Cardiopulmonary bypass management and neurologic outcomes: an evidence-based appraisal of current practices

Effects of Midazolam and Dexmedetomidine on Cognitive Dysfunction Following Open-Heart Surgery: A Comprehensive Review

PURPOSE

Patients undergoing open-heart surgery often face significant challenges in postoperative cognitive dysfunction (POCD). There has been growing interest in understanding how anesthesia medications, such as dexmedetomidine (DEX) and midazolam, impact cognitive function in these patients.

METHOD

This comprehensive review aims to detail the effect of DEX and midazolam on cognitive outcomes following open-heart surgery.

FINDINGS

Midazolam, a highly selective and commonly used benzodiazepine for preoperative anxiolytics and sedation has been associated with POCD. However, evidence regarding its impact on cognitive function is vague; some studies suggest a potential link between midazolam administration and cognitive impairment, while others report no effect or even an improvement in cognitive abilities. DEX is a potential neuroprotective agent in cardiac surgery. The effects of DEX on cognitive function, including a reduction in POCD incidence and severity, have been reported in several studies. It modulates the inflammatory responses, attenuates oxidative stress, and preserves cerebral perfusion. Although DEX and midazolam show promising results, their effects on cognitive function following open-heart surgery are yet to be elucidated.

CONCLUSION

Various factors, including patient characteristics, perioperative management, and surgical procedures, may influence these outcomes, highlighting the need for further research to better understand the roles of these agents in cognitive function following open-heart surgery.

Effect of oxygen delivery during cardiopulmonary bypass on postoperative neurological outcomes in patients undergoing cardiac surgery: A scoping review of the literature

BACKGROUND

Reduced oxygen delivery (DO2) during cardiopulmonary bypass (CPB) was proposed as a risk factor for the development of postoperative neurological complications (PONCs), including cerebrovascular accidents (CVA), delirium, and postoperative cognitive dysfunction (POCD). We aimed to review the current evidence on the association between intraoperative DO2 and the incidence of PONCs.

METHODS

MEDLINE, Embase, the Cochrane Library, and Web of Science were electronically searched to identify comparative studies from inception until July 2023 that reported the association between intraoperative DO2 levels and the incidence of PONCs (as defined by the scales and diagnostic tools utilized by the studies' authors) in adults patients undergoing cardiac surgery using CPB.

RESULTS

Of the 2513 papers identified, 10 studies, including 21,875 participants, were included. Of these, three studies reported on delirium, two on POCD, and five on CVA. Eight studies reported reduced intraoperative DO2 in patients who developed delirium and CVA. There was a lack of consensus on the cut-off of DO2 levels or the correlation between the period below these threshold values and the development of PONC.

CONCLUSIONS

Limited data suggest that maintaining intraoperative DO2 above the critical threshold levels and ensuring adequate intraoperative cerebral perfusion may play a role in minimizing the incidence of neurological events in adult patients undergoing cardiac surgery on cardiopulmonary bypass.

Intraoperative high and low blood pressures are not associated with delirium after cardiac surgery: A retrospective cohort study

STUDY OBJECTIVE

To evaluate the associations between high and low intraoperative time-weighted average mean arterial pressures before, during and after cardiopulmonary bypass on postoperative delirium.

DESIGN

Single center retrospective cohort study.

SETTING

Operating rooms and postoperative care units.

PATIENTS

11,382 patients, 18 years of age or older who had cardiac surgery requiring cardiopulmonary bypass between January 2017 and December 2020 at the Cleveland Clinic Main Campus.

INTERVENTIONS

All cardiac surgery requiring bypass except procedures requiring deep hypothermic circulatory arrest.

MEASUREMENTS

Post operative delirium was assessed from 12 to 96 h postoperatively, using the Confusion Assessment Method and brief Confusion Assessment Methods. Hypotension and hypertension were defined as time-weighted average mean arterial pressure < 60 and > 80 mmHg.

