Melatonin for the prevention of postoperative delirium in older adults: a systematic review and meta-analysis

Pharmacological Prevention of Postoperative Delirium in Adults: A Review of Recent Literature

PURPOSE OF REVIEW

Postoperative delirium (POD) is a common complication that has important implications for surgical patients, often leading to both short- and long-term cognitive deficits, worse outcomes, and increased healthcare costs. Given these implications, there may be a benefit in reducing the incidence of POD. Pharmacologic interventions may have the potential to reduce the risk of a patient developing POD.

RECENT FINDINGS

Recently studied therapies include dexmedetomidine, propofol, haloperidol, ketamine, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, acetaminophen, melatonin/ramelteon, corticosteroids, midazolam, physostigmine, and neostigmine. In addition, the implementation of regional anesthesia and reduction of overall anesthetic depth have been examined. Of these therapies, dexmedetomidine has been studied the most and has the most supporting evidence for prevention of POD, but current studies lack clarity on optimal dosing and timing of dexmedetomidine administration. Acetaminophen, corticosteroids, and melatonin/ramelteon are other plausible medications that have potential for reducing POD incidence, but they all require further investigation. Reduction of anesthetic depth and regional anesthetics are options for anesthetic management that show promise but still lack enough supporting evidence in recent literature to receive a strong recommendation. Future research should focus on identifying optimal strategies for the implementation of the pharmacological options listed, including doses and timing of administration. Attention should be given to dexmedetomidine given its promise demonstrated by recent literature.

Delirium in the ICU: how much do we know? A narrative review

Delirium in critical ill patients is a complex and common neurological syndrome in the intensive care unit (ICU) that is caused by a range of structural or functional abnormalities. ICU Delirium is associated with reduced compliance, prolonged hospital stays, greater use or delayed withdrawal of sedatives, higher rates and durations of mechanical ventilation, and higher rates of mortality. The aetiology and pathogenesis of ICU delirium are unclear, and the lack of better prediction, prevention, and treatment measures leads to a non-standardized control of delirium. By searching the relevant literature, we aim in this narrative review to describe progress in the pathogenesis, predictive biomarkers, diagnosis, and treatment of ICU delirium.

Incidence and related risk factors for postoperative delirium following revision total knee arthroplasty: a retrospective nationwide inpatient sample database study

BACKGROUND

Postoperative delirium (POD) is a common surgical complication. However, the incidence and risk factors associated with postoperative delirium after revision total knee arthroplasty (rTKA) have not been comprehensively explored through extensive national databases.

METHODS

Utilizing the National Inpatient Sample (NIS), the largest comprehensive U.S. hospital healthcare database, we undertook a retrospective investigation involving 127,400 patients who underwent rTKA between 2010 and 2019. We assessed various aspects, including patient demographics, hospital characteristics, pre-existing medical conditions, and perioperative complications.

RESULTS

The overall incidence of postoperative delirium (POD) in patients undergoing rTKA between 2010 and 2019 was 0.97%. The highest incidence rate of 1.31% was recorded in 2013. Notably, this patient cohort demonstrated advanced age, increased burden of co-morbidities, prolonged hospital stays, increased hospitalization costs, and elevated in-hospital mortality rates (P < 0.001). Moreover, non-elective admissions, non-private insurance payments, and a preference for teaching hospitals were commonly observed among these patients. During their hospitalization, individuals who developed delirium subsequent to rTKA were more prone to experiencing certain perioperative complications. These complications encompassed medical issues like acute myocardial infarction, continuous invasive mechanical ventilation, postoperative shock, sepsis, stroke and other medical problems. Additionally, surgical complications including hemorrhage / seroma / hematoma, irrigation and debridement, prosthetic joint infection, periprosthetic fracture, and wound dehiscence / nonunion were noted. Several risk factors were found to be linked with the development of POD. These included advanced age (≥ 75 years), alcohol abuse, coagulation disorders, congestive heart failure, depression, fluid and electrolyte imbalances, and more. Conversely, female sex, having private insurance, and undergoing elective hospitalization emerged as protective factors against POD.

CONCLUSION

Our findings suggest that the general prevalence of POD in rTKA is relatively low according to NIS. There was a significant connection between the POD of rTKA and advanced age, prolonged length of stay (LOS), more in-patients' costs, higher in-hospital mortality rate, increased comorbidities, postoperative medical complications and postoperative surgical complications. This study helps to understand the risk factors associated with POD to improve poor outcomes.

Postoperative use of sleep aids and delirium in older adults after major surgery: A retrospective cohort study

BACKGROUND

Sleep aids are commonly prescribed to treat sleep disturbance, a modifiable risk factor for postoperative delirium in older patients. The use of melatonin receptor agonists in the postoperative period has been increasing. The comparative safety of melatonin receptor agonists, zolpidem, and temazepam remains uncertain.

METHODS

This retrospective study included 22,083 patients ≥65 years old who initiated melatonin receptor agonists, zolpidem, or temazepam after major surgery in the Premier Healthcare Database 2009-2018. We performed propensity score-based overlap weighting and estimated the risk ratio (RR) and risk difference (RD) of postoperative delirium as the primary outcome and a composite of delirium or new antipsychotic initiation, pneumonia, and in-hospital mortality as secondary outcomes.

RESULTS

The mean age of the study population was 78 (SD, 7) years and 50% were female. There was no significant difference in the risk of postoperative delirium among patients treated with melatonin receptor agonists (3.4%, reference group), zolpidem (2.9%; RR [95% CI], 0.9 [0.7-1.2]; RD [95% CI] per 100 persons, -0.3 [-1.1 to 0.6]), and temazepam (3.1%; 0.9 [0.7-1.1]; RD [95% CI] per 100 persons, -0.5 [-1.2 to 0.3]). The risks of delirium or new antipsychotic initiation, pneumonia, and in-hospital mortality were also similar among all groups.

CONCLUSIONS

Melatonin receptor agonists were not associated with a lower risk of postoperative delirium and other adverse outcomes compared with zolpidem and temazepam in older adults after major surgery.

Nicotinamide Adenine Dinucleotide Does Not Improve Anesthetic Recovery in Rodents

Nicotinamide Adenine Dinucleotide (NAD+) is implicated in bioenergetics, DNA repair, and senescence. Depletion of NAD+ is associated with aging and neurodegenerative disease, prompting a growing interest in NAD+ supplementation. With rising over-the-counter use of NAD, understanding their impact on perioperative recovery becomes essential. This study investigates the effect of NADH, a common NAD+ precursor, on anesthesia in rodents. Baseline and post-anesthesia (1.5% isoflurane) open field and Y-maze activity were recorded in adult male and female C57/BL6 mice (n = 8-10/group). NADH (150 mg/kg, intraperitoneal) or vehicle (0.9% normal saline) were given at baseline or during anesthesia. The NADH-treated group exhibited a significant decrease in open-field activity relative to vehicle-treated. This diminished activity was reflected in reduced distance travelled and average velocity after emergence from anesthesia in the NADH-treated group. NADH treatment did not improve Y-maze performance after anesthesia as the number of visits to the novel arm was significantly decreased. This study demonstrates a potentially adverse impact of NADH on recovery from anesthesia. We revealed a depression in open-field activity and Y-maze performance with NADH supplementation, an indicator of cognitive recovery in rodents. The broad implications of NAD+ in aging are likely to shape supplementation trends, highlighting the importance of understanding the potential influence of administering NAD+ on anesthetic sensitivity and recovery.

The impact of melatonin on postoperative delirium in geriatric patients after colorectal surgery: a randomized placebo-controlled trial

BACKGROUND

The current study was designed to evaluate the role of prophylactic melatonin administration in reducing delirium occurrence in elderly patients undergoing colorectal cancer surgeries.

METHODS

One hundred patients of both genders undergoing elective colorectal cancer surgeries under general anesthesia were randomly allocated into two equal groups. A treatment group of patients (Melatonin group) received five mg of melatonin the night before surgery, twelve hours before the scheduled surgery time, and an additional five mg of melatonin two hours before surgery. The control group of patients received placebo tablets at the same time points. Delirium score, sedation score, pain score, hemodynamics, oxygen saturation, and blood requirements were recorded.

