Intraoperative ketamine for prevention of postoperative delirium or pain after major surgery in older adults: an international, multicentre, double-blind, randomised clinical trial

Regional anesthesia techniques and postoperative delirium: systematic review and meta-analysis

INTRODUCTION

Postoperative delirium is a frequent occurrence in the elderly surgical population. As a comprehensive list of predictive factors remains unknown, an opioid-sparing approach incorporating regional anesthesia techniques has been suggested to decrease its incidence. Due to the lack of conclusive evidence on the topic, we conducted a systematic review and meta-analysis to investigate the potential impact of regional anesthesia and analgesia on postoperative delirium.

EVIDENCE ACQUISITION

PubMed, Embase, and the Cochrane central register of Controlled trials (CENTRAL) databases were searched for randomized trials comparing regional anesthesia or analgesia to systemic treatments in patients having any type of surgery. This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We pooled the results separately for each of these two applications by random effects modelling. Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to evaluate the certainty of evidence and strength of conclusions.

EVIDENCE SYNTHESIS

Eighteen trials (3361 subjects) were included. Using regional techniques for surgical anesthesia failed to reduce the risk of postoperative delirium, with a relative risk (RR) of 1.21 (95% CI: 0.79 to 1.85); P=0.3800. In contrast, regional analgesia reduced the relative risk of perioperative delirium by a RR of 0.53 (95% CI: 0.42 to 0.68; P<0.0001), when compared to systemic analgesia. Post-hoc subgroup analysis for hip fracture surgery yielded similar findings.

CONCLUSIONS

These results show that postoperative delirium may be decreased when regional techniques are used in the postoperative period as an analgesic strategy. Intraoperative regional anesthesia alone may not decrease postoperative delirium since there are other factors that may influence this outcome.

Multicenter Retrospective Review of Ketamine Use in the ICU

IMPORTANCE:

The response of ICU patients to continuously infused ketamine when it is used for analgesia and/or sedation remains poorly established.

OBJECTIVES:

To describe continuous infusion (CI) ketamine use in critically ill patients, including indications, dose and duration, adverse effects, patient outcomes, time in goal pain/sedation score range, exposure to analgesics/sedatives, and delirium.

DESIGN, SETTING, AND PARTICIPANTS:

Multicenter, retrospective, observational study from twenty-five diverse institutions in the United States. Patients receiving CI ketamine between January 2014 and December 2017.

MAIN OUTCOMES AND MEASURES:

Chart review evaluating institutional and patient demographics, ketamine indication, dose, administration, and adverse effects. Pain/sedation scores, cumulative doses of sedatives and analgesics, and delirium screenings in the 24 hours prior to ketamine were compared with those at 0–24 hours and 25–48 hours after.

RESULTS:

A total of 390 patients were included (median age, 54.5 yr; interquartile range, 39–65 yr; 61% males). Primary ICU types were medical (35.3%), surgical (23.3%), and trauma (17.7%). Most common indications were analgesia/sedation (n = 357, 91.5%). Starting doses were 0.2 mg/kg/hr (0.1–0.5 mg/kg/hr) and continued for 1.6 days (0.6–2.9 d). Hemodynamics in the first 4 hours after ketamine were variable (hypertension 24.0%, hypotension 23.5%, tachycardia 19.5%, bradycardia 2.3%); other adverse effects were minimal. Compared with 24 hours prior, there was a significant increase in proportion of time spent within goal pain score after ketamine initiation (24 hr prior: 68.9% [66.7–72.6%], 0–24 hr: 78.6% [74.3–82.5%], 25–48 hr: 80.3% [74.6–84.3%]; p < 0.001) and time spent within goal sedation score (24 hr prior: 57.1% [52.5–60.0%], 0–24 hr: 64.1% [60.7–67.2%], 25–48 hr: 68.9% [65.5–79.5%]; p < 0.001). There was also a significant reduction in IV morphine (mg) equivalents (24 hr prior: 120 [25–400], 0–24 hr: 118 [10–363], 25–48 hr: 80 [5–328]; p < 0.005), midazolam (mg) equivalents (24 hr prior: 11 [4–67], 0–24 hr: 6 [0–68], 25–48 hr: 3 [0–57]; p < 0.001), propofol (mg) (24 hr prior: 942 [223–4,018], 0–24 hr: 160 [0–2,776], 25–48 hr: 0 [0–1,859]; p < 0.001), and dexmedetomidine (µg) (24 hr prior: 1,025 [276–1,925], 0–24 hr: 285 [0–1,283], 25–48 hr: 0 [0–826]; p < 0.001). There was no difference in proportion of time spent positive for delirium (24 hr prior: 43.0% [17.0–47.0%], 0–24 hr: 39.5% [27.0–43.8%], 25–48 hr: 0% [0–43.7%]; p = 0.233). Limitations to these data include lack of a comparator group, potential for confounders and selection bias, and varying pain and sedation practices that may have changed since completion of the study.

CONCLUSIONS AND RELEVANCE:

There is variability in the use of CI ketamine. Hemodynamic instability was the most common adverse effect. In the 48 hours after ketamine initiation compared with the 24 hours prior, proportion of time spent in goal pain/sedation score range increased and exposure to other analgesics/sedatives decreased.

Ambulatory Pain Management in the Pediatric Patient Population

PURPOSE OF REVIEW

Outpatient surgery in the pediatric population has become increasingly common. However, many patients still experience moderate to severe postoperative pain. A poor understanding of the extent of pain after pediatric ambulatory surgery and the lack of randomized control studies of pain management of the outpatient necessitate this review of scientific evidence and multimodal analgesia.

RECENT FINDINGS

A multimodal approach to pain management should be applied to the ambulatory setting to decrease postoperative pain. These include non-pharmacological techniques, multimodal pharmacologics, and neuraxial and peripheral nerve blocks. Postoperative pain management in pediatric ambulatory surgical patients remains suboptimal at most centers due to limited evidence-based approach to postoperative pain control. Pediatric ambulatory pain management requires a multipronged approach to address this inadequacy.

Ketamine Associated Intraoperative Electroencephalographic Signatures of Elderly Patients With and Without Preoperative Cognitive Impairment

BACKGROUND

Ketamine is typically used by anesthesiologists as an adjunct for general anesthesia and as a nonopioid analgesic. It has been explored for prevention of postoperative delirium, although results have been contradictory. In this study, we investigated the association of ketamine with postoperative delirium and specific encephalographic signatures. Furthermore, we examined these associations in the context of baseline neurocognition as measured by a validated assessment.

METHODS

We conducted a prospective observational study from January 2019 to December 2020. Ninety-eight patients aged ≥65 years and undergoing spine surgery scheduled for ≥3 hours were included in the study. All participants who completed the University of California San Francisco (UCSF) Brain Health Assessment preoperatively and postoperatively were assessed with the confusion assessment method for intensive care unit (CAM-ICU) and/or the Nursing Delirium Screening Scale (NuDESC). Patients had frontal electroencephalogram (EEG) recordings (SedLine Root, Masimo, Corp) quantitatively analyzed. We used 60 seconds of artifact-free EEG (without burst suppression) extracted from the middle of the maintenance period to calculate the normalized power spectral density (PSD). Comparisons were made between those who did or did not receive ketamine and according to results from neurocognitive assessments.

