European Society of Anaesthesiology evidence-based and consensus-based guideline on postoperative delirium

Evaluation of Anesthetic Specific EEG Dynamics during State Transitions between Loss and Return of Responsiveness

Purpose: electroencephalographic (EEG) information is used to monitor the level of cortical depression of a patient undergoing surgical intervention under general anesthesia. The dynamic state transitions into and out of anesthetic-induced loss and return of responsiveness (LOR, ROR) present a possibility to evaluate the dynamics of the EEG induced by different substances. We evaluated changes in the EEG power spectrum during anesthesia emergence for three different anesthetic regimens. We also assessed the possible impact of these changes on processed EEG parameters such as the permutation entropy (PeEn) and the cerebral state index (CSI). Methods: we analyzed the EEG from 45 patients, equally assigned to three groups. All patients were induced with propofol and the groups differed by the maintenance anesthetic regimen, i.e., sevoflurane, isoflurane, or propofol. We evaluated the EEG and parameter dynamics during LOR and ROR. For the emergence period, we focused on possible differences in the EEG dynamics in the different groups. Results: depending on the substance, the EEG emergence patterns showed significant differences that led to a substance-specific early activation of higher frequencies as indicated by the “wake” CSI values that occurred minutes before ROR in the inhalational anesthetic groups. Conclusion: our results highlight substance-specific differences in the emergence from anesthesia that can influence the EEG-based monitoring that probably have to be considered in order to improve neuromonitoring during general anesthesia.

Association Between Frailty and Clinical Outcomes and Quality of Life in Older Adults Following Hip Fracture Surgery: A Retrospective Cohort Study

BACKGROUND

Hip fracture is a serious event in the older population and is associated with morbidity, mortality, and disability among those who survive. Emerging evidence suggests that frailty is pertinent to the clinical outcomes of older patients with hip fracture.

METHODS

We conducted a retrospective cohort study on older patients (aged ≥65 years) who underwent orthopedic repair with hip fracture under spinal or general anesthesia between June 1, 2019 and May 31, 2020. Demographic, surgical, and anesthetic features; chart-derived frailty index (CFI); occurrence of complications; and length of stay were retrospectively collected by reviewing patients' anesthesia records and medical charts. Patients were divided into 2 groups according to their CFI: high CFI group (CFI, 3-5) and low CFI group (CFI, 0-2). The CFI was calculated as the addition of the patient's conditions, including age >70 years, preoperative body mass index <18.5 kg/m2, hematocrit <35%, albumin <34 g/L, and serum creatinine >176.8 mol/L (2.0 mg/dL). The EuroQol 5-dimensional questionnaire (EQ-5D) was obtained through telephone interviews 12 months after surgery to assess mortality and long-term quality of life.

RESULTS

During the study period, 381 patients met the inclusion criteria. Patients in the high CFI group had an increased incidence of delirium by 13.80% (95% confidence interval [CI], 6.31-21.29) (17 [16.6%] vs 8 [2.8%]; P < .001) compared to patients in the low CFI group. More patients in the high CFI group had pneumonia with an increased incidence of 17.71% (95% CI, 7.08-23.34) (40 [39.2%] vs 60 [21.5%]; P < .001) than patients in the low CFI group. Postoperative hospital stay was significantly longer in the high CFI group (8 [6-12] vs 7 [5-10] days; P = .0222) than in the low CFI group. More patients died in the high CFI group 1 year after surgery with an increased mortality of 19.33% (95% CI, 9.47-29.18) (26.4% [23/87] vs 7.1% [16/225]; P < .001) than patients in the low CFI group. A total of 64 patients in the high CFI group and 209 patients in the low CFI group completed the EQ-5D survey 1 year after surgery. The EQ-5D score in the high CFI group was significantly lower than that in the low CFI group (0.63 ± 0.22 vs 0.72 ± 0.22; P = .002).

CONCLUSIONS

Frailty status is associated with adverse postoperative outcomes, mortality, and low quality of life 12 months after hip fracture surgery in older patients.

Inclusion of interleukin-6 improved performance of postoperative delirium prediction for patients undergoing coronary artery bypass graft (POD-CABG): A derivation and validation study

BACKGROUND

Patients undergoing coronary artery bypass graft (CABG) are at high risk for developing postoperative delirium (POD). A simple prediction rule may benefit patients from early identification of POD followed by adequate preventive strategies. The purpose of the current study was to develop and validate a POD prediction rule for patients undergoing CABG (POD-CABG), by considering all possible perioperative factors.

METHODS

In this prospective cohort study, patients who underwent first elective isolated CABG were continuously enrolled from May 2014 to November 2015 in a tertiary hospital. Delirium was assessed using the Confusion Assessment Method for Intensive Care Unit. Patients' perioperative risk factors were collected through interviews and review of medical records. The area under receiver-operating characteristic curve (AUC) was used to assess the overall performance of the predictive rule.

RESULTS

A total of 242 and 148 patients were enrolled in the derivation and validation cohorts, respectively. Multiple logistic regression analysis identified seven variables that were independently associated with POD: age (≥65 years), gender (female), history of myocardial infarction and diabetes mellitus, postoperative atrial fibrillation, the use of intra-aortic balloon pump, and serum interleukin-6 ≥478 pg/ml at 18 hours after surgery. The AUC of the POD-CABG was 0.84 (95% CI, 0.79-0.90) in the derivation cohort, and was 0.86 (95% CI, 0.80-0.91) after bootstrap resampling. The AUC was 0.81 (95% CI, 0.73-0.88) after the POD-CABG was applied to the validation cohort.

CONCLUSIONS

The POD-CABG with inclusion of interleukin-6 demonstrated good performance in predicting POD.

Emergence agitation in paediatric day case surgery: A randomised, single-blinded study comparing narcotrend and heart rate variability with standard monitoring

BACKGROUND

Postoperative emergence agitation remains a significant challenge in paediatric anaesthesia. Although short-lived, it may cause harm to the patient and negative experiences for all. Differentiating agitation, delirium and pain is difficult. Electroencephalography allows precise titration of anaesthetic depth, and heart rate variability monitoring permits immediate intervention regarding nociception and pain. We examined if one of these measures could be used to reduce postoperative agitation in an unselected paediatric day surgical population.

OBJECTIVE

The primary outcome was postoperative agitation with a Richmond Agitation-Sedation Scale greater than 0. Secondary outcomes were: length of stay, postoperative nausea and vomiting, fentanyl and propofol consumption, pain scores and use of postoperative analgesics.

DESIGN

A randomised, single-blinded study constituting children aged 1 to 6 years, undergoing minor general day surgical procedures.

SETTING

Paediatric day surgical department 29th March 2019 to 12th June 2020.

PATIENTS

Ninety-eight children (ASA 1 or 2) were enrolled, and 93 children were included in the final analysis.

INTERVENTIONS

Children received standard monitoring (n=31), standard monitoring plus either Narcotrend (n=31), or Anaesthesia Nociception Index monitoring (n=31). Sevoflurane or fentanyl was titrated immediately according to monitor thresholds.

RESULTS

Kaplan-Meier analysis yielded a statistically significant difference between the groups (P = 0.016) with the lowest agitation levels in the Anaesthesia Nociception Index group, intermediate levels in the control group and the highest agitation levels in the Narcotrend monitored group. Intergroup pairwise comparison however, showed no difference. The Anaesthesia Nocioception Index group received slightly more fentanyl (P = 0.277). The control group patients had the highest pain scores despite receiving more caudal blocks and the Narcotrend group had more sevoflurane adjustments. Other secondary outcomes were comparable.

CONCLUSION

Children in the Anaesthesia Nociception Index group were the least agitated with the highest fentanyl doses, without increasing the length of stay in the PACU or postoperative nausea and vomiting.

CLINICAL REGISTRATION

The study was registered in RedCAP online trial database 1/11/2018 trial registration nr. OP720. https://open.rsyd.dk/OpenProjects/openProject.jsp?openNo=720&lang=da.

Comparison of restrictive fluid therapy with goal-directed fluid therapy for postoperative delirium in patients undergoing spine surgery: a randomized controlled trial

Background

Postoperative delirium (POD) is a common phenomenon after spinal surgery. Intraoperative fluid management may affect POD. The aim of this study was to compare the effects of restrictive fluid therapy (RF) with those of goal-directed fluid therapy (GDT) on POD.

Methods

A total of 195 patients aged ≥ 50 years who underwent spinal surgery were randomly divided into two groups: the RF group and the GDT group. In group RF, a bolus of lactated Ringer’s solution was administered at a dose of 5 mL·kg^-1 before the induction of anesthesia, followed by a dose of 5 mL·kg^-1·h^-1 until the end of surgery. For patients in the GDT group, in addition to the initial administration of lactated Ringer’s solution at 5 mL·kg^-1, the subsequent fluid therapy was adjusted by using a continuous noninvasive arterial pressure (CNAP) monitoring system to maintain pulse pressure variation (PPV) ≤ 14%. The primary endpoint was the incidence of POD, assessed once daily with the Confusion Assessment Method-Chinese Reversion (CAM-CR) scale at 1–3 days postoperatively. The secondary endpoints were intraoperative fluid infusion volume, urine volume, mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), regional cerebral oxygen saturation (rSO₂) value, lactic acid value, and visual analog scale (VAS) pain score at 1–3 days after surgery. Moreover, postoperative complications and the length of hospital stay were recorded.