RESULTS

Twenty-eight patients (56%) in the control group versus 18 (36%) in the melatonin group developed delirium (P=0.045), OR=2.26, 95% CI: 1.013-5.05. Five patients (18%) in the control group versus six (33%) ‎in the melatonin group developed delirium on discharge from the ‎recovery room (P=0.749), OR=1.22, 95% CI: 0.34-4.31, while 23 patients (82%) in the control group versus ‎‎12 (66%) in the melatonin group developed delirium six hours postoperative (P=0.021), OR=1.705, 95% CI: 1.02-2.81 ‎with higher nursing delirium screening score in the control group 2 (1, 4) versus 1 (0, 2) in the melatonin group (P=0.002), 95% CI: 1.77-2.71.

CONCLUSIONS

The prophylactic administration of melatonin may decrease the incidence of postoperative delirium in elderly patients undergoing colorectal surgeries under general anesthesia.

Assessing the Premedication Properties of Sublingual Melatonin in Young Women Undergoing Cesarean Section With Spinal Anesthesia: A Double-Blind Randomized Study

INTRODUCTION

Preoperative anxiety can negatively impact patient outcomes by influencing the intraoperative requirements for anesthetics and analgesics, increasing postoperative pain intensity, and augmenting the need for analgesia. Moreover, it may contribute to higher rates of postoperative morbidity and mortality following certain types of surgery. This study investigates the anxiolytic and sedative properties of sublingual melatonin as a premedication agent in young females undergoing cesarean section under spinal anesthesia.

METHODS

A double-blind, randomized, placebo-controlled trial was conducted in Nasiriyah, Iraq. Eighty females were included, 40 in each group, based on specific inclusion and exclusion criteria. Premedication was administered in the morning, 60 minutes before the procedure. In the melatonin group (M), patients received 10 mg of sublingual melatonin, while the placebo group (P) received placebo premedication. Anxiety and sedation levels were evaluated three times: before taking premedication, five minutes before the insertion of the spinal needle, and one hour postoperatively, using the visual analog scale and Richmond Sedation Scale.

RESULTS

The results show a highly significant P-value regarding anxiety levels between the M Group and P Group (p-value < 0.001). There was a significant difference in the median sedation scores between the studied groups at pre-spinal insertion and postoperatively (p-value < 0.001). The mean heart rate in the M Group was significantly lower than in the P Group (p-value = 0.0019). Significant differences were noted in systolic and diastolic blood pressures between the two groups, measured five minutes before and after spinal needle insertion (p-value < 0.001).

CONCLUSION

These findings contribute to understanding the impact of sublingual melatonin as an anxiolytic and sedative premedication agent on patients undergoing elective cesarean sections under spinal anesthesia. Further research is warranted to fully elucidate the benefits and implications of melatonin administration in such procedures.

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.

Sleep and circadian biomarkers of postoperative delirium (SLEEP-POD): protocol for a prospective and observational cohort study

INTRODUCTION

Surgical patients over 70 experience postoperative delirium (POD) complications in up to 50% of procedures. Sleep/circadian disruption has emerged as a potential risk factor for POD in epidemiological studies. This protocol presents a single-site, prospective observational study designed to examine the relationship between sleep/circadian regulation and POD and how this association could be moderated or mediated by Alzheimer's disease (AD) pathology and genetic risk for AD.

METHODS AND ANALYSIS

Study staff members will screen for eligible patients (age ≥70) seeking joint replacement or spinal surgery at Massachusetts General Hospital (MGH). At the inclusion visit, patients will be asked a series of questionnaires related to sleep and cognition, conduct a four-lead ECG recording and be fitted for an actigraphy watch to wear for 7 days before surgery. Blood samples will be collected preoperatively and postoperatively and will be used to gather information about AD variant genes (APOE-ε4) and AD-related pathology (total and phosphorylated tau). Confusion Assessment Method-Scale and Montreal Cognitive Assessment will be completed twice daily for 3 days after surgery. Seven-day actigraphy assessments and Patient-Reported Outcomes Measurement Information System questionnaires will be performed 1, 3 and 12 months after surgery. Relevant patient clinical data will be monitored and recorded throughout the study.

ETHICS AND DISSEMINATION

This study is approved by the IRB at MGH, Boston, and it is registered with the US National Institutes of Health on ClinicalTrials.gov (NCT06052397). Plans for dissemination include conference presentations at a variety of scientific institutions. Results from this study are intended to be published in peer-reviewed journals. Relevant updates will be made available on ClinicalTrials.gov.

TRIAL REGISTRATION NUMBER

NCT06052397.

A retrospective clinical practice study comparing the usefulness of dual-orexin receptor antagonists and a melatonin receptor agonist in patients switching from long-term benzodiazepine receptor agonists

STUDY OBJECTIVES

Although novel hypnotics have recently emerged, there are currently no data comparing the clinical potency of benzodiazepine receptor agonists (BZRAs) and novel hypnotics, or the effectiveness of different methods of switching between them. This study examined how novel hypnotics might help reduce BZRA use in real-world practice.

METHODS

289 patients with psychiatric disorders who took BZRAs for over 1 year before switching to either of 2 dual-orexin receptor antagonists (DORAs; suvorexant [SUV] or lemborexant [LEM]) or a melatonin receptor agonist (ramelteon [RMT]) were enrolled. We collected data on BZRAs at baseline and 3 months after commencement of SUV/LEM/RMT.

RESULTS

Significant reductions in BZRAs were observed for all 3 agents: -4.10, -2.80, and -1.65 mg in diazepam-equivalent doses in the SUV, LEM, and RMT groups, respectively. Dose reduction was significantly greater in the DORA than the RMT group (F = 15.053, P < .001). Within the DORA group, dose reduction was significantly greater in patients taking SUV than those taking LEM (F = 4.337, P = .043). The switching success rate did not differ among the switching methods for any of the hypnotics.

CONCLUSIONS

The reduction rate of BZRAs achieved by the switch fell into their equivalent-potency range estimated from clinical trials. The results suggest that DORAs can replace approximately 1 tablet of a BZRA. The difference in dose reduction between DORAs and RMT reflected the greater sleeping potency of the DORAs, whereas that between SUV and LEM might have reflected patient backgrounds: patients taking LEM may have been more strongly dependent on BZRAs.

CITATION

Tachibana M, Kanahara N, Oda Y, Hasegawa T, Kimura A, Iyo M. A retrospective clinical practice study comparing the usefulness of dual-orexin receptor antagonists and a melatonin receptor agonist in patients switching from long-term benzodiazepine receptor agonists. J Clin Sleep Med. 2024;20(4):603-613.

Impact of the addition of dexmedetomidine to patient-controlled intravenous analgesia on postoperative pain-sleep interaction cycle and delirium: A systematic review and meta-analysis of randomized controlled trials

Background

The reciprocal nexus between sleep and pain is well-documented, with the deleterious impact of operative trauma potentially playing a pivotal role in the dysregulation of this interplay, which could significantly contribute to the manifestation of postoperative delirium (POD). Studies have investigated the effect of adding dexmedetomidine (DEX) to patient-controlled intravenous analgesia (PCIA) pumps on postoperative pain-sleep interaction cycle and POD, but conclusions remained uncertain. The objective of this investigation is to perform a meta-analysis that thoroughly assesses the impact of integrating DEX into PCIA, focusing on analgesic effectiveness, sleep quality, and the incidence of delirium in postoperative patients.

Methods

PubMed, Embase, Cochrane Library, SinoMed, and Wanfang Data Knowledge Service Platform were searched, for publications in any language, from database inception to September 2023. Our analysis encompassed randomized controlled trials (RCTs) that examine the therapeutic efficacy and risk profile of adding DEX to the PCIA on the postoperative pain-sleep interaction cycle, by focusing on changes in postoperative analgesia (Visual analog scale (VAS) score), sleep efficiency, sleep structure, subjective sleep score (Assen insomnia scale and numerical rating scale) and adverse event rate.

Results

34 RCTs (4324 patients) were analyzed. This study shows DEX improved analgesia and reduced VAS scores at 6, 12, and 24 h after surgery. Sleep efficiency was enhanced on the 1st and 2nd postoperative night. DEX improved sleep structure at the 1st postoperative night by reducing non-rapid eye movement stage 1 (N1) sleep and increasing non-rapid eye movement stage 2 (N2) and non-rapid eye movement stage 3 (N3) sleep. At the 2nd night, DEX reduced N1 sleep and increased N2 sleep, but not N3 sleep. Data from AIS and NRS showed improvement in subjective sleep scores on the 1st postoperative night and 2nd night. Additionally, DEX decreased the occurrence of POD on the 24 h and first-three days.

