The effect of melatonin on early postoperative cognitive decline in elderly patients undergoing hip arthroplasty: A randomized controlled trial

Which Interventions Are Effective in Treating Sleep Disturbances After THA or TKA? A Systematic Review

BACKGROUND

Poor sleep quality is a common complaint after total joint arthroplasty (TJA), and it is associated with reports of higher pain and worse functional outcomes. Several interventions have been investigated with the intent to reduce the incidence of postoperative sleep disturbance with varying effectiveness. An aggregate of the best available evidence, along with an evaluation of the quality of those studies, is needed to provide valuable perspective to physicians and to direct future research.

QUESTIONS/PURPOSES

In this systematic review, we asked: (1) What is the reported efficacy of the most commonly studied medications and nonpharmacologic approaches, and (2) what are their side effects and reported complications?

METHODS

This systematic review was conducted in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search using a combination of controlled vocabulary and keywords was performed utilizing Medline (Ovid), Embase (Ovid), Cochrane Central, and Web of Science databases from database inception to 2023, with the last search occurring October 24, 2023, to identify studies that evaluated a sleep intervention on the effect of patient-reported sleep quality after THA or TKA. Inclusion criteria were clinical trials, comparative studies, and observational studies on adult patients who underwent primary TKA or THA for osteoarthritis and who completed validated sleep questionnaires to assess sleep quality postoperatively. We excluded studies on patients younger than 18 years, patients with sleep apnea, TKA or THA because of trauma or conditions other than osteoarthritis, revision TJA, studies in languages other than English, and studies from nonindexed journals or preprint servers. Two investigators independently screened 1535 studies for inclusion and exclusion criteria and extracted data from the included studies. Ultimately, 14 studies were included in this systematic review, including 12 randomized controlled trials and 2 prospective comparative studies. A total of 2469 participants were included, with a mean ± SD age of 65 ± 7 years and 38% men in control groups and 65 ± 7 years and 39% men in intervention groups. Sleep quality questionnaires utilized included the Pittsburgh Sleep Quality Index, Self-Rating Scale of Sleep, 100-mm VAS - Sleep, Sleep Disturbance Numeric Rating Scale, Likert scales, and one institutionally designed questionnaire. Quality analysis was performed utilizing the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Randomized Controlled Trials, where higher scores of 13 indicated a more reliable study, and the Newcastle-Ottawa Quality Assessment Scale for Cohort Studies, where higher scores of 9 indicated a more reliable study and scores < 5 represented a high risk of bias. Two of the randomized controlled trials scored a 12 of 13, and the remaining 10 met every criteria of the JBI checklist. Both comparative studies scored 5 of 9 possible points of the Newcastle-Ottawa Scale.

RESULTS

Melatonin and selective cyclooxygenase-2 inhibitor rofecoxib were found to provide a clinically important benefit to sleep quality within the first postoperative week after TJA. However, rofecoxib was withdrawn from the market globally in 2004 over concerns about increased risk of cardiovascular events. Another cyclooxygenase-2 inhibitor, celecoxib, remains available. No other intervention demonstrated a clinical benefit. Side effects of melatonin include dizziness, headache, paresthesia, and nausea, and it is contraindicated in patients with liver failure, autoimmune conditions, or who are receiving warfarin. Long-term adverse effects of rofecoxib include hypertension, edema, and congestive heart failure, and it is contraindicated in patients with renal insufficiency or who are receiving warfarin. Melatonin is considered safe in older patients, but more caution should be taken with rofecoxib.

CONCLUSION

Owing to limited evidence in support of most of the interventions we studied, none of these interventions can be recommended for routine use after TJA. Melatonin and rofecoxib may provide a benefit to sleep quality in some patients, but physicians need to understand the adverse effects and contraindications before recommending these interventions. Additionally, rofecoxib is no longer commercially available. Future investigation is warranted to evaluate the effectiveness of interventions with minimal side effect profiles for providers to be able to make an informed decision about interventions for sleep improvement after TJA.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The John N. Insall Award: Does Melatonin Improve Subjective Sleep Quality After Total Knee Arthroplasty? A Randomized, Placebo-Controlled Trial

BACKGROUND

Sleep disturbance is a common problem following total knee arthroplasty (TKA). The objective of this study was to determine if exogenous melatonin improves sleep quality following primary TKA.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted. A total of 172 patients undergoing unilateral TKA for primary knee osteoarthritis were randomized to receive either 5 mg melatonin (n = 86) or 125 mg vitamin C placebo (n = 86) nightly for 6 weeks. The primary outcome was the Pittsburgh Sleep Quality Index (PSQI) at 6 weeks and 90 days postoperatively. Secondary outcomes included 6-week and 90-day patient-reported outcome measures (PROMs), morphine milligram equivalents prescribed, medication compliance, adverse events, and 90-day readmissions.

RESULTS

Mean PSQI scores worsened at 6 weeks before returning to the preoperative baseline at 90 days in both groups. There were no differences in PSQI scores between melatonin and placebo groups at 6 weeks (10.2 ± 4.2 versus 10.5 ± 4.4, P = .66) or 90 days (8.1 ± 4.1 versus 7.5 ± 4.0, P = .43). Melatonin did not improve the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Lower Extremity Activity Scale, Visual Analog Scale for pain, or Veterans Rand 12 Physical Component Score or Mental Component Score at 6 weeks or 90 days. Poor sleep quality was associated with worse PROMs at 6 weeks and 90 days on univariate and multivariable analyses, but melatonin did not modify these associations. There were no differences in morphine milligram equivalents prescribed, medication compliances, adverse events, or 90-day readmissions between both groups.

CONCLUSIONS

Exogenous melatonin did not improve subjective sleep quality or PROMs at 6 weeks or 90 days following TKA. Poor sleep quality was associated with worse patient-reported function and pain. Our results do not support the routine use of melatonin after TKA.

The influence of sleep disorders on perioperative neurocognitive disorders among the elderly: A narrative review

This review comprehensively assesses the epidemiology, interaction, and impact on patient outcomes of perioperative sleep disorders (SD) and perioperative neurocognitive disorders (PND) in the elderly. The incidence of SD and PND during the perioperative period in older adults is alarmingly high, with SD significantly contributing to the occurrence of postoperative delirium. However, the clinical evidence linking SD to PND remains insufficient, despite substantial preclinical data. Therefore, this study focuses on the underlying mechanisms between SD and PND, underscoring that potential mechanisms driving SD-induced PND include uncontrolled central nervous inflammation, blood-brain barrier disruption, circadian rhythm disturbances, glial cell dysfunction, neuronal and synaptic abnormalities, impaired central metabolic waste clearance, gut microbiome dysbiosis, hippocampal oxidative stress, and altered brain network connectivity. Additionally, the review also evaluates the effectiveness of various sleep interventions, both pharmacological and nonpharmacological, in mitigating PND. Strategies such as earplugs, eye masks, restoring circadian rhythms, physical exercise, noninvasive brain stimulation, dexmedetomidine, and melatonin receptor agonists have shown efficacy in reducing PND incidence. The impact of other sleep-improvement drugs (e.g., orexin receptor antagonists) and methods (e.g., cognitive-behavioral therapy for insomnia) on PND is still unclear. However, certain drugs used for treating SD (e.g., antidepressants and first-generation antihistamines) may potentially aggravate PND. By providing valuable insights and references, this review aimed to enhance the understanding and management of PND in older adults based on SD.

Total Joint Arthroplasty and Sleep: The State of the Evidence

Background

As the number of total hip and knee arthroplasties (TJA) performed increases, there is heightened interest in perioperative optimization to improve outcomes. Sleep is perhaps one of the least understood perioperative factors that affects TJA outcomes. The purpose of this article is to review the current body of knowledge regarding sleep and TJA and the tools available to optimize sleep perioperatively.

Methods

A manual search was performed using PubMed for articles with information about sleep in the perioperative period. Articles were selected that examined: sleep and pain in the perioperative period; the effect of surgery on sleep postoperatively; the relationship between sleep and TJA outcomes; risk factors for perioperative sleep disturbance; the effect of anesthesia on sleep; and the efficacy of interventions to optimize sleep perioperatively.

Results

Sleep and pain are intimately associated; poor sleep is associated with increased pain sensitivity. Enhanced sleep is associated with improved surgical outcomes, although transient sleep disturbances are normal postoperatively. Risk factors for perioperative sleep disturbance include increasing age, pre-existing sleep disorders, medical comorbidities, and type of anesthesia used. Interventions to improve sleep include optimizing medical comorbidities preoperatively, increasing sleep time perioperatively, appropriating sleep hygiene, using cognitive behavioral therapy, utilizing meditation and mindfulness interventions, and using pharmacologic sleep aids.

Conclusions

Sleep is one of many factors that affect TJA. As we better understand the interplay between sleep, risk factors for suboptimal sleep, and interventions that can be used to optimize sleep, we will be able to provide better care and improved outcomes for patients.

