/A) versus general anesthesia (G/A) on the occurrence of psychiatric disorders in patients undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA).

METHODS

Data for this population-based cohort study were sourced from the National Health Insurance Service of South Korea. The study included adult patients who underwent TKA or THA between January 1, 2016, and December 31, 2021. The endpoint was the diagnosis of postoperative psychiatric disorders within 1 year postoperative.

RESULTS

This study included 411,967 patients who underwent THA or TKA. Among them, 290,476 (70.5 %) underwent THA or TKA under R/A (R/A group), while 121,491 (29.5 %) underwent THA or TKA under G/A (G/A group). In multivariate logistic regression, the R/A group had an 8 % lower incidence of postoperative psychiatric disorders (odds ratio [OR], 0.92; 95 % confidence interval [CI], 0.90-0.94; P < 0.001) than the G/A group. Specifically, a lower incidence of postoperative psychiatric disorder for depression (OR, 0.89; 95 % CI, 0.86-0.92; P < 0.001), bipolar disorder (OR, 0.88; 95 % CI, 0.83-0.94; P < 0.001), anxiety disorder (OR, 0.95; 95 % CI, 0.92-0.98; P = 0.001), and insomnia disorder (OR, 0.95; 95 % CI, 0.80-1.11; P = 0.496) was observed in the R/A versus G/A group.

CONCLUSIONS

Among these South Korean patients who underwent TKA or THA, the R/A group had a lower incidence of postoperative psychiatric disorders than the G/A group.

Oxidative stress in relation to serotonin under general anaesthesia in dogs undergoing ovariectomy

Abdominal surgery such as ovariectomy is a traumatic event that can cause oxidative stress. The aim of the present study was to evaluate the concentration of serotonin in relation to ovariectomy-induced oxidative stress in dogs undergoing general anesthesia. Thirty-two female dogs, under general anesthesia, received meloxicam before surgery (0.2 mgkg-1 SC) and after surgery (0.1 mgkg-1 OS every 24 h). The physiological, hematological, and biochemical parameters: glycemia, aspartate transaminase (AST), alanine aminotransferase (ALT), total protein, albumin and BUN were evaluated. Oxidative stress was determined by malondialdehyde (MDA) assay, catalase (CAT), superoxide dismutase (SOD), myeloperoxidase (MPO) and butyrylcholinesterase (BuChe) at baseline, 36 and 48 h after the last administration of meloxicam. Serotonin (5-HT) concentration was also evaluated at baseline, 36 and 48 h after the last administration of meloxicam. Responses to surgical stimulus were evaluated. Physiological and hematological parameters they fell within the normal ranges for anesthetized dogs. Glycemia increased, albumin levels decreased after surgery. No rescue analgesia was required. MDA and 5-HT concentrations significantly increased from the baseline at 36 and 48 h after surgery (p < .001). 5-HT levels could be used as an indicator for oxidative stress induced by surgery and it might be employed for objectively quantifying the well-being of the surgical patient.

Effect of desflurane maintenance on postoperative sleep quality in patients undergoing elective breast surgery: A non-inferiority randomized controlled trial

BACKGROUND

Postoperative sleep disturbance (PSD) is prevalent in perioperative patients，and has significant impact on postoperative recovery and prognosis. The aim of this study was to investigate the effect of desflurane maintenance on postoperative sleep quality, in order to optimize patients' perioperative sleep management.

METHOD

A total of 118 patients undergoing elective breast surgery were randomized to receive either desflurane-based volatile anesthesia (desflurane group) or propofol-based total intravenous anesthesia (propofol group) for anesthesia maintenance. The primary outcome was the quality of sleep, which was assessed by the Pittsburgh Sleep Quality Index (PSQI) on 3 days after operation (POD3). Secondary outcomes were PSQI on postoperative day 7 (POD7) and 30 (POD30), and postoperative anxiety, depression, and pain score, as well as objective sleep parameters including total sleep time (TST), WASO (Wakefulness after sleep onset), REM (Rapid eye movement) and NREM (Non-rapid Eye Movement) measured by Fitbit Charge 2TM during the initial 3 postoperative days.

RESULTS

The global PSQI scores on POD3 in the desflurane group was non-inferior to that in the propofol group [mean (SD) 8.47 (3.46) vs. 7.65 (3.16); mean difference (95 % CI) 0.82 (-0.43, 2.07); p < 0.001 for non-inferiority]. There were no significant differences in PSQI scores on POD3 and POD7. In addition, the score of anxiety, depression, and pain on the 3rd, 7th, and 30th day after surgery have no significant differences between the propofol and the desflurane group, respectively. The postoperative NREM was higher in the desflurane group than that in the propofol group.

CONCLUSION

The effects of desflurane-based volatile anesthesia maintenance on postoperative sleep quality is not inferior to that of propofol-based total intravenous anesthesia, and these two drugs may have different effects on the sleep structure.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04805775.

Propofol improves sleep deprivation-induced sleep structural and cognitive deficits via upregulating the BMAL1 expression and suppressing microglial M1 polarization

BACKGROUND

Sleep deprivation (SD) is a growing global health problem with many deleterious effects, such as cognitive impairment. Microglia activation-induced neuroinflammation may be an essential factor in this. Propofol has been shown to clear sleep debt after SD in rats. This study aims to evaluate the effects of propofol-induced sleep on ameliorating sleep quality impairment and cognitive decline after 48 h SD.

METHODS

Almost 8-12-week-old rats were placed in the SD system for 48 h of natural sleep or continuous SD. Afterwards, rats received propofol (20 mg·kg-1·h-1, 6 h) via the tail or slept naturally. The Morris water maze (MWM) and Y-maze test assessed spatial learning and memory abilities. Rat EEG/EMG monitored sleep. The expression of brain and muscle Arnt-like protein 1 (BMAL1), brain-derived neurotrophic factor (BDNF) in the hippocampus and BMAL1 in the hypothalamus were assessed by western blot. Enzyme-linked immunosorbent assay detected IL-6, IL-1β, arginase 1 (Arg1), and IL-10 levels in the hippocampus. Immunofluorescence was used to determine microglia expression as well as morphological changes.

RESULTS

Compared to the control group, the sleep-deprived rats showed poor cognitive performance on both the MWM test and the Y-maze test, accompanied by disturbances in sleep structure, including increased total sleep time, and increased time spent and delta power in non-rapid eye movement sleep. In addition, SD induces abnormal expression of the circadian rhythm protein BMAL1, activates microglia, and causes neuroinflammation and nerve damage. Propofol reversed these changes and saved sleep and cognitive impairment. Furthermore, propofol treatment significantly reduced hippocampal IL-1β and IL-6 levels, increased BDNF, Arg1, and IL-10 levels, and switched microglia surface markers from the inflammatory M1 type to the anti-inflammatory M2 type.

CONCLUSION

Propofol reduces SD-induced cognitive impairment and circadian rhythm disruption, possibly by lowering neuronal inflammation and switching the microglia phenotype from an M1 to an M2 activated state, thus exerting neuroprotective effects.

Isoflurane anesthesia and sleep deprivation trigger delayed and selective sleep alterations

Isoflurane anesthesia (IA) partially compensates NREM sleep (NREMS) and not REM sleep (REMS) requirement, eliciting post-anesthetic REMS rebound. Sleep deprivation triggers compensatory NREMS rebounds and REMS rebounds during recovery sleep as a result of the body's homeostatic mechanisms. A combination of sleep deprivation and isoflurane anesthesia is common in clinical settings, especially prior to surgeries. This study investigates the effects of pre-anesthetic sleep deprivation on post-anesthetic sleep-wake architecture. The effects of isoflurane exposure (90 min) alone were compared with the effects of isoflurane exposure preceded by experimental sleep deprivation (6 h, gentle handling) on recovery sleep in adult mice by studying the architecture of post-anesthetic sleep for 3 consecutive post-anesthetic days. Effects of isoflurane anesthesia on recovery sleep developed only during the first dark period after anesthesia, the active phase in mice. During this time, mice irrespective of preceding sleep pressure, showed NREMS and REMS rebound and decreased wakefulness during recovery sleep. Additionally, sleep deprivation prior to isoflurane treatment caused a persistent reduction of theta power during post-anesthetic REMS at least for 3 post-anesthetic days. We showed that isoflurane causes NREMS rebound during recovery sleep which suggests that isoflurane may not fully compensate for natural NREMS. The study also reveals that isoflurane exposure preceded by sleep deprivation caused a persistent disruption of REMS quality. We suggest that preoperative sleep deprivation may impair postoperative recovery through lasting disruption in sleep quality.