Conclusion

This study shows that the typical DEX doses added to PCIA with sufentanil were 2-5 μg/kg or approximately 200-250 μg, and the addition of DEX to PCIA can improve pain-sleep interaction cycle from multiple perspectives, and further decrease the occurrence of POD.

Effect of clock rhythm on emergence agitation and early postoperative delirium in older adults undergoing thoracoscopic lung cancer surgery: protocol for a prospective, observational, cohort study

INTRODUCTION

Surgeries conducted at night can impact patients' prognosis, and the mechanism may be related to circadian rhythm, which influence normal physiological functions and pathophysiological changes. Melatonin is primarily a circadian hormone with hypnotic and chronobiotic effects, thereby affecting disease outcomes through influencing the expression of inflammatory factors and biochemical metabolism. This study aims to observe the effects of circadian rhythms on emergence agitation and early postoperative delirium of older individuals undergoing thoracoscopic lung cancer surgery and explore the possible regulatory role of melatonin.

METHODS

This prospective, observational, cohort study will involve 240 patients. Patients will be routinely divided into three groups based on the time of the surgery: T1 (8:00-14:00), T2 (14:00-20:00) and T3 group (20:00-08:00). The primary outcome will be the incidence of emergence agitation assessed via the Richmond Agitation and Sedation Scale (RASS) in the post-anesthesia care unit (PACU). Secondary outcomes will include the incidence of early postoperative delirium assessed via the Confusion Assessment Method (CAM) on postoperative day 1, pain status assessed via the numerical rating scale (NRS) in the PACU, sleep quality on postoperative day 1 and changes in perioperative plasma melatonin, clock genes and inflammatory factor levels. Postoperative surgical complications, intensive care unit admission and hospital length of stay will also be evaluated.

DISCUSSION

This paper describes a protocol for investigating the effects of circadian rhythms on emergence agitation and early postoperative delirium of older individuals undergoing thoracoscopic lung cancer surgery, as well as exploring the potential regulatory role of melatonin. By elucidating the mechanism by which circadian rhythms impact postoperative recovery, we aim to develop a new approach for achieving rapid recovery during perioperative period.

TRIAL REGISTRATION

The study was registered at the Chinese Clinical Trials Registry (ChiCTR2000040252) on November 26, 2020, and refreshed on September 4, 2022.

Effects of short-term preoperative intranasal dexmedetomidine plus conventional treatment on delirium following cardiac surgery in patients with sleep disorders

STUDY OBJECTIVES

To assess whether preoperative dexmedetomidine (DEX) nasal drips combined with conventional treatment could mitigate the occurrence of postoperative delirium (POD).

DESIGN

A prospective randomised controlled study.

SETTING

The cardiac surgery intensive care unit (CSICU) and patient hospitalisation ward at a university hospital.

PARTICIPANTS

A total of 100 patients (aged ≥60 years) undergoing cardiac surgery at a university hospital between 7 January 2022, and 30 November 2022 met the eligibility criteria and were included in the study.

INTERVENTIONS

Patients with sleep disorders (Pittsburgh Sleep Quality Index ≥8) were divided into two groups: Group A (the placebo group, n=50), receiving a short-term preoperative placebo combined with conventional treatment and Group B (the DEX group, n=50), receiving short-term preoperative DEX combined with conventional treatment.

MEASUREMENTS AND RESULTS

The Confusion Assessment Method for the ICU (CAM-ICU) was used for POD assessment in the CSICU, while the CAM was employed to assess delirium in the patient ward. Group B demonstrated a reduced incidence of POD compared to Group A (12% vs. 30%, odds ratio: 0.318, 95% confidence interval: 0.112-0.905, p=0.027).

CONCLUSION

The combined treatment involving DEX demonstrated a decreased incidence of POD in elderly individuals with sleep disorders undergoing cardiac surgery compared to the placebo combination treatment.

TRIAL REGISTRATION

URL: www.chictr.org.cn with registration number ChiCTR 2100043968, registered on 06/03/2021.

The role of perioperative sedative anesthetics in preventing postoperative delirium: a systematic review and network-meta analysis including 6679 patients

OBJECTIVE

Postoperative delirium is a common and debilitating complication that significantly affects patients and their families. The purpose of this study is to investigate whether there is an effective sedative that can prevent postoperative delirium while also examining the safety of using sedatives during the perioperative period.

METHODS

The net-meta analysis was used to compare the incidence of postoperative delirium among four sedatives: sevoflurane, propofol, dexmedetomidine, and midazolam. Interventions were ranked according to their surface under the cumulative ranking curve (SUCRA).

RESULTS

A total of 41 RCT studies involving 6679 patients were analyzed. Dexmedetomidine can effectively reduce the incidence of postoperative delirium than propofol (OR 0.47 95% CI 0.25-0.90), midazolam (OR 0.42 95% CI 0.17-1.00), normal saline (OR 0.42 95% CI 0.33-0.54) and sevoflurane (OR 0.39 95% CI 0.18-0.82). The saline group showed a significantly lower incidence of bradycardia compared to the group receiving dexmedetomidine (OR 0.55 95% CI 0.37-0.80). In cardiac surgery, midazolam (OR 3.34 95%CI 2.04-5.48) and normal saline (OR 2.27 95%CI 1.17-4.39) had a higher rate of postoperative delirium than dexmedetomidine, while in non-cardiac surgery, normal saline (OR 1.98 95%CI 1.44-2.71) was more susceptible to postoperative delirium than dexmedetomidine.

CONCLUSION

Our analysis suggests that dexmedetomidine is an effective sedative in preventing postoperative delirium whether in cardiac surgery or non-cardiac surgery. The preventive effect of dexmedetomidine on postoperative delirium becomes more apparent with longer surgical and extubation times. However, it should be administered with caution as it was found to be associated with bradycardia.

Risk factors for postoperative delirium in orthopaedic hip surgery patients: a database review

BACKGROUND

Postoperative delirium is a common problem affecting admitted patients that decreases patient satisfaction and increases the cost and complexity of care. The purpose of this study was to use the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database to compare rates and risk factors of postoperative delirium for total hip arthroplasty (THA) and hemiarthroplasty patients indicated for osteoarthritis or proximal femur fracture.

METHODS

The 2021 NSQIP database was queried for patients using Current Procedural Terminology (CPT) codes for THA and hemiarthroplasty and ICD-10 codes for osteoarthritis or proximal femur fracture. Demographic, past medical history, preoperative labs, and functional status data were recorded. Procedural data were also collected. Finally, postoperative outcomes and complications were reviewed.

RESULTS

Overall, 16% of patients had postoperative delirium. Delirium patients were older on average (82.4 years vs. 80.7 years, p < 0.001), had a lower BMI (19.5 vs. 24.8, p < 0.001), were more likely to have a history of dementia (54.6% vs. 13.6%, p < 0.001), were less likely to have an independent functional status (p < 0.001) or live alone (p < 0.001), and were more likely to have sustained a recent fall (p < 0.001). Delirium patients were more likely to be hyponatremic or hypernatremic (p = 0.002), anemic (p < 0.001), and severely dehydrated (p < 0.001), among other lab abnormalities. Delirium patients were also more likely to experience additional postoperative complications, including pneumonia, pulmonary embolism, urinary tract infection, stroke, cardiac arrest, sepsis, and unplanned reoperation and readmission after discharge (all p < 0.05).

CONCLUSIONS

In this study, factors associated with postoperative delirium in patients undergoing hemiarthroplasty and THA were identified, including older age, lower BMI, certain medical conditions, decreased functional status, certain lab abnormalities, and postoperative complications. These findings can be used by clinicians to better inform care and to determine when orthopaedic joint replacement patients may be at an increased risk for postoperative delirium.

The nuts and bolts of multimodal anaesthesia in the 21st century: a primer for clinicians

PURPOSE OF REVIEW

This review article explores the application of multimodal anaesthesia in general anaesthesia, particularly in conjunction with locoregional anaesthesia, specifically focusing on the importance of EEG monitoring. We provide an evidence-based guide for implementing multimodal anaesthesia, encompassing drug combinations, dosages, and EEG monitoring techniques, to ensure reliable intraoperative anaesthesia while minimizing adverse effects and improving patient outcomes.