MAIN RESULTS

Postoperative delirium occurred in 678 (6.0 %) of 11,382 patients. Confounder-adjusted associations, using multivariable logistic regression models, between hypotension (time-weighted average mean arterial pressure < 60 mmHg) and hypertension (time-weighted average mean arterial pressure > 80 mmHg) and postoperative delirium were not statistically significant or clinically meaningful before, during, or after the cardiopulmonary bypass.

CONCLUSIONS

This large single-center cohort analysis found no evidence that exposure to high or low blood pressures during various intraoperative phases of cardiac surgery are associated with postoperative delirium.

Spatial metabolomics reveals key features of hippocampal lipid changes in rats with postoperative cognitive dysfunction

Postoperative cognitive dysfunction (POCD) is a common complication after cardiac surgery. Numerous evidence suggest that dysregulation of lipid metabolism is associated with cognitive impairment; however, its precise role in the development of POCD is still obscure. In this study, we established a cardiopulmonary bypass (CPB) model in rats and employed the Barnes maze to assess cognitive function, selecting POCD rats for subsequent experimentation. Utilizing mass spectrometry imaging, we detected plenty of lipids accumulates within the hippocampal CA1in the POCD group. Immunofluorescence staining revealed a significant reduction in the fluorescence intensity of calcium-independent phospholipases A2 (iPLA2) in the POCD group compared to the control, while serine palmitoyl transferase (SPT) was markedly increased in the POCD group. Transmission electron microscopy revealed that the number of synapses in hippocampal CA1decreased significantly and postsynaptic density became thinner in POCD group. Furthermore, after reversing the metabolic disorders of iPLA2 and SPT in the rat brain with docosahexaenoic acid and myriocin, the incidence of POCD after CPB was significantly reduced and the disrupted lipid metabolism in the hippocampus was also normalized. These findings may offer a novel perspective for exploring the etiology and prevention strategies of POCD after CPB.

Impact of Intraoperative Blood Transfusion on Cerebral Injury in Pediatric Patients Undergoing Congenital Septal Heart Defect Surgery

Background: The components of donor blood themselves have the potential to initiate a systemic inflammatory response and exacerbate neuroinflammation, resulting in subsequent cerebral injury. The aim of this study was to establish the role of transfusion in the development of cerebral injury during the correction of congenital heart defects in children. Material and Methods: A total of 78 patients aged from 1 to 78 months, with body weights ranging from 3.3 to 21.5 kg, were investigated. Biomarkers of cerebral injury and systemic inflammatory response were studied at three time points. First: prior to the surgical intervention. Second: after the completion of cardiopulmonary bypass. Third: 16 h after the conclusion of the surgery. Results: The strongest correlation was found for S-100-β protein with the volume of transfusion at the second (Rho = 0.48, p = 0.00065) and third time points (Rho = 0.36, p = 0.01330). Neuron-specific enolase demonstrated a similar trend: Rho = 0.41 and p = 0.00421 after the completion of cardiopulmonary bypass. Conclusions: The use of red blood cell suspension and its dosage per kilogram of body weight correlated with the biomarkers of cerebral injury and systemic inflammatory response with moderate to significant strength.

Delirium after Cardiac Surgery-A Narrative Review

Postoperative delirium (POD) after cardiac surgery is a well-known phenomenon which carries a higher risk of morbidity and mortality. Multiple patient-specific risk factors and pathophysiologic mechanisms have been identified and therapies have been proposed to mitigate risk of delirium development postoperatively. Notably, cardiac surgery frequently involves the use of an intraoperative cardiopulmonary bypass (CPB), which may contribute to the mechanisms responsible for POD. Despite our greater understanding of these causative factors, a substantial reduction in the incidence of POD remains high among cardiac surgical patients. Multiple therapeutic interventions have been implemented intraoperatively and postoperatively, many with conflicting results. This review article will highlight the incidence and impact of POD in cardiac surgical patients. It will describe some of the primary risk factors associated with POD, as well as anesthetic management and therapies postoperatively that may help to reduce delirium.

Cognitive Function Deterioration After Cardiopulmonary Bypass: Can Intraoperative Optimal Cerebral Regional Tissue Oxygen Saturation Predict Postoperative Cognitive Function?

