Current Recommendations for Perioperative Brain Health: A Scoping Review : Journal of Neurosurgical Anesthesiology

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Current Recommendations for Perioperative Brain Health: A Scoping Review

Wooding, Denise J. MD, MSc*; Field, Thalia S. MD, MSc, FRCPC; Schwarz, Stephan K.W. MD, PhD, FRCPC‡,§; MacDonell, Su-Yin MD, MSc, FRCPC‡,§; Farmer, Jaycee BSc‡,§; Rajan, Shobana MD, FASA; Flexman, Alana M. MD, MBA, FRCPC‡,§

Author Information
Journal of Neurosurgical Anesthesiology 35(1):p 10-18, January 2023. | DOI: 10.1097/ANA.0000000000000861


In highly resourced countries, older adults make up ~37% of patients undergoing anesthesia and surgery.1 Although the effects of anesthetic medications on the brain were once thought to last only as long as their pharmacological action, anesthesia and surgery are associated with both short-term and long-term neurocognitive sequelae, making cognitive recovery after surgery a concern for many patients, families, and care providers.1,2 Perioperative brain health refers to cognitive recovery after surgery, which can be impaired by neurological complications including perioperative stroke, postoperative delirium (POD), and postoperative cognitive dysfunction (POCD). Perioperative stroke is generally defined as brain infarction occurring within 30 days after surgery.3 Perioperative neurocognitive disorders is a term used to include both delirium and cognitive dysfunction after surgery.4 POD is broadly defined as an acute and fluctuating alteration of mental state with reduced awareness and disturbance of attention, occurring within days after surgery.5,6 POCD is an older term that has recently been replaced with the diagnoses of delayed neurocognitive recovery and postoperative neurocognitive disorder,4 and refers to transient or persistent worse performance on neurocognitive testing up to 12 months following anesthesia and surgery, and which may result from stroke, delirium, or other neurological dysfunction.7 Together, these complications are common and responsible for significant morbidity and health care costs.1,8 The incidence of perioperative stroke in patients undergoing noncardiac, non-neurological surgery is between 0.1% and 1%; patients with perioperative stroke have an 8-fold increased risk of 30-day mortality relative to those without perioperative stroke.8 In older adults, the incidences of POD and POCD are estimated to be up to 65% and 17% to 43%, respectively.1 Although distinct, the diagnoses of perioperative stroke, POD, and POCD are interrelated. For example, a recent study found that up to 7% of patients experience a perioperative covert stroke and these patients are more likely to experience acute POD and long-term cognitive decline.9

Current research has identified several perioperative strategies to prevent and to treat neurocognitive sequelae,10 although these are less well understood than other postoperative complications. Recently, postoperative neurological complications have been highlighted by the American Society of Anesthesiologists Perioperative Brain Health Initiative,11 as well as in a variety of clinical guidelines. These guidelines vary in scope, methodology, and content, and there exists no comprehensive synthesis of consistent recommendations. Our objective was to identify contemporary guidelines pertaining to perioperative stroke, POD, and POCD following noncardiac, non-neurologic surgery using a structured search and to characterize themes and associated areas of concordance and discordance between recommendations and publications. Secondarily, we sought to assess the level of evidence used for each recommendation, if available.


The protocol for this scoping review was registered on the Open Science Framework on May 18, 2021 ( On December 24, 2021, we conducted a structured search of PubMed ( and 23 relevant medical society websites identified a priori (Supplemental digital content 1, list of society websites manually searched) for guidelines pertaining to perioperative stroke, POD, and POCD published between January 1, 2016, and December 24, 2021. We focused our search on publications within the last 5 years to reflect the most contemporary guidance. We used the following search strategy for the PubMed search: “(perioperative[Title] OR postoperative[Title]) AND (guidelines[Title] OR consensus[Title] OR recommendations[Title] OR statement[Title] OR best practices[Title]) AND (stroke[Title] OR brain health[Title] OR delirium[Title] OR cognitive[Title] OR neuropsychological[Title] OR neurological[Title] OR neurologic[Title]).” We excluded recommendations for pediatric patients (age below 18 y), publications not providing recommendations for clinical care, and publications not pertaining to the perioperative period.