RECENT FINDINGS

Opioid-free and multimodal general anaesthesia have significantly reduced opioid addiction and chronic postoperative pain. However, the evidence supporting the effectiveness of these approaches is limited. This review attempts to integrate research from broader neuroscientific fields to generate new clinical hypotheses. It discusses the correlation between high-dose intraoperative opioids and increased postoperative opioid consumption and their impact on pain indices and readmission rates. Additionally, it explores the relationship between multimodal anaesthesia and pain processing models and investigates the potential effects of nonpharmacological interventions on preoperative anxiety and postoperative pain.

SUMMARY

The integration of EEG monitoring is crucial for guiding adequate multimodal anaesthesia and preventing excessive anaesthesia dosing. Furthermore, the review investigates the impact of combining regional and opioid-sparing general anaesthesia on perioperative EEG readings and anaesthetic depth. The findings have significant implications for clinical practice in optimizing multimodal anaesthesia techniques (Supplementary Digital Content 1: Video Abstract, http://links.lww.com/COAN/A96 ).

The relationship between major depression and delirium: A two-sample Mendelian randomization analysis

BACKGROUND

Major depression (MD) is a well-recognized risk factor for delirium. However, observational studies cannot provide direct evidence of causality between MD and delirium.

METHODS

This study explored the genetic causal association between MD and delirium using two-sample Mendelian randomization (MR). Genome-wide association study (GWAS) summary data for MD were obtained from the UK Biobank. GWAS summary data for delirium were obtained from the FinnGen Consortium. Inverse-variance weighted (IVW), MR Egger, weighted median, simple mode, and weighted mode were used to perform the MR analysis. In addition, the Cochrane's Q test was used to detect heterogeneity in the MR results. Horizontal pleiotropy was detected using the MR-Egger intercept test and MR pleiotropy residual sum and outliers (MR-PRESSO) test. Leave-one-out analysis was used to investigate the sensitivity of this association.

RESULTS

The IVW method showed that MD was an independent risk factor for delirium (P = 0.013). Horizontal pleiotropy was unlikely to bias causality (P > 0.05), and no evidence of heterogeneity was found between the genetic variants (P > 0.05). Finally, a leave-one-out test showed that this association was stable and robust.

LIMITATIONS

All participants included in the GWAS were of European ancestry. Due to database limitations, the MR analysis did not conduct stratified analyses for different countries, ethnicities, or age groups.

CONCLUSION

We conducted a two-sample MR analysis and found the evidence of genetic causal association between MD and delirium.

Critical care for patients with substance use disorders

PURPOSE OF REVIEW

To examine the impact of substance use disorders (SUDs) on critical illness and the role of critical care providers in treating SUDs. We discuss emerging evidence supporting hospital-based addiction treatment and highlight the clinical and research innovations needed to elevate the standards of care for patients with SUDs in the intensive care unit (ICU) amidst staggering individual and public health consequences.

RECENT FINDINGS

Despite the rapid increase of SUDs in recent years, with growing implications for critical care, dedicated studies focused on ICU patients with SUDs remain scant. Available data demonstrate SUDs are major risk factors for the development and severity of critical illness and are associated with poor outcomes. ICU patients with SUDs experience mutually reinforcing effects of substance withdrawal and pain, which amplify risks and consequences of delirium, and complicate management of comorbid conditions. Hospital-based addiction treatment can dramatically improve the health outcomes of hospitalized patients with SUDs and should begin in the ICU.

SUMMARY

SUDs have a significant impact on critical illness and post-ICU outcomes. High-quality cohort and treatment studies designed specifically for ICU patients with SUDs are needed to define best practices and improve health outcomes in this vulnerable population.

Association of general anesthesia exposure with risk of postoperative delirium in patients receiving transcatheter aortic valve replacement: a meta-analysis and systematic review

The aim of this meta-analysis was to assess the association of general anesthesia (GA) exposure with the risk of POD in this patient population. Databases including Medline, EMBASE, Cochrane library, and Google Scholar were searched from inception to December 2022. Analysis of 17 studies published between 2015 and 2021 involving 10,678 individuals revealed an association of GA exposure with an elevated risk of POD [odd ratio (OR) = 1.846, 95% CI 1.329 to 2.563, p = 0.0003, I2 = 68.4%, 10,678 patients]. Subgroup analysis of the diagnostic methods also demonstrated a positive correlation between GA exposure and POD risk when validated methods were used for POD diagnosis (OR = 2.199, 95% CI 1.46 to 3.31, p = 0.0002). Meta-regression analyses showed no significant impact of age, male proportion, and sample size on the correlation between GA and the risk of POD. The reported overall incidence of POD from the included studies regardless of the type of anesthesia was between 0.8 and 27%. Our meta-analysis showed a pooled incidence of 10.3% (95% CI 7% to 15%). This meta-analysis suggested an association of general anesthesia with an elevated risk of postoperative delirium, implying the necessity of implementing appropriate prophylactic strategies against this complication when general anesthesia was used in this clinical setting.

Preventing and treating delirium in clinical settings for older adults

Delirium is a serious consequence of many acute or worsening chronic medical conditions, a side effect of medications, and a precipitant of worsening functional and cognitive status in older adults. It is a syndrome characterized by fluctuations in cognition and impaired attention that develops over a short period of time in response to an underlying medical condition, a substance (prescribed, over the counter, or recreational), or substance withdrawal and can be multi-factorial. We present a narrative review of the literature on nonpharmacologic and pharmacologic approaches to prevention and treatment of delirium with a focus on older adults as a vulnerable population. Older adult patients are most at risk due to decreasing physiologic reserves, with delirium rates of up to 80% in critical care settings. Presentation of delirium can be hyperactive, hypoactive, or mixed, making identification and study challenging as patients with hypoactive delirium are less likely to come to attention in an inpatient or long-term care setting. Studies of delirium focus on prevention and treatment with nonpharmacological or medication interventions, with the preponderance of evidence favoring multi-component nonpharmacological approaches to prevention as the most effective. Though use of antipsychotic medication in delirium is common, existing evidence does not support routine use, showing no clear benefit in clinically significant outcome measures and with evidence of harm in some studies. We therefore suggest that antipsychotics be used to treat agitation, psychosis, and distress associated with delirium at the lowest effective doses and shortest possible duration and not be considered a treatment of delirium itself. Future studies may clarify the use of other agents, such as melatonin and melatonin receptor agonists, alpha-2 receptor agonists, and anti-epileptics.

Prophylactic Melatonin for Delirium in Intensive Care Unit: An Updated Systematic Review and Meta-analysis of Randomized Controlled Trials

Introduction

Delirium, being a common disorder among critically ill patients, has a reported incidence ranging 45-83% in the intensive care unit (ICU) population. The prophylactic use of melatonin and melatonergics has been shown to have a positive effect in reducing the incidence of delirium in many clinical trials. Our study was thus proposed to find out the role of melatonin on the incidence and severity of ICU delirium, ICU and hospital length of stay (LOS), requirement, duration of mechanical ventilation, and ICU mortality.

Methodology

A systematic search of various databases was performed to find out the trials which compare melatonin with a placebo or standard therapy for delirium prevention with the results conveyed as mean differences (MDs) or risk ratios. The statistical software, Review Manager (RevMan, version 5.4), was used for data synthesis.

Results

Twelve studies were included in the meta-analysis. Prophylactic administration of melatonin or ramelteon was not associated with a statistically significant reduction in the incidence of delirium (odds ratio [OR] 0.63; confidence interval [CI]: 0.60, 1.32; p = 0.22), the severity of delirium (MD: 0.22; 95% CI: From -1.36 to 1.81; p = 0.78), ICU LOS (MD: 0.05; 95% CI: From -0.65 to 0.75; p = 0.89), hospital LOS (MD: -1.46; 95% CI: From -4.50 to -1.59; p = 0.35), need for mechanical ventilation (OR: 0.74, 95% CI: 0.38-1.44; p = 0.37), and ICU mortality (MD: 0.78; 95% CI: 0.56; 1.11; p = 0.62). However, a significant reduction in the duration of mechanical ventilation (MD: -0.85; 95% CI: From -1.64 to -0.06; p = 0.03) was found.