OBJECTIVE

Cognitive impairment is a common neurologic complication after cardiac surgery with cardiopulmonary bypass (CPB). This study evaluated postoperative cognitive function to determine predictors of cognitive dysfunction, including intraoperative cerebral regional tissue oxygen saturation (rSO₂).

DESIGN

A prospective observational cohort study.

SETTING

At a single academic tertiary-care center.

PARTICIPANTS

A total of 60 adults undergoing cardiac surgery with CPB from January to August 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

All patients underwent Mini-Mental State Examination (MMSE) and quantified electroencephalography (qEEG) 1 day before cardiac surgery, 7 days postoperatively (POD7), and POD60. Intraoperative cerebral rSO₂ was monitored continuously. For MMSE, no significant decrease in MMSE score was found on POD7 versus preoperatively (p = 0.09), but POD60 scores showed significant improvement compared with both preoperative (p = 0.02) and POD7 scores (p < 0.001). On qEEG, relative theta power on POD7 was increased versus preoperatively (p < 0.001), but it was decreased on POD60 (POD7 versus POD60, p < 0.001), and was close to preoperative data (p > 0.99). Baseline rSO₂ was an independent factor for postoperative MMSE. Both baseline and mean rSO₂ showed a significant influence in postoperative relative theta activity, whereas mean rSO₂ was the only predictor for the theta-gamma ratio (p = 0.04).

CONCLUSIONS

The MMSE in patients undergoing CPB declined at POD7 and recovered by POD60. Lower baseline rSO₂ indicated a higher potential for MMSE decline at POD60. Inferior intraoperative mean rSO₂ was related to higher postoperative relative theta activity and theta-gamma ratio, implying subclinical or further cognitive impairment.

Bispectral Index (BIS) Monitoring and Postoperative Delirium in Elderly Patients Undergoing Surgery: A Systematic Review and Meta-Analysis With Trial Sequential Analysis

OBJECTIVE

To examine the effect of bispectral index (BIS)-guided anesthesia on the incidence of postoperative delirium (POD) in elderly patients undergoing surgery.

DESIGN

A systematic review, meta-analysis, and trial sequential analysis (TSA).

SETTING

In the operating room, postoperative anesthesia care units (PACU), and ward.

PARTICIPANTS

Elderly patients (>60 years old) undergoing surgery.

INTERVENTIONS

The EMBASE, MEDLINE, and CENTRAL databases were searched systematically from their inception until December 2020 for randomized controlled trials comparing BIS and usual care or blinded BIS.

MEASUREMENTS AND MAIN RESULTS

Ten trials (N = 3,891) were included for quantitative meta-analysis. In comparison to the control group, there was no significant difference in the incidence of POD in elderly patients randomized to BIS-guided anesthesia (odds ratio [OR] 0.71, 95% CI 0.47-1.08, I² = 76%, p = 0.11, level of evidence = very low, TSA = inconclusive). The authors' review demonstrated that elderly patients with BIS-guided anesthesia were significantly associated with a lower incidence of postoperative cognitive dysfunction (POCD) (OR 0.64, 95% CI 0.46-0.88, p = 0.006), extubation time (mean difference [MD] -3.38 minutes, 95% CI -4.38 to -2.39, p < 0.00001), time to eye opening (MD -2.17 minutes, 95% CI -4.21 to -0.14, p = 0.04), and time to discharge from the PACU (MD -10.77 minutes, 95% CI -11.31 to - 10.23, p < 0.00001).

CONCLUSION

The authors' meta-analysis demonstrated that BIS-guided anesthesia was not associated with a reduced incidence of POD, but it was associated with a reduced incidence of POCD and improved recovery parameters.

Clinically Optimal Neuropsychological Tests for Postoperative Cognitive Dysfunction in Heart Valve Surgeries

BACKGROUND

Postoperative cognitive dysfunction (POCD) is widely recognized and reported, but the lack of a uniform definition makes it difficult to evaluate its clinical impact. The aim of this study is to establish the optimal neuropsychological tests and definition of POCD relevant to clinical outcomes in heart valve surgeries.