We collected data on year of publication and geographic location, primary specialty, and society/medical body of the authors. We then summarized individual recommendations from each publication and categorized recommendations by subtopic (stroke, POD, and POCD), type (disclosure/ethics/policies, prevention, risk stratification, screening and diagnosis, and management), pharmacological versus nonpharmacological strategies, and phase of care (preoperative, intraoperative, and postoperative). We also noted which publications provided a formal assessment of the quality of evidence and categorized these recommendations by quality, as described in the original article, using either the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework, which ranges from A to D (GRADE A signifies that further research is very unlikely to change the authors’ confidence in the estimate of effect, and GRADE D signifies that any estimate of effect is very uncertain)12 or using the American College of Cardiology/American Heart Association framework, which ranges from Level A to D (Level A indicates high-quality evidence from ≥1 randomized controlled trial [RCT], meta-analyses of high-quality RCTs, or ≥1 RCT corroborated by high-quality registry studies, as well as class I to III where class I indicates benefit far outweighs risk, and class III indicates harm).13 We noted whether recommendations were concordant or discordant between 2 or more separate publications. Descriptive statistics were used to summarize the data, and all data analyses were performed using RStudio (version 1.1.383; Boston, MA).


Our structured PubMed search returned 19 articles, of which 12 were excluded (1 was an erratum pertaining to an included publication,14 1 was a duplicate publication,15 5 were duplicates of a publication that did not pertain to perioperative brain health,16 and 5 did not provide recommendations for clinical practice15,17–20). Through the society website search, 3 additional relevant publications were identified of which 2 were excluded for being outside the date range.21,22 Therefore, a total of 8 publications3,6,8,23–27 and 129 recommendations were available for analysis (Supplemental digital content 2: Figure showing study flow diagram, The characteristics of the 8 included publications are summarized in Table 1.

TABLE 1 - Summary of Publications Meeting the Inclusion Criteria for Scoping Review
Publication Journal (Y) Author Location Author Discipline (s) Topics Evidence Graded Number of Recommendations
American society for enhanced recovery and perioperative quality initiative joint consensus statement on postoperative delirium prevention23 Anesthesia and Analgesia (2020) USA Anesthesiology Critical care Delirium Yes 5
An overview of Chinese multidisciplinary expert consensus on perioperative brain health in elderly patients24 Chinese Medical Journal (2021) China Anesthesiology Critical care Stroke Delirium POCD No 18
Best practices for postoperative brain health: recommendations from the fifth international perioperative neurotoxicity working group25 Anesthesia and Analgesia (2018) USA Anesthesiology Critical care Delirium POCD No 4
European Society of Anaesthesiology evidence-based and consensus-based guideline on postoperative delirium6 European Journal of Anesthesiology (2017) Europe Anesthesiology Critical care Delirium Yes 16
Improving perioperative brain health: an expert consensus review of key actions for the perioperative care team26 British Journal of Anaesthesia (2021) USA Anesthesiology Delirium POCD No 6
Perioperative care of patients at high risk for stroke during or after noncardiac, non-neurological surgery: 2020 guidelines from the Society for Neuroscience in Anesthesiology and Critical Care3 Journal of Neurosurgical Anesthesiology (2020) USA Anesthesiology Stroke Yes 33
Guidelines for the perioperative care of people with dementia27 Anaesthesia (2019) UK Anesthesiology Geriatrics Psychiatry Allied health Delirium POCD No 10
Perioperative neurological evaluation and management to lower the risk of acute stroke in patients undergoing noncardiac, non-neurological surgery8 Circulation (2021) USA Anesthesiology Neurology Neurosurgery Radiology Stroke No 37
POCD indicates postoperative cognitive dysfunction; UK, United Kingdom; USA, United States of America; Y, year.