Conclusion

Our meta-analysis suggests that melatonin when given prophylactically has no significant role in reducing the incidence and severity of delirium, ICU and hospital LOS, need for mechanical ventilation, duration of mechanical ventilation, and ICU mortality. Further studies are warranted.

How to cite this article

Mukundarajan R, Soni KD, Trikha A. Prophylactic Melatonin for Delirium in Intensive Care Unit: An Updated Systematic Review and Meta-analysis of Randomized Controlled Trials. Indian J Crit Care Med 2023;27(9):675-685.

Associations between early in-hospital medications and the development of delirium in patients with stroke

OBJECTIVES

Patients hospitalized with stroke develop delirium at higher rates than general hospitalized patients. While several medications are associated with existing delirium, it is unknown whether early medication exposures are associated with subsequent delirium in patients with stroke. Additionally, it is unknown whether delirium identification is associated with changes in the prescription of these medications.

MATERIALS AND METHODS

We conducted a retrospective cohort study of patients admitted to a comprehensive stroke center, who were assessed for delirium by trained nursing staff during clinical care. We analyzed exposures to multiple medication classes in the first 48 h of admission, and compared them between patients who developed delirium >48 hours after admission and those who never developed delirium. Statistical analysis was performed using univariate testing. Multivariable logistic regression was used further to evaluate the significance of univariately significant medications, while controlling for clinical confounders.

RESULTS

1671 unique patients were included in the cohort, of whom 464 (27.8%) developed delirium >48 hours after admission. Delirium was associated with prior exposure to antipsychotics, sedatives, opiates, and antimicrobials. Antipsychotics, sedatives, and antimicrobials remained significantly associated with delirium even after accounting for several clinical covariates. Usage of these medications decreased in the 48 hours following delirium identification, except for atypical antipsychotics, whose use increased. Other medication classes such as steroids, benzodiazepines, and sleep aids were not initially associated with subsequent delirium, but prescription patterns still changed after delirium identification.

CONCLUSIONS

Early exposure to multiple medication classes is associated with the subsequent development of delirium in patients with stroke. Additionally, prescription patterns changed following delirium identification, suggesting that some of the associated medication classes may represent modifiable targets for future delirium prevention strategies, although future study is needed.

Does melatonin administration reduce the incidence of postoperative delirium in adults? Systematic review and meta-analysis

Postoperative delirium (POD) is common. It is associated with increased morbidity and mortality. Many cases may be preventable and melatonin offers promise as a preventative agent.

OBJECTIVE

This systematic review provides an up-to-date synthesis of the evidence on the effect of melatonin in preventing POD.

DESIGN

A systematic search of randomised controlled trials of melatonin in POD was run across multiple databases (EMBASE, MEDLINE, CINAHL, PsycINFO) and a clinical trials registry (ClinicalTrials.org) (1 January 1990 to 5 April 2022). Studies examining the effects of melatonin on POD incidence in adults are included. Risk of bias was assessed using the Cochrane risk of bias 2 tool.

OUTCOME MEASURES

The primary outcome is POD incidence. Secondary outcomes are POD duration and length of hospital stay. Data synthesis was undertaken using a random-effects meta-analysis and presented using forest plots. A summary of methodology and outcome measures in included studies is also presented.

RESULTS

Eleven studies, with 1244 patients from a range of surgical specialties were included. Seven studies used melatonin, in variable doses, and four used ramelteon. Eight different diagnostic tools were used to diagnose POD. Time points for assessment also varied. Six studies were assessed as low risk of bias and five as some concern. The combined OR of developing POD in the melatonin groups versus control was 0.41 (95% CI 0.21 to 0.80, p=0.01).

CONCLUSION

This review found that melatonin may reduce the incidence of POD in adults undergoing surgery. However, included studies displayed inconsistency in their methodology and outcome reporting. Further work to determine the optimum regime for melatonin administration, along with consensus of how best to evaluate results, would be beneficial.

PROSPERO REGISTRATION NUMBER

CRD42021285019.

Postoperative delirium in geriatric patients with hip fractures

Postoperative delirium (POD) is a frequent complication in geriatric patients with hip fractures, which is linked to poorer functional recovery, longer hospital stays, and higher short-and long-term mortality. Patients with increased age, preoperative cognitive impairment, comorbidities, perioperative polypharmacy, and delayed surgery are more prone to develop POD after hip fracture surgery. In this narrative review, we outlined the latest findings on postoperative delirium in geriatric patients with hip fractures, focusing on its pathophysiology, diagnosis, prevention, and treatment. Perioperative risk prediction, avoidance of certain medications, and orthogeriatric comprehensive care are all examples of effective interventions. Choices of anesthesia technique may not be associated with a significant difference in the incidence of postoperative delirium in geriatric patients with hip fractures. There are few pharmaceutical measures available for POD treatment. Dexmedetomidine and multimodal analgesia may be effective for managing postoperative delirium, and adverse complications should be considered when using antipsychotics. In conclusion, perioperative risk intervention based on orthogeriatric comprehensive care is the most effective strategy for preventing postoperative delirium in geriatric patients with hip fractures.

Postoperative Delirium in Neurosurgical Patients: Recent Insights into the Pathogenesis

Postoperative delirium (POD) is a complication characterized by disturbances in attention, awareness, and cognitive function that occur shortly after surgery or emergence from anesthesia. Since it occurs prevalently in neurosurgical patients and poses great threats to the well-being of patients, much emphasis is placed on POD in neurosurgical units. However, there are intricate theories about its pathogenesis and limited pharmacological interventions for POD. In this study, we review the recent insights into its pathogenesis, mainly based on studies within five years, and the five dominant pathological theories that account for the development of POD, with the intention of furthering our understanding and boosting its clinical management.

Comprehensive care for people living with heart failure and chronic obstructive pulmonary disease—Integration of palliative care with disease-specific care: From guidelines to practice

Heart failure (HF) and chronic obstructive pulmonary disease (COPD) are the leading global epidemiological, clinical, social, and economic burden. Due to similar risk factors and overlapping pathophysiological pathways, the coexistence of these two diseases is common. People with severe COPD and advanced chronic HF (CHF) develop similar symptoms that aggravate if evoking mechanisms overlap. The coexistence of COPD and CHF limits the quality of life (QoL) and worsens symptom burden and mortality, more than if only one of them is present. Both conditions progress despite optimal, guidelines directed treatment, frequently exacerbate, and have a similar or worse prognosis in comparison with many malignant diseases. Palliative care (PC) is effective in QoL improvement of people with CHF and COPD and may be a valuable addition to standard treatment. The current guidelines for the management of HF and COPD emphasize the importance of early integration of PC parallel to disease-modifying therapies in people with advanced forms of both conditions. The number of patients with HF and COPD requiring PC is high and will grow in future decades necessitating further attention to research and knowledge translation in this field of practice. Care pathways for people living with concomitant HF and COPD have not been published so far. It can be hypothesized that overlapping of symptoms and similarity in disease trajectories allow to draw a model of care which will address symptoms and problems caused by either condition.

Melatonin for the prevention of postoperative delirium in older adults: a protocol for a systematic review and meta-analysis

INTRODUCTION

Postoperative delirium (POD) is a major cause of morbidity, particularly in elderly patients. Melatonin has been suggested as a low-risk pharmacological intervention to help prevent POD. A previous systematic review found limited high-quality evidence to support the use of melatonin in the prevention of POD. Several further randomised studies have since been published. This systematic review aims to synthesise the evidence from randomised controlled trials (RCTs) examining the effect of melatonin on the prevention of POD in older adults.

METHODS AND ANALYSIS

A systematic search of RCTs of melatonin (any dose and formulation) in POD will be run across Embase, Medline, CINAHL and PsychInfo. RCTs published from January 1990 until the end of February 2022 and reporting outcomes for melatonin use to prevent POD in patients will be included. Screening of search results and data extraction from included articles will be performed by two independent reviewers. The primary outcome will be incidence of POD in older adults undergoing surgery. Secondary outcomes are delirium duration and length of hospital stay. The review will also describe the dosage, timing and administration regimes of melatonin therapy and as well as the scales and definitions used to describe POD. A registry review of ongoing trials will be also be performed. For the meta-analysis, data will be pooled using a random effects model to generate a forest plot and obtain an odds ratio (OR) for the incidence of POD. Results will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

ETHICS AND DISSEMINATION

No ethical approval is required. This review will be disseminated via peer-reviewed manuscript and conferences. The results will be used as the basis of work to optimise this intervention for future trials in surgical populations.