RESULTS

Ninety-eight patients (of a total of 155, enrolled and consented) had EEG of sufficient quality for analysis (42 women). Overall, we found a significant increase in the EEG power in the moderate frequency range (10-20 Hz) in patients that received ketamine. When the patients were divided by their preoperative cognitive status, this result in the ketamine group only held true for the cognitively normal patients. Patients that were cognitively impaired at baseline did not demonstrate a significant change in EEG characteristics based on ketamine administration, but impaired patients that received ketamine had a significantly higher rate of postoperative delirium (52% ketamine versus 20% no ketamine) (odds ratio [OR], 4.36; confidence interval [CI], 1.02-18.22; P = .048). In patients determined to be preoperatively cognitively normal, the incidence of postoperative delirium was not significantly associated with ketamine administration (19% ketamine versus 17% no ketamine) (OR, 1.10; CI, 0.30-4.04; P = .5833).

CONCLUSIONS

Ketamine-related changes in EEG are observed in a heterogeneous group of patients receiving spine surgery. This result was driven primarily by the effect of ketamine on cognitively normal patients and not observed in patients that were cognitively impaired at baseline. Furthermore, patients who were cognitively impaired at baseline and who had received ketamine were more likely to develop postoperative delirium, suggesting that cognitive vulnerability might be predicted by the lack of a neurophysiologic response to ketamine.

Clinical effects of low-dose esketamine for anaesthesia induction in the elderly: A randomized controlled trial

WHAT IS KNOWN AND OBJECTIVE

Esketamine is an N-methyl-D-aspartic acid (NMDA) receptor antagonist, which has stronger sedative and analgesic effects and fewer adverse events than ketamine. The effects of low-dose esketamine on haemodynamics and postoperative quality of recovery in elderly patients have not been evaluated. To evaluate whether low-dose esketamine can be safely used for anaesthesia induction in the elderly.

METHODS

Eighty elderly patients were selected for unilateral total knee replacement under general anaesthesia from February 2021 to August 2021. Patients were randomly divided into two groups (n = 40): control group (C group) and esketamine group (K group). During induction of anaesthesia, the control group was intravenously injected with normal saline of equal volume, and the esketamine group was intravenously injected with 0.2-mg/kg esketamine. Both groups were induced by etomidate, sufentanil and rocuronium and maintained by combined intravenous and inhaled anaesthesia during operation.

MAIN OUTCOME MEASURES

HR, SBP, DBP, MAP and BIS values were recorded before induction of anaesthesia (T₀ ), immediately before endotracheal intubation (T₁ ), 1min(T₂ ) and 5min(T₃ ) after endotracheal intubation, surgical skin incision (T₄ ), 1min(T₅ ) and 5min(T₆ ) after surgical skin incision.

RESULTS

Compared with the C group, SBP, DBP, MAP, HR and BIS of the K group were significantly higher at T₁ -T₃ (p < 0.05). There were no significant differences in SBP, DBP, MAP, HR and BIS between the two groups at T₄ -T₆ (p > 0.05). Compared with T₀ , SBP, MAP and BIS values of the two groups at T₁ -T₆ were decreased (p < 0.05). DBP of the K group at T₂ was not significantly different from DBP at T₀ (p < 0.05), but DBP of the C group decreased from T₁ to T₆ (p < 0.05). Compared with T₀ , HR in both groups decreased at T₁ , T₃ , T₄ , T₅ and T₆ (p < 0.05). Compared with the C group, the incidence of cough in the K group was significantly lower (p < 0.05); There was no significant difference in the number of myoclonus during induction between the two groups (p > 0.05). Compared with the C group, the number of hypotension episodes in the K group during induction was much smaller (p < 0.05). There were no significant differences in the incidence of hypertension, bradycardia and tachycardia (p > 0.05). There were no significant differences in postoperative recovery quality and incidence of adverse events between the two groups (p > 0.05).

WHAT IS NEW AND CONCLUSION

Low-dose esketamine for anaesthesia induction in the elderly undergoing knee arthroplasty may better maintain the stability of haemodynamics and has no adverse effect on the quality of early recovery after operation.

Delirium, Caffeine, and Perioperative Cortical Dynamics

Delirium is a major public health issue associated with considerable morbidity and mortality, particularly after surgery. While the neurobiology of delirium remains incompletely understood, emerging evidence suggests that cognition requires close proximity to a system state called criticality, which reflects a point of dynamic instability that allows for flexible access to a wide range of brain states. Deviations from criticality are associated with neurocognitive disorders, though the relationship between criticality and delirium has not been formally tested. This study tested the primary hypothesis that delirium in the postanesthesia care unit would be associated with deviations from criticality, based on surrogate electroencephalographic measures. As a secondary objective, the impact of caffeine was also tested on delirium incidence and criticality. To address these aims, we conducted a secondary analysis of a randomized clinical trial that tested the effects of intraoperative caffeine on postoperative recovery in adults undergoing major surgery. In this substudy, whole-scalp (16-channel) electroencephalographic data were analyzed from a subset of trial participants (n = 55) to determine whether surrogate measures of neural criticality – (1) autocorrelation function of global alpha oscillations and (2) topography of phase relationships via phase lag entropy – were associated with delirium. These measures were analyzed in participants experiencing delirium in the postanesthesia care unit (compared to those without delirium) and in participants randomized to caffeine compared to placebo. Results demonstrated that autocorrelation function in the alpha band was significantly reduced in delirious participants, which is important given that alpha rhythms are postulated to play a vital role in consciousness. Moreover, participants randomized to caffeine demonstrated increased alpha autocorrelation function concurrent with reduced delirium incidence. Lastly, the anterior-posterior topography of phase relationships appeared most preserved in non-delirious participants and in those receiving caffeine. These data suggest that early postoperative delirium may reflect deviations from neural criticality, and caffeine may reduce delirium risk by shifting cortical dynamics toward criticality.

Perioperative Buprenorphine Management: A Multidisciplinary Approach

Buprenorphine formulations (including buprenorphine/naloxone) are effective treatments of pain and opioid use disorder (OUD). Historically, perioperative management of patients prescribed buprenorphine involved abstinence from buprenorphine sufficient to allow for unrestricted mu-opioid receptor availability to full agonist opioid (FAO) treatment. Evidence is mounting that a multimodal analgesic strategy, including simultaneous administration of buprenorphine and FAO, nonopioid adjuncts such as acetaminophen and nonsteroidal anti-inflammatory drugs, and regional anesthesia, is a safe and effective perioperative strategy for the patient prescribed long-term buprenorphine treatment of OUD. This strategy will likely simplify management and more seamlessly provide continuous buprenorphine treatment of OUD after hospital discharge.

The AIR-SED Study: A Multicenter Cohort Study of SEDation Practices, Deep Sedation, and Coma Among Mechanically Ventilated AIR Transport Patients

Supplemental Digital Content is available in the text.

OBJECTIVES:

To characterize prehospital air medical transport sedation practices and test the hypothesis that modifiable variables related to the monitoring and delivery of analgesia and sedation are associated with prehospital deep sedation.