The majority of guidelines (5/8, 62%) were from the United States.3,8,23,25,26 Two guidelines (25%) included authors from multiple disciplines, including anesthesiology, geriatrics, psychiatry, radiology, neurology, neurosurgery, nursing, and other allied health professionals,8,27 whereas the remaining 6 guidelines were authored by specialists in anesthesiology and/or critical care.3,6,23–26

A summary of the included recommendations is shown in Figure 1. Most of the recommendations (77/129, 60%) pertained to perioperative stroke, and the most frequent recommendation category was stroke prevention (74/129, 57%). We identified 66 nonpharmacological recommendations (51%), 61 pharmacological recommendations (47%) and 2 (2%) that included both pharmacological and nonpharmacological recommendations. Fifty percent of recommendations (65/129) most frequently referenced the preoperative period (Fig. 2).

Characterization of recommendations. One hundred twenty-nine perioperative brain health recommendations were categorized from 8 guideline documents. Some recommendations applied to more than 1 category within a group (ie, both preoperative and postoperative).
Summary of prevention and management recommendations by subtype. Of 129 perioperative brain health recommendations from 8 guideline documents, 57% were related to prevention and 13% were related to management. These are further categorized into nonpharmacological (red tones) and pharmacological (blue tones) recommendations and complication type.

The majority (5/8, 62%) of publications did not provide an assessment of the level of evidence and used expert consensus only. Table 2 summarizes the highest quality recommendations, as denoted by either a GRADE A or Level A recommendation by the authors. Of the graded recommendations, the percentage of recommendations by GRADE/Level quality of evidence were A, 30%; B, 36%; C, 30%; D, 4%.

TABLE 2 - Summary of Recommendations With High-quality Evidence*
Condition Recommendation Quality of Evidence
POD6 Evaluate alcohol-related disorders as a preoperative risk factor for POD GRADE A
POD6 Consider duration of surgery as an intraoperative risk factor for POD GRADE A
POD6 Evaluate pain as a postoperative risk factor for POD GRADE A
POD6 Evaluate the following preoperative risk factors for POD: cognitive impairment, reduced functional status and/or frailty, malnutrition (low serum albumin), sensory impairment GRADE A
POD6 Screen for POD in all patients starting in the recovery room and in each shift up to postoperative day 5 GRADE A
POD6 Use a validated delirium score for POD screening (ie, Nu-DESC, CAM, or CAM-ICU) GRADE A
POD6 Monitor the depth of anesthesia for POD prevention GRADE A
POD6 Adequate pain assessment and treatment for POD prevention GRADE A
POD6 Promptly diagnose POD, establish a differential diagnosis, and institute treatment GRADE A
Stroke3 For patients on vitamin K anticoagulants (ie, warfarin), stop medication 5 d preoperatively, and consider bridging anticoagulation only in those with moderate-to-high thromboembolic risk Level A, Class I: clear benefit
Stroke3 For patients on DOACs, administer last dose 2–3 d preoperatively and resume 1–3 d postoperatively based on clinical risk factors. Avoid heparin bridging. Level A, Class I: clear benefit
Stroke3 Either propofol or inhalational anesthesia can be used for maintenance techniques, given that there does not appear to be a difference in relation to stroke risk Level A, Class III: no benefit
Stroke3 Nitrous oxide appears safe across broad surgical populations Level A, Class I: clear benefit
Stroke3 Emergency imaging of the brain is recommended before initiating any specific therapy to treat acute postoperative stroke Level A, Class I: clear benefit
Stroke3 For suspected large-vessel occlusion, CT angiography and diffusion/perfusion imaging should be obtained urgently for consideration of endovascular therapy Level A, Class I: clear benefit
Stroke3 Patients with large-vessel occlusion should receive mechanical thrombectomy as soon as possible if criteria are met Level A, Class I: clear benefit
Stroke3 American Anesthesiologists’ Society is generally recommended within 24–48 h after stroke onset. Delay administration until at least 24 h in patients treated with IV alteplase. Level A, Class I: clear benefit
There were no graded recommendations specific to perioperative neurocognitive dysfunction.
*High-quality evidence defined as GRADE A or Level A, by GRADE or ACC/AHA guidelines, respectively.
ACC/AHA indicates American College of Cardiology/American Heart Association; CAM, Confusion Assessment Method; CAM-ICU, Confusion Assessment Method for the intensive care unit; CT, computed tomography; DOAC, direct oral anticoagulant; GRADE, Grading of Recommendations, Assessment, Development, and Evaluations; Nu-DESC, Nursing Delirium Screening Scale; POD, postoperative delirium.