PROSPERO REGISTRATION NUMBER

This review is registered with PROSPERO (CRD42021285019).

Delirium in hospitalised adults with acute burns - A systematic review

INTRODUCTION

Delirium is a potentially modifiable, acutely altered mental state, commonly characterised as a hospital-acquired complication. Studies of adult inpatients with acute burns with and without delirium identify causative risks related to the injury or treatment and outcomes related to the patient and healthcare system. We compare patients with and without delirium, providing a high-level quantitative synthesis of delirium risks and outcomes to inform guidelines and future research.

METHODS

A systematic review, meta-analysis and GRADE evaluation of risks and outcomes associated with delirium in adults with acute burns was conducted using PRISMA guidelines and PROSPERO protocol CRD42021283055. The Newcastle-Ottawa Scale was used to assess quality.

RESULTS

Investigators reviewed ten studies. ASA score ≥ 3, Total Body Surface Area Percentage (TBSA)> 10%, surgery done, ICU admission, hospital and also Intensive Care Unit (ICU) lengths of stay all had statistically significant associations with delirium, with low-very low certainty on GRADE evaluation. Limitations were heterogeneous studies, review methodology and study bias.

CONCLUSION

Delirium represents a significant risk to comorbid patients with burns that are hospitalised, receive ICU care, and surgery. Further research is indicated to precisely categorise delirium along the clinical journey to identify modifiable factors, prevention, and proactive therapy.

Impact of perioperative inflammation on days alive and at home after surgery

Background

Perioperative inflammation is associated with perioperative complications, including delirium, that are associated with a reduced number of postoperative days alive and at home at 90 days (DAH90). We tested whether inflammation was associated with DAH90 even when adjusting for perioperative factors, and whether inflammation independently was associated with DAH90 when adjusting for delirium.

Methods

We conducted a prospective cohort study of major, non-intracranial surgical patients who were older than 65 yr (n=134). We measured postoperative delirium incidence and severity, and changes in interleukin (IL)-8 and IL-10 in blood plasma. Our primary outcome, DAH90, was analysed using quantile regression.

Results

Before adjusting for delirium, a postoperative day 1 increased IL-8 was associated with fewer DAH90 at the 0.75 quantile (β=-0.082; 95% confidence interval [CI], -0.19 to -0.006) after adjusting for demographic (age and sex) and perioperative factors (cardiovascular surgery, National Surgical Quality Improvement Program risk of death, and operative time). IL-10 was similarly associated with DAH90 at the 0.5 (β=-0.026; 95% CI, -0.19 to -0.001) and 0.75 (β= -0.035; 95% CI, -0.07 to -0.006) quantiles. Neither cytokine was significantly associated with DAH90 once delirium and baseline Trail Making Test B were added to the models.

Conclusions

Perioperative inflammation predicts DAH90, but when delirium is added to the model inflammation loses significance as a predictor, whereas delirium is significant. Targeting perioperative inflammation may reduce delirium and moderate hospital readmission and mortality.

Clinical trial registration

NCT03124303.

A systematic review of strategies for preventing delirium in patients undergoing vascular surgery

OBJECTIVES

Elderly patients undergoing vascular surgery are at risk of developing postoperative delirium, which is associated with a high mortality. Delirium prevention is difficult and is investigated in surgical patients from various specialisms, but little is known about delirium prevention in vascular surgery. For this reason we performed a systematic review on strategies for delirium prevention in patients undergoing elective surgery for peripheral arterial disease or for an aneurysm of the abdominal aorta.

METHODS

This systematic review included studies describing strategies for preventing delirium in patients undergoing elective surgery for peripheral arterial disease or for an aneurysm of the abdominal aorta. The search was conducted using the keywords 'vascular surgery', 'prevention' and 'delirium', and was last run on October 21st, 2021 in the electronic databases Pubmed, MEDLINE, Embase, Web of Science, the Cochrane library and Emcare. Risk of bias was assessed using the Cochrane Risk of Bias tool for randomized controlled trials and the ROBINS-1 tool for observational studies.

RESULTS

Four studies including 565 patients were included in the systematic review. A significant decrease in the incidence of delirium was reported by a study investigating the effect of comprehensive geriatric assessments within patients undergoing surgery for an aneurysm of the abdominal aorta or lower limb bypass surgery (24% in the control group versus 11% in the intervention group, p = 0.018), and in the total group of a study evaluating the effect of outpatient clinic multimodal prehabilitation for patients with an aneurysm of the abdominal aorta (11.7% in the control group versus 8.2% in the intervention group, p = 0.043, OR = 0.56). A non-significant decrease in delirium incidence was described for patients receiving a multidisciplinary quality improvement at the vascular surgical ward (21.4% in the control group versus 14.6% in the intervention group, p = 0.17). The study concerning the impact of the type of anaesthesia on delirium in eleven older vascular surgical patients, of which three developed delirium, did not differentiate between the different types of anaesthesia the patients received.

CONCLUSION

Despite the high and continuous increasing incidence of delirium in the growing elderly vascular population, little is known about effective preventive strategies. An approach to address multiple risk factors simultaneously seems to be promising in delirium prevention, whether through multimodal prehabilitation or comprehensive geriatric assessments. Several strategies including prehabilitation programs have been proven to be successful in other types of surgery and more research is required to evaluate effective preventive strategies and prehabilitation programs in vascular surgical patients.

Incidence and risk factors of postoperative delirium following total knee arthroplasty: A retrospective Nationwide Inpatient Sample database study

BACKGROUND

Postoperative delirium is a common complication following major surgeries, causing a variety of adverse effects. However, the incidence and risk factors of delirium after primary total knee arthroplasty (TKA) has not been well studied using a large-scale national database.

METHODS

A retrospective database analysis was performed based on Nationwide Inpatient Sample (NIS) from 2005-2014. Patients who underwent primary TKA were included. Patient demographics, comorbidities, length of stay (LOS), total charges, type of payer, in-hospital mortality, and perioperative complications were evaluated.

RESULTS

A total of 1,228,879 TKAs were obtained from the NIS database. The general incidence of delirium after TKA was 1.00%, which peaked in the year 2008.Patients with delirium after TKA presented increased comorbidities, LOS, hospital charges, usage of medicare, and in-hospital mortality (P < 0.0001). Delirium following TKA was associated with medical complications during hospitalization including acute renal failure, acute myocardial infarction, pneumonia, pulmonary embolism, stroke, and urinary tract infection. Risk factors of postoperative delirium included advanced age, neurological disorders, alcohol and drug abuse, depression, psychoses, fluid and electrolyte disorders, diabetes, weight loss, deficiency and chronic blood loss anemia, coagulopathy, congestive heart failure, chronic pulmonary disease, pulmonary circulation disorders, peripheral vascular disorders, chronic renal failure, and teaching hospital. Notably, neurological disorders were found to have the strongest association with the occurrence of postoperative delirium.

CONCLUSION

A relatively low incidence of delirium after TKA was identified. It is of benefit to study risk factors of postoperative delirium to ensure the appropriate management and moderate its consequences.

KIBRA, MTNR1B, and FKBP5 genotypes are associated with decreased odds of incident delirium in elderly post-surgical patients

Despite the association between cognitive impairment and delirium, little is known about whether genetic differences that confer cognitive resilience also confer resistance to delirium. To investigate whether older adults without postoperative delirium, compared with those with postoperative delirium, are more likely to have specific single nucleotide polymorphisms (SNPs) in the FKBP5, KIBRA, KLOTHO, MTNR1B, and SIRT1 genes known to be associated with cognition or delirium. This prospective nested matched exploratory case-control study included 94 older adults who underwent orthopedic surgery and screened for postoperative delirium. Forty-seven subjects had incident delirium, and 47 age-matched controls were not delirious. The primary study outcome was genotype frequency for the five SNPs. Compared with participants with delirium, those without delirium had higher adjusted odds of KIBRA SNP rs17070145 CT/TT [vs. CC; adjusted odds ratio (aOR) 2.80, 95% confidence interval (CI) 1.03, 7.54; p = 0.04] and MTNR1B SNP rs10830963 CG/GG (vs. CC; aOR 4.14, 95% CI 1.36, 12.59; p = 0.01). FKBP5 SNP rs1360780 CT/TT (vs. CC) demonstrated borderline increased adjusted odds of not developing delirium (aOR 2.51, 95% CI 1.00, 7.34; p = 0.05). Our results highlight the relevance of KIBRA, MTNR1B, and FKBP5 in understanding the complex relationship between delirium, cognition, and sleep, which warrant further study in larger, more diverse populations.