DESIGN:

Multicenter, retrospective cohort study.

SETTING:

A nationwide, multicenter (approximately 130 bases) air medical transport provider.

PATIENTS:

Consecutive, adult mechanically ventilated air medical transport patients treated in the prehospital environment (January 2015 to December 2020).

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

All data involving sedation (medications, monitoring) were recorded. Deep sedation was defined as: 1) Richmond Agitation-Sedation Scale of –3 to –5; 2) Ramsay Sedation Scale of 5 or 6; or 3) Glasgow Coma Scale of less than or equal to 9. Coma was defined as being unresponsive and based on median sedation depth: 1) Richmond Agitation-Sedation Scale of –5; 2) Ramsay of 6; or 3) Glasgow Coma Scale of 3. A total of 72,148 patients were studied. Prehospital deep sedation was observed in 63,478 patients (88.0%), and coma occurred in 42,483 patients (58.9%). Deeply sedated patients received neuromuscular blockers more frequently and were less likely to have sedation depth documented with a validated sedation depth scale (i.e., Ramsay or Richmond Agitation-Sedation Scale). After adjusting for covariates, a multivariable logistic regression model demonstrated that the use of longer-acting neuromuscular blockers (i.e., rocuronium and vecuronium) was an independent predictor of deep sedation (adjusted odds ratio, 1.28; 95% CI, 1.22–1.35; p < 0.001), while use of a validated sedation scale was associated with a lower odds of deep sedation (adjusted odds ratio, 0.29; 95% CI, 0.27–0.30; p < 0.001).

CONCLUSIONS:

Deep sedation (and coma) is very common in mechanically ventilated air transport patients and associated with modifiable variables related to the monitoring and delivery of analgesia and sedation. Sedation practices in the prehospital arena and associated clinical outcomes are in need of further investigation.

Awareness and Perspectives among Asian Anesthesiologists on Postoperative Delirium: A Multinational Survey

Postoperative delirium (POD) is a common perioperative complication. Although POD is preventable in up to 40% of patients, it is frequently overlooked. The objective of the survey is to determine the level of knowledge and clinical practices related to POD among anesthesiologists in different Asian countries. A questionnaire of 22 questions was designed by members of the Asian focus group for the study of POD, and it was sent to anesthesiologists in Singapore, Thailand, and South Korea from 1 April 2019 through 17 September 2019. In total, 531 anesthesiologists (Singapore: 224, Thailand: 124, Korea: 183) responded to the survey. Half the respondents estimated the incidence of POD to be 11–30% and believed that it typically occurs in the first 48 h after surgery. Among eight important postoperative complications, POD was ranked fifth. While 51.4% did not perform any test for POD, only 13.7% monitored the depth of anesthesia in all their patients. However, 83.8% preferred depth of anesthesia monitoring if they underwent surgery themselves. The results suggest that Asian anesthesiologists underestimate the incidence and relevance of POD. Because it increases perioperative mortality and morbidity, there is an urgent need to educate anesthesiologists regarding the recognition, prevention, detection, and management of POD.

Contemporary Neuroprotection Strategies during Cardiac Surgery: State of the Art Review

Open-heart surgery is the leading cause of neuronal injury in the perioperative state, with some patients complicating with cerebrovascular accidents and delirium. Neurological fallout places an immense burden on the psychological well-being of the person affected, their family, and the healthcare system. Several randomised control trials (RCTs) have attempted to identify therapeutic and interventional strategies that reduce the morbidity and mortality rate in patients that experience perioperative neurological complications. However, there is still no consensus on the best strategy that yields improved patient outcomes, such that standardised neuroprotection protocols do not exist in a significant number of anaesthesia departments. This review aims to discuss contemporary evidence for preventing and managing risk factors for neuronal injury, mechanisms of injury, and neuroprotection interventions that lead to improved patient outcomes. Furthermore, a summary of existing RCTs and large observational studies are examined to determine which strategies are supported by science and which lack definitive evidence. We have established that the overall evidence for pharmacological neuroprotection is weak. Most neuroprotective strategies are based on animal studies, which cannot be fully extrapolated to the human population, and there is still no consensus on the optimal neuroprotective strategies for patients undergoing cardiac surgery. Large multicenter studies using universal standardised neurological fallout definitions are still required to evaluate the beneficial effects of the existing neuroprotective techniques.

Evaluation of the 3-Minute Diagnostic Confusion Assessment Method for Identification of Postoperative Delirium in Older Patients

IMPORTANCE

Delirium is a common postoperative complication in older patients that often goes undetected and might lead to worse outcomes. The 3-Minute Diagnostic Confusion Assessment Method (3D-CAM) might be a practical tool for routine clinical diagnosis of delirium.

OBJECTIVE

To assess the 3D-CAM for detecting postoperative delirium compared with the long-form CAM used for research purposes.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study of older patients enrolled in ongoing clinical trials between 2015 and 2018 was conducted at a single tertiary US hospital. Included participants were aged 60 years or older undergoing major elective surgical procedures that required at least a 2-day hospital stay. Data were analyzed between February and April 2019.

EXPOSURES

Surgical procedures of at least 2 hours in length requiring general anesthesia with planned extubation.

MAIN OUTCOMES AND MEASURES

Patients were concurrently assessed for delirium using the 3D-CAM assessment and the long-form CAM, scored based on a standardized cognitive assessment. Agreement between these 2 methods was tested using Cohen κ with repeated measures, a generalized linear mixed-effects model, and Bland-Altman analysis.

RESULTS

Sixteen raters conducted 471 concurrent CAM and 3D-CAM interviews including 299 patients (mean [SD] age, 69 [6.5] years), the majority of whom were men (152 [50.8%]), were White (263 [88.0%]), and had noncardiac operations (211 [70.6%]). Both instruments had good intraclass correlation (0.84 for the CAM and 0.98 for the 3D-CAM). Cohen κ demonstrated good overall agreement between the CAM and 3D-CAM (κ = 0.71; 95% CI, 0.58 to 0.83). According to the mixed-effects model, there was statistically significant disagreement between the 3D-CAM and CAM (estimated difference in fixed effect, -0.68; 95% CI, -1.32 to -0.05; P = .04). Bland-Altman analysis showed the probability of a delirium diagnosis with the 3D-CAM was more than twice the probability of a delirium diagnosis with the CAM (probability ratio, 2.78; 95% CI, 2.44 to 3.23).

CONCLUSIONS AND RELEVANCE

The 3D-CAM instrument demonstrated agreement with the long-form CAM and might provide a pragmatic and sensitive clinical tool for detecting postoperative delirium, with the caveat that the 3D-CAM might overdiagnose delirium.

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.