Results

The incidence of POD was lower in the GDT group than in the RF group (12.4% vs 4.1%; P = 0.035) in the first 3 days after spine surgery. Compared to group RF, group GDT exhibited a significantly increased volume of intraoperative lactated Ringer’s solution [1500 (interquartile range: 1128 to 1775) mL vs 1000 (interquartile range: 765 to 1300) mL, P < 0.001] and urine volume [398 (interquartile range: 288 to 600) mL vs 300 (interquartile range: 200 to 530) mL, P = 0.012]. Intraoperative MAP, CI and rSO₂ values were higher in the GDT group than in the RF group (P < 0.05). Moreover, the length of hospital stay [17.0 (14 to 20) days versus 14.5 (13 to 17.0) days, P = 0.001] was shorter in the GDT group than in the RF group.

Conclusions

GDT reduced the incidence of POD in middle- and old-aged patients undergoing spinal surgery possibly by stabilizing perioperative hemodynamic and improving the supply and demand of oxygen.

Trial registration

ChiCTR2000032603; Registered on May 3, 2020.

Influences of remote ischemic preconditioning on postoperative delirium and cognitive dysfunction in adults after cardiac surgery: a meta-analysis of randomized controlled trials

Background

Remote ischemic preconditioning (RIPC) has been suggested to confer neuroprotective effect. However, influences of RIPC on postoperative delirium (POD) and cognitive dysfunction (POCD) in adults after cardiac surgery are less known. We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the effects of RIPC on POD and POCD.

Methods

Relevant studies were obtained by search of PubMed, Embase, and Cochrane’s Library databases. A random-effect model was used to pool the results.

Results

Ten RCTs including 2303 adults who received cardiac surgery were included. Pooled results showed that RIPC did not significantly affect the incidence of POD (six RCTs, odds ratio [OR] 1.07, 95% confidence interval [CI] 0.81 to 1.40, P = 0.65) with no significant heterogeneity (I² = 0%). In addition, combined results showed that RIPC did not significantly reduce the incidence of POCD either (six RCTs, OR 0.64, 95% CI 0.37 to 1.11, P = 0.11) with moderate heterogeneity (I² = 44%). Sensitivity analysis by excluding one RCT at a time showed consistent results (P values all > 0.05).

Conclusions

Current evidence from RCTs did not support that RIPC could prevent the incidence of POD or POCD in adults after cardiac surgery. Although these findings may be validated in large-scale RCTs, particularly for the results of POCD, based on these findings, RIPC should not be routinely used as a preventative measure for POD and POCD in adult patients after cardiac surgery.

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.

Frailty as a growing challenge for anesthesiologists - results of a Dutch national survey

BACKGROUND

Frailty is a multidimensional condition characterized by loss of functional reserve, which results in increased vulnerability to adverse outcomes following surgery. Anesthesiologists can reduce adverse outcomes when risk factors are recognized early and dedicated care pathways are operational. As the frail elderly population is growing, we investigated the perspective on the aging population, familiarity with the frailty syndrome and current organization of perioperative care for elderly patients among Dutch anesthesiologists.

METHODS

A fifteen-item survey was distributed among anesthesiologists and residents during the annual meeting of the Dutch Society of Anesthesiology. The first section included questions on self-reported competence on identification of frailty, acquaintance with local protocols and attitude towards the increasing amounts of elderly patients presenting for surgery. The second part included questions on demographic features of the participant such as job position, experience and type of hospital. Answers are presented as percentages, using the total number of replies for the question per group as a denominator.

RESULTS

A sample of 132 surveys was obtained. The increasing number of elderly patients was primarily perceived as challenging by 76% of respondents. Ninety-nine percent agreed that frailty should influence anesthetic management, while 85% of respondents claimed to feel competent to recognize frailty. Thirty-four percent of respondents reported the use of a dedicated pathway in the preoperative approach of frail elderly patients. However, only 30% of respondents reported to know where to find the frailty screening in the patient file and appointed that frailty is not consistently documented. Interestingly, only 43% of respondents reported adequate collaboration with geriatricians. This could include for example a standardized preoperative multidisciplinary approach or dedicated pathway for the elderly patient.

CONCLUSIONS

This survey demonstrated that the increasing number of frail elderly patients is perceived as important and relevant for anesthetic management. Opportunities lie in improving the organization and effectuation of perioperative care by more consistent involvement of anesthesiologists.

Feasibility of low-dose dexmedetomidine for prevention of postoperative delirium after intracranial operations: a pilot randomized controlled trial

Background

Clinical trials have shown that dexmedetomidine might decrease the occurrence of postoperative delirium after major surgery, but neurosurgical patients were excluded from these studies. We aimed to determine the feasibility of conducting a full-scale randomized controlled trial of the effect of prophylactic low-dose dexmedetomidine on postoperative delirium in patients after elective intracranial operation for brain tumors.

Methods

In this single-center, parallel-arm pilot randomized controlled trial, adult patients who underwent an elective intracranial operation for brain tumors were recruited. Dexmedetomidine (0.1 μg/kg/hour) or placebo was continuously infused from intensive care unit (ICU) admission on the day of surgery until 08:00 AM on postoperative day one. Adverse events during the study-drug administration were recorded. The primary feasibility endpoint was the occurrence of study-drug interruption. Delirium was assessed twice daily with the Confusion Assessment Method for the ICU during the first five postoperative days. The assessable rate of delirium evaluation was documented.

Results

Sixty participants were randomly assigned to receive either dexmedetomidine (n = 30) or placebo (n = 30). The study-drug was stopped in two patients (6.7%) in the placebo group due to desaturation after new-onset unconsciousness and an unplanned reoperation for hematoma evacuation and in one patient (3.3%) in the dexmedetomidine group due to unplanned discharge from the ICU. The absolute difference (95% confidence interval) of study-drug interruption between the two groups was 3.3% (− 18.6 to 12.0%), with a noninferiority P value of 0.009. During the study-drug infusion, no bradycardia occurred, and hypotension occurred in one patient (3.3%) in the dexmedetomidine group. Dexmedetomidine tended to decrease the incidence of tachycardia (10.0% vs. 23.3%) and hypertension (3.3% vs. 23.3%). Respiratory depression, desaturation, and unconsciousness occurred in the same patient with study-drug interruption in the placebo group (3.3%). Delirium was evaluated 600 times, of which 590 (98.3%) attempts were assessable except in one patient in the placebo group who remained in a coma after an unplanned reoperation.

Conclusions

The low rate of study-drug interruption and high assessable rate of delirium evaluation supported a fully powered trial to determine the effectiveness of low-dose dexmedetomidine on postoperative delirium in patients after intracranial operation for brain tumors.

Trial registration

The trial was registered at ClinicalTrials.gov (NCT04494828) on 31/07/2020.

Recent advances and perspectives of postoperative neurological disorders in the elderly surgical patients

Postoperative neurological disorders, including postoperative delirium (POD), postoperative cognitive dysfunction (POCD), postoperative covert ischemic stroke, and hemorrhagic stroke, are challenging clinical problems in the emerging aged surgical population. These disorders can deteriorate functional outcomes and long‐term quality of life after surgery, resulting in a substantial social and financial burden to the family and society. Understanding predisposing and precipitating factors may promote individualized preventive treatment for each disorder, as several risk factors are modifiable. Besides prevention, timely identification and treatment of etiologies and symptoms can contribute to better recovery from postoperative neurological disorders and lower risk of long‐term cognitive impairment, disability, and even death. Herein, we summarize the diagnosis, risk factors, prevention, and treatment of these postoperative complications, with emphasis on recent advances and perspectives.

Dexmedetomidine effect on delirium in elderly patients undergoing general anesthesia: A protocol for systematic review and meta-analysis

BACKGROUND

Delirium is a common postoperative complication. Many studies have found that dexmedetomidine is associated with a reduced incidence of postoperative delirium (POD). This meta-analysis aimed to analyze the effects of dexmedetomidine on POD incidence among elderly patients undergoing general anesthesia.

METHODS

We searched 4 electronic databases (i.e., Pubmed, Embase, Cochrane, and Web of Science) from inception to November 30, 2020, for randomized controlled trials that evaluated the effects of dexmedetomidine in preventing the occurrence of POD in elderly patients (aged ≥60 years). The study protocol was registered in PROSPERO (CRD42020192114).

RESULTS

14 studies with 4173 patients showed that dexmedetomidine was significantly associated with a decreased POD incidence among elderly patients (relative risk [RR] = 0.58; 95% confidence interval [CI] = 0.44-0.76). The incidence of POD was significantly reduced in the noncardiac surgery group (RR 0.51; 95% CI 0.37-0.72), when dexmedetomidine was applied during the postoperative period (RR = 0.53; 95% CI = 0.40-0.70), and in patients received low-doses (RR = 0.54; 95% CI = 0.34-0.87) and normal-doses (RR = 0.59; 95% CI = 0.42-0.83). There were no significant differences in POD incidence in the cardiac surgery group (RR = 0.71; 95% CI = 0.45-1.11), and when dexmedetomidine was applied during the intra- (RR = 0.55; 95% CI = 0.29-1.01) or perioperative period (RR = 0.95; 95% CI = 0.64-1.40).

CONCLUSIONS

Our meta-analysis suggests that dexmedetomidine may significantly reduce POD incidence in elderly noncardiac surgery patients and when applied during the postoperative period, in addition, both low- and normal-doses of dexmedetomidine may reduce POD incidence. However, its use in cardiac surgery patients and during the intra- or perioperative period may have no significant effects on POD incidence.