Melatonin does not reduce delirium severity in hospitalized older adults: Results of a randomized placebo-controlled trial

BACKGROUND

Delirium is common in older inpatients, causing distress, cognitive decline, and death. Current therapies are unsatisfactory, limited by lack of efficacy and adverse effects. There is an urgent need for effective delirium treatment. Sleep wake cycle is disturbed in delirium; endogenous Melatonin is perturbed, and exogenous Melatonin is a safe and effective medication for sleep disorders. This study aims to determine the effect of oral Melatonin 5 mg immediate release (IR) nightly for five nights on the severity of delirium in older (≥65 years) medical inpatients.

METHODS

This was a double-blinded, randomized controlled trial in general internal medicine units of a tertiary teaching hospital. Older inpatients with Confusion Assessment Method positive, hyperactive or mixed delirium within 48 h of admission or onset of in-hospital delirium were included. The primary outcome was change in delirium severity measured with the Memorial Delirium Assessment Scale (MDAS). A previous pilot trial showed 120 participants randomized 1:1 to Melatonin or Placebo would provide 90% power to demonstrate a 3-point reduction in the MDAS.

RESULTS

One hundred and twenty participants were randomized, 61 to Melatonin 5 mg and 59 to Placebo. The medication was well tolerated. The mean MDAS improvement was 4.9 (SD 7.6) in the Melatonin group and 5.4 (SD 7.2) in the Placebo group, p-value 0.42, a non-significant difference. A post-hoc analysis showed length of stay (LOS) was shorter in the intervention group (median 9 days [Interquartile Range (IQR) 4, 12] vs. Placebo group 10 [IQR 6, 16] p-value = 0.033, Wilcoxon Rank Sum test).

CONCLUSIONS

This trial does not support the hypothesis that Melatonin reduces the severity of delirium. This may be due to no effect of Melatonin, a smaller effect than anticipated, an effect not captured on a multidimensional delirium assessment scale, or a type II statistical error. Melatonin may improve LOS; this hypothesis should be studied.

Efficacy and safety of perioperative melatonin for postoperative delirium in patients undergoing surgery: a systematic review and meta-analysis

OBJECTIVE

To assess the efficacy and safety of perioperative melatonin and melatonin agonists in preventing postoperative delirium (POD).

METHODS

We conducted a systematic search for randomized controlled trials (RCTs) published through December 2022. The primary outcome was efficacy based on the incidence of POD (POD-I). Secondary outcomes included efficacy and safety according to the length of hospital or intensive care unit stay, in-hospital mortality, and adverse events. Subgroup analyses of POD-I were based on the type and dose of drug (low- and high-dose melatonin, ramelteon), the postoperative period (early or late), and the type of surgery.

RESULTS

In the analysis (16 RCTs, 1981 patients), POD-I was lower in the treatment group than in the control group (risk ratio [RR] = 0.57). POD-I was lower in the high-dose melatonin group than in the control group (RR = 0.41), whereas no benefit was observed in the low-dose melatonin and ramelteon groups. POD-I was lower in the melatonin group in the early postoperative period (RR = 0.35) and in patients undergoing cardiopulmonary surgery (RR = 0.54).

CONCLUSION

Perioperative melatonin or melatonin agonist treatment suppressed POD without severe adverse events, particularly at higher doses, during the early postoperative period, and after cardiopulmonary surgery.

Melatonin: a ferroptosis inhibitor with potential therapeutic efficacy for the post-COVID-19 trajectory of accelerated brain aging and neurodegeneration

The unprecedented pandemic of COVID-19 swept millions of lives in a short period, yet its menace continues among its survivors in the form of post-COVID syndrome. An exponentially growing number of COVID-19 survivors suffer from cognitive impairment, with compelling evidence of a trajectory of accelerated aging and neurodegeneration. The novel and enigmatic nature of this yet-to-unfold pathology demands extensive research seeking answers for both the molecular underpinnings and potential therapeutic targets. Ferroptosis, an iron-dependent cell death, is a strongly proposed underlying mechanism in post-COVID-19 aging and neurodegeneration discourse. COVID-19 incites neuroinflammation, iron dysregulation, reactive oxygen species (ROS) accumulation, antioxidant system repression, renin-angiotensin system (RAS) disruption, and clock gene alteration. These events pave the way for ferroptosis, which shows its signature in COVID-19, premature aging, and neurodegenerative disorders. In the search for a treatment, melatonin shines as a promising ferroptosis inhibitor with its repeatedly reported safety and tolerability. According to various studies, melatonin has proven efficacy in attenuating the severity of certain COVID-19 manifestations, validating its reputation as an anti-viral compound. Melatonin has well-documented anti-aging properties and combating neurodegenerative-related pathologies. Melatonin can block the leading events of ferroptosis since it is an efficient anti-inflammatory, iron chelator, antioxidant, angiotensin II antagonist, and clock gene regulator. Therefore, we propose ferroptosis as the culprit behind the post-COVID-19 trajectory of aging and neurodegeneration and melatonin, a well-fitting ferroptosis inhibitor, as a potential treatment.

Postoperative cognitive dysfunction: spotlight on light, circadian rhythms, and sleep

Postoperative cognitive dysfunction (POCD) is a neurological disorder characterized by the emergence of cognitive impairment after surgery. A growing body of literature suggests that the onset of POCD is closely tied to circadian rhythm disruption (CRD). Circadian rhythms are patterns of behavioral and physiological change that repeat themselves at approximately, but not exactly, every 24 h. They are entrained to the 24 h day by the daily light-dark cycle. Postoperative CRD affects cognitive function likely by disrupting sleep architecture, which in turn provokes a host of pathological processes including neuroinflammation, blood-brain barrier disturbances, and glymphatic pathway dysfunction. Therefore, to address the pathogenesis of POCD it is first necessary to correct the dysregulated circadian rhythms that often occur in surgical patients. This narrative review summarizes the evidence for CRD as a key contributor to POCD and concludes with a brief discussion of how circadian-effective hospital lighting can be employed to re-entrain stable and robust circadian rhythms in surgical patients.

N1-Acetyl-5-methoxykynuramine, which decreases in the hippocampus with aging, improves long-term memory via CaMKII/CREB phosphorylation

Melatonin is a molecule ubiquitous in nature and involved in several physiological functions. In the brain, melatonin is converted to N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) and then to N1-acetyl-5-methoxykynuramine (AMK), which has been reported to strongly enhance long-term object memory formation. However, the synthesis of AMK in brain tissues and the underlying mechanisms regarding memory formation remain largely unknown. In the present study, young and old individuals from a melatonin-producing strain, C3H/He mice, were employed. The amount of AMK in the pineal gland and plasma was very low compared with those of melatonin at night; conversely, in the hippocampus, the amount of AMK was higher than that of melatonin. Indoleamine 2, 3-dioxygenase (Ido) mRNA was expressed in multiple brain tissues, whereas tryptophan 2,3-dioxygenase (Tdo) mRNA was expressed only in the hippocampus, and its lysate had melatonin to AFMK conversion activity, which was blocked by the TDO inhibitor. The expression levels of phosphorylated cAMP response element binding protein (CREB) and PSD-95 in whole hippocampal tissue were significantly increased with AMK treatment. Before increasing in the whole tissue, CREB phosphorylation was significantly enhanced in the nuclear fraction. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, we found that downregulated genes in hippocampus of old C3H/He mice were more enriched for long-term potentiation (LTP) pathway. Gene set enrichment analysis showed that LTP and neuroactive receptor interaction gene sets were enriched in hippocampus of old mice. In addition, Ido1 and Tdo mRNA expression was significantly decreased in the hippocampus of old mice compared with young mice, and the decrease in Tdo mRNA was more pronounced than Ido1. Furthermore, there was a higher decrease in AMK levels, which was less than 1/10 that of young mice, than in melatonin levels in the hippocampus of old mice. In conclusion, we first demonstrated the Tdo-related melatonin to AMK metabolism in the hippocampus and suggest a novel mechanism of AMK involved in LTP and memory formation. These results support AMK as a potential therapeutic agent to prevent memory decline.

Perioperative neurocognitive disorder changes in elderly diabetes patients within 30 days after surgery: a retrospective cohort study

BACKGROUND

Perioperative neurocognitive disorders (PND) are a common central nervous system complication that predominantly affects the elderly. PND after surgery includes postoperative delirium (POD), delayed neurocognitive recovery up to 30 days (DNR), and postoperative neurocognitive disorder up to 12 months. Diabetes is an important independent risk factor for PND. Over the years, few studies have assessed the incidence of PND and the difference in serum biomarkers between diabetic and non-diabetic patients. We sought to examine the difference in the incidence of PND between elderly diabetic and non-diabetic patients in China and identify the risk factors of PND in elderly diabetics.

METHODS

We conducted a secondary and exploratory data analysis from our prior studies, including patients aged 65 years or older who underwent non-cardiac elective surgery with general anesthesia. We used the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) and Montreal Cognitive Assessment (MoCA) to assess patient cognition.