METHODS AND RESULTS

Between June 2015 and December 2019, 315 patients undergoing elective heart valve surgeries (age ≥65 years) were enrolled. The Mini-Mental Status Examination, Montreal Cognitive Assessment (MoCA), and the Trail Making Test A and B were performed to evaluate cognitive function. Clinical endpoints were defined as readmission and death. The postoperative readmission and death rate were 17% and 3% (54/315 and 8/315; follow-up 266-1,889 days). By multivariable Cox hazard analysis, Short Physical Performance Battery (adjusted hazard ratio [HR]: 0.84, 95% confidence interval [CI]: 0.49-0.98, P=0.001), MoCA change rate (adjusted HR: 0.64, 95% CI: 0.01-1.22, P=0.024), and intensive care unit stay (adjusted HR: 0.55%, 95% CI: 0.99-1.12, P=0.054) were detected as independent risk factors for combined events. The cutoff value was -12% in the change rate of MoCA.

CONCLUSIONS

MoCA was the only neuropsychological test that predicted the clinical impact on complex events and has the potential to define POCD.

Correlation and agreement of regional cerebral oxygen saturation measured from sensor sites at frontal and temporal areas in adult patients undergoing cardiovascular anesthesia

Background

The function and viability of the brain depend on adequate oxygen supply. A decrease in cerebral blood supply causing cerebral desaturation may lead to many neurological complications. Direct measurement of regional cerebral oxygen saturation (rScO₂) assists in early detection and management. Near-infrared spectroscopy (NIRS) has been introduced for measuring rScO₂. A pair of sensors are attached to the right and left forehead. However, there are some situations where the forehead of the patient is not accessible for sensor attachment (e.g., neurosurgery involving the frontal area; a bispectral index (BIS) sensor already attached, or a wound to the forehead); therefore, alternate sites for sensor attachment are required. The temporal area was proposed as an alternate site. The objective of this study was to assess the correlation and agreement of rScO₂ measured at the forehead vs. the temporal area.

Methods

Adult patients undergoing cardiothoracic or vascular surgery were monitored for rScO₂ using two pairs of ForeSight sensors. The first pair (A1 and A2) were attached to the right and left forehead, while the second pair (B1 and B2) were attached to the right and left temporal area. The rScO₂ values measured from A1 vs. B1 and A2 vs. B2 were assessed for correlation and agreement using the Bland-Altman analysis.

Results

Data from 19 patients with 14,364 sets of data were analyzed. The data from A1 vs. B1 and A2 vs. B2 showed moderate positive correlation (r = 0.627; P < 0.0001 and r = 0.548; P < 0.0001). The biases of A1 vs. B1 and A2 vs. B2 were -2.3% (95% CI [-2.5 to -2.2]; P < 0.0001) and 0.7% (95% CI [0.6-0.8]; P < 0.0001). The lower and upper limits of agreement of A1 vs. B1 were -17.5% (95% CI [-17.7 to -17.3]) and 12.8% (95% CI [12.6-13.0]). The lower and upper limits of agreement of A2 vs. B2 were -14.6% (95% CI [-14.8 to -14.4]) and 16.0% (95% [CI 15.8-16.3]).

Conclusions

The rScO₂ values measured from sensors at the frontal and temporal areas show a moderate correlation with sufficiently good agreement. The temporal area may be an alternative to the frontal area for cerebral oximetry monitoring.

Prophylactic effect of intravenous lidocaine against cognitive deficit after cardiac surgery: A PRISMA-compliant meta-analysis and trial sequential analysis

BACKGROUND

This study aimed at providing an updated evidence of the association between intraoperative lidocaine and risk of postcardiac surgery cognitive deficit.

METHODS

Randomized clinical trials (RCTs) investigating effects of intravenous lidocaine against cognitive deficit in adults undergoing cardiac surgeries were retrieved from the EMBASE, MEDLINE, Google scholar, and Cochrane controlled trials register databases from inception till May 2021. Risk of cognitive deficit was the primary endpoint, while secondary endpoints were length of stay (LOS) in intensive care unit/hospital. Impact of individual studies and cumulative evidence reliability were evaluated with sensitivity analyses and trial sequential analysis, respectively.