General anesthetic techniques for enhanced recovery after surgery: Current controversies

General anesthesia technique can influence not only immediate postoperative outcomes, but also long-term outcomes beyond hospital stay (e.g., readmission after discharge from hospital). There is lack of evidence regarding superiority of total intravenous anesthesia over inhalation anesthesia with regards to postoperative outcomes even in high-risk population including cancer patients. Optimal balanced general anesthetic technique for enhance recovery after elective surgery in adults includes avoidance of routine use preoperative midazolam, avoidance of deep anesthesia, use of opioid-sparing approach, and minimization of neuromuscular blocking agents and appropriate reversal of residual paralysis. Given that the residual effects of drugs used during anesthesia can increase postoperative morbidity and delay recovery, it is prudent to use a minimal number of drug combinations, and the drugs used are shorter-acting and administered at the lowest possible dose. It is imperative that the discerning anesthesiologist consider whether each drug used is really necessary for accomplishing perioperative goals.

Automated machine learning-based model predicts postoperative delirium using readily extractable perioperative collected electronic data

Objective

Postoperative delirium (POD) is a common postoperative complication that is relevant to poor outcomes. Therefore, it is critical to find effective methods to identify patients with high risk of POD rapidly. Creating a fully automated score based on an automated machine‐learning algorithm may be a method to predict the incidence of POD quickly.

Materials and methods

This is the secondary analysis of an observational study, including 531 surgical patients who underwent general anesthesia. The least absolute shrinkage and selection operator (LASSO) was used to screen essential features associated with POD. Finally, eight features (age, intraoperative blood loss, anesthesia duration, extubation time, intensive care unit [ICU] admission, mini‐mental state examination score [MMSE], Charlson comorbidity index [CCI], postoperative neutrophil‐to‐lymphocyte ratio [NLR]) were used to established models. Four models, logistic regression, random forest, extreme gradient boosted trees, and support vector machines, were built in a training set (70% of participants) and evaluated in the remaining testing sample (30% of participants). Multivariate logistic regression analysis was used to explore independent risk factors for POD further.

Results

Model 1 (logistic regression model) was found to outperform other classifier models in testing data (area under the curve [AUC] of 80.44%, 95% confidence interval [CI] 72.24%–88.64%) and achieve the lowest Brier Score as well. These variables including age (OR = 1.054, 95%CI: 1.017~1.093), extubation time (OR = 1.027, 95%CI: 1.012~1.044), ICU admission (OR = 2.238, 95%CI: 1.313~3.793), MMSE (OR = 0.929, 95%CI: 0.876~0.984), CCI (OR = 1.197, 95%CI: 1.038~1.384), and postoperative NLR (OR = 1.029, 95%CI: 1.002~1.057) were independent risk factors for POD in this study.

Conclusions

We have built and validated a high‐performing algorithm to demonstrate the extent to which patient risk changes of POD during the perioperative period, thus leading to a rational therapeutic choice.

Return of the Righting Reflex Does Not Portend Recovery of Cognitive Function in Anesthetized Rats

As the number of individuals undergoing general anesthesia rises globally, it becomes increasingly important to understand how consciousness and cognition are restored after anesthesia. In rodents, levels of consciousness are traditionally captured by physiological responses such as the return of righting reflex (RORR). However, tracking the recovery of cognitive function is comparatively difficult. Here we use an operant conditioning task, the 5-choice serial reaction time task (5-CSRTT), to measure sustained attention, working memory, and inhibitory control in male and female rats as they recover from the effects of several different clinical anesthetics. In the 5-CSRTT, rats learn to attend to a five-windowed touchscreen for the presentation of a stimulus. Rats are rewarded with food pellets for selecting the correct window within the time limit. During each session we tracked both the proportion of correct (accuracy) and missed (omissions) responses over time. Cognitive recovery trajectories were assessed after isoflurane (2% for 1 h), sevoflurane (3% for 20 min), propofol (10 mg/kg I.V. bolus), ketamine (50 mg/kg I.V. infusion over 10 min), and dexmedetomidine (20 and 35 μg/kg I.V. infusions over 10 min) for up to 3 h following RORR. Rats were classified as having recovered accuracy performance when four of their last five responses were correct, and as having recovered low omission performance when they missed one or fewer of their last five trials. Following isoflurane, sevoflurane, and propofol anesthesia, the majority (63-88%) of rats recovered both accuracy and low omission performance within an hour of RORR. Following ketamine, accuracy performance recovers within 2 h in most (63%) rats, but low omission performance recovers in only a minority (32%) of rats within 3 h. Finally, following either high or low doses of dexmedetomidine, few rats (25-32%) recover accuracy performance, and even fewer (0-13%) recover low omission performance within 3 h. Regardless of the anesthetic, RORR latency is not correlated with 5-CSRTT performance, which suggests that recovery of neurocognitive function cannot be inferred from changes in levels of consciousness. These results demonstrate how operant conditioning tasks can be used to assess real-time recovery of neurocognitive function following different anesthetic regimens.

Treatment of Delirium During Critical Illness

Delirium, an acute disturbance in mental status due to another medical condition, is common and morbid in the intensive care unit. Despite its clear association with multiple common risk factors and important outcomes, including mortality and long-term cognitive impairment, both the ultimate causes of and ideal treatments for delirium remain unclear. Studies suggest that neuroinflammation, hypoxia, alterations in energy metabolism, and imbalances in multiple neurotransmitter pathways contribute to delirium, but commonly used treatments (e.g., antipsychotic medications) target only one or a few of these potential mechanisms and are not supported by evidence of efficacy. At this time, the optimal treatment for delirium during critical illness remains avoidance of risk factors, though ongoing trials may expand on the promise shown by agents such as melatonin and dexmedetomidine. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Effects of methylprednisolone on early postoperative pain and recovery in patients undergoing thoracoscopic lung surgery: A randomized controlled trial

STUDY OBJECTIVE

Evidence from previous studies indicates that glucocorticoids offer effective postoperative analgesia and improve the quality of recovery (QoR). The aim of this study was to evaluate the efficacy of preoperative methylprednisolone on early postoperative pain and QoR following thoracoscopic lung surgery.

DESIGN

A prospective, single-center, three-arm, double-blinded, randomized trial.

SETTING

Tertiary university hospital.

PATIENTS

Adult patients aged ≥18 years undergoing thoracoscopic lung surgery were eligible for participation.

INTERVENTIONS

Patients enrolled in this study were randomized to receive preoperative methylprednisolone (40 mg or 120 mg) or identical volumes of 0.9% saline.

MEASUREMENTS

The primary outcome was the proportion of moderate-to-severe pain (numerical rating scale [NRS] ≥ 4 when coughing during pulmonary rehabilitation exercises) on the first day postoperatively. The postoperative pain scores, QoR-15 scores and other secondary outcomes were also recorded.

MAIN RESULTS

Of the 180 enrolled patients, 173 patients were included in the primary analysis. The results showed that the proportion of moderate-to-severe pain was not significantly different between the combined methylprednisolone group and the placebo group (51.7% vs. 64.9%; absolute difference, 13.2%; 95% CI, -2.1% to 29.3%; P = 0.10). Patients who received methylprednisolone treatment had lower pain scores at rest and coughing on the first day after surgery than those who received placebo treatment, with mean differences of 0.5 and 0.7, respectively (P < 0.01). QoR-15 scores were higher in patients treated with methylprednisolone at day 1 (mean difference, 6.9; P < 0.001) and day 2 (mean difference, 7.2; P < 0.001) than in patients who received placebo treatment. No side-effects associated with methylprednisolone treatment were observed.