Concordance of Recommendations

A summary of recommendations that were concordant between 2 or more publications is shown in Table 3, and of those that were discordant in Table 4. Overall, 33% (42/129) of recommendations were concordant regarding 15 themes, whereas 15% (19/129) of recommendations were discordant regarding 7 themes. The remaining 53% (68/129) of recommendations were unique, meaning they were neither concordant nor discordant with other recommendations. The proportion of recommendations that used grading of evidence was 45% for concordant, 38% for discordant, and 43% for unique recommendations. Fifty-three percent (8/15) of the concordant themes included recommendations from articles from more than 1 geographical area, whereas the remaining 47% (7/15) were from 1 geographic location (United States). Alternatively, 71% (5/7) of themes with discordant recommendations were derived from more than 1 geographic location, whereas 29% (2/7) were discordant despite originating from the same geographic location (United States).

TABLE 3 - Summary of Concordant Recommendations
Recommendation Perioperative Neurocognitive Disorders* Perioperative Stroke
Risk should be disclosed to patients and families preoperatively3,8,23,25,27
Risk factors should be identified preoperatively3,6,8,23,26
At-risk patients should undergo baseline neurocognitive screening preoperatively25,26
A multidisciplinary team should be involved in the prevention, diagnosis, and management23,26,27
Monitor and titrate depth of anesthesia (eg, using EEG-based intraoperative brain monitor)6,25
Nonpharmacological measures should be used for prevention6,23,24,26
Routine use of benzodiazepines should be avoided6,24,26
Pain should be adequately assessed and treated postoperatively6,26
Patients should be routinely screened postoperatively for these complications6,23,24,26
Hospitals should have pre-established systems including a dedicated multidisciplinary stroke team to promote a rapid, efficient, and effective response to perioperative stroke3,8
Elective operations should be deferred ≥9 mo after ischemic stroke3,8
Heparin bridging should not be used while holding DOACs perioperatively3,8
Normocapnia should be maintained intraoperatively for patients at elevated stroke risk3,8
Emergency cerebral imaging should be pursued once perioperative stroke is suspected3,8
Cerebral perfusion should be rapidly restored once perioperative stroke is identified3,8
Recommendations that were concordant between 2 or more publications are shown.
*Perioperative neurocognitive disorders include postoperative delirium and postoperative cognitive dysfunction.
Check marks indicate the relevant perioperative complication.
DOACs indicates direct oral anticoagulants; EEG, electroencephalography.