Postoperative Pneumonia and Aspiration Pneumonia Following Elderly Hip Fractures

OBJECTIVES

The present study aimed to investigate the incidence of and risk factors for postoperative pneumonia and aspiration pneumonia after hip fracture surgery.

DESIGN

Retrospective cohort study from 2005 to 2021.

SETTING

Asan Medical Center in Seoul, Republic of Korea.

PARTICIPANTS

A total 1,208 patients aged ≥ 65 years who underwent hip fracture surgery.

MEASUREMENTS

Postoperative pneumonia was defined as cases with new infiltration on chest x-ray or chest computed tomography (CT) after surgery or confirmed by a pulmonologist's consultation and diagnosis. Aspiration pneumonia was defined as: 1) radiologic findings of hospital-acquired pneumonia on chest radiographs or CT, medical record of aspiration pneumonia confirmed by a pulmonologist's consultation, and history of vomiting or aspiration, or 2) gravity-dependent opacity on chest CT when the history of vomiting or aspiration is ambiguous. Patient demographics, past medical history, pre-injury Koval score, Charlson Comorbidity Index (CCI), blood test results, length of hospital stay, and in-hospital mortality were evaluated. A comparison analysis and binary logistic regression were performed to identify the incidence and risk factors for postoperative pneumonia and aspiration pneumonia.

RESULTS

Postoperative pneumonia was diagnosed in 47 patients (3.9%), including 20 with aspiration pneumonia (1.7%). In the multivariate analysis, postoperative delirium (odds ratio [OR], 3.42; P < 0.001), American Society of Anesthesiologists (ASA) scores ≥ 3 (OR, 2.11; P = 0.021), and CCI (OR, 1.21; P = 0.013) were significant risk factors for postoperative pneumonia. Male sex (OR, 3.01; P = 0.017), postoperative delirium (OR, 3.16; P = 0.014), and preoperative serum albumin levels < 3.5 g/dL (OR, 7.00; P = 0.010) were significant risk factors for aspiration pneumonia.

CONCLUSION

ASA classification ≥ 3, higher CCI, and postoperative delirium were the risk factors for postoperative pneumonia. Male sex, postoperative delirium, and lower preoperative serum albumin level were the risk factors for aspiration pneumonia. Thus, physicians should pay attention to patients with the risk factors.

[Delirium, a poorly understood syndrome]

The word delirium is a more appropriate term than agitation or confusion to describe clinical realities that are common in intensive care units, postoperative units, geriatric units and palliative care units. Its recognition by carers will allow more appropriate care and treatment.

Melatonin Receptor Agonists for the Prevention of Delirium: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Although a previous review illustrated the efficacy of melatonin receptor agonists (MRAs) in preventing delirium, some recent randomized controlled trials (RCTs) did not confirm these effects.

OBJECTIVES

This study systematically reviewed the efficacy, acceptability, and tolerability of MRAs for delirium prevention.

MATERIALS AND METHODS

We searched electronic databases, including Scopus, PubMed, CINAHL, and Controlled Trials Register, from their inception to February 20, 2022. The primary efficacy outcome was delirium incidence rate after MRA administration; relative risks (RRs), overall discontinuation, and discontinuation due to adverse events are also presented.

RESULTS

The overall pooled incidence rates of delirium in MRA-treated and placebo-treated groups were significantly different with RR (95% CI)=0.66(0.52, 0.84, ), I2=59%. Similarly, the incidence rate was significantly lower in the melatonin-treated group than in the placebo-treated group [RR (95% CI) =0.65 (0.49, 0.88), I2=65%]. Unfortunately, incidence rates were not significantly different between ramelteon-treated and placebo-treated groups [RR (95% CI) =0.67 (0.42, 1.08), I2=50%]. The pooled incidence rate of delirium in either melatonin or ramelteon-treated groups was not significantly different from the placebo-treated group in elderly patients. The pooled incidence rate of delirium was significantly lower in the melatonin-treated group than in the benzodiazepinetreated group.

CONCLUSION

Based on this review, melatonin could prevent delirium with a small effect size. However, ramelteon did not show efficacy in preventing delirium. Additionally, neither melatonin nor ramelteon individually showed effectiveness in preventing delirium in elderly patients. Therefore, using MRAs to prevent delirium in clinical practice should be cautious. However, future welldefined and large sample size studies could verify these findings.

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.

Melatonin and melatonin-receptor agonists to prevent delirium in hospitalized older adults: An umbrella review

BACKGROUND

Alterations in circadian rhythm play an important role in the development of delirium. In this umbrella review, we examined the efficacy of melatonin and ramelteon for delirium prevention in hospitalized older adults.

METHODS

Umbrella review methodology from the Joanna Briggs Institute guided the review process. Only meta-analyses were included. Risk of bias was evaluated using the AMSTAR-2 checklist.

RESULTS

Three meta-analyses were included in this review. The quality of studies was low-to-moderate. Two meta-analyses reported a significant reduction in delirium using melatonin or ramelteon (pooled OR and 95% confidence intervals ranged from 0.41 [0.19-0.86] to 0.63 [0.46-0.87]). Melatonergics significantly reduced delirium on medical units (OR = 0.25, 95% CI 0.07-0.88) but not surgical units (OR = 0.62, 0.16-2.43). Heterogenity was high, with I² ranging from 72.14% to 84%.

CONCLUSIONS

Melatonergics appear to prevent delirium among hospitalized older adults, particularly those on medical units. Based on these results, providers may consider using melatonergics as complements to high-quality multicomponent delirium prevention.

Evaluation and Management of Delirium

Delirium, sometimes referred to as encephalopathy, is an acute confusional state that is both common in hospitalized patients and associated with poor outcomes. For patients, families, and caregivers, delirium can be a traumatic experience. While delirium is one of the most common diagnoses encountered by the consulting neurologist, the majority of the time it will have been previously unrecognized as such by the care team. Neurologic syndromes such as dementia or aphasia can either be misdiagnosed as delirium or may coexist with it, necessitating careful neurologic assessment. Once the diagnosis of delirium has been established, a careful evaluation for predisposing and precipitating factors can help uncover modifiable contributors, which should be addressed as part of a multicomponent, primarily nonpharmacologic intervention. Importantly, delirium management, which begins with comprehensive prevention, should emphasize the humanity of the delirious patient and the challenges of caring for this vulnerable population. When considered, delirium represents an important opportunity for the neurologist to substantially enhance patient care.

Unusual Bioactive Compounds with Antioxidant Properties in Adjuvant Therapy Supporting Cognition Impairment in Age-Related Neurodegenerative Disorders

Cognitive function decline is strictly related to age, resulting in the loss of the ability to perform daily behaviors and is a fundamental clinical neurodegeneration symptom. It has been proven that an adequate diet, comprehensive nutrition, and a healthy lifestyle may significantly inhibit neurodegenerative processes, improving cognitive functions. Therefore, intensive research has been conducted on cognitive-enhancing treatment for many years, especially with substances of natural origin. There are several intervention programs aimed at improving cognitive functions in elderly adults. Cognitive functions depend on body weight, food consumed daily, the quality of the intestinal microflora, and the supplements used. The effectiveness in the prevention of dementia is particularly high before the onset of the first symptoms. The impact of diet and nutrition on age-associated cognitive decline is becoming a growing field as a vital factor that may be easily modified, and the effects may be observed on an ongoing basis. The paper presents a review of the latest preclinical and clinical studies on the influence of natural antioxidants on cognitive functions, with particular emphasis on neurodegenerative diseases. Nevertheless, despite the promising research results in animal models, the clinical application of natural compounds will only be possible after solving a few challenges.