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.

Anatomical Substrates of Rapid Eye Movement Sleep Rebound in a Rodent Model of Post-sevoflurane Sleep Disruption

BACKGROUND

Previous research suggests that sevoflurane anesthesia may prevent the brain from accessing rapid eye movement (REM) sleep. If true, then patterns of neural activity observed in REM-on and REM-off neuronal populations during recovery from sevoflurane should resemble those seen after REM sleep deprivation. In this study, the authors hypothesized that, relative to controls, animals exposed to sevoflurane present with a distinct expression pattern of c-Fos, a marker of neuronal activation, in a cluster of nuclei classically associated with REM sleep, and that such expression in sevoflurane-exposed and REM sleep-deprived animals is largely similar.

METHODS

Adult rats and Targeted Recombination in Active Populations mice were implanted with electroencephalographic electrodes for sleep-wake recording and randomized to sevoflurane, REM deprivation, or control conditions. Conventional c-Fos immunohistochemistry and genetically tagged c-Fos labeling were used to quantify activated neurons in a group of REM-associated nuclei in the midbrain and basal forebrain.

RESULTS

REM sleep duration increased during recovery from sevoflurane anesthesia relative to controls (157.0 ± 24.8 min vs. 124.2 ± 27.8 min; P = 0.003) and temporally correlated with increased c-Fos expression in the sublaterodorsal nucleus, a region active during REM sleep (176.0 ± 36.6 cells vs. 58.8 ± 8.7; P = 0.014), and decreased c-Fos expression in the ventrolateral periaqueductal gray, a region that is inactive during REM sleep (34.8 ± 5.3 cells vs. 136.2 ± 19.6; P = 0.001). Fos changes similar to those seen in sevoflurane-exposed mice were observed in REM-deprived animals relative to controls (sublaterodorsal nucleus: 85.0 ± 15.5 cells vs. 23.0 ± 1.2, P = 0.004; ventrolateral periaqueductal gray: 652.8 ± 71.7 cells vs. 889.3 ± 66.8, P = 0.042).

CONCLUSIONS

In rodents recovering from sevoflurane, REM-on and REM-off neuronal activity maps closely resemble those of REM sleep-deprived animals. These findings provide new evidence in support of the idea that sevoflurane does not substitute for endogenous REM sleep.

EDITOR’S PERSPECTIVE

General anesthesia alters the diversity and composition of the lung microbiota in rat

BACKGROUND

The lung microbiome plays a crucial role in human health and disease. Extensive studies have demonstrated that the disturbance of the lung microbiome influences immune response, cognition, and behavior. The goal of this study was to investigate the effect of general anesthetics on lung microbiome.

METHODS

Eight-week-old male SD rats received a continuous intravenous infusion of propofol or inhalation of isoflurane for 4 h. 16S rRNA gene amplification from BALF samples was used to investigate the changes in the lung microbiome after interventions. We further performed neurobehavioral assessments to find the differential strains' association with behavior disorder after isoflurane anesthesia.

RESULTS

The absolute and relative quantitation of 16S rRNA sequencing data showed that isoflurane altered the diversity and abundance of the lung microbiome in rats more than propofol. Elusimicrobia increased significantly in the isoflurane group. Both EPM and OFT results showed that rats exhibited depression-like behaviors after inhalation of isoflurane. In addition, significant differences were found in the COG/KO/MetaCyc/KEGG pathway enrichment analyses among the groups.

CONCLUSION

Continuous inhalation of isoflurane changed the diversity and composition of the lung microbiota in rats, resulting in post-anesthesia depression.

Effects of propofol and sevoflurane on social and anxiety-related behaviours in sleep-deprived rats

BACKGROUND

Sleep disorders can profoundly affect neurological function. We investigated changes in social and anxiety-related brain functional connectivity induced by sleep deprivation, and the potential therapeutic effects of the general anaesthetics propofol and sevoflurane in rats.

METHODS

Twelve-week-old male Sprague-Dawley rats were subjected to sleep deprivation for 20 h per day (from 14:00 to 10:00 the next day) for 4 consecutive weeks. They were free from sleep deprivation for the remaining 4 h during which they received propofol (40 mg kg-1 i.p.) or sevoflurane (2% for 2 h) per day or no treatment. These cohorts were instrumented for EEG/EMG recordings on days 2, 14, and 28. Different cohorts were used for open field and three-chambered social behavioural tests, functional MRI, nuclear magnetic resonance spectroscopy, and positron emission tomography imaging 48 h after 4 weeks of sleep deprivation.

RESULTS

Propofol protected against sleep deprivation-induced anxiety behaviours with more time (44.7 [8.9] s vs 24.2 [4.1] s for the sleep-deprivation controls; P<0.001) spent in the central area of the open field test and improved social preference index by 30% (all P<0.01). Compared with the sleep-deprived rats, propofol treatment enhanced overall functional connectivity by 74% (P<0.05) and overall glucose metabolism by 30% (P<0.01), and improved glutamate kinetics by 20% (P<0.05). In contrast, these effects were not found after sevoflurane treatment.

CONCLUSIONS

Unlike sevoflurane, propofol reduced sleep deprivation-induced social and anxiety-related behaviours. Propofol might be superior to sevoflurane for patients with sleep disorders who receive anaesthesia, which should be studied in clinical studies.

Neonatal exposure to a neuroactive steroid alters low-frequency oscillations in the subiculum

Preclinical studies have established that neonatal exposure to contemporary sedative/hypnotic drugs causes neurotoxicity in the developing rodent and primate brains. Our group recently reported that novel neuroactive steroid (3β,5β,17β)-3-hydroxyandrostane-17-carbonitrile (3β-OH) induced effective hypnosis in both neonatal and adult rodents but did not cause significant neurotoxicity in vulnerable brain regions such as subiculum, an output region of hippocampal formation particularly sensitive to commonly used sedatives/hypnotics. Despite significant emphasis on patho-morphological changes, little is known about long-term effects on subicular neurophysiology after neonatal exposure to neuroactive steroids. Hence, we explored the lasting effects of neonatal exposure to 3β-OH on sleep macrostructure as well as subicular neuronal oscillations in vivo and synaptic plasticity ex vivo in adolescent rats. At postnatal day 7, we exposed rat pups to either 10 mg/kg of 3β-OH over a period of 12 h or to volume-matched cyclodextrin vehicle. At weaning age, a cohort of rats was implanted with a cortical electroencephalogram (EEG) and subicular depth electrodes. At postnatal day 30-33, we performed in vivo assessment of sleep macrostructure (divided into wake, non-rapid eye movement, and rapid eye movement sleep) and power spectra in cortex and subiculum. In a second cohort of 3β-OH exposed animals, we conducted ex vivo studies of long-term potentiation (LTP) in adolescent rats. Overall, we found that neonatal exposure to 3β-OH decreased subicular delta and sigma oscillations during non-rapid eye movement sleep without altering sleep macrostructure. Furthermore, we observed no significant changes in subicular synaptic plasticity. Interestingly, our previous study found that neonatal exposure to ketamine increased subicular gamma oscillations during non-rapid eye movement sleep and profoundly suppressed subicular LTP in adolescent rats. Together these results suggest that exposure to different sedative/hypnotic agents during a critical period of brain development may induce distinct functional changes in subiculum circuitry that may persist into adolescent age.

Pontine control of rapid eye movement sleep and fear memory

AIMS

We often experience dreams of strong irrational and negative emotional contents with postural muscle paralysis during rapid eye movement (REM) sleep, but how REM sleep is generated and its function remain unclear. In this study, we investigate whether the dorsal pontine sub-laterodorsal tegmental nucleus (SLD) is necessary and sufficient for REM sleep and whether REM sleep elimination alters fear memory.

METHODS

To investigate whether activation of SLD neurons is sufficient for REM sleep induction, we expressed channelrhodopsin-2 (ChR2) in SLD neurons by bilaterally injecting AAV1-hSyn-ChR2-YFP in rats. We next selectively ablated either glutamatergic or GABAergic neurons from the SLD in mice in order to identify the neuronal subset crucial for REM sleep. We finally  investigated the role of REM sleep in consolidation of fear memory using rat model with complete SLD lesions.