TABLE 4 - Summary of Discordant Recommendations
Topic Recommendations
Optimal pharmacological management of POD Recommend avoiding antipsychotics and benzodiazepines for the first-line treatment of delirium unless benefits far outweigh known risks (ie, alcohol withdrawal management) (NA)26 Recommend low-dose haloperidol or low-dose atypical neuroleptics to treat POD (GRADE B)6 Recommend IV haloperidol and dexmedetomidine for the management of delirium with severe agitation (NA)24
Optimal perioperative management of anticoagulation for stroke prevention Consider thromboembolic risk for decisions regarding holding anticoagulation for surgery (Level A, Class I: is recommended)3 Consider thromboembolic risk and procedure-specific risk of bleeding for decisions regarding holding anticoagulation for surgery (NA)8
Preferential use of regional anesthesia over general anesthesia for stroke prevention Regional anesthesia may reduce the incidence of stroke in patient undergoing limb surgeries (NA)24 When appropriate, given a particular surgery, and regional anesthetic techniques may be considered for reducing stroke risk, though the effect is likely small (Level B-NR, Class IIb: may be reasonable)3 There is insufficient evidence to make clear suggestions on the use of general anesthesia vs. regional anesthesia for prevention of perioperative stroke (NA)8
Use of intraoperative monitoring for stroke detection Intraoperative transcranial Doppler and regional cerebral oxygenation monitoring may be beneficial for perioperative stroke prevention (NA)24 Neither serum-based biomarkers (Level B-NR, Class III: no benefit) nor neurophysiological monitoring (Level C-EO, Class III: no benefit), including EEG and transcranial Doppler, are recommended for clinical detection of perioperative cerebral ischemia3
Optimal intraoperative blood pressure targets for stroke prevention Maintaining intraoperative blood pressure near preoperative baseline may help lower incidence of stroke (NA)24 Although no specific thresholds are recommended to reduce stroke risk, an effect of relative hypotension cannot be excluded (Level B-NR, Class IIb: may be reasonable).3 Intraoperatively, consider maintaining a MAP >70 mm Hg, especially in patients who are at moderate-high risk for perioperative stroke (NA)8
Optimal intraoperative transfusion thresholds for stroke prevention Avoid Hb <70 g/L to prevent perioperative stroke (NA)24 For noncardiac, non-neurological surgical patients already taking a β blocker, a relatively high transfusion threshold of Hb <90 g/L may reduce perioperative stroke risk (Level B-NR, Class IIb: may be reasonable).3 Intraoperatively, it is reasonable to consider a transfusion threshold of Hb <80 g/L for patients with a history of recent stroke or significant cerebrovascular disease, or 80–90 g/L for patients with acute perioperative stroke, ongoing bleeding, hemodynamic instability, and known cerebrovascular insufficiency attributable to stenosis or occlusion (NA).8
Use of routine postoperative screening for stroke detection Timely screening for suspected stroke using NIHSS, radiological exam, and neurology consult is vital for early diagnosis and management of perioperative stroke (NA).24 Currently available clinical assessment tools such as NIHSS are not recommended for routine screening given high likelihood of false-positive results (Level B-NR, Class III: no benefit)3 PACUs should consider routinely performing neurological assessments for early identification of stroke in high-risk patients (NA).8
Recommendations that were discordant between ≥2 publications are summarized. The level of evidence associated with each recommendation is shown in brackets, or NA if not graded.
GRADE B, conflicting evidence and/or a divergence of opinion about the treatment or procedure; however, evidence is in favor of usefulness/efficacy.
ACC/AHA Level A, high-quality evidence from ≥1 RCT; ACC/AHA Level B, moderate-quality evidence from ≥1 well-designed, nonrandomized studies, observational studies, or registry studies.
See primary publications for details of exact recommendations for management of anticoagulation, including specific considerations relating to anticoagulant agent, risk stratification, and indication.
ACC/AHA indicates American College of Cardiology/American Heart Association; GRADE, Grading of Recommendations, Assessment, Development, and Evaluations; Hb, hemoglobin; MAP, mean arterial pressure; NA, not applicable; NIHSS, National Institutes of Health Stroke Scale; PACU, postanesthetic care unit; POD, postoperative delirium; RCT, randomized controlled trial.

Of the concordant themes, 93% (14/15) had at least 1 graded recommendation. On average, 48% of concordant recommendations were graded with the following distribution of GRADE/Level: A, 31%; B, 37%; C, 37%; and D, 12%. All discordant themes (7/7, 100%) had at least 1 graded recommendation, and, on average, 37% of discordant recommendations were graded. The GRADE/Level distribution for graded discordant recommendations was A, 12%; B, 75%; C, 12%; and D, 0%.

Perioperative Stroke

There were 77 recommendations from 3 articles3,8,24 regarding perioperative stroke, of which 33 (43%) were graded.