CONCLUSIONS

Our findings suggested that preoperative methylprednisolone (either high or low dose) has limited impact on early postoperative pain and recovery in patients undergoing thoracoscopic lung surgery, with no clinically relevant benefits detected when compared with placebo.

TRIAL REGISTRATION

Chinese Clinical Trail Register (identifier: ChiCTR1900021020).

Impact of chronic medications in the perioperative period -anesthetic implications (Part II)

Background: This review article discusses the pharmacodynamic effects of the most commonly used chronic medications by patients undergoing elective surgical procedures, namely cardiovascular drugs (e.g., beta blockers, alpha-2 agonist, calcium channel blockers, ACE inhibitors, diuretics, etc.), lipid-lowering drugs, gastrointestinal medications (H2-blockers, proton pump inhibitors), pulmonary medications (inhaled β-agonists, anticholinergics,), antibiotics (tetracyclines, clindamycin and macrolide, linezolid.), opioids and non-opioids analgesics (NSAIDs, COX-2 inhibitors, acetaminophen), gabapentanoids, erectile dysfunction (ED) drugs, psychotropic drugs (tricyclic antidepressants [TCAs], monoamine oxidase inhibitors [MAOI], selective serotonin reuptake inhibitors [SSRIs], serotonin norepinephrine reuptake inhibitors [SNRIs], and cannabinol-containing drugs).  In addition, the potential adverse drug-interactions between these chronic medications and commonly used anesthetic drugs during the perioperative period will be reviewed. Finally, recommendations regarding the management of chronic medications during the preoperative period will be provided.Materials and Methods: An online search was conducted from January 2000 through February 2021 with the Medline database through PubMed and Google Scholar using the following search terms/keywords: "chronic medications in the perioperative period", and "chronic medications and anesthetic implications." In addition, we searched for anesthetic side effects associated with the major drug groups.Results and Conclusions: An understanding of the pharmacodynamic effects of most used chronic medications is important to avoid untoward outcomes in the perioperative period. These drug interactions may result in altered efficacy and toxicity of the anesthetic medications administered during surgery. These drug-drug interactions can also affect the morbidity, mortality, recovery time of surgical patients and acute relapse of chronic illnesses which could lead to last minute cancellation of surgical procedures. Part II of this two-part review article focuses on the reported interactions between most commonly taken chronic medications by surgical patients and anesthetic and analgesic drugs, as well as recommendations regarding the handling these chronic medications during the perioperative period.

Intraoperative Dexmedetomidine and Ketamine Infusions in an Enhanced Recovery After Thoracic Surgery Program: A Propensity Score Matched Analysis

OBJECTIVES

To assess the impact of intraoperative dexmedetomidine and ketamine on postoperative pain and opioid consumption within an ERAS program in thoracic pulmonary oncologic surgery.

DESIGN

Retrospective, propensity-score matched analysis SETTING: Enhanced Recovery After Surgery (ERAS) program.

PARTICIPANTS

Patients undergoing thoracic pulmonary oncologic surgery between March 2016 and April 2020.

INTERVENTIONS

Continuous infusion of dexmedetomidine and ketamine.

MEASUREMENTS & MAIN RESULTS

The authors initially analyzed data of 1,630 patients undergoing thoracic pulmonary oncologic surgery within their ERAS program. In total, 117 matched pairs were included in this analysis. Patients in the intraoperative dexmedetomidine + ketamine group were more likely to be opioid-free (76.6% vs 60.9%, P<0.01). Raw analysis showed lower pain scores at PACU admission (2.8±2.0 vs 3.4±2.0, P=0.03) and less opioid consumption at PACU admission (5 MED [0-10] vs 7.5 MED [0-15], P=0.03) in the dexmedetomidine + ketamine group; however, these differences were not present after adjusting for multiplicity. There were no significant differences in the length of PACU stay (1.9 hours [1.5-2.8] vs 2.0 hours [1.4-2.9], P=0.48) or hospital stay (three days [two-five] vs three days [two-five], P=0.08). Both groups had similar rates of pulmonary complications (5.9% vs 9.4%, P=0.326), ileus (0.9% vs 0.9%, P=1.00), and 30-day readmission (2.6% vs 4.3%, P=0.722).

CONCLUSIONS

There were no differences in postoperative pain scores and opioid consumption throughout their hospital stay between patients receiving concomitant dexmedetomidine and ketamine infusions versus patients who did not receive these infusions during thoracic surgery.

Risk factors associated with the development of delirium in general ICU patients. A prospective observational study

Objective

We aimed to analyze risk factors related to the development of delirium, aiming for early intervention in patients with greater risk.

Material and methods

Observational study, including prospectively collected patients treated in a single general ICU. These were classified into two groups, according to whether they developed delirium or not (screening performed using CAM-ICU tool). Demographics and clinical data were analyzed. Multivariate logistic regression analyses were performed to quantify existing associations.

Results

1462 patients were included. 93 developed delirium (incidence: 6.3%). These were older, scored higher on the Clinical Frailty Scale, on the risk scores on admission (SAPS-3 and SOFA), and had a greater number of organ failures (OF). We observed more incidence of delirium in patients who (a) presented more than two OF (20.4%; OR 4.9; CI95%: 2.9–8.2), and (b) were more than 74 years old albeit having <2 OF (8.6%; OR 2.1; CI95%: 1.3–3.5). Patients who developed delirium had longer ICU and hospital length-of-stays and a higher rate of readmission.

Conclusions

The highest risk observed for developing delirium clustered in patients who presented more than 2 OF and patients over 74 years old. The detection of patients at high risk for developing delirium could imply a change in management and improved quality of care.

Perioperative Pain Management Issues Unique to Older Adults Undergoing Surgery: A Narrative Review

INTRODUCTION

The older population is growing and with this growth there is a parallel rise in the operations performed on this vulnerable group. The perioperative pain management strategy for older adults is unique and requires a team-based approach for provision of high-quality surgical care.

METHODS

Literature search was performed using PubMed in addition to review of relevant protocols and guidelines from geriatric, surgical, and anesthesia societies. Systematic reviews and meta-analyses, randomized trials, observational studies, and society guidelines were summarized in this review.

MANAGEMENT

The optimal approach to a pain management strategy for older adults undergoing surgery involves addressing all phases of perioperative care. For example, preoperative assessment of a patient's cognitive function and presence of chronic pain may impact the pain management plan. Consideration should be also given to intraoperative strategies to improve pain control and minimize both the dose and side effects from opioids (e.g. regional anesthetic techniques). Postoperative pain control (e.g. under or over treatment of pain) may impact the development of elderly-specific complications such as postoperative delirium and functional decline. Finally, pain management does not stop after the older adult patient leaves the hospital. Both discharge planning and post-operative clinic follow-up provide important opportunities for collaboration and intervention.

CONCLUSIONS

An opioid-sparing pain management strategy for older adults can be accomplished with a comprehensive and collaborative interdisciplinary strategy addressing all phases of perioperative care.