RESULTS

A total of 236 patients were analyzed; the incidence of PND was significantly higher in diabetic than in non-diabetic patients within 30 days (59.2% vs. 36.8%) (P = 0.022). Multivariate logistic regression analysis showed that the preoperative MoCA was an independent risk factor for PND (odds ratio, 0.88 [0.8 to 0.97]; P = 0.014), and Hosmer-Lemeshow tests showed that it could predict PND in diabetic patients (P = 0.360). According to the maximum Youden index, the optimal cutoff for preoperative MoCA was 21.5 points, yielding a specificity and sensitivity of 88.0% and 55.2% for PND. The levels of glial fibrillary acidic protein (GFAP) and Tau in diabetic patients before and after surgery were significantly higher than in non-diabetic patients among cases of PND (P = 0.002 and 0.011, respectively).

CONCLUSION

The incidence of PND is higher in diabetic than in non-diabetic patients in China, and preoperative MoCA is an independent risk factor for PND in diabetics. Meanwhile, the changes in GFAP and p-Tau in diabetic patients who experienced PND were significantly higher than in non-diabetic ones.

Postsurgery Subjective Cognitive and Short-Term Memory Impairment Among Middle-Aged Chinese Patients

Importance

Perioperative neurocognitive disorder, particularly postoperative cognitive impairment, is common and associated with multiple medical and social adversities, although data from China are lacking.

Objective

To examine the incidence, trajectory, and risk factors for subjective cognitive and short-term memory impairment after surgery in the Chinese population.

Design, Setting, and Participants

This cohort study used data from the China Surgery and Anesthesia Cohort to assess surgical patients aged 40 to 65 years from 2 medical centers between July 15, 2020, and March 31, 2023, with active follow-up within 1 year after the surgery. Of 11 158 patients who were successfully recruited (response rate, 94.4%), 10 149 participants were eligible and available for analysis. From this population, separate cohorts were constructed for analyzing subjective cognitive impairment (8105 noncardiac and 678 cardiac surgery patients) and short-term memory impairment (5246 noncardiac and 454 cardiac surgery patients).

Exposures

Twenty-four potential risk factors regarding comorbidities, preoperative psychological conditions, anesthesia- or surgery-related factors, and postsurgical events were included.

Main Outcomes and Measures

Outcomes included subjective cognitive function measured by the 8-Item Informant Interview to Differentiate Aging and Dementia (AD8; scores range from 0 to 8, with higher scores indicating more severe cognitive impairment) and short-term memory measured by the 3-Word Recall Test (TRT; scores range from 0 to 3, with lower scores indicating more severe short-term memory impairment) at 1, 3, 6, and 12 months after noncardiac and cardiac surgery. Generalized linear mixed models were used to identify risk factors associated with the presence of AD8 (score ≥2) or TRT (score <3) abnormality as well as the aggressively deteriorative trajectories of those cognitive measurements.

Results

For noncardiac surgery patients, the AD8 analysis included 8105 patients (mean [SD] age, 52.3 [7.1] years; 3378 [41.7%] male), and the TRT analysis included 5246 patients (mean [SD] age, 51.4 [7.0] years; 1969 [37.5%] male). The AD8 abnormality incidence rates after noncardiac surgery increased from 2.2% (175 of 8105) at 7 days to 17.1% (1059 of 6191) at 6 months after surgery, before appearing to decrease. In contrast, the TRT abnormality incidence rates followed a U-shaped pattern, with the most pronounced incidence rates seen at 7 days (38.9% [2040 of 5246]) and 12 months (49.0% [1394 of 2845]). Similar patterns were seen among cardiac surgery patients for the AD8 analysis (678 patients; mean [SD] age, 53.2 [6.3] years; 393 [58.0%] male) and TRT analysis (454 patients; mean [SD] age, 52.4 [6.4] years; 248 [54.6%] male). Among noncardiac surgery patients, the top risk factors for aggressively deteriorative AD8 trajectory and for AD8 abnormality, respectively, after surgery were preoperative sleep disturbances (Pittsburgh Sleep Quality Index ≥16 vs 0-5: odds ratios [ORs], 4.04 [95% CI, 2.20-7.40] and 4.54 [95% CI, 2.40-8.59]), intensive care unit stay of 2 days or longer (ORs, 2.43 [95% CI, 1.26-4.67] and 3.07 [95% CI, 1.67-5.65]), and preoperative depressive symptoms (ORs, 1.76 [95% CI, 1.38-2.24] and 2.23 [95% CI, 1.79-2.77]). Analyses for TRT abnormality and trajectory, as well as the analyses conducted among cardiac surgery patients, found fewer associated factors.

Conclusions and Relevance

This cohort study of middle-aged Chinese surgery patients found subjective cognitive and short-term memory impairment within 12 months after both cardiac and noncardiac surgery, with multiple identified risk factors, underscoring the potential of preoperative psychological interventions and optimized perioperative management for postoperative cognitive impairment prevention.

Effect of transcutaneous electrical acupoint stimulation on postoperative cognitive function in older patients with lung cancer: A randomized, double-blind, placebo-controlled trial

Objective

This trial was to examine the effect of transcutaneous electrical acupoint stimulation (TEAS) on postoperative cognitive function in older patients who underwent thoracoscopic pulmonary resection.

Methods

This was a prospective, randomized, double-blind, placebo-controlled study. 128 patients scheduled for surgery were randomly assigned to the TEAS group and sham-TEAS group. A standardized intervention of TEAS or sham-TEAS on the acupoints of Baihui (DU20) and bilateral Neiguan (PC6), Hegu (LI4), and Zusanli (ST36) from 30 min before anesthesia induction until the end of the surgery, combined with a general anesthetic protocol performed in the two groups respectively. The primary outcome was the incidence of postoperative cognitive dysfunction (POCD) assessed via the Montreal Cognitive Assessment (MoCA) scale at each time point. The secondary outcomes included the results of the Mini-Mental State Examination (MMSE) score, the Numerical Rating Scale (NRS) on pain and sleep, the European Organization for Research and Treatment of Cancer Quality of Life (EORTC-QLQ-C30), and a chronic pain questionnaire at relative time points.

Results

Participants who completed the 12-month trial of the two groups were well-matched in baseline demographic and clinical parameters. At postoperative day 1, day 7, and day 30 time points, the incidence of POCD in the sham-TEAS group was always significantly higher than in the TEAS group (65.4% vs 20%, 43.6% vs 7.3%, 40% vs 3.6%, all P < 0.001). Also, the TEAS group showed better scores of MMSE, sleep, and pain compared with the sham-TEAS group (all P < 0.001). At 6 and 12 months points, the global health scores of the TEAS group were still significantly higher than the sham-TEAS group, and the prevalence of chronic pain was significantly lower than the sham-TEAS group (all P < 0.05).

Conclusion

TEAS could effectively improve the postoperative cognitive function and long-term life quality of geriatric patients with lung cancer.

Effects of Different Injection Rates of Propofol on Postoperative Cognition in Elderly Patients Undergoing Laparoscopic Inguinal Hernia Repair

Purpose

This study aimed to explore the effects of different injection rates of propofol on postoperative cognition in elderly patients undergoing laparoscopic inguinal hernia repair.

Methods

A total of 180 elderly patients who planned to undergo laparoscopic inguinal hernia repair were randomly divided into three groups: slow injection of propofol (V_S-Group, 30 mg kg^-1 h^-1); medium injection of propofol (V_M-Group, 100 mg kg^-1 h^-1) or fast injection of propofol (V_F-Group, 300 mg kg^-1 h^-1). Propofol was induced by microinfusion pump, and the depth of anesthesia was monitored by bispectral index (BIS). Propofol and remifentanil were continuously infused during anesthesia maintenance and adjusted according to BIS. The primary outcome was the use of the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) to measure the incidence of postoperative cognitive decline (POCD) in elderly patients on the first and seventh postoperative day. Secondary outcomes included induced dose of propofol, incidence of burst suppression and maximum electroencephalographic (EEG) effect of propofol (BIS-min) during induction.

Results

The incidence of POCD on the first and seventh day postoperatively was similar among the three groups (P > 0.05). However, with the increase of propofol injection rate, induced dose of propofol, incidence of burst suppression and BIS-min during induction, the number of patients requiring vasoactive agents were significantly increased (P < 0.001). Multivariate regression analysis showed that the brief duration of burst suppression during induction did not affect the occurrence of POCD, while age and duration of hospitalization were risk factors for POCD.

Conclusion

For elderly patients undergoing laparoscopic inguinal hernia repair, lowering the injection rate of propofol (such as 30 mg kg^-1 h^-1) cannot decrease the incidence of early POCD, but reduces induction dose of propofol and use of vasoactive drugs, making the patient's hemodynamics more stable.

The effect of melatonin on cognitive functions following coronary artery bypass grafting: A triple-blind randomized-controlled trial

Background

Cognitive dysfunction presents one of the chief causes of postoperative morbidity. Melatonin as a neurohormone can improve neurocognitive functioning and sleep disorders. We evaluated the effect of melatonin on the postoperative cognitive function of patients undergoing coronary artery bypass grafting (CABG).