There were 3 recommendations in the category of disclosure, ethics, or policies for perioperative stroke. One article recommended that patients with high stroke risk be informed of their risk preoperatively,3 and another recommended that nonsurgical alternatives be discussed with high-risk patients and their families.8 Two articles recommended risk stratification by identifying risk factors for perioperative stroke, including assessing recent or remote stroke history and using risk calculators.3,8 One article recommended against performing physiological testing to assess cerebrovascular vulnerability preoperatively.3 With regard to policies, it was recommended that all centers performing surgery should consider establishing algorithms or some form of organized protocol for the evaluation and the treatment of patients with perioperative stroke by stroke code teams.8

There were 53 perioperative stroke recommendations regarding stroke prevention. Three of these were concordant among multiple articles as follows: (1) elective operations should be deferred ≥9 months after an ischemic stroke,3,8 (2) normocapnia should be maintained intraoperatively for patients at elevated stroke risk,3,8 and (3) heparin bridging should not be used while holding direct oral anticoagulants preoperatively.3,8 Conversely, there were 4 areas of discordance, regarding (1) optimal perioperative management of anticoagulation for stroke prevention,3,8 (2) preferential use of regional anesthesia over general anesthesia for stroke prevention,3,8,24 (3) optimal intraoperative blood pressure targets for stroke prevention,3,8,24 and (4) optimal intraoperative transfusion thresholds for stroke prevention.3,8,24 Over one third of stroke recommendations (26/77, 34%) focused on optimal perioperative management of anticoagulants, antiplatelets, and β blockers.3,8 The remainder of recommendations in the prevention category were unique, and included (1) preoperative optimization of patients,24 (2) either propofol or inhalational anesthesia is considered safe for the maintenance of anesthesia with no difference in stroke risk,3 (3) nitrous oxide appears safe across broad surgical populations,3 and (4) given evidence of increased stroke risk with metoprolol, alternative intraoperative β blockers may be considered.3

There were 9 recommendations for the screening and diagnosis of perioperative stroke. There was 1 area of concordance, which was that patients should undergo urgent imaging as soon as stroke is suspected.3,8 There were 2 areas of discordance, regarding the (1) use of intraoperative monitoring such as transcranial Doppler, regional cerebral oxygenation, or electroencephalography (EEG) for early stroke detection3,24 and the (2) use of routine postoperative stroke screening.3,8,24 Other recommendations in this category were unique, including recommending emergent brain imaging for suspected stroke before initiating any specific therapy, as well as urgent computed tomography angiography and diffusion/perfusion imaging in suspected large-vessel occlusion for the consideration of endovascular therapy.3

Finally, there were 11 recommendations regarding the treatment of perioperative stroke. There was 1 area of concordance, which was that cerebral perfusion should be rapidly restored once perioperative stroke is identified.3,8 The remaining recommendations in this category were unique and referred largely to specifics of stroke management, including initiating a multidisciplinary discussion of the risks and benefits of administering tissue plasminogen activator (alteplase), use of mechanical thrombectomy, appropriate investigations, blood pressure and blood glucose targets, and use of other interventions such as acetylsalicylic acid, supplemental oxygen, and tracheal intubation.3,8,24


The nomenclature for perioperative neurocognitive disorders evolved during our search period;4 however, most articles referred to POCD rather than the updated terms of delayed neurocognitive recovery and major/minor postoperative neurocognitive disorder. We have therefore referred to these collectively as POCD for our synthesis to remain accurate with the source articles. There were 52 recommendations from 6 articles pertaining to either POD, POCD, or both.6,23–27 There were some instances where the authors did not clearly specify whether a recommendation pertained to POD, POCD, or both; therefore, we have presented these together as “perioperative neurocognitive disorders.” Forty percent (22/52) of recommendations in this category were graded.