Pain management after complex spine surgery: A systematic review and procedure-specific postoperative pain management recommendations

BACKGROUND

Complex spinal procedures are associated with intense pain in the postoperative period. Adequate peri-operative pain management has been shown to correlate with improved outcomes including early ambulation and early discharge.

OBJECTIVES

We aimed to evaluate the available literature and develop recommendations for optimal pain management after complex spine surgery.

DESIGN AND DATA SOURCES

A systematic review using the PROcedure SPECific postoperative pain managemenT methodology was undertaken. Randomised controlled trials and systematic reviews published in the English language from January 2008 to April 2020 assessing postoperative pain after complex spine surgery using analgesic, anaesthetic or surgical interventions were identified from MEDLINE, EMBASE and Cochrane Databases.

RESULTS

Out of 111 eligible studies identified, 31 randomised controlled trials and four systematic reviews met the inclusion criteria. Pre-operative and intra-operative interventions that improved postoperative pain were paracetamol, cyclo-oxygenase (COX)-2 specific-inhibitors or non-steroidal anti-inflammatory drugs (NSAIDs), intravenous ketamine infusion and regional analgesia techniques including epidural analgesia using local anaesthetics with or without opioids. Limited evidence was found for local wound infiltration, intrathecal and epidural opioids, erector spinae plane block, thoracolumbar interfascial plane block, intravenous lidocaine, dexmedetomidine and gabapentin.

CONCLUSIONS

The analgesic regimen for complex spine surgery should include pre-operative or intra-operative paracetamol and COX-2 specific inhibitors or NSAIDs, continued postoperatively with opioids used as rescue analgesics. Other recommendations are intra-operative ketamine and epidural analgesia using local anaesthetics with or without opioids. Although there is procedure-specific evidence in favour of intra-operative methadone, it is not recommended as it was compared with shorter-acting opioids and due to its limited safety profile. Furthermore, the methadone studies did not use non-opioid analgesics, which should be the primary analgesics to ultimately reduce overall opioid requirements, including methadone. Further qualitative randomised controlled trials are required to confirm the efficacy and safety of these recommended analgesics on postoperative pain relief.

Urinary albumin creatinine ratio associated with postoperative delirium in elderly patients undergoing elective non-cardiac surgery: A prospective observational study

Introduction

The blood‐brain barrier (BBB) disruption contributes to postoperative delirium, but cost‐effective and non‐invasive assessment of its permeability is not practicable in the clinical settings. Urine albumin to creatinine ratio (UACR), reflecting systemic vascular endothelial dysfunction, may be a prognostic and predictive factor associated with postoperative delirium. The aim was to analyze the relationship between UACR and postoperative delirium in elderly patients undergoing elective non‐cardiac surgery.

Materials and methods

Through stratified random sampling, a cohort of 408 individuals aged 60 years and older scheduled for elective non‐cardiac surgery were included between February and August 2019 in the single‐center, prospective, observational study. The presence of delirium was assessed using the Confusion Assessment Method (CAM) or Confusion Assessment Method for the ICU (CAM‐ICU) on the day of surgery, at 2 h after the surgery ending time and on the first 3 consecutive days with repeated twice‐daily, with at least 6‐h intervals between assessments. Urine samples were collected on one day before surgery, and 1st day and 3rd day after surgery. The primary outcome was the presence of postoperative delirium, and association of the level of UACR with postoperative delirium was evaluated with unadjusted/adjusted analyses and multivariable logistic regression.

Results

Postoperative delirium was observed in 26.75% (107 of 400) of patients within 3 days post‐surgery. UACR‐Pre (OR, 1.30; 95% CI, 1.14–1.49, p < 0.001), UACR‐POD1 (OR, 1.20; 95% CI, 1.13–1.27, p < 0.001), and UACR‐POD3 (OR, 1.14; 95% CI, 1.08–1.20, p < 0.001) between the delirium and non‐delirium groups show a significant difference, even after adjusting for age, education levels, and other factors.

Conclusion

As the marker of endothelial dysfunction, the high perioperative UACR value may be linked to the postoperative delirium in elderly patients undergoing elective non‐cardiac surgery.

Ketamine for Acute Pain Management and Sedation

TOPIC

Ketamine is beneficial in clinical settings ranging from procedural sedation to the treatment of chronic pain. This article describes the clinical benefits of ketamine for treatment of acute pain and for sedation of patients undergoing mechanical ventilation.

CLINICAL RELEVANCE

Ketamine causes analgesic and amnestic effects by noncompetitive inhibition of the N-methyl-D-aspartate receptor and activation of the opioid μ and κ receptors. Unlike other sedatives, ketamine provides analgesia and amnesia without causing hypotension or respiratory depression. Several studies have elucidated the clinical benefits of ketamine. The use of ketamine has extended beyond critical care areas such as the operating room and intensive care units. Nurses must be familiar with optimal clinical scenarios, monitoring parameters, and contraindications of ketamine.

PURPOSE

To highlight the clinical utility and pharmacological properties of ketamine through a literature review. Current studies of ketamine in acute pain and sedation management are summarized.

CONTENT COVERED

This narrative review describes pharmacological properties, dosing strategies, adminis-tration considerations, and adverse effects of ketamine.

Delirium in critical illness: clinical manifestations, outcomes, and management

Delirium is the most common manifestation of brain dysfunction in critically ill patients. In the intensive care unit (ICU), duration of delirium is independently predictive of excess death, length of stay, cost of care, and acquired dementia. There are numerous neurotransmitter/functional and/or injury-causing hypotheses rather than a unifying mechanism for delirium. Without using a validated delirium instrument, delirium can be misdiagnosed (under, but also overdiagnosed and trivialized), supporting the recommendation to use a monitoring instrument routinely. The best-validated ICU bedside instruments are CAM-ICU and ICDSC, both of which also detect subsyndromal delirium. Both tools have some inherent limitations in the neurologically injured patients, yet still provide valuable information about delirium once the sequelae of the primary injury settle into a new post-injury baseline. Now it is known that antipsychotics and other psychoactive medications do not reliably improve brain function in critically ill delirious patients. ICU teams should systematically screen for predisposing and precipitating factors. These include exacerbations of cardiac/respiratory failure or sepsis, metabolic disturbances (hypoglycemia, dysnatremia, uremia and ammonemia) receipt of psychoactive medications, and sensory deprivation through prolonged immobilization, uncorrected vision and hearing deficits, poor sleep hygiene, and isolation from loved ones so common during COVID-19 pandemic. The ABCDEF (A2F) bundle is a means to facilitate implementation of the 2018 Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU (PADIS) Guidelines. In over 25,000 patients across nearly 100 institutions, the A2F bundle has been shown in a dose-response fashion (i.e., greater bundle compliance) to yield improved survival, length of stay, coma and delirium duration, cost, and less ICU bounce-backs and discharge to nursing homes.

Anaesthetic management using remimazolam in a patient with severe aortic stenosis: a case report

Background

The administration of general anaesthesia in patients with aortic stenosis (AS) requires careful attention to haemodynamics. We used remimazolam for the induction and maintenance of anaesthesia in a woman with severe AS undergoing a total mastectomy.