RESULTS

Six RCTs involving 963 patients published from 1999 to 2019 were included. In early postoperative period (i.e., 2 weeks), the use of intravenous lidocaine (overall incidence = 14.8%) was associated with a lower risk of cognitive deficit compared to that with placebo (overall incidence = 33.1%) (relative risk = 0.49, 95% confidence interval: 0.32-0.75). However, sensitivity analysis and trial sequential analysis signified insufficient evidence to arrive at a firm conclusion. In the late postoperative period (i.e., 6-10 weeks), perioperative intravenous lidocaine (overall incidence = 37.9%) did not reduce the risk of cognitive deficit (relative risk = 0.99, 95% confidence interval: 0.84) compared to the placebo (overall incidence = 38.6%). Intravenous lidocaine was associated with a shortened LOS in intensive care unit/hospital with weak evidence.

CONCLUSION

Our results indicated a prophylactic effect of intravenous lidocaine against cognitive deficit only at the early postoperative period despite insufficient evidence. Further large-scale studies are warranted to assess its use for the prevention of cognitive deficit and enhancement of recovery (e.g., LOS).

Neuroprotection by the noble gases argon and xenon as treatments for acquired brain injury: a preclinical systematic review and meta-analysis

BACKGROUND

The noble gases argon and xenon are potential novel neuroprotective treatments for acquired brain injuries. Xenon has already undergone early-stage clinical trials in the treatment of ischaemic brain injuries, with mixed results. Argon has yet to progress to clinical trials as a treatment for brain injury. Here, we aim to synthesise the results of preclinical studies evaluating argon and xenon as neuroprotective therapies for brain injuries.

METHODS

After a systematic review of the MEDLINE and Embase databases, we carried out a pairwise and stratified meta-analysis. Heterogeneity was examined by subgroup analysis, funnel plot asymmetry, and Egger's regression.

RESULTS

A total of 32 studies were identified, 14 for argon and 18 for xenon, involving measurements from 1384 animals, including murine, rat, and porcine models. Brain injury models included ischaemic brain injury after cardiac arrest (CA), neurological injury after cardiopulmonary bypass (CPB), traumatic brain injury (TBI), and ischaemic stroke. Both argon and xenon had significant (P<0.001), positive neuroprotective effect sizes. The overall effect size for argon (CA, TBI, stroke) was 18.1% (95% confidence interval [CI], 8.1-28.1%), and for xenon (CA, TBI, stroke) was 34.1% (95% CI, 24.7-43.6%). Including the CPB model, only present for xenon, the xenon effect size (CPB, CA, TBI, stroke) was 27.4% (95% CI, 11.5-43.3%). Xenon, both with and without the CPB model, was significantly (P<0.001) more protective than argon.

CONCLUSIONS

These findings provide evidence to support the use of xenon and argon as neuroprotective treatments for acquired brain injuries. Current evidence suggests that xenon is more efficacious than argon overall.

Comparison of different metrics of cerebral autoregulation in association with major morbidity and mortality after cardiac surgery

BACKGROUND

Cardiac surgery studies have established the clinical relevance of personalised arterial blood pressure management based on cerebral autoregulation. However, variabilities exist in autoregulation evaluation. We compared the association of several cerebral autoregulation metrics, calculated using different methods, with outcomes after cardiac surgery.

METHODS

Autoregulation was measured during cardiac surgery in 240 patients. Mean flow index and cerebral oximetry index were calculated as Pearson's correlations between mean arterial pressure (MAP) and transcranial Doppler blood flow velocity or near-infrared spectroscopy signals. The lower limit of autoregulation and optimal mean arterial pressure were identified using mean flow index and cerebral oximetry index. Regression models were used to examine associations of area under curve and duration of mean arterial pressure below thresholds with stroke, acute kidney injury (AKI), and major morbidity and mortality.