RESULTS

We demonstrate the sufficiency of the SLD for REM sleep by showing that photo-activation of ChR2 transfected SLD neurons selectively promotes transitions from non-REM (NREM) sleep to REM sleep in rats. Diphtheria toxin-A (DTA) induced lesions of the SLD in rats or specific deletion of SLD glutamatergic neurons but not GABAergic neurons in mice completely abolish REM sleep, demonstrating the necessity of SLD glutamatergic neurons for REM sleep. We then show that REM sleep elimination by SLD lesions in rats significantly enhances contextual and cued fear memory consolidation by 2.5 and 1.0 folds, respectively, for at least 9 months. Conversely, fear conditioning and fear memory trigger doubled amounts of REM sleep in the following night, and chemo-activation of SLD neurons projecting to the medial septum (MS) selectively enhances hippocampal theta activity in REM sleep; this stimulation immediately after fear acquisition reduces contextual and cued fear memory consolidation by 60% and 30%, respectively.

CONCLUSION

SLD glutamatergic neurons generate REM sleep and REM sleep and SLD via the hippocampus particularly down-regulate contextual fear memory.

The Association between General Anesthesia and New Postoperative Uses of Sedative-Hypnotics: A Nationwide Matched Cohort Study

Sedative−hypnotic misuse is associated with psychiatric diseases and overdose deaths. It remains uncertain whether types of anesthesia affect the occurrence of new postoperative uses of sedative−hypnotics (NPUSH). We used reimbursement claims data of Taiwan’s National Health Insurance and conducted propensity score matching to compare the risk of NPUSH between general and neuraxial anesthesia among surgical patients who had no prescription of oral sedative−hypnotics or diagnosis of sleep disorders within the 12 months before surgery. The primary outcome was NPUSH within 180 days after surgery. Multivariable logistic regression models were used to calculate the adjusted odds ratio (aOR) and 95% confidence interval (CI). A total of 92,222 patients were evaluated after matching. Among them, 15,016 (16.3%) had NPUSH, and 2183 (4.7%) were made a concomitant diagnosis of sleep disorders. General anesthesia was significantly associated both with NPUSH (aOR: 1.17, 95% CI: 1.13−1.22, p < 0.0001) and NPUSH with sleep disorders (aOR: 1.11, 95% CI: 1.02−1.21, p = 0.0212) compared with neuraxial anesthesia. General anesthesia was also linked to NPUSH that occurred 90−180 days after surgery (aOR: 1.12, 95% CI: 1.06−1.19, p = 0.0002). Other risk factors for NPUSH were older age, female, lower insurance premium, orthopedic surgery, specific coexisting diseases (e.g., anxiety disorder), concurrent medications (e.g., systemic steroids), postoperative complications, perioperative blood transfusions, and admission to an intensive care unit. Patients undergoing general anesthesia had an increased risk of NPUSH compared with neuraxial anesthesia. This finding may provide an implication in risk stratification and prevention for sedative−hypnotic dependence after surgery.

Association between sleep quality and general anesthesia in teenager under elective surgery: a prospective study

OBJECTIVE

Anesthesia was reported to be associated with lowered postoperative sleep quality in adults, but its effect on teenager was less understood. This study was conducted to explore the association between postoperative sleep quality and general anesthesia in teenagers.

METHODS

A prospective study was conducted. Teenagers aged from 12 to 16 years who were treated with general anesthesia and under urologic or otolaryngologic surgery were recruited. Healthy teenagers matched by sex and age (± 3 years) with the specific case were recruited as the controls. The Sleep Habits Questionnaire was applied to assess the sleep quality of the teenagers. We applied a logistic regression analysis to evaluate the association between general anesthesia in teenagers under elective surgery and poor sleep quality. Risk ratio (RR) and its corresponding 95% confidence interval (CI) were computed.

RESULTS

A total of 212 teenagers were included comprising 106 patients with general anesthesia who underwent urologic or otolaryngologic surgery and 106 healthy controls. The male participants were accounting for 47.2% (100/212). Anesthesia duration and surgery duration in the patients were 103.7 ± 14.4 min and 162.1 ± 17.0 min, respectively. Positive associations between general anesthesia and poor sleep quality in the 1st, 3rd, and 7th postoperative days were found, and RRs and their corresponding 95%CIs were 4.87 (1.72-13.79), 3.33 (1.22-9.1), and 3.26 (1.07-9.93), respectively. However, there was a lack of statistical associations before surgery and after 14 postoperative days.

CONCLUSIONS

Teenagers who were treated with general anesthesia and under urologic or otolaryngologic surgery might have poor sleep quality within 7 postoperative days.

The Neural Circuits Underlying General Anesthesia and Sleep

General anesthesia is characterized by loss of consciousness, amnesia, analgesia, and immobility. Important molecular targets of general anesthetics have been identified, but the neural circuits underlying the discrete end points of general anesthesia remain incompletely understood. General anesthesia and natural sleep share the common feature of reversible unconsciousness, and recent developments in neuroscience have enabled elegant studies that investigate the brain nuclei and neural circuits underlying this important end point. A common approach to measure cortical activity across the brain is electroencephalogram (EEG), which can reflect local neuronal activity as well as connectivity among brain regions. The EEG oscillations observed during general anesthesia depend greatly on the anesthetic agent as well as dosing, and only some resemble those observed during sleep. For example, the EEG oscillations during dexmedetomidine sedation are similar to those of stage 2 nonrapid eye movement (NREM) sleep, but high doses of propofol and ether anesthetics produce burst suppression, a pattern that is never observed during natural sleep. Sleep is primarily driven by withdrawal of subcortical excitation to the cortex, but anesthetics can directly act at both subcortical and cortical targets. While some anesthetics appear to activate specific sleep-active regions to induce unconsciousness, not all sleep-active regions play a significant role in anesthesia. Anesthetics also inhibit cortical neurons, and it is likely that each class of anesthetic drugs produces a distinct combination of subcortical and cortical effects that lead to unconsciousness. Conversely, arousal circuits that promote wakefulness are involved in anesthetic emergence and activating them can induce emergence and accelerate recovery of consciousness. Modern neuroscience techniques that enable the manipulation of specific neural circuits have led to new insights into the neural circuitry underlying general anesthesia and sleep. In the coming years, we will continue to better understand the mechanisms that generate these distinct states of reversible unconsciousness.

Cerebellar malfunction and postoperative sleep disturbances after general anesthesia: a narrative review

The cerebellum is widely regarded as a brain region involved in motor processing, non-motor processing, and even sleep-wake cycles. Cerebellar dysfunction may cause changes in the sleep-wake cycle, leading to sleep disturbances. At present, there is limited research on its effect on postoperative sleep after general anesthesia, despite the suspicion of its implication in postoperative sleep disturbances. With this review, we aim to provide a clear and comprehensive review of the cerebellar activity during the normal sleep-wake cycle, the correlation between cerebellar dysfunction and postoperative sleep disturbances, and the effects of general anesthesia on cerebellar dysfunction. Future large-scale multicenter trials are needed to objectively support the present results, identify the initial cerebellar dysfunction to prevent postoperative sleep disturbances, and develop new therapeutic measures targeting sleep disturbances with possible far-reaching implications for neurodegenerative diseases in general.

Effect of basal forebrain somatostatin and parvalbumin neurons in propofol and isoflurane anesthesia

Aims

The basal forebrain (BF) plays an essential role in wakefulness and cognition. Two subtypes of BF gamma‐aminobutyric acid (GABA) neurons, including somatostatin‐expressing (GABA^SOM) and parvalbumin‐positive (GABA^Parv) neurons, function differently in mediating the natural sleep–wake cycle. Since the loss of consciousness induced by general anesthesia and the natural sleep–wake cycle probably share similar mechanisms, it is important to clarify the accurate roles of these neurons in general anesthesia procedure.

Methods

Based on two transgenic mouse lines expressing SOM‐IRES‐Cre and PV‐IRES‐Cre, we used a combination of genetic activation, inactivation, and chronic ablation approaches to further explore the behavioral and electroencephalography (EEG) roles of BF^SOM and BF^Parv neurons in general anesthesia. After a single intravenous injection of propofol and the induction and recovery times of isoflurane anesthesia, the anesthesia time was compared. The changes in cortical EEG under different conditions were also compared.