Materials and Methods

A triple-blind randomized-controlled trial was conducted on 66 CABG candidates in Namazee Hospital (Shiraz, Iran). Patients were assigned equally into two groups receiving melatonin 10 mg or a placebo daily for 4 weeks before surgery and 2 days after surgery in the intensive care unit. The Mini-Mental State Examination (MMSE), Tower of London (ToL), and Wechsler Adults Intelligence Scale-Revised (WAIS-R) cognitive function tests were performed in both groups 4 weeks before surgery (time point 1), 2 days after surgery (time point 2), and 6 weeks after initial administration of melatonin (time point 3).

Results

The mean change score (time point 3-time point 1) differed significantly between the two groups in the MMSE (P ≤ 0.001), ToL total score (P = 0.001), and WAIS-R general IQ (P ≤ 0.001), picture completion (P ≤ 0.001), vocabulary (P = 0.024), and digit span (P = 0.01). On the other hand, no significant differences were detected in the WAIS-R block design, ToL total time delay, ToL total lab, and ToL total result scores.

Conclusion

The MMSE and WAIS-R tests revealed that melatonin might have prophylactic effects against postoperative cognitive disturbance in patients undergoing elective CABG.

Cognitive impairment induced by sevoflurane anesthesia is mediated by the cholinergic system after gastrointestinal surgery in older patients: A randomized, controlled trial

Delayed neurocognitive recovery after surgery is associated with increased morbidity and mortality. However, its mechanism of action remains controversial and complex. A prospective, double-blind, randomized controlled trial was performed at the Affiliated Hospital of Zunyi Medical University. Older patients (aged 65 years and older) who underwent gastrointestinal surgery were randomly divided into sevoflurane-based or propofol-based anesthesia groups. The Mini-Mental State Examination was performed to evaluate cognitive function. Peripheral venous blood was collected to test the levels of choline acetyltransferase and acetylcholinesterase. A total of 75 patients were enrolled and 30 patients in each group completed the study. On Day 1 postoperation, patients in the sevoflurane group showed worse performance on the Mini-Mental State Examination than patients in the propofol group. Lower blood choline acetyltransferase concentrations and higher acetylcholinesterase concentrations were observed in patients who had sevoflurane anesthesia than in patients who had propofol anesthesia 1 day postoperative. At 3 days postoperation, patients with sevoflurane- or propofol-based general anesthesia did not differ regardless of Mini-Mental State Examination score or choline acetyltransferase and acetylcholinesterase levels. Sevoflurane-based anesthesia has short-term delayed neurocognitive recovery in older surgical patients, which may be related to central cholinergic system degeneration.

Perioperative neurocognitive disorders: A narrative review focusing on diagnosis, prevention, and treatment

Perioperative neurocognitive disorders (NCDs) refer to neurocognitive abnormalities detected during the perioperative periods, including preexisting cognitive impairment, preoperative delirium, delirium occurring up to 7 days after surgery, delayed neurocognitive recovery, and postoperative NCD. The Diagnostic and Statistical Manual of Mental Disorders‐5th edition (DSM‐5) is the golden standard for diagnosing perioperative NCDs. Given the impracticality of using the DSM‐5 by non‐psychiatric practitioners, many diagnostic tools have been developed and validated for different clinical scenarios. The etiology of perioperative NCDs is multifactorial and includes predisposing and precipitating factors. Identifying these risk factors is conducive to preoperative risk stratification and perioperative risk reduction. Prevention for perioperative NCDs should include avoiding possible contributors and implementing nonpharmacologic and pharmacological interventions. The former generally includes avoiding benzodiazepines, anticholinergics, prolonged liquid fasting, deep anesthesia, cerebral oxygen desaturation, and intraoperative hypothermia. Nonpharmacologic measures include preoperative cognitive prehabilitation, comprehensive geriatric assessment, implementing fast‐track surgery, combined use of regional block, and sleep promotion. Pharmacological measures including dexmedetomidine, nonsteroidal anti‐inflammatory drugs, and acetaminophen are found to have beneficial effects. Nonpharmacological treatments are the first‐line measures for established perioperative NCDs. Pharmacological treatments are still limited to severely agitated or distressed patients.

Progress in Research on the Effect of Melatonin on Postoperative Cognitive Dysfunction in Older Patients

Postoperative cognitive dysfunction (POCD) is a common complication of the central nervous system in elderly patients after operation. It will prolong the length of stay, reduce the independence and quality of daily life, and increase the risk of death. However, at present, there is a lack of safe and effective ideal drugs for the prevention and treatment of POCD. Melatonin is one of the hormones secreted by the pineal gland of the brain, which has the functions of regulating circadian rhythm, anti-inflammation, anti-oxidation, anti-apoptosis, and so on. Some recent studies have shown that MT can prevent and treat POCD by adjusting circadian rhythm, restoring cholinergic system function, neuroprotection, and so on. This article will introduce POCD, melatonin and the mechanism of melatonin on POCD, respectively, to provide a basis for clinical prevention and treatment of POCD in the elderly.

Effects of Melatonin Treatment on Perioperative Sleep Quality: A Systematic Review and Meta-Analysis with Trial Sequential Analysis of Randomized Controlled Trials

PURPOSE

Perioperative sleep disorders have attracted much attention due to their high prevalence and severe harm, and the current treatment methods are insufficient. Some randomized controlled trials (RCTs) have produced controversial results on whether melatonin can improve perioperative sleep quality. This review aimed to evaluate the effects of melatonin treatment on perioperative sleep quality.

PATIENTS AND METHODS

A systematic search of six databases was performed to identify RCTs investigating melatonin and perioperative sleep. The outcomes analyzed were subjective sleep quality, sleep latency (SL), total sleep time (TST), sleep efficiency (SE), the behavior of awakenings and daily naps, and the incidence of poor sleep quality. RevMan 5.4 and Stata 16 software was used for the meta-analysis and sensitivity analysis, and trial sequential analysis was conducted using TSA 0.9.5.10 Beta software. This study was registered in PROSPERO (registration number: CRD42022311378).

RESULTS

10 studies containing 725 participants were included. Melatonin improved postoperative subjective sleep quality (SMD: -0.30; 95% CI: [-0.47, -0.14]; P = 0.0004) but not preoperative sleep quality (MD: -2.76; 95% CI: [-10.44, 4.91]; P = 0.48). In the postoperative period, 6mg dose had the best efficacy (SMD: -0.31; 95% CI: [-0.57, -0.04]; P = 0.02). Melatonin increased postoperative TST (P = 0.02) and SE (P = 0.002) and decreased the incidence of postoperative poor sleep quality (P = 0.002) but had no effect on SL (P = 0.11), the number and duration of awakenings (P = 0.28; P=0.55), and the number and duration of daily naps (P = 0.26; P = 0.38). The trial sequential analysis showed that the accumulated Z value crossed both the traditional boundary value and the TSA boundary value, further confirming the stability of the result of the meta-analysis.

CONCLUSION

Melatonin treatment can improve postoperative sleep quality. A 6mg daily dose of melatonin may have a better beneficial effect, which needs further exploration. This study supports the application of melatonin for improving postoperative sleep quality.

The Dose and Duration-dependent Association between Melatonin Treatment and Overall Cognition in Alzheimer's Dementia: A Network Meta- Analysis of Randomized Placebo-Controlled Trials

BACKGROUND

While Alzheimer's dementia (AD) has a prevalence as high as 3-32% and is associated with cognitive dysfunction and the risk of institutionalization, no efficacious and acceptable treatments can modify the course of cognitive decline in AD. Potential benefits of exogenous melatonin for cognition have been divergent across trials.

OBJECTIVE

The current network meta-analysis (NMA) was conducted under the frequentist model to evaluate the potential beneficial effects of exogenous melatonin supplementation on overall cognitive function in participants with AD in comparison to other FDA-approved medications (donepezil, galantamine, rivastigmine, memantine, and Namzaric).

METHODS

The primary outcome was the changes in the cognitive function [measured by mini-mental state examination (MMSE)] after treatment in patients with Alzheimer's dementia. The secondary outcomes were changes in the quality of life, behavioral disturbance, and acceptability (i.e., drop-out due to any reason and rate of any adverse event reported).

RESULTS

The current NMA of 50 randomized placebo-controlled trials (RCTs) revealed the medium-term lowdose melatonin to be associated with the highest post-treatment MMSE (mean difference = 1.48 in MMSE score, 95% confidence intervals [95% CIs] = 0.51 to 2.46) and quality of life (standardized mean difference = -0.64, 95% CIs = -1.13 to -0.15) among all of the investigated medications in the participants with AD. Finally, all of the investigated exogenous melatonin supplements were associated with similar acceptability as was the placebo.

CONCLUSION

The current NMA provides evidence for the potential benefits of exogenous melatonin supplementation, especially medium-term low-dose melatonin, in participants with AD.