RESULTS

Both mean flow index and cerebral oximetry index identified the cerebral lower limit of autoregulation below which MAP was associated with a higher incidence of AKI and major morbidity and mortality. Based on magnitude and significance of the estimates in adjusted models, the area under curve of MAP < lower limit of autoregulation had the strongest association with AKI and major morbidity and mortality. The odds ratio for area under the curve of MAP < lower limit of autoregulation was 1.05 (95% confidence interval, 1.01-1.09), meaning every 1 mm Hg h increase of area under the curve was associated with an average increase in the odds of AKI by 5%.

CONCLUSIONS

For cardiac surgery patients, area under curve of MAP < lower limit of autoregulation using mean flow index or cerebral oximetry index had the strongest association with AKI and major morbidity and mortality. Trials are necessary to evaluate this target for MAP management.

Intraoperative Hypotension and Acute Kidney Injury, Stroke, and Mortality during and outside Cardiopulmonary Bypass: A Retrospective Observational Cohort Study

BACKGROUND

In cardiac surgery, the association between hypotension during specific intraoperative phases or vasopressor-inotropes with adverse outcomes remains unclear. This study's hypothesis was that intraoperative hypotension duration throughout the surgery or when separated into hypotension during and outside cardiopulmonary bypass may be associated with postoperative major adverse events.

METHODS

This retrospective observational cohort study included data for adults who had cardiac surgery between 2008 and 2016 in a tertiary hospital. Intraoperative hypotension was defined as mean arterial pressure of less than 65 mmHg. The total duration of hypotension was divided into three categories based on the fraction of overall hypotension duration that occurred during cardiopulmonary bypass (more than 80%, 80 to 60%, and less than 60%). The primary outcome was a composite of stroke, acute kidney injury, or mortality during the index hospitalization. The association with the composite outcome was evaluated for duration of hypotension during the entire surgery, outside cardiopulmonary bypass, and during cardiopulmonary bypass and the fraction of hypotension during cardiopulmonary bypass adjusting for vasopressor-inotrope dose, milrinone dose, patient, and surgical factors.

RESULTS

The composite outcome occurred in 256 (5.1%) of 4,984 included patient records; 66 (1.3%) patients suffered stroke, 125 (2.5%) had acute kidney injury, and 109 (2.2%) died. The primary outcome was associated with total duration of hypotension (adjusted odds ratio, 1.05; 95% CI, 1.02 to 1.08; P = 0.032), hypotension outside cardiopulmonary bypass (adjusted odds ratio, 1.06; 95% CI, 1.03 to 1.10; P = 0.001) per 10-min exposure to mean arterial pressure of less than 65 mmHg, and fraction of hypotension duration during cardiopulmonary bypass of less than 60% (reference greater than 80%; adjusted odds ratio, 1.67; 95% CI, 1.10 to 2.60; P = 0.019) but not with each 10-min period hypotension during cardiopulmonary bypass (adjusted odds ratio, 1.04; 95% CI, 0.99 to 1.09; P = 0.118), fraction of hypotension during cardiopulmonary bypass of 60 to 80% (adjusted odds ratio, 1.45; 95% CI, 0.97 to 2.23; P = 0.082), or total vasopressor-inotrope dose (adjusted odds ratio, 1.00; 95% CI, 1.00 to 1.00; P = 0.247).

CONCLUSIONS

This study confirms previous single-center findings that intraoperative hypotension throughout cardiac surgery is associated with an increased risk of acute kidney injury, mortality, or stroke.

EDITOR’S PERSPECTIVE

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

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

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.

Influence of cardiopulmonary bypass set-up and management on clinical outcomes after minimally invasive aortic valve surgery

INTRODUCTION

Minimally invasive aortic valve replacement (MIAVR) requires changes in cannulation strategy and cardiopulmonary bypass (CPB) management when compared to the conventional approach (CAVR). We aimed at evaluating if these differences could influence perfusion-related quality parameters and impair postoperative outcomes.

METHODS

Overall, 339 consecutive patients underwent MIAVR or CAVR between 2014 and 2020 and were analyzed retrospectively. To account for baseline differences, a propensity-matching analysis was performed, obtaining two groups of 97 patients each.