Case presentation

An 81-year-old woman with severe AS was scheduled to undergo a total mastectomy. We decided to administer total intravenous anaesthesia with remimazolam to minimize haemodynamic changes. Although the patient showed transient hypotension after anaesthesia induction, the cardiac index was preserved with a low dose of continuous noradrenaline. The anaesthesia was then safely maintained without a decrease in the patient’s cardiac index.

Conclusions

General anaesthesia using remimazolam preserved cardiac output in this patient; therefore, remimazolam can be safely used to avoid the risk of cardiac suppression in patients with severe AS.

Delirium in Older Patients after Combined Epidural-General Anesthesia or General Anesthesia for Major Surgery: A Randomized Trial

BACKGROUND

Delirium is a common and serious postoperative complication, especially in the elderly. Epidural anesthesia may reduce delirium by improving analgesia, reducing opioid consumption, and blunting stress response to surgery. This trial therefore tested the hypothesis that combined epidural-general anesthesia reduces the incidence of postoperative delirium in elderly patients recovering from major noncardiac surgery.

METHODS

Patients aged 60 to 90 yr scheduled for major noncardiac thoracic or abdominal surgeries expected to last 2 h or more were enrolled. Participants were randomized 1:1 to either combined epidural-general anesthesia with postoperative epidural analgesia or general anesthesia with postoperative intravenous analgesia. The primary outcome was the incidence of delirium, which was assessed with the Confusion Assessment Method for the Intensive Care Unit twice daily during the initial 7 postoperative days.

RESULTS

Between November 2011 and May 2015, 1,802 patients were randomized to combined epidural-general anesthesia (n = 901) or general anesthesia alone (n = 901). Among these, 1,720 patients (mean age, 70 yr; 35% women) completed the study and were included in the intention-to-treat analysis. Delirium was significantly less common in the combined epidural-general anesthesia group (15 [1.8%] of 857 patients) than in the general anesthesia group (43 [5.0%] of 863 patients; relative risk, 0.351; 95% CI, 0.197 to 0.627; P < 0.001; number needed to treat 31). Intraoperative hypotension (systolic blood pressure less than 80 mmHg) was more common in patients assigned to epidural anesthesia (421 [49%] vs. 288 [33%]; relative risk, 1.47, 95% CI, 1.31 to 1.65; P < 0.001), and more epidural patients were given vasopressors (495 [58%] vs. 387 [45%]; relative risk, 1.29; 95% CI, 1.17 to 1.41; P < 0.001).

CONCLUSIONS

Older patients randomized to combined epidural-general anesthesia for major thoracic and abdominal surgeries had one third as much delirium but 50% more hypotension. Clinicians should consider combining epidural and general anesthesia in patients at risk of postoperative delirium, and avoiding the combination in patients at risk of hypotension.

EDITOR’S PERSPECTIVE

Ready for a "breakthrough" with ketamine? A look at recent pharmacological insights!

PURPOSE OF REVIEW

To update pharmacological insights on ketamine integrating information from different disciplines for developing steps to "breakthrough" approaches in clinical challenges.

RECENT FINDINGS

Pharmacokinetic/pharmacodynamic (PK/PD) models have incorporated recirculation, ketamine metabolites, drug-drug interaction, and covariates such as age. Ketamine-induced relief from treatment-resistant depression has been explained by "disinhibition" of gamma-aminobutyric acid-ergic interneurons and synaptogenic mechanisms requiring neurotrophic signals. Neuroimaging/electroencephalographic investigations have shown an increase in gamma spectral power in healthy volunteers and patients with depression, but also opposite changes in functional network connectivity after subanesthetic ketamine. Volunteer data may not be transferable to clinical conditions. Altered states of consciousness induced by subanesthetic ketamine have been described by disruption of resisting-state functional networks and frontoparietal connectivity with preservation of multisensory and sensor-motor networks. This has been interpreted as a "disconnected consciousness".

SUMMARY

More precise PK/PD models may improve the ketamine use regimen. The findings from research on depression are an important discovery because ketamine's impact on neuronal plasticity and synaptogenesis in human brain disease has directly been documented. Psychic adverse effects with subanesthetic ketamine are related to a "disconnected consciousness". Overall, progress has been made, but the "breakthrough" still has to come.

The Effects of Intraoperative Caffeine on Postoperative Opioid Consumption and Related Outcomes After Laparoscopic Surgery: A Randomized Controlled Trial

BACKGROUND

Surgical patients are vulnerable to opioid dependency and related risks. Clinical-translational data suggest that caffeine may enhance postoperative analgesia. This trial tested the hypothesis that intraoperative caffeine would reduce postoperative opioid consumption. The secondary objective was to assess whether caffeine improves neuropsychological recovery postoperatively.

METHODS

This was a single-center, randomized, placebo-controlled trial. Participants, clinicians, research teams, and data analysts were all blinded to the intervention. Adult (≥18 years old) surgical patients (n = 65) presenting for laparoscopic colorectal and gastrointestinal surgery were randomized to an intravenous caffeine citrate infusion (200 mg) or dextrose 5% in water (40 mL) during surgical closure. The primary outcome was cumulative opioid consumption through postoperative day 3. Secondary outcomes included subjective pain reporting, observer-reported pain, delirium, Trail Making Test performance, depression and anxiety screens, and affect scores. Adverse events were reported, and hemodynamic profiles were also compared between the groups.

RESULTS

Sixty patients were included in the final analysis, with 30 randomized to each group. The median (interquartile range) cumulative opioid consumption (oral morphine equivalents, milligrams) was 77 mg (33-182 mg) for caffeine and 51 mg (15-117 mg) for placebo (estimated difference, 55 mg; 95% confidence interval [CI], -9 to 118; P = .092). After post hoc adjustment for baseline imbalances, caffeine was associated with increased opioid consumption (87 mg; 95% CI, 26-148; P = .005). There were otherwise no differences in prespecified pain or neuropsychological outcomes between the groups. No major adverse events were reported in relation to caffeine, and no major hemodynamic perturbations were observed with caffeine administration.

CONCLUSIONS

Caffeine appears unlikely to reduce early postoperative opioid consumption. Caffeine otherwise appears well tolerated during anesthetic emergence.

Effects of perioperative rosuvastatin on postoperative delirium in elderly patients: A randomized, double-blind, and placebo-controlled trial

BACKGROUND

Experimental evidence has indicated the benefits of statins for the treatment of postoperative delirium. Previously, clinical trials did not reach definite conclusions on the effects of statins on delirium. Some clinical trials have indicated that statins reduce postoperative delirium and improve outcomes, while some studies have reported negative results.

AIM

To evaluate whether perioperative rosuvastatin treatment reduces the incidence of delirium and improves clinical outcomes.

METHODS

This randomized, double-blind, and placebo-controlled trial was conducted in a single center in Jiangsu, China. This study enrolled patients aged greater than 60 years who received general anesthesia during elective operations and provided informed consent. A computer-generated randomization sequence (in a 1:1 ratio) was used to randomly assign patients to receive either rosuvastatin (40 mg/d) or placebo. Participants, care providers, and investigators were all masked to group assignments. The primary endpoint was the incidence of delirium, which was assessed twice daily with the Confusion Assessment Method during the first 7 postoperative days. Analyses were performed on intention-to-treat and safety populations.