Postoperative delirium is a risk factor for complications and poor outcome after total hip and knee arthroplasty

Background and purpose - Improving health care and demographic change have resulted in a steady increase in geriatric patients undergoing total hip (THA) and knee (TKA) arthroplasty. Postoperative delirium (POD) is a frequent and severe complication after major surgery. Therefore, we analyzed the impact of POD on outcome after THA and TKA.Patients and methods - In a consecutive series of 10,140 patients who had undergone elective THA or TKA between 2011 and 2020, rates of reoperation within 90 days, readmission within 90 days, complications, and responder rate as defined by the OMERACT-OARSI criteria were compared between patients with and without POD. Multivariable logistic regression models were used to assess the relationship between POD and other postoperative complications.Results - Patients with POD showed higher rates of reoperation (12% vs. 5%), readmission (15% vs. 5%), surgical complications (7% vs. 2%), non-surgical complications (8% vs. 4%), Clavien-Dindo IV° complications (10% vs. 2%) and transfusion (14% vs. 2%). POD led to lower responder rate (76% vs. 87%) 1 year after total joint replacement. All previous comparisons statistically significant. Multivariable logistic regression analyses revealed POD as an independent risk factor for reoperation (OR = 2; CI 1-3), readmission (OR = 2; CI 2-4) and Clavien-Dindo IV° complications (OR = 3; CI 2-5).Interpretation - POD is a serious problem in elective joint replacement. Affected patients suffer more complications and show poor patient-reported outcome 1 year postoperatively. Systematic prevention strategies and standardized therapy protocols are mandatory to avoid burden to patients and healthcare providers.

[Intraoperative Neuromonitoring: Electroencephalography]

Intraoperative neuromonitoring using electroencephalography (EEG) enables anaesthesiologists to monitor the depth of anaesthesia. It is intended to reduce the occurrence of intraoperative wakefulness, postoperative delirium and postoperative cognitive deficits and to shorten process times in the operating room. This article shows how to interpret the raw EEG, spectrograms and processed indices for different age groups and anaesthetics and summarizes the resulting clinical benefits. While propofol and volatile anesthetics produce characteristic frontal EEG signatures with a high activity of coherent α- and δ-waves, ketamine triggers an increase in rapid γ-waves, which leads to incorrectly high indices (BIS, PSI, NI) despite deep anaesthetic levels.In children, frontal α-waves do not appear until the age of approx. 6 months and valid indices (BIS, PSI, NI) can only be derived starting at an age of approx. 12 months. Furthermore, children of preschool and elementary school age often show epileptiform discharges in the EEG during induction of anaesthesia, what is linked to emergence delirium. In adults, the intraoperative frontal α-power decreases significantly with increasing age and older patients tend to have an increased occurrence of burst suppression patterns during anaesthesia. Clinical benefits of EEG-based neuromonitoring comprise reduced doses of anaesthesia, shorter wake-up times after surgery and a lower incidence of intraoperative awareness during total intravenous anaesthesia. Moreover, anaesthesia guided by processed EEG indices can reduce the incidence of postoperative delirium and postoperative cognitive deficits in older patients. In-depth knowledge about intraoperative EEG changes that go beyond the interpretation of processed indices could lead to a further reduction in intra- and postoperative complications in the future.

Current trends in anesthetic depth and antinociception monitoring: an international survey

Current trends in anesthetic depth (i.e., hypnosis) and antinociception monitoring are unclear. We thus aimed to determine contemporary perspectives on monitoring these components of anesthesia during general anesthesia. Participants received and responded anonymously to an internet-based international survey supported by the European Society of Anaesthesiology and Intensive Care. Comparisons, when applicable, were carried out using Chi² analysis or Fischer's exact test. A total of 564 respondents, predominantly from Europe (80.1%), participated. There was a strong participation from Belgium (11.5%). A majority (70.9%) of anesthetists considered hypnotic monitoring important on most occasions to always. In contrast, a majority (62.6%) never or only occasionally considered antinociception monitoring important. This difference in the perceived importance of anesthetic depth versus antinociception monitoring was significant (p < 0.0001). A majority of respondents (70.1%) believed that guiding hypnosis and antinociception using these monitors would improve patient care on most occasions to always. Nonetheless, a substantial number of participants were unsure if hypnotic (23%) or antinociception (32%) monitoring were recommended and there was a lack of knowledge (58%) of any published algorithms to titrate hypnotic and/or antinociceptive drugs based on the information provided by the monitors. In conclusion, current trends in European academic centers prioritize anesthesia depth over antinociception monitoring. Despite an agreement among respondents that applying strategies that optimize anesthetic depth and antinociception could improve outcome, there remains a lack of knowledge of appropriate algorithms. Future studies and recommendations should focus on clarifying goal-directed anesthetic strategies and determine their impact on perioperative patient outcome.

Systematic review of clinical evidence on postoperative delirium: literature search of original studies based on validated diagnostic scales

BACKGROUND

Postoperative delirium is a serious complication that can occur within the 5th postoperative day. In 2017, the European Society of Anesthesiologists delivered dedicated guidelines that reported the need for routine monitoring using validated scales.

OBJECTIVE

Aim of this systematic review is to identify clinical studies related to postoperative delirium that included postoperative monitoring with validated scales.

DESIGN

Systematic review METHODS: Searched keywords included the following terms: postoperative, postsurgical, post anesthesia, anesthesia recovery, delirium, and confusion. Two researchers independently screened retrieved studies using a data extraction form.

RESULTS

Literature search led to retrieve 6475 hits; of these, 260 studies (5.6% of the retrieved), published between 1987 and 2021, included in their methods a diagnostic workup with the use of a postoperative delirium validated scale and monitored patients for more than 24 h, therefore are qualified to be included in the present systematic review.

CONCLUSION

In conclusion, available clinical literature on postoperative delirium relies on a limited number of studies, that included a validated diagnostic workup based on validated scales, extracted from a large series of studies that used inconsistent diagnostic criteria. In order to extract indications based on reliable evidence-based criteria, these are the studies that should be selectively considered. The analysis of these studies can also serve to design future projects and to test clinical hypothesis with a more standardized methodological approach.

[Nonpharmaceutical concepts for prevention and treatment of delirium]

BACKGROUND

Cognitive impairment is common among older patients in German hospitals (40%). Dementia, other brain diseases and frailty significantly increase the risk of delirium and pose great challenges to interdisciplinary and interprofessional teams. Delirium prevention is achievable but requires complex interdepartmental strategies with specific components for timely recognition of the individual delirium risk, to carry out structured and sustained implementation of appropriate measures for delirium prevention as well as prompt etiological diagnostics and immediate treatment when delirium occurs.

OBJECTIVE

The present work aims to shed light on the role of interprofessional and interdisciplinary collaboration in evidence-based, nonpharmacological delirium prevention programs.

MATERIAL AND METHODS

Narrative review of international best practice programs.

RESULTS

Nonpharmacological prevention of delirium is effective but requires differentiated risk identification, regular delirium screening and daily targeted cognitive activation and sleep promotion. This can only be achieved in close interprofessional collaboration and is mostly carried out interdepartmentally by specialized teams.

DISCUSSION

Interprofessional multicomponent programs for delirium prevention hold the potential to reduce delirium and complication rates in older high-risk patients in regular care, thereby improving treatment and long-term quality of life. Additional interprofessional delirium prevention teams are deployed in different settings simultaneously and provide regular training on optimal delirium management. Demonstration of the effectiveness of cross-setting programs requires large multicenter studies and is therefore particularly laborious.

A survey of current practices, attitudes and demands of anaesthesiologists regarding the depth of anaesthesia monitoring in China

Background

In this study, we aimed to analyse survey data to explore two different hypotheses; and for this purpose, we distributed an online survey to Chinese anaesthesiologists. The hypothetical questions in this survey include: (1) Chinese anaesthesiologists mainly use the depth of anaesthesia (DoA) monitors to prevent intraoperative awareness and (2) the accuracy of these monitors is the most crucial performance factor during the clinical daily practice of Chinese anaesthesiologists.

Methods

We collected and statistically analysed the response of a total of 12,750 anesthesiologists who were invited to participate in an anonymous online survey. The Chinese Society of Anaesthesiologists (CSA) trial group provided the email address of each anaesthesiologist, and the selection of respondents was random from the computerized system.

Results

The overall response rate was 32.0% (4037 respondents). Only 9.1% (95% confidence interval, 8.2-10.0%) of the respondents routinely used DoA monitors. Academic respondents (91.5, 90.3-92.7%) most frequently used DoA monitoring to prevent awareness, whereas nonacademic respondents (88.8, 87.4-90.2%) most frequently used DoA monitoring to guide the delivery of anaesthetic agents. In total, the number of respondents who did not use a DoA monitor and whose patients experienced awareness (61.7, 57.8-65.6%) was significantly greater than those who used one or several DoA monitors (51.5, 49.8-53.2%). Overall, the crucial performance factor during DoA monitoring was considered by 61.9% (60.4-63.4%) of the respondents to be accuracy. However, most respondents (95.7, 95.1-96.3%) demanded improvements in the accuracy of the monitors for DoA monitoring. In addition, broad application in patients of all ages (86.3, 85.2-87.4%), analgesia monitoring (80.4, 79.2-81.6%), and all types of anaesthetic agents (75.6, 74.3-76.9%) was reported. In total, 65.0% (63.6-66.5%) of the respondents believed that DoA monitors should be combined with EEG and vital sign monitoring, and 53.7% (52.1-55.2%) believed that advanced DoA monitors should include artificial intelligence.

Conclusions

Academic anaesthesiologists primarily use DoA monitoring to prevent awareness, whereas nonacademic anaesthesiologists use DoA monitoring to guide the delivery of anaesthetics. Anaesthesiologists demand high-accuracy DoA monitors incorporating EEG signals, multiple vital signs, and antinociceptive indicators. DoA monitors with artificial intelligence may represent a new direction for future research on DoA monitoring.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01510-7.