RESULTS

MIAVR group had longer CPB time [107 (95-120) vs 95 (86-105) min, p = .003] than CAVR group. Of note, average pump flow rate index [2.4 (2.2-2.5) vs 2.7 (2.4-2.8) l/min/m², p = .004] was lower in the MIAVR group. Mean arterial pressure was 73 = 9 mmHg vs 62 = 11 mmHg for the MIAVR and CAVR group, respectively (p < .001). Cell-salvaged blood was most commonly used in the MIAVR group (25.8% vs 11.3%, p = .02). Finally, CPB temperature was 32.8°C (32.1-34.8) for MIAVR group vs 34.9°C (33.2-36.1) for the CAVR group (p = .02). Postoperative complications were similar between groups.

CONCLUSIONS

In conclusion, despite differences in CPB parameters in patients undergoing CAVR and MIAVR, the incidences of adverse outcomes were similar. However, compared to CAVR, MIAVR was associated with shorter durations of mechanical ventilation and hospital stay as well as less transfusion of blood products.

Risk factors for acute kidney injury and mortality in high risk patients undergoing cardiac surgery

Background

Acute Kidney Injury (AKI) represents a clinical condition with poor prognosis. The incidence of AKI in hospitalized patients was about 22–57%. Patients undergoing cardiac surgery (CS) are particularly exposed to AKI because of the related oxidative stress, inflammation and ischemia-reperfusion damage. Hence, the risk profile of patients undergoing CS who develop AKI and who are consequently at increased mortality risk deserves further investigation.

Methods

We designed a retrospective study examining consecutive patients undergoing any type of open-heart surgery from January to December 2018. Patients with a history of AKI were excluded. AKI was diagnosed according to KDIGO criteria. Univariate associations between clinical variables and AKI were tested using logistic regression analysis. Variable thresholds maximizing the association with AKI were measured with the Youden index. Multivariable logistic regression analysis was performed to assess predictors of AKI through backward selection. Mortality risk factors were assessed through the Cox proportional hazard model.

Results

We studied 158 patients (mean age 51.2±9.7 years) of which 74.7% were males. Types of procedures performed were: isolated coronary artery bypass (CABG, 50.6%), valve (28.5%), aortic (3.2%) and combined (17.7%) surgery. Overall, incidence of AKI was 34.2%. At multivariable analysis, young age (p = 0.016), low blood glucose levels (p = 0.028), estimated Glomerular Filtration Rate (p = 0.007), pH (p = 0.008), type of intervention (p = 0.031), prolonged extracorporeal circulation (ECC, p = 0.028) and cross-clamp (p = 0.021) times were associated with AKI. The threshold for detecting AKI were 91 and 51 minutes for ECC and cross-clamp times, respectively. At survival analysis, the presence of AKI, prolonged ECC and cross-clamp times, and low blood glucose levels forecasted mortality.

Conclusions

AKI is common among CS patients and associates with shortened life-expectancy. Several pre-operative and intra-operative predictors are associated with AKI and future mortality. Future studies, aiming at improving prognosis in high-risk patients, by a stricter control of these factors, are awaited.

Neurocognitive disorders amongst patients with congenital heart disease undergoing procedures in childhood

BACKGROUND

Amongst children with congenital heart disease (CHD), earlier age of repair improves cardiovascular outcomes. The effects of early intervention on neurodevelopment remains unclear. We assessed the association between early life repair, cardiopulmonary bypass (CPB) and the incidence of neurocognitive disorders (NCD) amongst CHD patients.

METHODS

We created two retrospective cohorts from the Quebec CHD Database; with data from 1988 to 2010. Complexity of reparative procedures for CHD lesions were used as the proxy of CPB exposure with more complex procedure means longer exposure to CPB. Study Population 1 included pediatric patients with a single reparative procedure and compared patients with complex (long CBP) versus isolated shunt (short CBP) lesions. To assess the effects of CPB alone in Study Population 2 we compared patients with isolated atrial septal defects (ASD) who had surgical (short CBP) versus percutaneous (no CBP) repairs. The primary endpoint for both cohorts was development of an NCD.