Twelve of the 52 (23%) recommendations for POD/POCD pertained to disclosure of risk, ethics, or policies. Specifically, 4 of the 6 articles recommended that patients should be informed of their risk of POD/POCD preoperatively.23,25–27 Examples of ethical recommendations were that patients with cognitive impairment should receive the same standards of care as those without, and that caregivers and relatives should be appropriately involved in the perioperative care of patients with cognitive impairment, including being allowed to accompany them to the operating department.27 Examples of policy recommendations included that hospitals should have an established process to reduce the consequences of POD/POCD through the involvement of a multidisciplinary team,23,26,27 or a lead anesthesiologist involved in the care of cognitively impaired adults,27 or specific training for assessment and treatment of pain in people with cognitive impairment.27

Twenty-one of the 52 (40%) recommendations related to the prevention of POD/POCD, with several themes that were concordant among multiple articles. For example, it was recommended that the depth of anesthesia monitoring should be used to prevent POD/POCD,6,25 that nonpharmacological measures (ie, orientation, returning glasses and hearing aids, noise reduction, maintaining normal circadian rhythms, removal of unnecessary indwelling catheters, early mobilization, early nutrition) should be used for the prevention of POD,6,23,24,26 that routine use of benzodiazepines should be avoided,6,24 and that pain should be adequately assessed and treated postoperatively.6,26

Thirteen of the 52 (25%) POD/POCD recommendations pertained to preoperative risk stratification. Specifically, there were 7 congruent recommendations that patients should be assessed for POD/POCD risk factors preoperatively.6,23–27 Cited preoperative risk factors included advanced age, comorbidities, comorbidity scores, preoperative fasting and dehydration, use of medications with anticholinergic effects, alcohol-related disorders, baseline cognitive impairment, reduced functional status, frailty, malnutrition, and sensory impairment.6 In addition, there were 3 concordant recommendations that “at-risk” patients should undergo formal baseline neurocognitive screening preoperatively24–26 using a “brief screening tool”25 or another validated test, with 1 article strongly recommending the Mini-Cog.26

Thirteen percent (7/52) of recommendations pertained to screening and diagnosis of POD/POCD in the postoperative period. There were 4 concordant recommendations that patients should be routinely screened postoperatively for POD,6,23,24,26 and no discordant recommendations relating to prevention, screening, or diagnosis of POD/POCD.

Finally, 12% (6/52) of recommendations from 5 articles pertained to the treatment of POD/POCD. There was discordance among 3 articles regarding the optimal pharmacologic management of POD, with 2 articles recommending haloperidol6,24 and 1 recommending against the use of antipsychotics as first-line treatment.26 The 3 other recommendations in this category were unique and nonpharmacological: (1) rigorous assessment and management of cognitive impairment should apply equally to patients undergoing elective and emergent surgery,27 (2) more research is needed to assess strategies for assessment and short-term and long-term management of patients with POD/POCD,25 and (3) POD should be promptly diagnosed and treated postoperatively.6


Overall, our review provides an up-to-date synthesis of current recommendations for perioperative brain health encompassing perioperative stroke and perioperative neurocognitive disorders (POD and POCD). We identified 8 articles providing 129 recommendations. Most publications (62%) originated from the United States, and only 25% had multidisciplinary authorship despite several advocating for multidisciplinary care. Areas with concordant recommendations were the need for risk stratification, disclosure of risks for all neurological complications, and multidisciplinary involvement. For POD/POCD, concordant recommendations included the implementation of preoperative baseline neurocognitive assessment, use of nonpharmacological measures to prevent POD/POCD, avoidance of benzodiazepines, adequate pain management, and perioperative screening using standardized tools. Consistent stroke-specific recommendations included risk stratification and disclosure of risk, the need to delay elective surgery after stroke if possible, perioperative management of anticoagulation, maintenance of normocapnia, and rapid restoration of cerebral perfusion after stroke. Other recommendations were conflicting and clearly highlight the need for further study; these included the pharmacological management of POD, anesthetic technique including blood pressure management, and postoperative screening for stroke. Discordant recommendations arose more commonly from publications from different geographic areas, suggesting that regional differences in practice may contribute to these discrepancies. Taken together, our findings provide an up-to-date synthesis of the evidence, which included several consistent recommendations for perioperative clinicians to consider implementing in their practice. Our analysis also highlights specific areas where recommendations are conflicting, and where additional high-quality research is required to resolve areas of uncertainty.