The Impact of Morning Surgery or Afternoon Surgery on Postoperative Sleep Quality and Melatonin Levels of Elderly Patients: A Prospective, Randomized Study

OBJECTIVE

Postoperative sleep disturbance after surgery is not conducive to the recovery of patients. The purpose of this study was to determine the influence of the timing of surgery (morning vs afternoon) on the postoperative sleep quality of elderly patients and to analyze the relationship between the timing of surgery and the change in the melatonin level.

METHODS

Sixty patients who received hip surgery were randomly assigned to the Morning Group (Group M) or the Afternoon Group (Group A). The sleep quality was assessed by the Richards-Campbell Sleep Questionnaire. Before and after surgery, the nocturnal urine was collected over a 12-h period, and the 6-sulfatoxymelatonin concentration was measured. Also, the incidence of postoperative delirium (POD) was observed.

RESULTS

On the first and second nights after surgery, the sleep quality scores of the patients in Group A were greater than those in Group M, and there was no difference in the sleep quality scores between the two groups on the third night after surgery (P=0.000, P=0.002, P>0.05, respectively). In addition, the urine 6-sulphatoxymelatonin concentration was found to be greater in Group A than in Group M on the first night of surgery (P=0.00). Both the postoperative sleep quality scores and urine 6-sulphatoxymelatonin concentration were significantly less than those before surgery (P=0.00, P=0.00).

CONCLUSION

The postoperative sleep quality scores and melatonin levels of elderly patients who received hip surgery under general anesthesia were significantly less than those of the patients before surgery. Furthermore, the short-term sleep quality of the patients who received surgery in the afternoon was better than that of the patients who received surgery in the morning. This difference may be related to the short-term change of the melatonin level after surgery.

Predicting Delayed Neurocognitive Recovery After Non-cardiac Surgery Using Resting-State Brain Network Patterns Combined With Machine Learning

Delayed neurocognitive recovery (DNR) is a common subtype of postoperative neurocognitive disorders. An objective approach for identifying subjects at high risk of DNR is yet lacking. The present study aimed to predict DNR using the machine learning method based on multiple cognitive-related brain network features. A total of 74 elderly patients (≥ 60-years-old) undergoing non-cardiac surgery were subjected to resting-state functional magnetic resonance imaging (rs-fMRI) before the surgery. Seed-based whole-brain functional connectivity (FC) was analyzed with 18 regions of interest (ROIs) located in the default mode network (DMN), limbic network, salience network (SN), and central executive network (CEN). Multiple machine learning models (support vector machine, decision tree, and random forest) were constructed to recognize the DNR based on FC network features. The experiment has three parts, including performance comparison, feature screening, and parameter adjustment. Then, the model with the best predictive efficacy for DNR was identified. Finally, independent testing was conducted to validate the established predictive model. Compared to the non-DNR group, the DNR group exhibited aberrant whole-brain FC in seven ROIs, including the right posterior cingulate cortex, right medial prefrontal cortex, and left lateral parietal cortex in the DMN, the right insula in the SN, the left anterior prefrontal cortex in the CEN, and the left ventral hippocampus and left amygdala in the limbic network. The machine learning experimental results identified a random forest model combined with FC features of DMN and CEN as the best prediction model. The area under the curve was 0.958 (accuracy = 0.935, precision = 0.899, recall = 0.900, F1 = 0.890) on the test set. Thus, the current study indicated that the random forest machine learning model based on rs-FC features of DMN and CEN predicts the DNR following non-cardiac surgery, which could be beneficial to the early prevention of DNR. Clinical Trial Registration: The study was registered at the Chinese Clinical Trial Registry (Identification number: ChiCTR-DCD-15006096).

Sleep, Pain, and Cognition: Modifiable Targets for Optimal Perioperative Brain Health

The prevention of perioperative neurocognitive disorders is a priority for patients, families, clinicians, and researchers. Given the multiple risk factors present throughout the perioperative period, a multicomponent preventative approach may be most effective. The objectives of this narrative review are to highlight the importance of sleep, pain, and cognition on the risk of perioperative neurocognitive disorders and to discuss the evidence behind interventions targeting these modifiable risk factors. Sleep disruption is associated with postoperative delirium, but the benefit of sleep-related interventions is uncertain. Pain is a risk factor for postoperative delirium, but its impact on other postoperative neurocognitive disorders is unknown. Multimodal analgesia and opioid avoidance are emerging as best practices, but data supporting their efficacy to prevent delirium are limited. Poor preoperative cognitive function is a strong predictor of postoperative neurocognitive disorder, and work is ongoing to determine whether it can be modified to prevent perioperative neurocognitive disorders.

Improved Perioperative Sleep Quality or Quantity Reduces Pain after Total Hip or Knee Arthroplasty: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate the effects of improved perioperative sleep on pain, analgesic consumption, and postoperative nausea and vomiting (PONV) in patients who were undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA).

METHODS

Original studies published from 1 January 1970 to 30 September 2020 were queried in three unique databases using a common search term. The searches sought randomized controlled trials (RCT) investigating the effectiveness of sleep quality or quantity interventions for pain control early after TKA or THA. Grey literature was also searched by screening trial registers. There was no limitation on published language and patients. Two reviewers then assessed studies for eligibility. Eligible studies should have primary outcomes including perioperativeWe have comfirmed the edits. visual analogue scale (VAS) pain score and analgesic consumption; and secondary outcomes including side effects, such as PONV. Data extracted from the literature were abstracted into a comma-separated database spreadsheet using Microsoft Excel. A meta-analysis was then performed. Pooled statistics were calculated with weighting by inverse variance assuming a random effect model. I² was calculated as a quantifier of heterogeneity and interpreted according to the Cochrane manual. All data analysis was performed using Revman software.

RESULTS

From a total of 1285 potential records identified in the electronic search, six studies eventually fulfilled the eligibility criteria. The six controlled RCTs consisted of 207 patients in the sleep-improving group and 209 patients in the control group. The severity of rest pain was significantly lower in the sleep-improving group compared with the control group at day 1 and day 3 postoperatively; the severity of active pain was significantly lower in the sleep-improving group compared with the control group at day 3 postoperatively. Data concerning analgesic drugs could not undergo a meta-analysis due to the difference of eligible studies. No significant difference was found in the incidence of PONV between the sleep-improving group and the control group.

CONCLUSION

Improved perioperative sleep, regardless of quality or quantity, could significantly reduce the pain level at the early stage after TKA or THA, thus the total amount of analgesic drugs consumed was decreased, without significant increase in the incidence of PONV.

Perioperative Sleep Disorder: A Review

Patients in the perioperative period usually present with different types and degrees of sleep disorders, which can severely affect their post-operative outcomes. Multiple risk factors may lead to the occurrence of perioperative sleep disorders, including personal factors, psychological factors, surgery factors, and environmental factors. In this review, we summarize the potential risk factors for perioperative sleep disorders during hospitalization. And it also provides an overview of perioperative outcomes and potential therapeutic prevention of perioperative sleep disorders. However, the further search is necessary to investigate the effectiveness and safety of preventions in the clinical practice and push forward the therapies.

Effects of preoperative melatonin on postoperative pain following cesarean section: A randomized clinical trial

BACKGROUND

Data regarding the analgesic effects of melatonin after the surgery is scare. So far, only one study has investigated the analgesic effect of melatonin during cesarean section. Objective: The present study was performed to investigate the effect of preoperative oral melatonin on pain intensity after cesarean section during spinal anesthesia.

METHODS

In a double-blind randomized controlled clinical trial study, 204 patients undergoing elective cesarean section with class 1 and 2 anesthesia (ASA) were enrolled. Patients were randomly divided into 3 groups of 68 patients. Patients in group A were given 5 mg melatonin tablets, patients in group B were given 10 mg melatonin tablets, and group C was given placebo. All patients underwent spinal anesthesia with the same anesthesia protocol. Pain intensity, nausea, vomiting, pruritus and headache were assessed and recorded 2, 6, 12 and 24 h after surgery. The time of first dose of analgesia, the amount of opioid consumed within 24 h, and the time to resume physical activity was also recorded. Statistical analysis of data was performed using SPSS 20 software.

RESULTS

Repeated measurements of pain intensity during the study showed that in all 3 groups pain intensity was significantly reduced during the study, p < 0.001, respectively. The intensity of pain was significantly different in groups B and C, groups B and A and groups A and C, P < 0.001, respectively. The pain reduction was greatest in group B, followed by group A and group C, respectively. The time interval between the end of surgery and the patient's need for analgesia was significant in group B compared to group A (P = 0.035) and C (P < 0.001) and also in group A compared to group C (P = 0.011). The mean dose of opioid was significantly least in group B, p < 0.001. The mean time to resume physical activity was also shortest in group B, p < 0.001 Headache and nausea/vomiting were observed in 7 patients (10.7%) group A and 7 patients (10.7%) in group C. None of the patients in group B developed complications.