International Expert Opinions and Recommendations on the Use of Melatonin in the Treatment of Insomnia and Circadian Sleep Disturbances in Adult Neuropsychiatric Disorders

Introduction: Insomnia and circadian rhythm disorders, such as the delayed sleep phase syndrome, are frequent in psychiatric disorders and their evaluation and management in early stages should be a priority. The aim of this paper was to express recommendations on the use of exogenous melatonin, which exhibits both chronobiotic and sleep-promoting actions, for the treatment of these sleep disturbances in psychiatric disorders. Methods: To this aim, we conducted a systematic review according to PRISMA on the use of melatonin for the treatment of insomnia and circadian sleep disorders in neuropsychiatry. We expressed recommendations for the use of melatonin in psychiatric clinical practice for each disorder using the RAND/UCLA appropriateness method. Results: We selected 41 studies, which included mood disorders, schizophrenia, substance use disorders, attention deficit hyperactivity disorders, autism spectrum disorders, neurocognitive disorders, and delirium; no studies were found for both anxiety and eating disorders. Conclusion: The administration of prolonged release melatonin at 2-10 mg, 1-2 h before bedtime, might be used in the treatment of insomnia symptoms or comorbid insomnia in mood disorders, schizophrenia, in adults with autism spectrum disorders, neurocognitive disorders and during sedative-hypnotics discontinuation. Immediate release melatonin at <1 mg might be useful in the treatment of circadian sleep disturbances of neuropsychiatric disorders.

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.

Melatonin and melatonergic agents for the prevention of postoperative delirium: A meta-analysis of randomized placebo-controlled trials

Studies on melatonin and melatonergic agents (MMA) for the prevention of postoperative delirium (POD) have produced inconsistent findings. We conducted a meta-analysis to assess the effect of perioperative MMA on the prevention for POD. This meta-analysis is registered in the PROSPERO (CRD42020164900). We searched PubMed, Embase, and Cochrane Library through August 1, 2020 to identify randomized placebo-controlled trials (RCTs) that assessed MMA for the prevention for POD in adult patients undergoing surgery. The primary outcome was POD. Relative risk (RR) with 95% confidence interval (CI) was pooled using a random-effects model. Nine RCTs with 1452 patients were included. The incidence of POD was 23.8% (173/726) and 24.4% (177/726) in the MMA and placebo groups, respectively. Compared with placebo, MMA did not reduce the occurrence of POD (9 trails, 1452 patients, RR 0.93, 95% CI 0.70-1.24), with modest heterogeneity (I² = 40%). Sensitivity analyses suggested that MMA also did not reduce the occurrence of POD in elderly patients (age ≥65 years) (6 trails, 810 patients, RR 0.71, 95% CI 0.38-1.32), patients given melatonin (4 trails, 806 patients, RR 0.78, 95% CI 0.43-1.41) or ramelteon (4 trails, 345 patients, RR 0.89, 95% CI 0.44-1.78), and patients undergoing general anesthesia (4 trails, 681 patient, RR 1.02, 95% CI 0.82-1.28). Based on the current evidence, perioperative MMA may have no effect on the prevention of POD.

Effects of Ramelteon on the Prevention of Postoperative Delirium in Older Patients Undergoing Orthopedic Surgery: The RECOVER Randomized Controlled Trial

OBJECTIVES

Postoperative delirium, associated with negative consequences including longer hospital stays and worse cognitive and physical outcomes, is frequently accompanied by sleep-wake disturbance. Our objective was to evaluate the efficacy and short-term safety of ramelteon, a melatonin receptor agonist, for the prevention of postoperative delirium in older patients undergoing orthopedic surgery.

DESIGN

A quadruple-masked randomized placebo-controlled trial (Clinical Trials.gov NCT02324153) conducted from March 2017 to June 2019.

SETTING

Tertiary academic medical center.

PARTICIPANTS

Patients aged 65 years or older, undergoing elective primary or revision hip or knee replacement.

INTERVENTION

Ramelteon (8 mg) or placebo MEASUREMENTS: Eighty participants were randomized to an oral gel cap of ramelteon or placebo for 3 consecutive nights starting the night before surgery. Trained research staff conducted delirium assessments for 3 consecutive days starting on postoperative day (POD) 0, after recovery from anesthesia, and on to POD2. A delirium diagnosis was based upon DSM-5 criteria determined by expert panel consensus.

RESULTS

Of 80 participants, five withdrew consent (one placebo, four ramelteon) and four were excluded (four ramelteon) after randomization. Delirium incidence during the 2 days following surgery was 7% (5 of 71) with no difference between the ramelteon versus placebo: 9% (3 of 33) and 5% (2 of 38), respectively. The adjusted odds ratio for postoperative delirium as a function of assignment to the ramelteon treatment arm was 1.28 (95% confidence interval: 0.21-7.93; z-value 0.27; p-value = 0.79). Adverse events were similar between the two groups.

CONCLUSION

In older patients undergoing elective primary or revision hip or knee replacement, ramelteon was not efficacious in preventing postoperative delirium.

Melatonin for delirium prevention in hospitalized patients: A systematic review and meta-analysis

BACKGROUND AND AIMS

Melatonin, a pineal gland hormone is reported to have a protective effect against delirium. This systematic review and meta-analysis explores the effect of melatonin and melatonin receptor agonist, ramelteon on delirium prevention in adult hospitalized patients.

METHODS

Randomized Controlled trials of melatonin/ramelteon published up to May 7, 2020 were identified from MEDLINE, PREMEDLINE, Embase, PsycINFO, the Cochrane Central Register of Controlled trials, PubMed, and Google Scholar. The primary outcome was delirium incidence. The secondary outcomes were sleep quality, sedation score, sedatives requirement, delirium duration, length of hospital stay, length of Intensive Care Unit (ICU) stay, mortality and adverse events. A meta-analysis with a random-effects models was performed. Estimates were presented as Risk Ratio (RR) or Mean Differences (MD) with 95% Confidence Interval (CI).

FINDINGS

Fourteen studies with 1712 participants were included. Melatonin/ramelteon significantly reduced delirium incidence (RR 0·61, 95% CI 0·42-0·89, p 0·009) with risk reduction of 49% in surgical patients and 34% in ICU patients. Non-significant reduction was found in medical patients. Melatonin/ramelteon were associated with improvement in sleep quality, increased sedation score and lower sedatives consumption. However, they did not reduce delirium duration, length of hospital stay, length of ICU stay and mortality. Hallucinations, nightmares and gastrointestinal disorders were prevalent in melatonin group.

INTERPRETATION

Melatonin/ramelteon are associated with reduction in delirium incidence in hospitalized patients. However, this effect seems confined to surgical and ICU patients. The optimum dosage and formulation of melatonin, and treatment duration remain uncleared and open to further studies with larger sample sizes.

Does melatonin prevent postoperative delirium?

Overview of: Campbell AM, Axon DR, Martin JR, et al. Melatonin for the prevention of postoperative delirium in older adults: a systematic review and meta--analysis. BMC Geriatrics 2019;19:272.

Preventative effects of ramelteon against postoperative delirium after elective liver resection

Background

Postoperative delirium was reported to be associated with increased postoperative mortality after liver resection. Therefore, it is crucial to prevent postoperative delirium in such cases. Ramelteon, an agonist of melatonin receptor has been suggested to be useful for preventing delirium. The aim of this study was to examine whether ramelteon is effective at preventing delirium after elective liver resection.

Methods

The cases of patients who underwent liver resection at Nara Medical University (Nara, Japan) between January 2014 and August 2018 were analyzed. During the period from January 2017 to August 2018, ramelteon was prospectively administered to patients who underwent liver resection [8 mg/day on the day before surgery and on postoperative days 1 to 3] (ramelteon group), whereas ramelteon was not administered during the period from January 2014 to December 2016 (control group). The perioperative outcomes of the two groups were compared.

Results

There were 120 patients in the ramelteon group and 186 patients in the control group. No significant intergroup differences in background factors, including age, gender, and preoperative serological laboratory data, were detected. The incidence of postoperative delirium was significantly lower in the ramelteon group (5.8% vs. 15.1%, P = 0.035). Multivariate analysis revealed that being aged ≥75 (P = 0.002), being male (P = 0.020), cardiovascular disease (P = 0.023), blood loss ≥1000ml (P = 0.001) and the absence of ramelteon treatment (P = 0.046) were independent risk factors for postoperative delirium.

Conclusion

The administration of ramelteon might reduce the risk of postoperative delirium after elective liver resection.