RESULTS

Between January 1, 2017 and January 1, 2020, 3512 patients were assessed. A total of 821 patients were randomly assigned to receive either placebo (n = 411) or rosuvastatin (n = 410). The incidence of postoperative delirium was significantly lower in the rosuvastatin group [23 (5.6%) of 410 patients] than in the placebo group {42 (13.5%) of 411 patients [odds ratios (OR) = 0.522, 95% confidence interval (CI): 0.308-0.885; P < 0.05]}. No significant difference in 30-d all-cause mortality (6.1% vs 8.7%, OR = 0.67, 95%CI: 0.39-1.2, P = 0.147) was observed between the two groups. Rosuvastatin decreased the hospitalization time (13.8 ± 2.5 vs 14.2 ± 2.8, P = 0.03) and hospitalization expenses (9.3 ± 2.5 vs 9.8 ± 2.9, P = 0.007). No significant differences in abnormal liver enzymes (9.0% vs 7.1%, OR = 1.307, 95%CI: 0.787-2.169, P = 0.30) or rhabdomyolysis (0.73% vs 0.24%, OR = 3.020, 95%CI: 0.31-29.2, P = 0.37) were observed between the two groups.

CONCLUSION

The current study suggests that perioperative rosuvastatin treatment reduces the incidence of delirium after an elective operation under general anesthesia. However, the evidence does not reveal that rosuvastatin improves clinical outcomes. The therapy is safe. Further investigation is necessary to fully understand the potential usefulness of rosuvastatin in elderly patients.

Ketamine in the Past, Present, and Future: Mechanisms, Metabolites, and Toxicity

PURPOSE OF REVIEW

While ketamine's analgesia has mostly been attributed to antagonism of N-methyl-D-aspartate receptors, evidence suggests multiple other pathways are involved in its antidepressant and possibly analgesic activity. These mechanisms and ketamine's role in the nociplastic pain paradigm are discussed. Animal studies demonstrating ketamine's neurotoxicity have unclear human translatability and findings from key rodent and human studies are presented.

RECENT FINDINGS

Ketamine's metabolites, and (2R,6R)-hydroxynorketamine in particular, may play a greater role in its clinical activity than previously believed. The activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and the mammalian target of rapamycin by ketamine are mechanisms that are still being elucidated. Ketamine might work best in nociplastic pain, which involves altered pain processing. While much is known about ketamine, new studies will continue to define its role in clinical medicine. Evidence supporting ketamine's neurotoxicity in humans is lacking and should not impede future ketamine clinical trials.

Epidural Anesthesia-Analgesia and Recurrence-free Survival after Lung Cancer Surgery: A Randomized Trial

BACKGROUND

Regional anesthesia and analgesia reduce the stress response to surgery and decrease the need for volatile anesthesia and opioids, thereby preserving cancer-specific immune defenses. This study therefore tested the primary hypothesis that combining epidural anesthesia-analgesia with general anesthesia improves recurrence-free survival after lung cancer surgery.

METHODS

Adults scheduled for video-assisted thoracoscopic lung cancer resections were randomized 1:1 to general anesthesia and intravenous opioid analgesia or combined epidural-general anesthesia and epidural analgesia. The primary outcome was recurrence-free survival (time from surgery to the earliest date of recurrence/metastasis or all-cause death). Secondary outcomes included overall survival (time from surgery to all-cause death) and cancer-specific survival (time from surgery to cancer-specific death). Long-term outcome assessors were blinded to treatment.

RESULTS

Between May 2015 and November 2017, 400 patients were enrolled and randomized to general anesthesia alone (n = 200) or combined epidural-general anesthesia (n = 200). All were included in the analysis. The median follow-up duration was 32 months (interquartile range, 24 to 48). Recurrence-free survival was similar in each group, with 54 events (27%) with general anesthesia alone versus 48 events (24%) with combined epidural-general anesthesia (adjusted hazard ratio, 0.90; 95% CI, 0.60 to 1.35; P = 0.608). Overall survival was also similar with 25 events (13%) versus 31 (16%; adjusted hazard ratio, 1.12; 95% CI, 0.64 to 1.96; P = 0.697). There was also no significant difference in cancer-specific survival with 24 events (12%) versus 29 (15%; adjusted hazard ratio, 1.08; 95% CI, 0.61 to 1.91; P = 0.802). Patients assigned to combined epidural-general had more intraoperative hypotension: 94 patients (47%) versus 121 (61%; relative risk, 1.29; 95% CI, 1.07 to 1.55; P = 0.007).

CONCLUSIONS

Epidural anesthesia-analgesia for major lung cancer surgery did not improve recurrence-free, overall, or cancer-specific survival compared with general anesthesia alone, although the CI included both substantial benefit and harm.

EDITOR’S PERSPECTIVE

[Perioperative Medicine in Visceral Surgery in the Elderly Patient from an Anaesthesiological Perspective]

Demographic change is leading to an increasing number of old patients both in our society and in hospitals. With increasing age, not only the number of pre-existing conditions increases, but also the postoperative complication rate and mortality. Ultimately, however, it is not age that is decisive, but the condition of the patient and his or her capacity to face the physical and mental challenges of a surgical procedure. Frail patients are particularly at risk of complications, and an essential strategy - known as prehabilitation - is to put them in a better state pre-operatively through physical and mental training, as well as nutritional counselling. Delirium is one of the most frequent postoperative complications. Measures such as refraining from premedication with benzodiazepines, measuring the depth of anaesthesia, refraining from long-acting opioids, performing fast-track surgery, and providing glasses/hearing aids quickly postoperatively can reduce the risk of delirium. Close interdisciplinary consultation between surgeons, anaesthetists, geriatricians and physiotherapists is essential to coordinate the perioperative procedure and reduce the perioperative risk for elderly patients.

Comparative effectiveness of pharmacological interventions to prevent postoperative delirium: a network meta-analysis

Many pharmacologic agents were investigated for the effect to prevent delirium. We aimed to comprehensively compare the effect of the pharmacological interventions to prevent postoperative delirium. A Bayesian network meta-analysis of randomized trials was performed using random effects model. PubMed, the Cochrane Central Register of Controlled Trials, and Embase were searched on 20 January 2021. Randomized trials comparing the effect of a drug to prevent postoperative delirium with another drug or placebo in adult patients undergoing any kind of surgery were included. Primary outcome was the postoperative incidence of delirium. Eighty-six trials with 26,992 participants were included. Dexmedetomidine, haloperidol, and atypical antipsychotics significantly decreased the incidence of delirium than placebo [dexmedetomidine: odds ratio 0.51, 95% credible interval (CrI) 0.40-0.66, moderate quality of evidence (QOE); haloperidol: odds ratio 0.59, 95% CrI 0.37-0.95, moderate QOE; atypical antipsychotics: odds ratio 0.27, 95% CrI 0.14-0.51, moderate QOE]. Dexmedetomidine and atypical antipsychotics had the highest-ranking probabilities to be the best. However, significant heterogeneity regarding diagnostic time window as well as small study effects precludes firm conclusion.