CONCLUSION

The results of the present study showed that the use of 10 mg of melatonin before cesarean section with spinal anesthesia is not only safe, but also reduces the severity of patients' pain, increases the duration of postoperative analgesia, reduces the need for analgesics after surgery and resumption of physical activity.

Delirium REduction after administration of melatonin in acute ischemic stroke (DREAMS): A propensity score-matched analysis

BACKGROUND AND PURPOSE

Poststroke delirium (PSD) comprises a common and severe complication after stroke. However, treatment options for PSD remain insufficient. We investigated whether prophylactic melatonin supplementation may be associated with reduced risk for PSD.

METHODS

Consecutive patients admitted to the Tübingen University Stroke Unit, Tübingen, Germany, with acute ischemic stroke (AIS), who underwent standard care between August 2017 and December 2017, and patients who additionally received prophylactic melatonin (2 mg per day at night) within 24 h of symptom onset between August 2018 and December 2018 were included. Primary outcomes were (i) PSD prevalence in AIS patients and (ii) PSD risk and PSD-free survival in patients with cerebral infarction who underwent melatonin supplementation compared to propensity score-matched (PSM) controls. Secondary outcomes included time of PSD onset and PSD duration.

RESULTS

Out of 465 (81.2%) patients with cerebral infarction and 108 (18.8%) transient ischemic attack (TIA) patients, 152 (26.5%) developed PSD (median time to onset [IQR]: 16 [8-32] h; duration 24 [8-40] h). Higher age, cerebral infarction rather than TIA, and higher National Institutes of Health Stroke Scale score and aphasia on admission were significant predictors of PSD. After PSM (164 melatonin-treated patients with cerebral infarction versus 164 matched controls), 42 (25.6%) melatonin-treated patients developed PSD versus 60 (36.6%) controls (odds ratio, 0.597; 95% confidence interval, 0.372-0.958; p = 0.032). PSD-free survival differed significantly between groups (p = 0.027), favoring melatonin-treated patients. In patients with PSD, no between-group differences in the time of PSD onset and PSD duration were noted.

CONCLUSIONS

Patients prophylactically treated with melatonin within 24 h of AIS onset had lower risk for PSD than patients undergoing standard care. Prospective randomized trials are warranted to corroborate these findings.

Swedish Web Version of the Quality of Recovery Scale Adapted for Patients Undergoing Local Anesthesia and Peripheral Nerve Blockade (SwQoR-LA): Prospective Psychometric Evaluation Study

BACKGROUND

The frequency and timing of assessing patient symptoms and discomfort during postoperative recovery are goals. Therefore, real-time recovery evaluation has been suggested to identify specific deficits in patient recovery.

OBJECTIVE

This study aimed to psychometrically evaluate the Swedish Web Version of the Quality of Recovery (SwQoR) Scale adapted for patients undergoing local and peripheral nerve block (SwQoR-LA).

METHODS

This was a secondary analysis of a psychometric evaluation of 107 patients aged ≥18 years undergoing day surgery under local or peripheral nerve block anesthesia at 4 different day surgery departments in Sweden. The SwQoR-LA, available through a mobile app called Recovery Assessment by Phone Points (RAPP), was completed daily on postoperative days 1-7.

RESULTS

Some evidence of construct validity was supported, and discriminant validity was found in 7 of 8 items related to general anesthesia. The internal consistency was acceptable (.87-.89), and the split-half reliability was 0.80-0.86. Cohen d effect size was 0.98, and the percentage of change from baseline was 43.4%. No floor nor ceiling effects were found.

CONCLUSIONS

The SwQoR-LA is valid, reliable, responsive, and clinically feasible for digital real-time recovery assessment of patient recovery to identify specific deficits in patient recovery and detect those patients who might benefit from a timely intervention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02492191; https://clinicaltrials.gov/ct2/show/NCT02492191.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1136/bmjopen-2015-009901.

The Role of Perioperative Sleep Disturbance in Postoperative Neurocognitive Disorders

Postoperative neurocognitive disorder (PND) increases the length of hospital stay, mortality, and risk of long-term cognitive impairment. Perioperative sleep disturbance is prevalent and commonly ignored and may increase the risk of PND. However, the role of perioperative sleep disturbances in PND remains unclear. Nocturnal sleep plays an indispensable role in learning, memory, and maintenance of cerebral microenvironmental homeostasis. Hospitalized sleep disturbances also increase the incidence of postoperative delirium and cognitive dysfunction. This review summarizes the role of perioperative sleep disturbances in PND and elucidates the potential mechanisms underlying sleep-deprivation-mediated PND. Activated neuroinflammation and oxidative stress; impaired function of the blood-brain barrier and glymphatic pathway; decreased hippocampal brain-derived neurotrophic factor, adult neurogenesis, and sirtuin1 expression; and accumulated amyloid-beta proteins are associated with PND in individuals with perioperative sleep disorders. These findings suggest that the improvement of perioperative sleep might reduce the incidence of postoperative delirium and postoperative cognitive dysfunction. Future studies should further investigate the role of perioperative sleep disturbance in PND.

Melatonin for preoperative and postoperative anxiety in adults

BACKGROUND

Anxiety in relation to surgery is a well-known problem. Melatonin offers an alternative treatment to benzodiazepines for ameliorating this condition in the preoperative and postoperative periods.

OBJECTIVES

To assess the effects of melatonin on preoperative and postoperative anxiety compared to placebo or benzodiazepines.

SEARCH METHODS

We searched the following databases on 10 July 2020: CENTRAL, MEDLINE, Embase, CINAHL, and Web of Science. For ongoing trials and protocols, we searched clinicaltrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform.

SELECTION CRITERIA

We included randomized, placebo-controlled or standard treatment-controlled (or both) studies that evaluated the effects of preoperatively administered melatonin on preoperative or postoperative anxiety. We included adult patients of both sexes (15 to 90 years of age) undergoing any kind of surgical procedure for which it was necessary to use general, regional, or topical anaesthesia.

DATA COLLECTION AND ANALYSIS

One review author conducted data extraction in duplicate. Data extracted included information about study design, country of origin, number of participants and demographic details, type of surgery, type of anaesthesia, intervention and dosing regimens, preoperative anxiety outcome measures, and postoperative anxiety outcome measures.

MAIN RESULTS

We included 27 randomized controlled trials (RCTs), involving 2319 participants, that assessed melatonin for treating preoperative anxiety, postoperative anxiety, or both. Twenty-four studies compared melatonin with placebo. Eleven studies compared melatonin to a benzodiazepine (seven studies with midazolam, three studies with alprazolam, and one study with oxazepam). Other comparators in a small number of studies were gabapentin, clonidine, and pregabalin. No studies were judged to be at low risk of bias for all domains. Most studies were judged to be at unclear risk of bias overall. Eight studies were judged to be at high risk of bias in one or more domain, and thus, to be at high risk of bias overall. Melatonin versus placebo Melatonin probably results in a reduction in preoperative anxiety measured by a visual analogue scale (VAS, 0 to 100 mm) compared to placebo (mean difference (MD) -11.69, 95% confidence interval (CI) -13.80 to -9.59; 18 studies, 1264 participants; moderate-certainty evidence), based on a meta-analysis of 18 studies. Melatonin may reduce immediate postoperative anxiety measured on a 0 to 100 mm VAS compared to placebo (MD -5.04, 95% CI -9.52 to -0.55; 7 studies, 524 participants; low-certainty evidence), and may reduce delayed postoperative anxiety measured six hours after surgery using the State-Trait Anxiety Inventory (STAI) (MD -5.31, 95% CI -8.78 to -1.84; 2 studies; 73 participants; low-certainty evidence). Melatonin versus benzodiazepines (midazolam and alprazolam) Melatonin probably results in little or no difference in preoperative anxiety measured on a 0 to 100 mm VAS (MD 0.78, 95% CI -2.02 to 3.58; 7 studies, 409 participants; moderate-certainty evidence) and there may be little or no difference in immediate postoperative anxiety (MD -2.12, 95% CI -4.61 to 0.36; 3 studies, 176 participants; low-certainty evidence). Adverse events Fourteen studies did not report on adverse events. Six studies specifically reported that no side effects were observed, and the remaining seven studies reported cases of nausea, sleepiness, dizziness, and headache; however, no serious adverse events were reported. Eleven studies measured psychomotor and cognitive function, or both, and in general, these studies found that benzodiazepines impaired psychomotor and cognitive function more than placebo and melatonin. Fourteen studies evaluated sedation and generally found that benzodiazepine caused the highest degree of sedation, but melatonin also showed sedative properties compared to placebo. Several studies did not report on adverse events; therefore, it is not possible to conclude with certainty, from the data on adverse effects collected in this review, that melatonin is better tolerated than benzodiazepines.