Results

Activation of BF GABA^SOM neurons facilitates both the propofol and isoflurane anesthesia, manifesting as a longer anesthesia duration time with propofol anesthesia and a fast induction time and longer recovery time with isoflurane anesthesia. Moreover, BF GABA^SOM‐activated mice displayed a greater suppression of cortical electrical activity during anesthesia, showing an increase in δ power bands or a simultaneous decrease in high‐frequency power bands. However, only a limited and nuanced effect on propofol and isoflurane anesthesia was observed with the manipulated BF GABA^Parv neurons.

Conclusions

Our results suggested that BF GABA^SOM neurons play a critical role in propofol and isoflurane general anesthesia, while BF GABA^Parv neurons appeared to have little effect.

The Inert Brain: Explaining Neural Inertia as Post-anaesthetic Sleep Inertia

"Neural inertia" is the brain's tendency to resist changes in its arousal state: it is manifested as emergence from anaesthesia occurring at lower drug doses than those required for anaesthetic induction, a phenomenon observed across very different species, from invertebrates to mammals. However, the brain is also subject to another form of inertia, familiar to most people: sleep inertia, the feeling of grogginess, confusion and impaired performance that typically follows awakening. Here, we propose a novel account of neural inertia, as the result of sleep inertia taking place after the artificial sleep induced by anaesthetics. We argue that the orexinergic and noradrenergic systems may be key mechanisms for the control of these transition states, with the orexinergic system exerting a stabilising effect through the noradrenergic system. This effect may be reflected at the macroscale in terms of altered functional anticorrelations between default mode and executive control networks of the human brain. The hypothesised link between neural inertia and sleep inertia could explain why different anaesthetic drugs induce different levels of neural inertia, and why elderly individuals and narcoleptic patients are more susceptible to neural inertia. This novel hypothesis also enables us to generate several empirically testable predictions at both the behavioural and neural levels, with potential implications for clinical practice.

Preoptic Area Modulation of Arousal in Natural and Drug Induced Unconscious States

The role of the hypothalamic preoptic area (POA) in arousal state regulation has been studied since Constantin von Economo first recognized its importance in the early twentieth century. Over the intervening decades, the POA has been shown to modulate arousal in both natural (sleep and wake) as well as drug-induced (anesthetic-induced unconsciousness) states. While the POA is well known for its role in sleep promotion, populations of wake-promoting neurons within the region have also been identified. However, the complexity and molecular heterogeneity of the POA has made distinguishing these two populations difficult. Though multiple lines of evidence demonstrate that general anesthetics modulate the activity of the POA, the region's heterogeneity has also made it challenging to determine whether the same neurons involved in sleep/wake regulation also modulate arousal in response to general anesthetics. While a number of studies show that sleep-promoting POA neurons are activated by various anesthetics, recent work suggests this is not universal to all arousal-regulating POA neurons. Technical innovations are making it increasingly possible to classify and distinguish the molecular identities of neurons involved in sleep/wake regulation as well as anesthetic-induced unconsciousness. Here, we review the current understanding of the POA's role in arousal state regulation of both natural and drug-induced forms of unconsciousness, including its molecular organization and connectivity to other known sleep and wake promoting regions. Further insights into the molecular identities and connectivity of arousal-regulating POA neurons will be critical in fully understanding how this complex region regulates arousal states.

The Inert Brain: Explaining Neural Inertia as Post-anaesthetic Sleep Inertia

"Neural inertia" is the brain's tendency to resist changes in its arousal state: it is manifested as emergence from anaesthesia occurring at lower drug doses than those required for anaesthetic induction, a phenomenon observed across very different species, from invertebrates to mammals. However, the brain is also subject to another form of inertia, familiar to most people: sleep inertia, the feeling of grogginess, confusion and impaired performance that typically follows awakening. Here, we propose a novel account of neural inertia, as the result of sleep inertia taking place after the artificial sleep induced by anaesthetics. We argue that the orexinergic and noradrenergic systems may be key mechanisms for the control of these transition states, with the orexinergic system exerting a stabilising effect through the noradrenergic system. This effect may be reflected at the macroscale in terms of altered functional anticorrelations between default mode and executive control networks of the human brain. The hypothesised link between neural inertia and sleep inertia could explain why different anaesthetic drugs induce different levels of neural inertia, and why elderly individuals and narcoleptic patients are more susceptible to neural inertia. This novel hypothesis also enables us to generate several empirically testable predictions at both the behavioural and neural levels, with potential implications for clinical practice.

Effects of Intravenous Anesthetics vs Inhaled Anesthetics on Early Postoperative Sleep Quality and Complications of Patients After Laparoscopic Surgery Under General Anesthesia

OBJECTIVE

Decreased postoperative sleep quality remains a serious problem in surgical settings at present. The purpose of our study was to compare the effect of propofol vs sevoflurane on early postoperative sleep quality and complications of patients receiving laparoscopic surgery after general anesthesia.

METHODS

Seventy-four patients undergoing selective laparoscopic surgery under general anesthesia were randomly assigned to the propofol group or sevoflurane group. The wireless portable sleep monitor (WPSM) is used to collect sleep quality on the night before surgery (sleep preop 1), the first night after surgery (sleep POD 1), and the third night after surgery (sleep POD 3). Record the subjective sleep quality and dreaming state during the operation. The perioperative hemodynamics, postoperative sleep and complications were also evaluated.

RESULTS

Compared with Sleep preop 1, patients showed lower sleep efficiency, Stable sleep and Unstable sleep during Sleep POD 1 and Sleep POD 3. In addition, compared with the propofol group, the proportion of REM sleep in the sevoflurane group was much higher during Sleep POD 1 and Sleep POD 3, and the incidence of dreaming was also higher in the sevoflurane group. Patients in the propofol group had better pain relief at 2, 4, and 6 hours after surgery. And the incidence of postoperative nausea and vomiting and dizziness in the sevoflurane group was significantly higher than that in the propofol group.

CONCLUSION

The degree of postoperative sleep efficiency was better on Sleep POD1 and Sleep POD3; the incidence of postoperative nausea and vomiting, and dizziness was lower; and postoperative pain was slighter when the operation was performed under propofol anesthesia compared with patients in the sevoflurane group. Propofol should be considered a better choice during the operation to promote the patient's postoperative sleep quality, relieve postoperative pain and improve the incidence of postoperative dizziness and nausea and vomiting.

Differences between natural sleep and the anesthetic state

The anesthetic state and natural sleep share many neurobiological features and yet are two distinct states. The hallmarks of general anesthesia include hypnosis, analgesia, akinesia and anxiolysis. These are the principal parameters by which the anesthetic state differs from natural sleep. These properties are mediated by systemic administration of a combination of agents producing balanced anesthesia. The exact nature of anesthetic narcosis is dose dependent and agent specific. It exhibits a relative lack of nociceptive response and active suppression of motor and autonomic reflexes. Surgical anesthesia displays a signature electroencephalogram pattern of burst suppression that differs from rapid eye movement sleep, representing more widespread disruption of thalamocortical connectivity, impairing information integration and processing. These differences underpin successful anesthetic action. This review explores the differences between natural sleep and anesthetic-induced unconsciousness as induced by balanced anesthesia.

Basal Forebrain Cholinergic Activity Modulates Isoflurane and Propofol Anesthesia

Cholinergic neurons in the basal forebrain (BF) have long been considered to be the key neurons in the regulation of cortical and behavioral arousal, and cholinergic activation in the downstream region of the BF can arouse anesthetized rats. However, whether the activation of BF cholinergic neurons can induce behavior and electroencephalogram (EEG) recovery from anesthesia is unclear. In this study, based on a transgenic mouse line expressing ChAT-IRES-Cre, we applied a fiber photometry system combined with GCaMPs expression in the BF and found that both isoflurane and propofol inhibit the activity of BF cholinergic neurons, which is closely related to the consciousness transition. We further revealed that genetic lesion of BF cholinergic neurons was associated with a markedly increased potency of anesthetics, while designer receptor exclusively activated by designer drugs (DREADD)-activated BF cholinergic neurons was responsible for slower induction and faster recovery of anesthesia. We also documented a significant increase in δ power bands (1-4 Hz) and a decrease in β (12-25 Hz) power bands in BF cholinergic lesioned mice, while there was a clearly noticeable decline in EEG δ power of activated BF cholinergic neurons. Moreover, sensitivity to anesthetics was reduced after optical stimulation of BF cholinergic cells, yet it failed to restore wake-like behavior in constantly anesthetized mice. Our results indicate a functional role of BF cholinergic neurons in the regulation of general anesthesia. Inhibition of BF cholinergic neurons mediates the formation of unconsciousness induced by general anesthetics, and their activation promotes recovery from the anesthesia state.