Effect of dexmedetomidine on postoperative delirium in patients undergoing brain tumour resections: study protocol of a randomised controlled trial

INTRODUCTION

Postoperative delirium (POD) is a common complication. The incidence of POD is about 25% in non-cardiac surgery and ranges from 10% to 30% in neurological procedures. A lot of trials show that dexmedetomidine might help to reduce the incidence of delirium in patients undergoing non-cardiac surgery. However, the impact of dexmedetomidine on POD for patients undergoing craniotomy and tumour resections remains unclear.

METHODS AND ANALYSIS

The study is a prospective, single-centre, randomised, double-blinded, paralleled-group controlled trial. Patients undergoing elective frontotemporal tumour resections will be randomly assigned to the dexmedetomidine group and the control group. After endotracheal intubation, patients in the dexmedetomidine group will be administered with a loading dose of dexmedetomidine 0.6 µg/kg in 10 min followed by continuous infusion at a rate of 0.4 µg/kg/hour until the start of dural closure. In the control group, patients will receive the identical volume of normal saline in the same setting. The primary outcome will be the cumulative incidence of POD within 5 days. The delirium assessment will be performed by using the confusion assessment method in the first 5 consecutive days after surgery. Secondary outcomes include the pain severity assessed by Numerical Rating Scale pain score, quality of postoperative sleep assessed by the Richards Campbell sleep questionnaire and postoperative quality of recovery from anaesthesia by the Postoperative Quality Recovery Scale.

ETHICS AND DISSEMINATION

The protocol (V.1.0, 10 November 2020) has been approved by the Ethics Review Committee of the Chinese Clinical Trial Registry (number ChiECRCT-20200436). The findings of the study will be disseminated in a peer-reviewed journal and at a scientific conference.

TRIAL REGISTRATION NUMBER

NCT04674241.

Using the nursing delirium screening scale in assessing postoperative delirium: A meta-regression

The nursing delirium screening scale (Nu-DESC) was developed for the rapid assessment of delirium, but little is known regarding the performance of the Nu-DESC in assessing postoperative delirium. The purpose of this systematic review and meta-analysis was to review and summarize the evidence of the diagnostic accuracy of the Nu-DESC in assessing postoperative delirium. The EMBASE, MEDLINE, Cochrane Library, CINAHL, and a Chinese e-Journal database were searched from the period of the inception of the Nu-DESC to June 18, 2020. Participants were adult (age ≥ 18 years) postoperative patients who received any type of surgery and any method of anesthesia. The quality assessment of diagnostic accuracy studies-2 was employed to assess the risk of bias among the selected studies, and meta-regression analyses were used to detect sources of between-study heterogeneity. Eleven studies involving 2062 postoperative patients in surgical settings were included. The Nu-DESC revealed a pooled sensitivity of 0.73 (95% confidence interval, 0.44-0.90) and a specificity of 0.93 (0.87-0.96). The area under the summary receiver operating characteristics curve was 0.94 (0.91-0.96), which also confirmed the accuracy of the Nu-DESC. Covariates, including the region of study and the standard reference used, were identified as possible sources of heterogeneity in the meta-regression. The findings of this review can update existing clinical guidelines for postoperative delirium. On the basis of its satisfactory diagnostic performance, we suggest that the Nu-DESC could be considered for nurses and allied health professionals for assessing postoperative delirium. However, because of the heterogeneity, the result of this meta-analysis should be considered with caution.

Postoperative delirium after cardiac surgery of elderly patients as an independent risk factor for prolonged length of stay in intensive care unit and in hospital

Background

Postoperative delirium (POD) is a relevant and underdiagnosed complication after cardiac surgery that is associated with increased intensive care unit (ICU) and hospital length of stay (LOS). The aim of this subgroup study was to compare the frequency of tested POD versus the coded International Statistical Classification of Diseases and Related Health Problems (ICD) diagnosis of POD and to evaluate the influence of POD on LOS in ICU and hospital.

Methods

254 elective cardiac surgery patients (mean age, 70.5 ± 6.4 years) at the University Hospital Bonn between September 2018 and October 2019 were evaluated. The endpoint tested POD was considered positive, if one of the tests Confusion Assessment Method for ICU (CAM-ICU) or Confusion Assessment Method (CAM), 4 'A's Test (4AT) or Delirium Observation Scale (DOS) was positive on one day.

Results

POD occurred in 127 patients (50.0%). LOS in ICU and hospital were significantly different based on presence (ICU 165.0 ± 362.7 h; Hospital 26.5 ± 26.1 days) or absence (ICU 64.5 ± 79.4 h; Hospital 14.6 ± 6.7 days) of POD (p < 0.001). The multiple linear regression showed POD as an independent predictor for a prolonged LOS in ICU (48%; 95%CI 31–67%) and in hospital (64%; 95%CI 27–110%) (p < 0.001). The frequency of POD in the study participants that was coded with the ICD F05.0 and F05.8 by hospital staff was considerably lower than tests revealed by the study personnel.

Conclusion

Approximately 50% of elderly patients who underwent cardiac surgery developed POD, which is associated with an increased ICU and hospital LOS. Furthermore, POD is highly underdiagnosed in clinical routine.

The Association Between Preoperative Frailty and Postoperative Delirium: A Systematic Review and Meta-analysis

PURPOSE

Identifying factors that place patients at high risk for developing postoperative delirium is an important first step to reduce incidence. Frailty is associated with poor postoperative outcomes. This meta-analysis aims to determine the association between preoperative frailty and postoperative delirium.

DESIGN

This is a systematic review and meta-analysis.

METHODS

We used PubMed, Scopus, Embase, CINAHL, Cochrane, and Web of Science as databases for the search up to April 23, 2020. We included cohort studies that assessed postoperative delirium as the outcome and described the prevalence of delirium among participants during the postoperative period. Odds ratio and 95% confidence interval were calculated to examine the association.

FINDINGS

Twenty cohort studies met our inclusion criteria, which included a total of 4,568 patients. We found that preoperative frailty was significantly associated with an increased risk of postoperative delirium (crude odds ratio: 3.28; 95% confidence interval: 2.51 to 4.28; I² = 46.7%) (adjusted odds ratio: 2.45; 95% confidence interval: 1.58 to 3.81; I² = 88.6%).

CONCLUSIONS

This meta-analysis showed that preoperative frailty is an independent risk factor for postoperative delirium. In patients undergoing cardiovascular surgery, there is a lower association between frailty and postoperative delirium. In patients with other types of surgery, preoperative frailty is closely related to postoperative delirium.

Association between genetic variants of the cholinergic system and postoperative delirium and cognitive dysfunction in elderly patients

Background

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are frequent and serious complications after surgery. We aim to investigate the association between genetic variants in cholinergic candidate genes according to the Kyoto encyclopedia of genes and genomes - pathway: cholinergic neurotransmission with the development of POD or POCD in elderly patients.

Methods

This analysis is part of the European BioCog project (www.biocog.eu), a prospective multicenter observational study with elderly surgical patients. Patients with a Mini-Mental-State-Examination score ≤ 23 points were excluded. POD was assessed up to seven days after surgery using the Nursing Delirium Screening Scale, Confusion Assessment Method and a patient chart review. POCD was assessed three months after surgery with a neuropsychological test battery. Genotyping was performed on the Illumina Infinium Global Screening Array. Associations with POD and POCD were analyzed using logistic regression analysis, adjusted for age, comorbidities and duration of anesthesia (for POCD analysis additionally for education). Odds ratios (OR) refer to minor allele counts (0, 1, 2).

Results

745 patients could be included in the POD analysis, and 452 in the POCD analysis. The rate of POD within this group was 20.8% (155 patients), and the rate of POCD was 10.2% (46 patients). In a candidate gene approach three genetic variants of the cholinergic genes CHRM2 and CHRM4 were associated with POD (OR [95% confidence interval], rs8191992: 0.61[0.46; 0.80]; rs8191992: 1.60[1.22; 2.09]; rs2067482: 1.64[1.10; 2.44]). No associations were found for POCD.

Conclusions

We found an association between genetic variants of CHRM2 and CHRM4 and POD. Further studies are needed to investigate whether disturbances in acetylcholine release and synaptic plasticity are involved in the development of POD.

Trial registration: ClinicalTrials.gov: NCT02265263.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01071-1.

Is Perioperative Dexmedetomidine Associated With a Reduced Risk of Perioperative Neurocognitive Disorders Following Cardiac Surgery? A Systematic Review and Meta-Analysis With Trial Sequential Analysis of Randomized Controlled Trials

Background: To assess the effect of dexmedetomidine on the reducing risk of perioperative neurocognitive disorders (PNDs) following cardiac surgery.

Methods: A systematic review and meta-analysis with trial sequential analysis (TSA) of randomized controlled trials were performed. PubMed, Embase, Cochrane Library, and CNKI databases (to August 16, 2020) were searched for relevant articles to analyze the incidence of PND for intraoperative or postoperative dexmedetomidine administration after cardiac surgery. PND included postoperative cognitive dysfunction (POCD) and postoperative delirium (POD).