We observed variation between different publications, with only a third being concordant between documents. This is consistent with reviews of clinical practice guidelines in other areas of medicine, which have also identified discrepancies between guidelines on various topics.28,29 We observed inconsistent recommendations in several areas. This clinical equipoise may result from lack of a robust evidence base and overreliance on expert opinion. Fewer than half of the included publications incorporated an assessment of the quality of evidence. Compared with other analyses of clinical guidelines, the perioperative brain health recommendations included in our study had a greater proportion of higher quality recommendations (ie, GRADE/Level A or B) than the previous assessments, including pediatric traumatic brain injury guidelines30 and critical care guidelines.31 Evidence-based guidelines are considered superior to consensus-based guidelines,32 although we are cognizant that assessment of the quality of evidence using the GRADE system has limitations, with low internal consistency and low inter-rater agreement.33

Although 2 publications recommended monitoring depth of anesthesia using an EEG-based modality,6,25 we note that this topic remains controversial. Two guidelines, including 1 that provided a formal recommendation,25 explicitly noted equipoise in this area and a need for further high-quality evidence.25,26 Furthermore, a recent joint consensus statement on the role of EEG in perioperative outcomes from the American Society for Enhanced Recovery and the Perioperative Quality Initiative stated that there is insufficient evidence to recommend the use of EEG monitoring for preventing POD, neurocognitive disorder, or postoperative mortality.34

The use of clinical practice guidelines in medicine is widespread and has been shown to improve patient care.35 For example, compliance with practice guidelines for cancer care has resulted in shorter lengths of stay, lower complication rates, and improved financial outcomes.36 Similarly, a previous review found that in 55 of 59 studies, the process of clinical care was improved after the introduction of guidelines.35 However, the mere existence of clinical practice guidelines does not necessarily translate to equivalent changes in practice; “leakage” occurs at all 4 stages of guideline uptake and knowledge translation, from awareness, adoption, and adherence to guidelines.37 A previous systematic review found only a median of 35% adherence to clinical practice guidelines for a variety of clinical conditions,37 and another study identified a lag of 2 to 6 years from the publication of new evidence to incorporation into clinical guidelines.38 The overall timeline spanning from research discovery, through human trials, guideline production, and clinical implementation has varying estimates, but is likely to be in excess of 20 years.39 In addition, the existence of multiple conflicting or unique recommendations such as those seen in our study may further impede uptake into clinical practice.

Our review has several limitations. We restricted our search to publications within the past 5 years to reflect contemporary practice and evidence; nevertheless, we may have missed older but relevant recommendations. In addition, though we identified recommendations that were consistent across publications we could not determine whether these recommendations reflect best clinical practice, particularly across different geographic regions. In identifying recommendations across different perioperative brain health complications, we observed several overlapping recommendations, which may have increased the variability seen in our analysis. However, we were able to identify at least 2 directly relevant publications to allow comparison for each condition. We also acknowledge that our synthesis evaluates each recommendation individually, although many guidelines suggest that employing a “bundle of care,” or implementation of multiple recommendations together could have synergistic effects.14,23,24,26,27


Our review compiles the current published recommendations for perioperative brain health and highlights those with consistency between guidelines that should be prioritized for incorporation into clinical practice. Most publications did not formally assess the quality of evidence and used expert consensus, highlighting the ongoing need for high-quality evidence to inform guidelines in this area. Future guidelines could consider multidisciplinary involvement and incorporate formal grading of evidence to facilitate knowledge translation to clinicians. Finally, our review highlights key areas for future research in perioperative brain health, where recommendations are conflicting.


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