The efficacy of acupuncture in postoperative sleep quality: a literature review

PURPOSE

General anesthesia may affect the quality of postoperative sleep, especially after surgery on elderly patients. The decline of postoperative sleep quality may produce harmful effects on the postoperative recovery of patients. In this review, we summarized the efficacy and potential mechanism of acupuncture on postoperative sleep quality.

METHODS

We review the effect of general anesthesia on circadian sleep rhythm. In addition, to provide evidence about the impairment of decreased postoperative sleep quality, we also emphasize the mechanism of acupuncture alleviates factors that affect sleep quality after general anesthesia.

RESULTS

The application of acupuncture technology has been helpful to improve sleep quality and alleviate postoperative complications affecting postoperative sleep quality after general anesthesia.

CONCLUSION

Acupuncture at different acupoints could effectively improve body's neurotransmitter levels and regulate biological clock genes through various mechanisms, and then improve postoperative sleep quality. Large-scale multi-center trials are needed to verify these findings.

Roles of motor and cortical activity in sleep rebound in rat

Sleep pressure that builds up gradually during the extended wakefulness results in sleep rebound. Several lines of evidence, however, suggest that wake per se may not be sufficient to drive sleep rebound and that rapid eye movement (REM) and non-rapid eye movement (NREM) sleep rebound may be differentially regulated. In this study, we investigated the relative contribution of brain versus physical activities in REM and NREM sleep rebound by four sets of experiments. First, we forced locomotion in rats in a rotating wheel for 4 hr and examined subsequent sleep rebound. Second, we exposed the rats lacking homeostatic sleep response after prolonged quiet wakefulness and arousal brain activity induced by chemoactivation of parabrachial nucleus to the same rotating wheel paradigm and tested if physical activity could rescue the sleep homeostasis. Third, we varied motor activity levels while concurrently inhibiting the cortical activity by administering ketamine or xylazine (motor inhibitor), or ketamine + xylazine mixture and investigated if motor activity in the absence of activated cortex can cause NREM sleep rebound. Fourth and finally, we manipulated cortical activity by administering ketamine (that induced active wakefulness and waking brain) alone or in combination with atropine (that selectively inhibits the cortex) and studied if cortical inhibition irrespective of motor activity levels can block REM sleep rebound. Our results demonstrate that motor activity but not cortical activity determines NREM sleep rebound whereas cortical activity but not motor activity determines REM sleep rebound.

The Biology of General Anesthesia from Paramecium to Primate

General anesthesia serves a critically important function in the clinical care of human patients. However, the anesthetized state has foundational implications for biology because anesthetic drugs are effective in organisms ranging from paramecia, to plants, to primates. Although unconsciousness is typically considered the cardinal feature of general anesthesia, this endpoint is only strictly applicable to a select subset of organisms that are susceptible to being anesthetized. We review the behavioral endpoints of general anesthetics across species and propose the isolation of an organism from its environment - both in terms of the afferent arm of sensation and the efferent arm of action - as a generalizable definition. We also consider the various targets and putative mechanisms of general anesthetics across biology and identify key substrates that are conserved, including cytoskeletal elements, ion channels, mitochondria, and functionally coupled electrical or neural activity. We conclude with a unifying framework related to network function and suggest that general anesthetics - from single cells to complex brains - create inefficiency and enhance modularity, leading to the dissociation of functions both within an organism and between the organism and its surroundings. Collectively, we demonstrate that general anesthesia is not restricted to the domain of modern medicine but has broad biological relevance with wide-ranging implications for a diverse array of species.

Electroacupuncture: A New Approach for Improved Postoperative Sleep Quality After General Anesthesia

General anesthesia produces a state of drug-induced unconsciousness that is controlled by the extent and duration of administered agents. Whether inhalation or intravenous in formulation, such agents may interfere with normal sleep-wake cycles, impairing postoperative sleep quality and creating complications. Electroacupuncture is a new approach widely applied in clinical practice during recent years. This particular technology helps regulate neurotransmitter concentrations in the brain, lowering norepinephrine and dopamine levels to improve sleep quality. It also alleviates surgical pain that degrades postoperative sleep quality after general anesthesia by downregulating immune activity (SP, NK-1, and COX-1) and upregulating serotonin receptor (5-HT1AR, 5-HT2AR) and endocannabinoid expression levels. However, large-scale, multicenter studies are still needed to determine the optimal duration, frequency, and timing of electroacupuncture for such use.

Sleep Disturbances After General Anesthesia: Current Perspectives

The purpose of this article is to review (1) sleep mechanism under general anesthesia, harmful effects of postoperative sleep disturbances; (2) risk factors associated with postoperative sleep disturbances; (3) measures to prevent and improve postoperative sleep disturbances. General anesthesia changes the postoperative sleep structure especially in elderly patients after major surgery and results in a high incidence rate of sleep disturbances. Sleep disturbances produce harmful effects on postoperative patients and lead to a higher risk of delirium, more cardiovascular events, and poorer recovery. Some researchers do propose non-pharmacological treatments such as attention to environmental and psychological factors, application of electroacupuncture (EA) technology and pharmacological treatments are helpful, but larger high-quality clinical trials with longer following-up are needed to further investigate the efficacy and safety.

Neonatal Ketamine Alters High-Frequency Oscillations and Synaptic Plasticity in the Subiculum But Does not Affect Sleep Macrostructure in Adolescent Rats

Exposure to sedative/hypnotic and anesthetic drugs, such as ketamine, during the critical period of synaptogenesis, causes profound neurotoxicity in the developing rodent and primate brains and is associated with poor cognitive outcomes later in life. The subiculum is especially vulnerable to acute neurotoxicity after neonatal exposure to sedative/hypnotic and anesthetic drugs. The subiculum acts as a relay center between the hippocampal complex and various cortical and subcortical brain regions and is also an independent generator of gamma oscillations. Gamma oscillations are vital in neuronal synchronization and play a role in learning and memory during wake and sleep. However, there has been little research examining long-term changes in subicular neurophysiology after neonatal exposure to ketamine. Here we explore the lasting effects of neonatal ketamine exposure on sleep macrostructure as well as subicular neuronal oscillations and synaptic plasticity in rats. During the peak of rodent synaptogenesis at postnatal day 7, rat pups were exposed to either 40 mg/kg of ketamine over 12 h or to volume matched saline vehicle. At weaning age, a subset of rats were implanted with a cortical and subicular electroencephalogram electrode, and at postnatal day 31, we performed in vivo experiments that included sleep macrostructure (divided into the wake, non-rapid eye movement, and rapid eye movement sleep) and electroencephalogram power spectra in cortex and subiculum. In a second subset of ketamine exposed animals, we conducted ex vivo studies of long-term potentiation (LTP) experiments in adolescent rats. Overall, we found that neonatal exposure to ketamine increased subicular gamma oscillations during non-rapid eye movement sleep but it did not alter sleep macrostructure. Also, we observed a significant decrease in subicular LTP. Gamma oscillations during non-rapid eye movement sleep are implicated in memory formation and consolidation, while LTP serves as a surrogate for learning and memory. Together these results suggest that lasting functional changes in subiculum circuitry may underlie neurocognitive impairments associated with neonatal exposure to anesthetic agents.

Disruption of Rapid Eye Movement Sleep Homeostasis in Adolescent Rats after Neonatal Anesthesia

BACKGROUND

Previous studies suggest that rapid eye movement sleep rebound and disruption of rapid eye movement sleep architecture occur during the first 24 h after general anesthesia with volatile anesthetics in adult rats. However, it is unknown whether rapid eye movement sleep alterations persist beyond the anesthetic recovery phase in neonatal rats. This study tested the hypothesis that rapid eye movement sleep disturbances would be present in adolescent rats treated with anesthesia on postnatal day 7.

METHODS

Forty-four neonatal rats were randomly allocated to treatment with anesthesia consisting of midazolam, nitrous oxide, and isoflurane or control conditions for 2 h or 6 h. Electroencephalographic and electromyographic electrodes were implanted and recordings obtained between postnatal days 26 and 34. The primary outcome was time spent in rapid eye movement sleep. Data were analyzed using two-tailed unpaired t tests and two-way repeated measures analysis of variance.