Results: A total of 24 studies with 3,610 patients were included. Compared with the control group, the incidence of POD in the dexmedetomidine group was significantly lower (odds ratio [OR]: 0.59, 95% CI: 0.43–0.82, P = 0.001), with firm evidence from TSA. Subgroup analyses confirmed that dexmedetomidine reduced the incidence of POD with firm evidence following coronary artery bypass grafting surgery (OR: 0.45, 95% CI: 0.26–0.79, P = 0.005), and intervention during the postoperative period (OR: 0.48, 95% CI: 0.34–0.67, P < 0.001). Furthermore, the incidence of POD in the dexmedetomidine group was also decreased in mixed cardiac surgery (OR: 0.68, 95% CI: 0.47–0.98, P = 0.039). Irrespective of whether “Confusion Assessment Method/Confusion Assessment Method for intensive care unit” or “other tools” were used as diagnostic tools, the results showed a decreased risk of POD in the dexmedetomidine group. There was no significant difference in the incidence of POCD (OR: 0.47, 95% CI: 0.22–1.03, P = 0.060) between the two groups, but this result lacked firm evidence from TSA.

Conclusion: The administration of dexmedetomidine during the perioperative period reduced the incidence of POD in patients after cardiac surgery, but there was no significant benefit in the incidence of POCD. The effect of dexmedetomidine on the incidence of POD or POCD following different types of surgery and the optimal dose and timing of dexmedetomidine warrant further investigation.

Trial registration: PROSPERO registration number: CRD42020203980. Registered on September 13, 2020.

Lack of Association Between Perioperative Medication and Postoperative Delirium in Hip Fracture Patients in an Orthogeriatric Care Pathway

OBJECTIVES

Units for perioperative geriatric care are playing a growing role in the care of older patients after hip fracture surgery. Postoperative delirium is one of the most common complications after hip fracture, but no study has assessed the impact of therapeutics received during a dedicated orthogeriatric care pathway on its incidence. Our main objective was to assess the association between drugs used in emergency, operating, and recovery departments and postoperative delirium during the acute stay.

DESIGN

Retrospective cohort study.

SETTING AND PARTICIPANTS

All patients ≥70 years old admitted for hip fracture to the emergency department and hospitalized in our unit for perioperative geriatric care after hip fracture surgery under general anesthesia between July 2009 and December 2019 in an academic hospital in Paris.

METHODS

Demographic, clinical, and biological data and all medications administered pre-, peri-, and postoperatively were prospectively collected by 3 geriatricians. Postoperative delirium in the unit for perioperative geriatric care was assessed by using the confusion assessment method scale. Logistic regression analysis was used to assess variables independently associated with postoperative delirium.

RESULTS

A total of 490 patients were included [mean (SD) age 87 (6) years]; 215 (44%) had postoperative delirium. The occurrence was not associated with therapeutics administered during the dedicated orthogeriatric care pathway. Probability of postoperative delirium was associated with advanced age [>90 years, odds ratio (OR) 2.03, 95% confidence interval (CI) 1.07-3.89], dementia (OR 3.51, 95% CI 2.14--5.82), depression (OR 1.85, 95% CI 1.14-3.01), and preoperative use of beta-blockers (OR 1.75, 95% CI 1.10-2.79).

CONCLUSIONS AND IMPLICATIONS

No emergency or anesthetic drugs were significantly associated with postoperative delirium. Further studies are needed to demonstrate a possible causal link between preoperative use of beta-blockers and postoperative delirium.

Emergence Delirium in a 29-Year-Old Man following an Uneventful Appendectomy

Emergence delirium (ED) is defined as the delirium that occurs during the transition from the sleep state to full consciousness. ED increases the risk for injury, self-extubation, hemorrhages, and prolonged hospitalization and occurs in patients of any age but most often in children and elderly patients. However, ED in young adults is rarely reported. We presented a case of typical ED occurring in a young healthy man following an uneventful appendectomy. The causes of ED can be classified as either predisposing or precipitating factors. In this case, the unnoticeable mental stress may be the predisposing factor and the sevoflurane maintenance of anesthesia may be the precipitating factor. ED occurs at any age of patient and in any minor surgery, and anesthesiologists should do some work to prevent it from happening.

Interventions Triggered During Routine Use of NIRS Cerebral Oxygenation Monitoring in Cardiac Surgical Patients

OBJECTIVE

The purpose of this study was to determine the incidence and types of interventions triggered during a drop of baseline near-infraredspectroscopy (NIRS) values in consecutive cardiac surgical patients.

DESIGN

A single-center, retrospective observational study.

SETTING

A university-affiliated tertiary care center.

PARTICIPANTS

Three thousand three hundred two consecutive cardiac surgical patients from October 2016 to August 2017 Interventions: None.

MEASUREMENTS AND MAIN RESULTS

Of the 1,972 patients who met the inclusion criteria, 576 (29.2%) patients showed NIRS deviation of -20% from baseline. Interventions performed during the drop of baseline NIRS values were documented in 285 (14.4%) patients, with a total of 391 interventions. Three hundred fifteen (80%) interventions were triggered by a deviation in NIRS and concomitant changes in standard monitoring parameters. Seventy-six (20%) interventions were triggered by NIRS deviation alone, with no concomitant pathologic deviation in standard monitoring. A total of 279 (71%) interventions were performed on patients who had no recommendation for NIRS monitoring by current national guidelines. Out of these, 30 (7.7%) interventions (1.3% of all patients) were performed based on NIRS monitoring alone. The higher risk deviation group had longer intensive care unit and hospital lengths of stays (one and 15 days) and postoperative delirium when compared with the no-deviation group (zero and 13 days) Conclusions: The authors' data suggested that most interventions triggered during the drop of baseline values during routine use of NIRS would have also been triggered by the concomitant changes in standard monitoring parameters. Routine use of NIRS for all cardiac surgical patients still is debatable and needs to be evaluated in a large prospective trial.

The Polish Version of the Nursing Delirium Screening Scale (NuDESC PL)-Experience of Using in Nursing Practice in Cardiac Surgery Intensive Care Unit

Introduction: Delirium is a common complication of patients hospitalized in Intensive care units (ICU). The risk of delirium is estimated at approximately 80% in intensive care units. In the case of cardiac surgery ICU, the risk of delirium increases due to the type of procedures performed with the use of extracorporeal circulation. The aim of this study was to provide an official translation and evaluation of Nursing Delirium Screening Scale (NuDESC) into Polish. The NuDESC scale is a scale used by nurses around the world to detect delirium at an early stage in treatment. Methods: The method used in the study was the NuDESC tool, which was translated into Polish. The study was conducted by Cardiac ICU nurses during day shift (at 8 a.m.), night shift (at 8 p.m.) and in other situations where the patients showed delirium-like symptoms. Results: Statistically significant differences were observed between the first and second day in the studied group of patients in the case of illusions/hallucinations. Delirium occurred more frequently during the night, but statistical significance was demonstrated for both daytime and nighttime shifts. It was not demonstrated in relation to the NuDESC scale in the case of insomnia disorders. The diagnosis of delirium and disorientation was the most common diagnosis observed in patients on the first day of their stay in the ICU, followed by problems with communication. Delirium occurred on the first day, mainly at night. On the second day, delirium was much less frequent during the night; the biggest problem was disorientation and problems with communication. Conclusion: This study contributed to the development of the Polish version of the scale (NuDESC PL) which is now used as the Polish screening tool for delirium detection. The availability of an easy-to-use nurse-based delirium instrument is a prerequisite for widespread implementation.

Enhanced Recovery after Surgery: Perspective in Elder Women

Enhanced recovery after surgery (ERAS) is a multimodal convention first reported for colorectal and gynecologic procedures. The main benefits have been a shorter length of stay and reduced complications, leading to improved clinical outcomes and cost savings substantially. With increase in life expectancy, recent years has shown a significant rise in advanced age population, and similarly, a rise in age-related disorders requiring surgical management. Due to pathophysiological and metabolic changes in geriatric age group with increased incidence of medical comorbidities, there is higher risk of enhanced surgical stress response with undesirable postoperative morbidity, complications, prolonged immobility, and extended convalescence. The feasibility and effectiveness of ERAS protocols have been well researched and documented among all age groups, including the geriatric high-risk population.^[1] Adhering to ERAS protocols after colorectal surgery showed no significant difference in postoperative complications, hospital stay, or readmission rate among various age groups.^[2] A recent report mentions the safety and benefits following ERAS guidelines with reduced length of stay in elderly patients with short-level lumbar fusion surgery.^[3] The concept of prehabilitation has evolved as an integral part of ERAS to build up physiological reserve, especially in geriatric high-risk group, and to adapt better to surgical stress.^[4] High levels of compliance with ERAS interventions combined with prehabilitation can be achieved when a dedicated multidisciplinary team is involved in care of these high-risk patients.

Thoracic Paravertebral Block Ameliorates Postoperative Delirium in Geriatric Patients

OBJECTIVES

 Thoracic surgery often causes postoperative delirium (POD) in geriatric patients. This study aimed to explore the effect of ultrasound-guided continuous thoracic paravertebral block (UG-TPVB) on POD in geriatric patients undergoing pulmonary resection.

METHODS

 Total 128 patients who underwent pulmonary resection were randomly allocated to either the conventional patient-controlled analgesia (PCA) group or the UG-TPVB group (n = 64 per group). The consumption of opioid agents (propofol and remifentanil), postoperative hospital stay, postoperative pulmonary atelectasis, postoperative nausea/vomiting, and postoperative itchiness were recorded. The diagnosis of delirium was dependent on the Nursing Delirium Screening Scale. The postoperative pain was assessed by visual analogue scale (VAS) score. The serum levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α were used to evaluate the postoperative neuroinflammation.