AUTHORS' CONCLUSIONS

When compared with placebo, melatonin given as premedication (as tablets or sublingually) probably reduces preoperative anxiety in adults (measured 50 to 120 minutes after administration), which is potentially clinically relevant. The effect of melatonin on postoperative anxiety compared to placebo (measured in the recovery room and six hours after surgery) was also evident but was much smaller, and the clinical relevance of this finding is uncertain. There was little or no difference in anxiety when melatonin was compared with benzodiazepines. Thus, melatonin may have a similar effect to benzodiazepines in reducing preoperative and postoperative anxiety in adults.

The Effect and Optimal Dosage of Dexmedetomidine Plus Sufentanil for Postoperative Analgesia in Elderly Patients With Postoperative Delirium and Early Postoperative Cognitive Dysfunction: A Single-Center, Prospective, Randomized, Double-Blind, Controlled Trial

Background

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are common complications after major surgery among elderly patients. Dexmedetomidine (DEX) is less frequently explored for its effects in patients with postoperative neurocognitive disorders. This study investigated the effect and optimal dosage of DEX for patient-controlled analgesia (PCA) on POD and early POCD after major surgery among elderly patients.

Methods

Patients in four groups received continuous infusion of DEX 0, 100, 200, and 400 μg with sufentanil 150 μg for PCA immediately after surgery. POD and POCD were assessed on postoperative days 1, 2, 3, and 7 by using the Confusion Assessment Method (CAM) and Mini-Mental State Examination (MMSE) scales. Furthermore, the incidence of POD and POCD of all the four groups in postoperative 7 days classified by high risk factors (age, education, surgical site, and surgical category), sedation level, postoperative pain intensity, and side effects were assessed.

Results

The overall incidence rates of POD and early POCD 7 days after surgery were lower in the DEX 200 μg 400 μg groups than in the DEX 0 μg and 100 μg groups (P < 0.05). Compared with DEX 200 μg, DEX 400 μg reduced early POCD in patients who underwent open surgery (P < 0.05). There were no intergroup differences in the postoperative sedation level, pain intensity, and side effects.

Conclusion

The continuous infusion of DEX 200 μg or DEX 400 μg in PCA significantly decreased the incidence of POD and early POCD after major surgery without increasing any side effects. Compared with DEX 200 μg, DEX 400 μg was preferred for reducing early POCD in patients who underwent open surgery.

Effect of Melatonin on Postoperative Pain and Perioperative Opioid Use: A Meta-analysis and Trial Sequential Analysis

OBJECTIVES

We performed this meta-analysis in order to assess the effect of melatonin on postoperative pain and perioperative opioid consumption.

METHODS

We systematically searched PubMed, EMBASE, and the Cochrane Library until October 2019 for studies concerning the effect of melatonin vs. placebo on postoperative pain. We also searched for grey literature in ClnicalTrials.gov and grey literature databases, including OpenGrey and Grey Literature Report. We performed a meta-analysis of postoperative pain scores, perioperative opioid use, the number of patients with analgesic requirements, the time to the first analgesic requirement, length of hospital stay, and common reported adverse events of melatonin.

RESULTS

According to the inclusion and exclusion criteria, 15 studies with a total of 1,102 patients were included in the final analysis. Melatonin was significantly associated with decreased VAS score (24 hours postoperatively) compared to placebo (trial sequential analysis = conclusive; mean difference [MD] -0.86; 95% confidence interval [CI] -1.38, -0.34; P = 0.001). Patients randomly assigned to melatonin were administered less postoperative opioids than patients in the control groups (trial sequential analysis = inconclusive; MD -3.33 mg; 95% CI -5.28, -1.38; P = 0.0008). The need for analgesic requirements was significantly decreased in the melatonin group. Patients who received melatonin had a significantly longer time to the first analgesic requirement. Compared to the placebo group, there were no significant differences in terms of length of hospital stay, dizziness, headache, paresthesia, and nausea.

CONCLUSIONS

Given the low quality of evidence, minor degree of VAS score reduction, and inconclusive trial sequential analysis of postoperative opioid consumption, this meta-analysis neither supports nor opposes the effect of melatonin on postoperative pain.

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.

Postoperative cognitive dysfunction in elderly patients undergoing hip arthroplasty

Even after successful hip arthroplasty, elderly patients who have undergone this procedure remain subject to cognitive decline and may collectively develop postoperative cognitive dysfunction (POCD). However, no consensus exists as to the risk factors resulting in a higher likelihood that a patient may present with this complication, and the aetiology of POCD is not well understood. We conducted a systematic review of papers concerning the influence of POCD-related risk factors in patients undergoing hip arthroplasty but limited the literature search to papers in English. A systematic and electronic search for manuscripts in the PubMed database was performed in order to identify all studies in which the risk factors for POCD were investigated. Articles were also obtained from the authors' files. Keywords for the search were postoperative cognitive dysfunction/change/impairment/decline/deficit, elderly/older/aged patients, and hip arthroplasty/replacement surgery. The evidence published to date suggests that POCD is a multifactorial disease, which includes an individual patient's characteristics, surgery, type of anaesthesia, and pain levels. All of these factors can increase the risk of POCD incidence. There are a number of factors that appear to influence the risk of early cognitive dysfunction after hip arthroplasty. Nevertheless, the specific mechanism and explicit risk factors associated with this cognitive dysfunction are not completely understood. Hip arthroplasty has made it possible for older patients to find relief from pain and improve their function, whereas it also increases the risk for suffering POCD that may affect these patients' quality of life and increase their mortality. Therefore, it is worthwhile investigating the mechanism of POCD in future studies in order to prevent and treat this condition.

Anesthetic management of geriatric patients

The number of elderly patients who frequently access health care services is increasing worldwide. While anesthesiologists are developing the expertise to care for these elderly patients, areas of concern remain. We conducted a comprehensive search of major international databases (PubMed, Embase, and Cochrane) and a Korean database (KoreaMed) to review preoperative considerations, intraoperative management, and postoperative problems when anesthetizing elderly patients. Preoperative preparation of elderly patients included functional assessment to identify preexisting cognitive impairment or cardiopulmonary reserve, depression, frailty, nutrition, polypharmacy, and anticoagulation issues. Intraoperative management included anesthetic mode and pharmacology, monitoring, intravenous fluid or transfusion management, lung-protective ventilation, and prevention of hypothermia. Postoperative checklists included perioperative analgesia, postoperative delirium and cognitive dysfunction, and other complications. A higher level of perioperative care was required for older surgical patients, as multiple chronic diseases often makes them prone to developing postoperative complications, including functional decline and loss of independence. Although the guiding evidence remains poor so far, elderly patients have to be provided optimal perioperative care through close interdisciplinary, interprofessional, and cross-sectional collaboration to minimize unwanted postoperative outcomes. Furthermore, along with adequate anesthetic care, well-planned postoperative care should begin immediately after surgery and extend until discharge.

BIS-guided deep anesthesia decreases short-term postoperative cognitive dysfunction and peripheral inflammation in elderly patients undergoing abdominal surgery

OBJECTIVES

Postoperative cognitive dysfunction (POCD) is a common clinical complication, with an underlying pathophysiology linked to heightened levels of neuroinflammation. However, it requires clarification as to whether the depth of anesthesia modulates postoperative cognitive dysfunction. This study investigated the association between depth of anesthesia and POCD in elderly patients undergoing abdominal surgery.

METHODS

A total of 120 patients aged 60 years or older who were planned for abdominal surgery under total intravenous anesthesia were included in this study. The depth of anesthesia was guided by monitoring Bispectral Index (BIS) data. All study participants completed a battery of nine neuropsychological tests before surgery and at 7 days and 3 months after surgery. POCD was calculated by using the reliable change index. Plasma concentration of C-reactive protein (CRP), interleukin (IL)-1β, IL-10, S-100β, and norepinephrine (NE) were measured.

RESULTS

The incidence of POCD at 7 days after surgery in the deep anesthesia group was 19.2% (10/52), which was significantly lower (p = 0.032) than the light anesthesia group 39.6% (21/53). The depth of anesthesia had no effect on POCD at 3 months after surgery (10.3% vs 14.6%, respectively, p = 0.558). Similarly, plasma levels of CRP and IL-1β in deep anesthesia group were lower than that in light anesthesia group at 7 days after surgery (p < 0.05), but not at 3 months after surgery (p > 0.05). There were no significant differences in the plasma concentration of IL-10, S-100β, and NE between the groups (p > 0.05).

CONCLUSIONS

Deep anesthesia under total intravenous anesthesia could decrease the occurrence of short-term POCD and inhibit postoperative peripheral inflammation in elderly patients undergoing abdominal surgery, compared with light anesthesia.

Protocol for a prospective cohort study of assessing postoperative cognitive changes after total hip and knee arthroplasty in the Greater Toronto area

INTRODUCTION

Cognitive changes after anaesthesia and surgery, such as delirium and postoperative cognitive dysfunction (POCD), are common and lead to poor outcomes and increased healthcare costs. While several interventions for delirium exist, there are no effective treatment strategies for POCD. Understanding the risks and contributing factors may offer clinicians unique opportunities to better identify and develop preventative interventions for those at higher risk. Elderly patients undergoing orthopaedic surgery are at high risk of developing postoperative delirium (PD) and POCD. The incidence of POCD has not been rigorously studied in the total hip and knee arthroplasty (THA/TKA) population. Therefore, we have designed a prospective, observational cohort study to assess POCD in patients undergoing THA/TKA, both increasingly common procedures. The incidence of PD and POCD in a high volume, tertiary care arthroplasty centre will be determined and associated risk factors will be identified.