RESULTS

Rats treated with midazolam, nitrous oxide, and isoflurane exhibited a significant increase in rapid eye movement sleep three weeks later when compared with control rats, regardless of whether they were treated for 2 h (174.0 ± 7.2 min in anesthetized, 108.6 ± 5.3 in controls, P < 0.0001) or 6 h (151.6 ± 9.9 min in anesthetized, 108.8 ± 7.1 in controls, P = 0.002).

CONCLUSIONS

Treatment with midazolam, nitrous oxide, and isoflurane on postnatal day 7 increases rapid eye movement sleep three weeks later in rats.

Activation of Preoptic GABAergic or Glutamatergic Neurons Modulates Sleep-Wake Architecture, but Not Anesthetic State Transitions

The precise mechanism of general anesthesia remains unclear. In the last two decades, there has been considerable focus on the hypothesis that anesthetics co-opt the neural mechanisms regulating sleep. This hypothesis is supported by ample correlative evidence at the level of sleep-promoting nuclei, but causal investigations of potent inhaled anesthetics have not been conducted. Here, we tested the hypothesis that chemogenetic activation of discrete neuronal subpopulations within the median preoptic nucleus (MnPO) and ventrolateral preoptic nucleus (VLPO) of the hypothalamus would modulate sleep/wake states and alter the time to loss and resumption of consciousness associated with isoflurane, a potent halogenated ether in common clinical use. We show that activating MnPO/VLPO GABAergic or glutamatergic neurons does not alter anesthetic induction or recovery time. However, activation of these neuronal subpopulations did alter sleep-wake architecture. Notably, we report the novel finding that stimulation of VLPO glutamatergic neurons causes a strong increase in wakefulness. We conclude that activation of preoptic GABAergic or glutamatergic neurons that increase sleep or wakefulness does not substantively influence anesthetic state transitions. These data indicate that the correlative evidence for a mechanistic overlap of sleep and anesthesia at the level of an individual nucleus might not necessarily have strong causal significance.

Comparison of Morning and Evening Operation Under General Anesthesia on Intraoperative Anesthetic Requirement, Postoperative Sleep Quality, and Pain: A Randomized Controlled Trial

OBJECTIVE

Postoperative sleep disorders can cause serious adverse effects on postoperative outcomes. The purpose of our study was to compare the effects of the timing of surgery under general anesthesia on intraoperative anesthetic drug requirements, postoperative sleep quality and pain in patients.

MATERIALS AND METHODS

Eighty-four patients who underwent selective laparoscopic abdominal surgeries under general anesthesia were randomly assigned to the Day Group (8:00-12:00) or the Night Group (18:00-22:00). The portable sleep monitor (PSM) was used to determine sleep quality on the night before surgery (Sleep-preop), the first night after surgery (Sleep POD 1), and the third night after surgery (Sleep POD 3). The visual analog scale (VAS) was used to evaluate postoperative pain scores and the Athens Insomnia Scale (AIS) was used for assessing insomnia symptoms. The total dose of general anesthetics required and adverse effects after surgery were also assessed.

RESULTS

Compared to Sleep-preop, patients presented with a lower sleep efficiency and a higher AIS score during Sleep POD 1 and Sleep POD 3. Furthermore, the Night Group had a significantly lower proportion of rapid eye movement sleep, stable sleep, and unstable sleep than did the Day Group at Sleep POD 1 and Sleep POD 3. The dosage of propofol and remifentanil required in the Day Group was significantly higher than that in the Night Group. Furthermore, patients in the Day Group had better pain relief, with a lower VAS score at 1, 6, 12, and 24 hours after surgery. The incidences of postoperative nausea and vomiting and dizziness were significantly higher in the Night Group than those in the Day Group.

CONCLUSION

Morning operations required a higher dose of anesthetic drugs than did evening operations, which may be related to the circadian rhythm. The degree of postoperative sleep disorders was greater when the operation was performed in the evening than in the morning, which was also associated with increased pain perception and increased incidence of postoperative adverse effects. Thus, our results suggest that patients with hyperalgesia and sleep disorders may benefit from operations performed in the morning.

Escape From Oblivion: Neural Mechanisms of Emergence From General Anesthesia

The question of how general anesthetics suppress consciousness has persisted since the mid-19th century, but it is only relatively recently that the field has turned its focus to a systematic understanding of emergence. Once assumed to be a purely passive process, spontaneously occurring as residual levels of anesthetics dwindle below a critical value, emergence from general anesthesia has been reconsidered as an active and controllable process. Emergence is driven by mechanisms that can be distinct from entry to the anesthetized state. In this narrative review, we focus on the burgeoning scientific understanding of anesthetic emergence, summarizing current knowledge of the neurotransmitter, neuromodulators, and neuronal groups that prime the brain as it prepares for its journey back from oblivion. We also review evidence for possible strategies that may actively bias the brain back toward the wakeful state.

Evaluating the effects of general anesthesia on sleep in children undergoing elective surgery: an observational case-control study

Study Objectives

Previous research has suggested that general anesthetics can disturb postoperative sleep patterns by affecting the sleep-wake cycle. The objective was to identify the effects of general anesthetics on sleep quality and related behavioral changes in children.

Methods

This was a prospective, observational case-control study with children, aged 18 months to 8 years, undergoing general anesthesia for elective surgery. Participants wore an actigraph for 7 days on three occasions: prior to surgery, the immediate postoperative period, and 3 months after surgery. Data regarding behavior patterns were collected using behavioral assessments at baseline, the first postoperative week, and 3 months following surgery.

Results

Thirty-one participants (mean age 4.8 ± 2.0 years, 81% male) underwent urologic or otolaryngologic surgery. The median (interquartile range) anesthetic duration was 132.0 (80.0-184.0) min. No significant differences were found in sleep efficiency, total sleep time, wake time after sleep onset, or sleep onset latency between baseline, 7 day postoperative period, and the 3 month follow-up. No significant differences were found in sleep-related behavioral metrics including internalizing and externalizing behaviors, and executive functioning. Data were compared with a control group of 18 participants (mean age 5.3 ± 1.8 years, 61% male). No significant differences were found in sleep patterns and related behavioral metrics between both groups.

Conclusions

In this study, general anesthesia did not result in disturbed sleep or associated negative behavioral changes in otherwise healthy children undergoing elective surgeries of low complexity. Physicians can advise parents that a child's surgery and associated general anesthetic exposure may not result in significant changes in postoperative sleep patterns.

REM sleep deprivation-induced circadian clock gene abnormalities participate in hippocampal-dependent memory impairment by enhancing inflammation in rats undergoing sevoflurane inhalation

Sleep disturbance can result in memory impairment, and both sleep and hippocampal memory formation are maintained by circadian clock genes. Although preoperative sleep deprivation is known to be an independent risk factor for postoperative cognitive dysfunction (POCD) after inhalation anesthesia, the circadian mechanisms involved are currently unclear. To examine this issue, we constructed models of rapid eye movement sleep deprivation (RSD) and POCD after sevoflurane inhalation, to evaluate the circadian mechanisms underlying preoperative sleep deprivation-induced POCD after sevoflurane inhalation. Morris water maze probe test performance revealed that RSD aggravated the hippocampal-dependent memory impairment induced by sevoflurane anesthesia, and the recovery period of memory impairment was prolonged for more than a week by sleep deprivation. Western blot analysis revealed that sleep deprivation inhibited hippocampal Bmal1 and Egr1 expression for more than 7 days after sevoflurane inhalation. Importantly, hippocampal Per2 expression levels were first decreased by sevoflurane inhalation then increased from the third day by sleep deprivation. Sleep deprivation enhanced the expression of hippocampal inflammatory factors IL-1β and IL-6 after sevoflurane inhalation. In addition, sevoflurane inhalation activated the plasma expression of S100β and IL-6, particularly after sleep deprivation. Sleep deprivation aggravated pathogenic impairment of pyramidal neurons and activated astrocytes in CA1 after sevoflurane inhalation. These results suggest that preoperative RSD aggravates hippocampal memory impairment by enhancing neuroinflammatory injuries after sevoflurane inhalation, which is related to hippocampal clock gene abnormalities.

The Effect Of Intraoperative Use Of Dexmedetomidine During The Daytime Operation Vs The Nighttime Operation On Postoperative Sleep Quality And Pain Under General Anesthesia

OBJECTIVES

The aim of our study was to compare the effect of using dexmedetomidine (DEX) during the daytime operation or the nighttime operation under general anesthesia on postoperative sleep quality and pain of patients.