RESULTS

 The consumption of propofol and remifentanil, postoperative hospital stay, postoperative pulmonary atelectasis, postoperative nausea/vomiting, and postoperative itchiness in the UG-TPVB group were lower than that in the PCA group. Compared with the PCA group, the prevalence of POD was decreased in the UG-TPVB group. In addition, use of UG-TPVB not only reduced postoperative pain (VAS score) but also decreased postoperative neuroinflammation compared with PCA in geriatric patients undergoing pulmonary resection.

CONCLUSIONS

 This study determined the benefits of UG-TPVB over PCA, providing an effectiveness approach to alleviate POD in geriatric patients undergoing pulmonary resection.

Neuroleptic malignant syndrome in a postoperative patient: a case report

Neuroleptic malignant syndrome is a rare medical emergency associated with the use of antipsychotics and other antidopaminergic drugs. There is no specific test, and diagnosis is based on high clinical suspicion and good differential diagnosis. A clinical picture consistent with hyperthermia, muscle rigidity, altered level of consciousness, together with signs of rhabdomyolysis in analytical studies and a history of taking neuroleptic drugs are the key elements in the detection of this entity. Due to its low incidence and potential mortality, it is essential to publish case reports of neuroleptic malignant syndrome in order to raise awareness of this entity and facilitate diagnostic suspicion when encountering a patient with compatible symptoms. The following is the case of a 79 year old patient with chronic alcohol consumption as the only history of interest, who was given a single dose of haloperidol after an episode of delirium in the postoperative period of conventional trauma surgery. She subsequently developed a picture of progressive deterioration of the level of consciousness, diaphoresis, generalized muscle rigidity, hyperthermia, together with severe metabolic acidosis, hyperlacticaemia, rhabdomyolysis, hypertransaminasemia and hypocalcemia. After ruling out other entities compatible with the clinical picture, neuroleptic malignant syndrome was given as the main diagnostic hypothesis. Diagnosis was confirmed after clinical and analytical improvement following treatment with dantrolene. The patient was discharged from hospital with no sequelae a few days after onset of the condition.

Association Between Intraoperative Arterial Hypotension and Postoperative Delirium After Noncardiac Surgery: A Retrospective Multicenter Cohort Study

BACKGROUND

It is unclear whether intraoperative arterial hypotension is associated with postoperative delirium. We hypothesized that intraoperative hypotension within a range frequently observed in clinical practice is associated with increased odds of delirium after surgery.

METHODS

Adult noncardiac surgical patients undergoing general anesthesia at 2 academic medical centers between 2005 and 2017 were included in this retrospective cohort study. The primary exposure was intraoperative hypotension, defined as the cumulative duration of an intraoperative mean arterial pressure (MAP) <55 mm Hg, categorized into and short (<15 minutes; median [interquartile range {IQR}], 2 [1-4] minutes) and prolonged (≥15 minutes; median [IQR], 21 [17-31] minutes) durations of intraoperative hypotension. The primary outcome was a new diagnosis of delirium within 30 days after surgery. In secondary analyses, we assessed the association between a MAP decrease of >30% from baseline and postoperative delirium. Multivariable logistic regression adjusted for patient- and procedure-related factors, including demographics, comorbidities, and markers of procedural severity, was used.

RESULTS

Among 316,717 included surgical patients, 2183 (0.7%) were diagnosed with delirium within 30 days after surgery; 41.7% and 2.6% of patients had a MAP <55 mm Hg for a short and a prolonged duration, respectively. A MAP <55 mm Hg was associated with postoperative delirium compared to no hypotension (short duration of MAP <55 mm Hg: adjusted odds ratio [ORadj], 1.22; 95% confidence interval [CI], 1.11-1.33; P < .001 and prolonged duration of MAP <55 mm Hg: ORadj, 1.57; 95% CI, 1.27-1.94; P < .001). Compared to a short duration of a MAP <55 mm Hg, a prolonged duration of a MAP <55 mm Hg was associated with greater odds of postoperative delirium (ORadj, 1.29; 95% CI, 1.05-1.58; P = .016). The association between intraoperative hypotension and postoperative delirium was duration-dependent (ORadj for every 10 cumulative minutes of MAP <55 mm Hg: 1.06; 95% CI, 1.02-1.09; P =.001) and magnified in patients who underwent surgeries of longer duration (P for interaction = .046; MAP <55 mm Hg versus no MAP <55 mm Hg in patients undergoing surgery of >3 hours: ORadj, 1.40; 95% CI, 1.23-1.61; P < .001). A MAP decrease of >30% from baseline was not associated with postoperative delirium compared to no hypotension, also when additionally adjusted for the cumulative duration of a MAP <55 mm Hg (short duration of MAP decrease >30%: ORadj, 1.13; 95% CI, 0.91-1.40; P = .262 and prolonged duration of MAP decrease >30%: ORadj, 1.19; 95% CI, 0.95-1.49; P = .141).

CONCLUSIONS

In patients undergoing noncardiac surgery, a MAP <55 mm Hg was associated with a duration-dependent increase in odds of postoperative delirium. This association was magnified in patients who underwent surgery of long duration.

Association of postoperative delirium with cognitive outcomes: A meta-analysis

STUDY OBJECTIVE

To determine the association between postoperative delirium (POD) and cognitive outcomes at least 1 month after surgery in elderly patients, and synthesize the dynamic risk trajectory of cognition impairment after POD.

DESIGN

Meta-analysis searching PubMed, Cochrane and EMBASE from inception to November 1, 2020. The terms postoperative delirium, delirium after surgery, postsurgical delirium, postoperative cogniti*, postoperative cognitive dysfunction, postoperative cognition decline, cognitive decline, cognitive impair* and dement* were searched alone or in combination.

MEASUREMENTS

Inclusion criteria were prospective cohort studies investigating the association between POD and cognitive outcomes in patients aged ≥60 years underwent surgery. The primary outcome was the association between POD and cognitive outcomes at 1 or more months after surgery. We considered cognitive outcomes measured up to 12 months after surgery as short-term and beyond 12 months as long-term. Two authors performed the study screening, data extraction and quality assessments. Effect sizes were calculated as Hedges g or Odds ratio (OR) based on random- and fixed-effects models. Meta-regression was conducted to analyze the role of potential contributors to heterogeneity.

MAIN RESULTS

Eighteen studies were included. Our result showed a significant and medium association between POD and cognitive outcomes after at least 1 month postoperatively (g = 0.61 95% CI 0.43-0.79; I² = 65.1%), indicating that patients with POD were associated with worse cognitive outcomes. The association of POD with short- and long-term cognitive impairment were also both significant (short-term: g = 0.46 95% CI 0.24-0.68; I² = 53.1%; and long-term: g = 0.82 95% CI 0.57-1.06; I² = 57.1%). A multivariate meta-regression suggested that age and measure of delirium were significant sources of heterogeneity. POD was also associated with the significant risk for dementia (OR = 6.08 95% CI 3.80-9.72; I² = 0) as well as attention (OR = 1.74 95% CI 1.13-2.68; I² = 0), executive (OR = 1.33 95% CI 1.00-1.80; I² = 0) and memory impairment (OR = 1.59 95% CI 1.20-2.10; I² = 43.0%). Additionally, our results showed that the risk trajectory for cognitive decline associated with POD within five years after surgery revealed exponential growth.

CONCLUSIONS

This is the first meta-analysis quantifying the association between POD and cognitive outcomes. Our results showed that POD was significantly associated with worse cognitive outcomes, including short- and long-term cognitive outcomes following surgery.

Research status and prospect of peri-extubation delirium

Peri-extubation delirium is a clinical syndrome caused by multiple factors, and it is not a simple disease. It occurs within a period of time after extubation when the effect of general anesthesia is reduced. And the incidence is different in disparate populations, and it is more common in elderly patients. Current studies have shown that iatrogenic factors and patients' own factors are the main risk factors for the syndrome. Early identification of risk factors can help clinicians make early diagnosis. The earlier the diagnosis and treatment begin, the more significantly the prognosis of patients can be improved. At present, the treatment of perioperative delirium is based on non-drug therapy, supplemented by drug therapy. This review will introduce in detail the risk factors, population status and prevention measures of delirium during peri-extubation, and look forward to the new research direction in the future.

Association of pharmacological prophylaxis with the risk of pediatric emergence delirium after sevoflurane anesthesia: An updated network meta-analysis

STUDY OBJECTIVE

This updated network meta-analysis aims at exploring whether the concurrent use of midazolam or antiemetics may enhance the efficacy of other pharmacological regimens for delirium prophylaxis in pediatric population after general anesthesia (GA).

DESIGN

Network meta-analysis (PROSPERO registration: CRD42020179483).

SETTING

Postoperative recovery area.

PATIENTS

Pediatric patients undergoing GA with sevoflurane.

INTERVENTIONS

Pharmacological interventions applied during GA with sevoflurane.

MEASUREMENTS

This network meta-analysis of randomized controlled trials (RCTs) was conducted with a frequentist model. PubMed, Embase, ProQuest, ScienceDirect, Cochrane CENTRAL, ClinicalKey, Web of Science, and ClinicalTrials.gov were searched from their inception dates to April 12, 2020, for RCTs of either placebo-controlled or active-controlled design containing information on the incidence of emergence delirium in pediatric patients undergoing sevoflurane anesthesia.

MAIN RESULTS

Seventy studies comprising 6904 participants were included for the analysis of 30 pharmacological interventions. Based on surface under the cumulative ranking curve (SUCRA) analysis, midazolam was ranked the lowest in therapeutic effect (SUCRA: 20%), while antiemetics as a monotherapy had no effect on delirium prophylaxis. However, there was a trend that most combination therapies with midazolam or antiemetics were superior to monotherapies for delirium prophylaxis. Subgroup analyses based on age (i.e., ≤7 years) and a validated scoring system (i.e., the Pediatric Anesthesia Emergence Delirium scale) for delirium also suggested a better efficacy of combination therapies than monotherapies. Overall, combination therapies with midazolam or antiemetics did not have a negative impact on the incidence of postoperative nausea and vomiting, length of stay in the postanesthesia care unit, or time to extubation. The dexmedetomidine-midazolam-antiemetic combination was the most effective strategy for the prevention of emergence delirium.