METHODS AND ANALYSIS

Cognitive function will be tested with a computer-based cognitive assessment tool [CogState Brief Battery], preoperatively at baseline and postoperatively while in hospital at (<3 days), 6 weeks and 4.5 months. The primary outcome is the incidence of postoperative cognitive decline at 4.5 months. Logistic regression analysis is planned to test the association of POCD with several potential risk factors. In addition, delirium will be assessed preoperatively and postoperatively in the hospital using the Confusion Assessment Method (3D-CAM).

ETHICS AND DISSEMINATION

The protocol for this prospective observational study was approved by the Sunnybrook Health Sciences Centre Research Ethics Board (REB#: 040-2017). Recruitment commenced in May 2017 and will continue until 2019. The results will be disseminated in a peer-reviewed journal and in scientific meetings.

TRIAL REGISTRATION NUMBER

NCT03147937.

Perioperative cognitive evaluation

PURPOSE OF REVIEW

This article reviews the recent clinical evidence published between January 2017 and June 2018 - related to perioperative cognitive evaluation. Namely, new insights into risk factors, prevention, diagnosis and diagnostic tools and treatment.

RECENT FINDINGS

Several risk factors (preoperative, intraoperative and postoperative) have been found to be associated with the development of postoperative delirium (POD) and/or postoperative cognitive dysfunction (POCD). Short-term and long-term postoperative consequences can be reduced by targeting risk factors, introducing preventive strategies and including frequent cognitive monitoring. Administration of medications such as ketamine, opioids and benzodiazepines are associated with increased cognitive dysfunction. Prevention of POD/POCD starts with creating an environment, which promotes return to preoperative baseline functioning. This includes frequent monitoring of cognitive status, access to rehabilitation and psychological and social supports, and avoiding polypharmacy. In addition, patients should have early access to their sensory aids and maintain normal circadian rhythm. Treatment of POD/POCD has pharmacological and nonpharmacological approaches.

SUMMARY

Clinical evidence on POD/POCD is continuously evolving, which is essential in guiding clinical management to provide the highest quality of clinical care.

Melatonin: Clinical Perspectives in Neurodegeneration

Prevention of neurodegenerative diseases is presently a major goal for our Society and melatonin, an unusual phylogenetically conserved molecule present in all aerobic organisms, merits consideration in this respect. Melatonin combines both chronobiotic and cytoprotective properties. As a chronobiotic, melatonin can modify phase and amplitude of biological rhythms. As a cytoprotective molecule, melatonin reverses the low degree inflammatory damage seen in neurodegenerative disorders and aging. Low levels of melatonin in blood characterizes advancing age. In experimental models of Alzheimer's disease (AD) and Parkinson's disease (PD) the neurodegeneration observed is prevented by melatonin. Melatonin also increased removal of toxic proteins by the brain glymphatic system. A limited number of clinical trials endorse melatonin's potentiality in AD and PD, particularly at an early stage of disease. Calculations derived from animal studies indicate cytoprotective melatonin doses in the 40-100 mg/day range. Hence, controlled studies employing melatonin doses in this range are urgently needed. The off-label use of melatonin is discussed.

Adverse events associated with oral administration of melatonin: A critical systematic review of clinical evidence

While melatonin was once thought of simply as a sleep-inducing hormone, recent research has resulted in development of a deeper understanding of the complex physiological activity of melatonin in the human body. Along with this understanding has come widespread, increasing use of melatonin supplementation, extending beyond its traditional use as a sleep aid into novel fields of application. This increased use often involves off-label and self-prescription, escalating the importance of safety data. In order to examine the current knowledge relating to safety of the exogenous neurohormone, we conducted a comprehensive, critical systematic review of clinical evidence. We examined controlled studies of oral melatonin supplementation in humans when they presented any statistical analysis of adverse events. Of the fifty articles identified, twenty-six found no statistically significant adverse events, while twenty-four articles reported on at least one statistically significant adverse event. Adverse events were generally minor, short-lived and easily managed, with the most commonly reported adverse events relating to fatigue, mood, or psychomotor and neurocognitive performance. A few studies noted adverse events relating to endocrine (e.g. reproductive parameters, glucose metabolism) and cardiovascular (e.g. blood pressure, heart rate) function, which appear to be influenced by dosage, dose timing and potential interactions with antihypertensive drugs. Oral melatonin supplementation in humans has a generally favourable safety profile with some exceptions. Most adverse effects can likely be easily avoided or managed by dosing in accordance with natural circadian rhythms. Further research is required to explore the potential for melatonin to interact with endogenous hormones and pharmaceuticals.

Short- and Long-Term Protective Effects of Melatonin in a Mouse Model of Sepsis-Associated Encephalopathy

Brain dysfunction is a common complication after sepsis and is an independent risk factor for a poor prognosis, which is partly attributed to the dysregulated inflammatory response and oxidative damage. Melatonin regulates the sleep-wake cycle and also has potent anti-inflammatory and antioxidant properties, yet the protective effects of melatonin on sepsis-induced neurobehavioral dysfunction remain to be elucidated. In the present study, melatonin was administered intraperitoneally daily at a dose of 10 mg/kg for three consecutive days immediately (early treatment) or 7 days (delayed treatment) after sham operation or cecal ligation and puncture (CLP), followed by an additional treatment in drinking water until the end of behavioral tests. The concentrations of pro-inflammatory cytokines (tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), IL-6, IL-10), malondialdehyde (MDA), superoxide dismutase (SOD), reactive oxygen species (ROS), brain-derived neurotrophic factor (BDNF), and glial cell line-derived neurotrophic factor (GDNF) were determined at the indicated time points. Compared with the CLP + vehicle group, we found that early melatonin treatment resulted in increased survival rate but not improvement in measures of neurobehavioral outcomes, which was accompanied by significantly lower plasma level of IL-1β. Intriguingly, delayed melatonin treatment improved neurobehavioral dysfunction by normalization of hippocampal BDNF and GDNF expressions. In conclusion, our study suggests the beneficial effects of both early and delayed melatonin treatment after sepsis development, which implicates melatonin has a potential therapeutic value in sepsis-associated organ damage including brain dysfunction.

Melatonin and the Prevention and Management of Delirium: A Scoping Study

Background

The therapeutic benefit of melatonin in the prevention and treatment of delirium is uncertain.

Objective

To perform a scoping study to describe the existing literature regarding the use of melatonin and ramelteon in the prevention and treatment of delirium.

Methods

We performed a scoping study using the Arksey and O’Malley framework to explore our objective. Two independent panels searched MEDLINE, OVID, EMBASE, PubMed, Google Scholar, and Cochrane Library for relevant articles up to November 2017 describing the use of melatonin and ramelteon in the prevention or management of delirium. We extracted relevant summary data from the studies and attempted to draw conclusion regarding benefit.

Results

We summarized evidence from 20 relevant articles. There were a total of nine articles: five randomized controlled trials (RCTs), two retrospective medical record reviews, one non-randomized observational study, and one case report describing the role of either melatonin or ramelteon in preventing delirium. There were a total of 11 studies studying the role of either melatonin or ramelteon in the management of established delirium. None of these were RCT and were predominantly case series and case reports. Four of the five trials studying the effect of melatonin analogs in preventing delirium reported a beneficial effect but study heterogeneity limited any broad recommendations. Similarly, the lack of any well-designed trials limits any recommendations regarding the effect of melatonin analogs in treating delirium.

Conclusion

Large, well-designed clinical trials are required to explore the potential beneficial effects of melatonin and ramelteon on delirium prevention and management.

The Role of Neuroinflammation in Postoperative Cognitive Dysfunction: Moving From Hypothesis to Treatment

Postoperative cognitive dysfunction (POCD) is a common complication of the surgical experience and is common in the elderly and patients with preexisting neurocognitive disorders. Animal and human studies suggest that neuroinflammation from either surgery or anesthesia is a major contributor to the development of POCD. Moreover, a large and growing body of literature has focused on identifying potential risk factors for the development of POCD, as well as identifying candidate treatments based on the neuroinflammatory hypothesis. However, variability in animal models and clinical cohorts makes it difficult to interpret the results of such studies, and represents a barrier for the development of treatment options for POCD. Here, we present a broad topical review of the literature supporting the role of neuroinflammation in POCD. We provide an overview of the cellular and molecular mechanisms underlying the pathogenesis of POCD from pre-clinical and human studies. We offer a brief discussion of the ongoing debate on the root cause of POCD. We conclude with a list of current and hypothesized treatments for POCD, with a focus on recent and current human randomized clinical trials.