METHODS

Seventy-five patients scheduled for elective laparoscopic abdominal surgeries under general anesthesia were randomly assigned to receive operation in the Day Group (8:00-12:00) and the Night Group (18:00-22:00). The Portable Sleep Monitor (PSM) was performed on the following 3 nights: the night before surgery (Sleep 1), the first night after surgery (Sleep 2), and the third night after surgery (Sleep 3). Postoperative pain scores using visual analogue scoring scale, subjective sleep quality using the Athens Insomnia Scale, total dose of general anesthetics and PCA pump press numbers were also recorded.

RESULTS

Intraoperative administration of DEX for patients in the Day Group could improve sleep quality with a higher sleep efficiency and a lower AIS subjective sleep quality than patients in the Night Group at Sleep 2 (P < 0.001 and P = 0.001, respectively) and Sleep 3 (P < 0.001, respectively). There were marked lower rapid eye movement (REM) sleep and Stable sleep in the Night Group than that in the Day Group at Sleep 2 (P < 0.001 and P = 0.032, respectively) and Sleep 3 (P < 0.001, respectively). Patients in the Day Group have better pain relief and less PCA pump press numbers than patients in the Night Group.

CONCLUSION

Using dexmedetomidine during the daytime operation can better improve postoperative sleep quality and pain than nighttime operation in patients undergoing laparoscopic abdominal surgeries.

Changes in the first postoperative night bispectral index of patients after thyroidectomy with different types of primary anesthetic management: a randomized controlled trial

Despite major advances in anesthesia management and developments in anesthetic agents, postoperative sleep disturbances remain dissatisfactory for many patients. We hypothesized that propofol might have a subtle influence on sleep after thyroidectomy compared to sevoflurane. A randomized, single-blinded, controlled trial was conducted at the First Hospital of China Medical University from October 2014 to October 2015. One hundred and twenty-four patients undergoing thyroidectomy were enrolled and received sevoflurane (sevoflurane group) or propofol (propofol group) as anesthesia maintenance. Major assessments were made during the operation (different types of anesthetic management) and on the first postoperative night (sleep status). The primary outcome was postoperative sleep status, measured by the BIS-Vista monitor on the first night after surgery between propofol and sevoflurane groups. A total of 105 patients (79 women, 26 men; mean age 49 years; range 18-65 years) were included in the final study sample. All patients in both groups showed one of the five sleep patterns classified by this trial. The BIS-area under the curve was decreased, the sleep efficiency index was significantly increased, and the durations of postoperative sleep and sleep stage N3 were increased by 110.5 and 36.5 min per patient, respectively, in the propofol compared to the sevoflurane group. Propofol might preserve sleep time immediately after thyroidectomy. Clinical Trials.gov identifier: NCT 02146976.

Brain energetics during the sleep-wake cycle

Brain activity during wakefulness is associated with high metabolic rates that are believed to support information processing and memory encoding. In spite of loss of consciousness, sleep still carries a substantial energy cost. Experimental evidence supports a cerebral metabolic shift taking place during sleep that suppresses aerobic glycolysis, a hallmark of environment-oriented waking behavior and synaptic plasticity. Recent studies reveal that glial astrocytes respond to the reduction of wake-promoting neuromodulators by regulating volume, composition and glymphatic drainage of interstitial fluid. These events are accompanied by changes in neuronal discharge patterns, astrocyte-neuron interactions, synaptic transactions and underlying metabolic features. Internally-generated neuronal activity and network homeostasis are proposed to account for the high sleep-related energy demand.

Effects of γ-Aminobutyric Acid Type A Receptor Modulation by Flumazenil on Emergence from General Anesthesia

BACKGROUND

Transitions into conscious states are partially mediated by inactivation of sleep networks and activation of arousal networks. Pharmacologic hastening of emergence from general anesthesia has largely focused on activating subcortical monoaminergic networks, with little attention on antagonizing the γ-aminobutyric acid type A receptor (GABAAR). As the GABAAR mediates the clinical effects of many common general anesthetics, the authors hypothesized that negative GABAAR modulators would hasten emergence, possibly via cortical networks involved in sleep.

METHODS

The authors investigated the capacity of the benzodiazepine rescue agent, flumazenil, which had been recently shown to promote wakefulness in hypersomnia patients, to alter emergence. Using an in vivo rodent model and an in vitro GABAAR heterologous expression system, they measured flumazenil's effects on behavioral, neurophysiologic, and electrophysiologic correlates of emergence from isoflurane anesthesia.

RESULTS

Animals administered intravenous flumazenil (0.4 mg/kg, n = 8) exhibited hastened emergence compared to saline-treated animals (n = 8) at cessation of isoflurane anesthesia. Wake-like electroencephalographic patterns occurred sooner and exhibited more high-frequency electroencephalography power after flumazenil administration (median latency ± median absolute deviation: 290 ± 34 s) compared to saline administration (473 ± 186 s; P = 0.042). Moreover, in flumazenil-treated animals, there was a decreased impact on postanesthesia sleep. In vitro experiments in human embryonic kidney-293T cells demonstrated that flumazenil inhibited isoflurane-mediated GABA current enhancement (n = 34 cells, 88.7 ± 2.42% potentiation at 3 μM). Moreover, flumazenil exhibited weak agonist activity on the GABAAR (n = 10 cells, 10.3 ± 3.96% peak GABA EC20 current at 1 μM).

CONCLUSIONS

Flumazenil can modulate emergence from isoflurane anesthesia. The authors highlight the complex role GABAARs play in mediating consciousness and provide mechanistic links between emergence from anesthesia and arousal.

Histamine H3 Receptor Antagonist Prevents Memory Deficits and Synaptic Plasticity Disruption Following Isoflurane Exposure

BACKGROUND

Exposure to pharmacological concentration of inhaled anesthetics such as isoflurane can cause short- or long-term cognitive impairments in preclinical studies. The selective antagonists of the histamine H3 receptors are considered as a promising group of novel therapeutic agents for the treatment of cognitive disorders. In this study, we investigated whether ciproxifan, a nonimidazole antagonist of H3 histamine receptors, could overcome the functional and electrophysiological sequela associated with isoflurane anesthesia.

METHODS

Adult male Sprague Dawley rats were exposed to 1.4% isoflurane or vehicle gas for 2 h. The memory tests (novel object recognition and passive avoidance) as well as in vivo hippocampal excitatory synaptic potentials were recorded 24 h postanesthesia. Locomotor activity, anxiety, and nociception 24 h after isoflurane were also examined. The drugs (ciproxifan 3 mg/kg or saline) were intraperitoneally injected 30 min prior to the behavioral tests or long-term potentiation induction.

RESULTS

Animals that were previously (24 h) exposed to 1.4% isoflurane for 2 h displayed no preference for novel objects and had impaired retention of a passive avoidance response at 1 h after sample phase. Treating isoflurane-exposed rats with ciproxifan significantly improved the memory performance, as evidenced by an increased discrimination ratio in objects recognition and prolonged retention time in passive avoidance test. Accordingly, hippocampus long-term potentiation was reduced in animals that received isoflurane, while administration of ciproxifan completely abolished the effect of isoflurane exposure on synaptic plasticity. Neither isoflurane nor ciproxifan altered motor performance, anxiety, and nociceptive responses.

CONCLUSION

These results suggest that H3R in the CNS, probably in the hippocampus, may serve as therapeutic target for improvement of anesthesia-associated cognitive deficits.

The effects of intensive care environment on postoperative nightmare

PURPOSE

We retrospectively investigated the incidence of postoperative nightmares and evaluated the impact of postoperative intensive care on the incidence of during subsequent hospital stay. To reduce the effect of selection bias, we compared the incidence of nightmares in propensity-matched pairs with postoperative management in ICUs or in surgical wards.

METHODS

This is a retrospective review of an institutional registry containing 21,606 anesthesia cases and was conducted with ethics board approval. Outcomes of surgical patients treated in ICUs and in postsurgical wards (ICU admission vs non ICU admission) were compared first for nightmares using the initial 12,508 patients. To avoid channeling bias, propensity score analysis was used to generate a set of matched cases (ICU admission) and controls (non ICU admission), yielding 642 matched patient pairs. The incidence rate of nightmares was compared as the primary outcome.