CONCLUSIONS

This network meta-analysis suggested that the incorporation of midazolam or antiemetics as adjuncts for combination therapies may have synergistic effects against pediatric postoperative emergence delirium. Future large-scale placebo-controlled RCTs are warranted to validate our findings.

Comparison of the '4-item assessment test' and 'nursing delirium screening scale' delirium screening tools on non-intensive care unit wards: A prospective mixed-method approach

BACKGROUND

In elderly patients following surgery, postoperative delirium (POD) is the most frequent complication and is associated with negative outcomes. The 2017 European Society of Anaesthesiology guideline on POD aims to improve patient care by implementing structured delirium prevention, diagnosis and treatment. However, these recommendations, especially systematic delirium screening, are still incompletely adopted in clinical practice. The aim of this study was to evaluate the feasibility and acceptance of validated delirium screening tools and to identify barriers to their implementation on nonintensive care unit wards.

METHODS

Screening rates, as well as practicability, acceptance and the interprofessional handling of positive results, were assessed for each group. Screening rates were calculated as a percentage of the total potential testing episodes completed (up to 15 per patient). Patients were considered eligible when aged 65 years and above. Barriers and motivating factors were assessed in a mixed method approach by utilising questionnaires and focus group discussions.

INTERVENTION

In a 3-month phase, a guideline-compliant screening protocol involving screening for POD three times daily for 5 days following surgery was introduced in five wards: both the 4-item assessment test (4AT) and the nursing delirium screening scale (NuDESC) were used. Before commencing the study and again after 6 weeks, medical staff of the respective wards underwent a 45 min training session.

RESULTS

Of a total of 3183 potential testing episodes, 999 (31.4%) were completed, with more NuDESC observational tests (43%) than 4AT bedside tests completed (20%). The 4AT was considered more difficult to integrate into daily working routines, it took longer to administer, and nurses felt uncomfortable conducting the screening (53 vs. 13%). Screening results indicating delirium were often not discussed within the team (47%), and nurses felt that often such results were not taken seriously by physicians (54%).

CONCLUSION

The observational NuDESC showed a higher completion rate than the bedside 4AT, although overall testing rates were low. The necessary time needed to conduct the screening, the negative reactions by patients, insufficient team communication and a lack of initiation of any therapy were identified as major barriers in the implementation of the guideline-compliant screening protocol. For all staff, further education and awareness of the importance of POD diagnosis and treatment might improve the screening rates. The NuDesc received better results concerning acceptance, practicability and introduction into daily work routine, leading to higher screening rates compared with the 4AT. The latter instrument, which was intended to be used rather selectively or when POD is suspected, might therefore not be suitable for guideline-compliant regular and repeated screening for POD.

Physostigmine for prevention of postoperative delirium and long-term cognitive dysfunction in liver surgery: A double-blinded randomised controlled trial

BACKGROUND

Anecdotally, cholinergic stimulation has been used to treat delirium and reduce cognitive dysfunction.

OBJECTIVE

The aim of this investigation was to evaluate whether physostigmine reduced the incidence of postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) in patients undergoing liver resection.

DESIGN

This was a double-blind, randomised, placebo-controlled trial. Between 11 August 2009 and 3 March 2016, patients were recruited at the Charité - Universitätsmedizin Berlin in Germany. Follow-ups took place at 1 week (T1), 90 days (T2) and 365 days (T3) after surgery.

SETTING

This single-centre study was conducted at an academic medical centre.

PARTICIPANTS

In total, 261 participants aged at least 18 years scheduled for elective liver surgery were randomised. The protocol also included 45 non-surgical matched controls to provide normative data for POCD and neurocognitive deficit (NCD).

INTERVENTION

Participants were allocated to receive either intravenous physostigmine, as a bolus of 0.02 mg kg-1 body weight followed by 0.01 mg kg-1 body weight per hour (n = 130), or placebo (n = 131), for 24 h after induction of anaesthesia.

MAIN OUTCOMES AND MEASURES

Primary outcomes were POD, assessed using the Diagnostic and Statistical Manual of Mental Disorders (DSM-4-TR) twice daily up to day 7 after surgery, and POCD assessed via the CANTAB neuropsychological test battery, and two paper pencil tests on the day before surgery, and on postoperative days 7, 90 and 365.

RESULTS

In total, 261 patients were randomised, 130 to the physostigmine and 131 to the placebo group. The incidence of POD did not differ significantly between the physostigmine and placebo groups (20 versus 15%; P = 0.334). Preoperative cognitive impairment and POCD frequencies did not differ significantly between the physostigmine and placebo groups at any time. Lower mortality rates were found in the physostigmine group compared with placebo at 3 months [2% (95% confidence interval (CI), 0 to 4) versus 11% (95% CI, 6 to 16), P = 0.002], and 6 months [7% (95% CI, 3 to 12) versus 16% (95% CI, 10 to 23), P = 0.012] after surgery.

CONCLUSION

Physostigmine had no effect on POD and POCD when applied after induction of anaesthesia up to 24 h.

TRIAL REGISTRATION

DOI 10.1186/ISRCTN18978802, EudraCT 2008-007237-47, Ethics approval ZS EK 11 618/08 (15 January 2009).

Related Factors and Treatment of Postoperative Delirium in Old Adult Patients: An Integrative Review

“Postoperative delirium” is defined as delirium occurring in the hospital up to one week after a procedure or before discharge (whichever occurs first) that meets the DSM-5 diagnostic criteria. Objectives: To describe the risk factors related to this pathology and identify effective non-pharmacological forms of treatment. An integrative review of the available literature was performed. The search results considered included all quantitative studies published between 2011 and 2019 in both English and Spanish. A total of 117 studies were selected. Advanced age was identified as the principal risk factor for postoperative delirium. Nursing interventions appear to be the key to preventing or reducing the seriousness of delirium after an anaesthetic episode. The aetiology of postoperative delirium remains unknown, and no treatment exists to eliminate this pathology. The role of nursing staff is fundamental in the prevention, diagnosis, and management of the pathology.

The effect of pre-operative methylprednisolone on postoperative delirium in elderly patients undergoing gastrointestinal surgery: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Pre-operative administration of methylprednisolone reduced circulating markers of endothelial activation. This randomized, double-blind was to evaluate whether a single pre-operative dose of methylprednisolone reduced the rate of postoperative delirium (POD) in older patients undergoing gastrointestinal surgery, and its association with the shedding of endothelial glycocalyx markers.

METHODS

168 patients, aged 65-80 years and scheduled for laparoscopic gastrointestinal surgery, were randomized to 2 mg·kg -1 methylprednisolone (Group M, n = 84); or equivalent dose of placebo (Group C, n = 84). The primary outcome was the incidence of delirium during the first 5 days after surgery, assessed by the confusion assessment method (CAM). POD severity was rated daily using CAM-Severity (CAM-S). Level of syndecan-1, heparan sulfate, tumor necrosis factor-α(TNF-α), and brain-derived neurotrophic factor (BDNF) were measured at baseline, 1-day, and 3-day after surgery.

RESULTS

Compared with placebo, methylprednisolone greatly reduced the incidence of delirium at 72 h following surgery [9(10.7%) versus 20(23.8%), P =0.03, OR=2.22(95%CI 1.05-4.59)]. No between-group difference was found in the cumulative CAM-S score (P=0.14). The levels of heparan sulfate, syndecan-1, and TNF-α in Group M were lower than that in Group C (P <0.05 and P <0.01), while the level of BDNF in Group M was higher than that in Group C (P <0.01).

CONCLUSIONS

Pre-operative administration of methylprednisolone does not reduce the severity of POD, but may reduce the incidence of delirium after gastrointestinal surgery in elderly patients, which may be related to a reduction in circulating markers of endothelial degradation, followed by the increase of BNDF level.

Management of delirium within intraoperative settings for older adults with hip fracture: a scoping review

BACKGROUND

Delirium is a common adverse event in older patients undergoing hip fracture repair surgery. The impact of hospital-acquired delirium during intraoperative phase of their treatment can have a significant impact on post-operative outcomes. While non-pharmacological, multicomponent delirium prevention interventions are considered standard practice in acute medical units, delirium management in the intraoperative setting is less clear.

OBJECTIVES

The aim was to identify evidence-based delirium management interventions which are, and could be, undertaken within the intraoperative setting for older patients undergoing hip fracture repair surgery.

DESIGN

A scoping review following the principles developed by Arksey and O'Malley (2005).

DATA SOURCES

Seven databases including Cochrane, CINAHL, Embase, MEDLINE, PsychINFO, PubMed and SCOPUS were systematically searched. The search was limited to the last 11 years (2009-2020). Research studies included both primary and secondary sources of evidence.

RESULTS

A total of 2464 articles were initially identified. These articles were further refined using keyword searches and exclusion criteria, with a final set of 16 articles meeting the inclusion criteria. Three main themes were as follows: anaesthetic-related interventions used to prevent delirium; recognising non-modifiable and potentially modifiable risk factors; and screening and diagnosis of delirium.

CONCLUSIONS

While there is a strong focus on anaesthetist-led interventions in the intraoperative setting, there are opportunities for more nurse-led interventions through adequate pain management and haemodynamic monitoring that require further research. Identifying the best test for screening and diagnosing delirium in the intraoperative setting requires further research.

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

Propofol for Induction and Maintenance of Anesthesia in Patients With Brugada Syndrome: A Single-Center, 25-Year, Retrospective Cohort Analysis

BACKGROUND

Propofol administration in patients with Brugada syndrome (BrS) is still a matter of debate. Despite lacking evidence for its feared arrhythmogenicity, up to date, expert cardiologists recommend avoiding propofol. The main aim of this study is to assess the occurrence of malignant arrhythmias or defibrillations in patients with BrS, during and 30 days after propofol administration. The secondary aim is to investigate the occurrence of adverse events during propofol administration and hospitalization, as the 30-day readmission and 30-day mortality rate.

METHODS

We performed a retrospective cohort study on patients with BrS who received propofol anytime from January 1, 1996 to September 30, 2020. Anesthesia was induced by propofol in both groups. In the total intravenous anesthesia (TIVA) group, anesthesia was maintained by propofol, while in the BOLUS group, volatile anesthesia was provided. The individual anesthetic charts and the full electronic medical records up to 30 postprocedural days were scrutinized.

RESULTS

One hundred thirty-five BrS patients who underwent a total of 304 procedures were analyzed. The TIVA group included 27 patients for 33 procedures, and the BOLUS group included 108 patients for 271 procedures. In the TIVA group, the median time of propofol infusion was 60 minutes (interquartile range [IQR] = 30-180). The estimated plasma or effect-site concentration ranged between 1.0 and 6.0 µg·mL-1 for target-controlled infusion (TCI). The infusion rate for manually driven TIVA varied between 0.8 and 10.0 mg·kg-1·h-1. In the BOLUS group, the mean propofol dose per kilogram total body weight was 2.4 ± 0.9 mg·kg-1. No malignant arrhythmias or defibrillations were registered in both groups. The estimated 95% confidence interval (CI) of the risk for malignant arrhythmias in the BOLUS and TIVA groups was 0-0.011 and 0-0.091, respectively.

CONCLUSIONS

The analysis of 304 anesthetic procedures in BrS patients, who received propofol, either as a TIVA or as a bolus during induction of volatile-based anesthesia, revealed no evidence of malignant arrhythmias or defibrillations. The present data do not support an increased risk with propofol-based TIVA compared to propofol-induced volatile anesthesia. Prospective studies are needed to investigate the electrophysiologic effects of propofol in BrS patents.

Presurgical Screening Improves Risk Prediction for Delirium in Elective Surgery of Older Patients: The PAWEL RISK Study

Introduction: The number of elective surgeries for patients who are over 70 years of age is continuously growing. At the same time, postoperative delirium (POD) is common in older patients (5–60%) depending on predisposing risk factors, such as multimorbidity, cognitive impairment, neurodegenerative disorders and other dementing disorders, and precipitating factors, such as duration of surgery. Knowledge of individual risk profiles prior to elective surgery may help to identify patients at increased risk for development of POD. In this study, clinical and cognitive risk factors for POD were investigated in patients undergoing various elective cardiac and non-cardiac surgeries.

Methods: The PAWEL study is a prospective, interventional trial on delirium prevention. At baseline, 880 inpatients at five surgical centers were recruited for sub-sample PAWEL-R. Multimodal assessments included clinical renal function, medication, American Society of Anesthesiologists (ASA) Physical Status Classification System, geriatric and cognitive assessments, which comprised the Montreal Cognitive Assessment Scale (MoCA), Trail-making Test, and Digit Span backward. Delirium incidence was monitored postoperatively by the Confusion Assessment Method (CAM) and a chart review for up to a week or until discharge. Multivariate regression models and Chi-square Automatic Interaction Detectors (CHAID) analyses were performed using delirium incidence as the primary outcome.

Results: Eighteen risk factors were investigated in elective cardiovascular and orthopedic or general surgery. A total of 208 out of 880 patients (24%) developed POD. A global regression model that included all risk variables predicted delirium incidence with high accuracy (AUC = 0.81; 95% CI 0.77, 0.85). A simpler model (clinical and cognitive variables; model CLIN-COG) of 10 factors that only included surgery type, multimorbidity, renal failure, polypharmacy, ASA, cut-to-suture time, and cognition (MoCA, Digit Span backward, and preexisting dementia), however, exhibited similar predictive accuracy (AUC = 0.80; 95% CI 0.76, 0.84).

Conclusion: The risk of developing POD can be estimated by preoperative assessments, such as ASA classification, expected cut-to-suture time, and short cognitive screenings. This rather efficient approach predicted POD risk over all types of surgery. Thus, a basic risk assessment including a cognitive screen can help to stratify patients at low, medium, or high POD risk to provide targeted prevention and/or management strategies for patients at risk.

Association Between Cerebral Desaturation and Postoperative Delirium in Thoracotomy With One-Lung Ventilation: A Prospective Cohort Study

BACKGROUND

The association between cerebral desaturation and postoperative delirium in thoracotomy with one-lung ventilation (OLV) has not been specifically studied.

METHODS

A prospective observational study performed in thoracic surgical patients. Cerebral tissue oxygen saturation (Scto2) was monitored on the left and right foreheads using a near-infrared spectroscopy oximeter. Baseline Scto2 was measured with patients awake and breathing room air. The minimum Scto2 was the lowest measurement at any time during surgery. Cerebral desaturation and hypersaturation were an episode of Scto2 below and above a given threshold for ≥15 seconds during surgery, respectively. The thresholds based on relative changes by referring to the baseline measurement were <80%, <85%, <90%, <95%, and <100% baseline for desaturation and >105%, >110%, >115%, and >120% baseline for hypersaturation. The thresholds based on absolute values were <50%, <55%, <60%, <65%, and <70% for desaturation and >75%, >80%, >85%, and >90% for hypersaturation. The given area under the threshold (AUT)/area above the threshold (AAT) was analyzed. Delirium was assessed until postoperative day 5. The primary analysis was the association between the minimum Scto2 and delirium using multivariable logistic regression controlled for confounders (age, OLV time, use of midazolam, occurrence of hypotension, and severity of pain). The secondary analysis was the association between cerebral desaturation/hypersaturation and delirium, and between the AUT/AAT and delirium using multivariable logistic regression controlled for the same confounders. Multiple testing was corrected using the Holm-Bonferroni method. We additionally monitored somatic tissue oxygen saturation on the forearm and upper thigh.

RESULTS

Delirium occurred in 35 (20%) of 175 patients (65 ± 6 years old). The minimum left or right Scto2 was not associated with delirium. Cerebral desaturation defined by <90% baseline for left Scto2 (odds ratio [OR], 5.82; 95% confidence interval [CI], 2.12-19.2; corrected P =.008) and <85% baseline for right Scto2 (OR, 4.27; 95% CI, 1.77-11.0; corrected P =.01) was associated with an increased risk of delirium. Cerebral desaturation defined by other thresholds, cerebral hypersaturation, the AUT/AAT, and somatic desaturation and hypersaturation were all not associated with delirium.

CONCLUSIONS

Cerebral desaturation defined by <90% baseline for left Scto2 and <85% baseline for right Scto2, but not the minimum Scto2, may be associated with an increased risk of postthoracotomy delirium. The validity of these thresholds needs to be tested by randomized controlled trials.

Levels of Evidence Supporting the North American and European Perioperative Care Guidelines for Anesthesiologists between 2010 and 2020: A Systematic Review

BACKGROUND

Although there are thousands of published recommendations in anesthesiology clinical practice guidelines, the extent to which these are supported by high levels of evidence is not known. This study hypothesized that most recommendations in clinical practice guidelines are supported by a low level of evidence.

METHODS

A registered (Prospero CRD42020202932) systematic review was conducted of anesthesia evidence-based recommendations from the major North American and European anesthesiology societies between January 2010 and September 2020 in PubMed and EMBASE. The level of evidence A, B, or C and the strength of recommendation (strong or weak) for each recommendation was mapped using the American College of Cardiology/American Heart Association classification system or the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. The outcome of interest was the proportion of recommendations supported by levels of evidence A, B, and C. Changes in the level of evidence over time were examined. Risk of bias was assessed using Appraisal of Guidelines for Research and Evaluation (AGREE) II.

RESULTS

In total, 60 guidelines comprising 2,280 recommendations were reviewed. Level of evidence A supported 16% (363 of 2,280) of total recommendations and 19% (288 of 1,506) of strong recommendations. Level of evidence C supported 51% (1,160 of 2,280) of all recommendations and 50% (756 of 1,506) of strong recommendations. Of all the guidelines, 73% (44 of 60) had a low risk of bias. The proportion of recommendations supported by level of evidence A versus level of evidence C (relative risk ratio, 0.93; 95% CI, 0.18 to 4.74; P = 0.933) or level of evidence B versus level of evidence C (relative risk ratio, 1.63; 95% CI, 0.72 to 3.72; P = 0.243) did not increase in guidelines that were revised. Year of publication was also not associated with increases in the proportion of recommendations supported by level of evidence A (relative risk ratio, 1.07; 95% CI, 0.93 to 1.23; P = 0.340) or level of evidence B (relative risk ratio, 1.05; 95% CI, 0.96 to 1.15; P = 0.283) compared to level of evidence C.

CONCLUSIONS

Half of the recommendations in anesthesiology clinical practice guidelines are based on a low level of evidence, and this did not change over time. These findings highlight the need for additional efforts to increase the quality of evidence used to guide decision-making in anesthesiology.

EDITOR’S PERSPECTIVE