RESULTS

Before adjusting patients' characteristics, ICU environment exposure increased the incidence of nightmares compared with non-ICU environment during subsequent hospital stay [ICU vs non-ICU: 101/718 (12.3 %) vs 1147/10,542 (9.81 %)]. The odds ratio (95 % CIs) for ICU was 1.29 (1.03-1.61) for nightmares (p = 0.022). After propensity score matching, however, an equal rate of nightmares occurred in the ICU environment exposure compared to the non-ICU environment [ICU vs non-ICU: 81/561 (12.6 %) vs 73/569 (11.4 %)]. The odds ratio and 95 % CIs for ICU were 1.13 (0.80-1.58) for nightmares (p = 0.54).

CONCLUSIONS

The incidence of nightmares did not become more evident during subsequent hospital stay after ICU environment exposure.

Sleep Homeostasis and General Anesthesia: Are Fruit Flies Well Rested after Emergence from Propofol?

BACKGROUND

Shared neurophysiologic features between sleep and anesthetic-induced hypnosis indicate a potential overlap in neuronal circuitry underlying both states. Previous studies in rodents indicate that preexisting sleep debt discharges under propofol anesthesia. The authors explored the hypothesis that propofol anesthesia also dispels sleep pressure in the fruit fly. To the authors' knowledge, this constitutes the first time propofol has been tested in the genetically tractable model, Drosophila melanogaster.

METHODS

Daily sleep was measured in Drosophila by using a standard locomotor activity assay. Propofol was administered by transferring flies onto food containing various doses of propofol or equivalent concentrations of vehicle. High-performance liquid chromatography was used to measure the tissue concentrations of ingested propofol. To determine whether propofol anesthesia substitutes for natural sleep, the flies were subjected to 10-h sleep deprivation (SD), followed by 6-h propofol exposure, and monitored for subsequent sleep.

RESULTS

Oral propofol treatment causes anesthesia in flies as indicated by a dose-dependent reduction in locomotor activity (n = 11 to 41 flies from each group) and increased arousal threshold (n = 79 to 137). Recovery sleep in flies fed propofol after SD was delayed until after flies had emerged from anesthesia (n = 30 to 48). SD was also associated with a significant increase in mortality in propofol-fed flies (n = 44 to 46).

CONCLUSIONS

Together, these data indicate that fruit flies are effectively anesthetized by ingestion of propofol and suggest that homologous molecular and neuronal targets of propofol are conserved in Drosophila. However, behavioral measurements indicate that propofol anesthesia does not satisfy the homeostatic need for sleep and may compromise the restorative properties of sleep.

Ketamine and propofol have opposite effects on postanesthetic sleep architecture in rats: relevance to the endogenous sleep-wakefulness substances orexin and melanin-concentrating hormone

BACKGROUND

Anesthesia and surgery disturb sleep. Disturbed sleep adversely affects postoperative complications involving the cardiovascular system, diabetes, and infection. General anesthetics share neuronal mechanisms involving endogenous sleep-wakefulness-related substances, such as orexin (OX) and melanin-concentrating hormone (MCH). We evaluated changes in sleep architecture and the concentration of OX and MCH during the peri-anesthetic period.

METHODS

To examine sleep architecture, male Sprague-Dawley rats weighing 350-450 g received ketamine 100 mg/kg (n = 9) or propofol 80 mg/kg (n = 6) by intraperitoneal injection. Electroencephalography was recorded from 2 days pre- to 5 days postanesthesia. To quantify levels of OX and MCH, 144 similar rats received the same doses of ketamine (n = 80) or propofol (n = 64). Brain concentrations of these substances were determined at 0, 20, 60, and 120 min after anesthetic administration.

RESULTS

Ketamine decreased OX content in the hypothalamus during the anesthesia period. OX content was restored to pre-anesthesia levels in the hypothalamus and pons. Both anesthetics increased brain MCH content in the postanesthetic period, with the degree of increase being greater with propofol. Ketamine enhanced wakefulness and inhibited non-rapid eye movement sleep (NREMS) immediately after anesthesia. Conversely, propofol inhibited wakefulness and enhanced NREMS in that period. Ketamine inhibited wakefulness and enhanced NREMS during the dark phase on the first postanesthesia day.

CONCLUSIONS

Anesthetics affect various endogenous sleep-wakefulness-related substances; however, the modulation pattern may depend on the type of anesthetic. The process of postanesthetic sleep disturbance was agent specific. Our results provide fundamental evidence to treat anesthetic-related sleep disturbance.

RGS Proteins and Gαi2 Modulate Sleep, Wakefulness, and Disruption of Sleep/ Wake States after Isoflurane and Sevoflurane Anesthesia

STUDY OBJECTIVES

This study tested the hypothesis that Regulators of G protein Signaling (RGS) proteins contribute to the regulation of wakefulness, non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep, and to sleep disruption caused by volatile anesthetics.

METHODS

The three groups used in this study included wild-type (WT; n = 7) mice and knock-in mice that were heterozygous (+/GS; n = 7) or homozygous (GS/GS; n = 7) for an RGS-insensitive allele that causes prolonged Gαi2 signaling. Mice were implanted with electrodes for recording sleep and conditioned for 1 week or more to sleep in the laboratory. Using within and between groups designs, 24-h recordings of wakefulness, NREM sleep, and REM sleep were compared across three interventions: (1) baseline (control) and after 3 h of being anesthetized with (2) isoflurane or (3) sevoflurane.

RESULTS

Baseline recordings during the light phase revealed that relative to WT mice, homozygous RGS-insensitive (GS/GS) mice exhibit significantly increased wakefulness and decreased NREM and REM sleep. During the dark phase, these state-specific differences remained significant but reversed direction of change. After cessation of isoflurane and sevoflurane anesthesia there was a long-lasting and significant disruption of sleep and wakefulness. The durations of average episodes of wakefulness, NREM sleep, and REM sleep were significantly altered as a function of genotype and isoflurane and sevoflurane anesthesia.

CONCLUSIONS

RGS proteins and Gαi2 play a significant role in regulating states of wakefulness, NREM sleep, and REM sleep. Genotype-specific differences demonstrate that RGS proteins modulate sleep disruption caused by isoflurane and sevoflurane anesthesia. The results also support the conclusion that isoflurane and sevoflurane anesthesia do not satisfy the homeostatic drive for sleep.

Optimizing Sedation Management to Promote Early Mobilization for Critically Ill Children

Achieving successful early mobilization for the intubated, critically ill child is dependent on optimizing sedation and analgesia. Finding the fine balance between oversedation and undersedation can be challenging. The ideal is for a child to be lucid and interactive during the daytime and demonstrate normal circadian rhythm for sleep with rest at night. Being alert during the day facilitates active participation in therapy including potential ambulation, while decreasing the risk of delirium during mechanical ventilation. An active state during the day with frequent mobilization promotes restorative sleep at night, which brings with it multiple benefits for healing and recovery. Indeed, this ideal may not be physiologically feasible given a child's critical illness and trajectory, but defining it as the "gold standard" for early mobilization provides a consistent goal for the pediatric intensive care unit (PICU) hospitalization. As such, goal-directed, patient-specific sedation plans are integral to creating a culture of mobility in the PICU. We review currently available sedation strategies for mechanically ventilated children for successful implementation of early mobilization in the PICU, as well as pharmacologic considerations for specific classes of sedative-analgesics.

Effect of sedative-hypnotics, anesthetics and analgesics on sleep architecture in obstructive sleep apnea

The perioperative care of obstructive sleep apnea (OSA) patients is currently receiving much attention due to an increased risk for complications. It is established that postoperative changes in sleep architecture occur and this may have pathophysiological implications for OSA patients. Upper airway muscle activity decreases during rapid eye movement sleep (REMS). Severe OSA patients exhibit exaggerated chemoreceptor-driven ventilation during non-rapid eye movement sleep (NREMS), which leads to central and obstructive apnea. This article critically reviewed the literature relevant to preoperative screening for OSA, prevalence of OSA in surgical populations and changes in postoperative sleep architecture relevant to OSA patients. In particular, we addressed three questions in regard to the effects of sedative-hypnotics, anesthetics and analgesics on sleep architecture, the underlying mechanisms and the relevance to OSA. Indeed, these classes of drugs alter sleep architecture, which likely significantly contributes to abnormal postoperative sleep architecture, exacerbation of OSA and postoperative complications.