RESULTS

In Study population 1, 1174 patients underwent complex surgical repair and 1620 had a shunt closure. The incidence of NCDs was 2.45/100 person-years in the complex surgery group, and 2.08/100 person-years in the shunt closure group. The following were associated with increased risk of developing a NCD: surgical complexity (Hazard Ratio [HR] = 1.20, 95% Confidence Interval [CI]: 1.01-1.42), younger age at intervention (AAI) (HR = 1.20, 95% CI: 1.16-1.25), male sex (HR = 1.91, 95% CI: 1.61-2.27), and later calendar year at intervention (HR = 1.06, 95% CI: 1.04-1.07). Study population 2 had 527 isolated ASD patients; 202 underwent surgical repair and 325 had percutaneous closure. The incidence of NCDs was not statistically different between groups. Male sex (HR = 1.77, 95% CI: 1.08-2.89) and younger AAI (HR = 1.15, 95% CI: 1.06-1.25) were associated with increased NCD risk.

CONCLUSION

Increased surgical complexity, male sex and younger AAI were associated with increased risk of NCDs in pediatric CHD patients. Surveillance protocols should be considered to identify NCDs in CHD patients after cardiac intervention.

MiRNA-124a: a Potential Biomarker for Neurological Deficits Following Cardiac Surgery in Pediatric Patients

Brain injury is a major source of patient morbidity after cardiac surgery in children. New early accurate biomarkers are needed for the diagnosis of patients at risk for cerebral postoperative damage. Specific circulating miRNAs have been found as suitable biomarkers for many diseases. We tested whether miRNA-124a reflects neurological injury in pediatric patients following heart surgery. Serum samples were obtained from 34 patients before and six hours after heart surgery. MiRNAs-124a was quantified by RQ-PCR. MiRNA-124a levels six hours after heart surgery correlated with the neurological outcome of the patients. In children with neurological deficits, miRNA-124a levels increased while in those with no neurological deficits the levels decreased. MiRNA-124a was able, at six hours after the operation, to identify patients who are at risk for the appearance of neurological deficits. Circulating miRNA-124a is a potential biomarker for the appearance of neurological deficits in pediatric patients following heart surgery. Graphical Abstract.

Contribution of Baroreceptor Function to Pain Perception and Perioperative Outcomes

Baroreceptors are mechanosensitive elements of the peripheral nervous system that maintain homeostasis by coordinating physiologic responses to external and internal stimuli. While it is recognized that carotid and cardiopulmonary baroreceptor reflexes modulate autonomic output to mitigate excessive fluctuations in arterial blood pressure and to maintain intravascular volume, increasing evidence suggests that baroreflex pathways also project to key regions of the central nervous system that regulate somatosensory, somatomotor, and central nervous system arousal. In addition to maintaining autonomic homeostasis, baroreceptor activity modulates the perception of pain, as well as neuroimmune, neuroendocrine, and cognitive responses to physical and psychologic stressors. This review summarizes the role that baroreceptor pathways play in modulating acute and chronic pain perception. The contribution of baroreceptor function to postoperative outcomes is also presented. Finally, methods that enhance baroreceptor function, which hold promise in improving postoperative and pain management outcomes, are presented.

Does uncontrolled diabetes mellitus affect cerebral hemodynamics in heart surgery?

Background

In this study, we aimed to investigate the effects of poor blood glucose control on the intraoperative cerebral system in patients undergoing coronary artery bypass grafting using various neuromonitors.

Methods

Between January 2011 and December 2011, a total of 40 adult patients (31 males, 9 females; mean age 58.8±9.2 years; range, 38 to 78 years) who were scheduled for elective coronary artery bypass grafting were included in the study. The patients were divided into four groups according to hemoglobin A1c levels as follows: Group 1 including non-diabetic controls (n=11); Group 2 including those with a hemoglobin A1c value of <7% (n=10); Group 3 including those with a hemoglobin A1c value of 7 to 10% (n=11); and Group 4 including those with a hemoglobin A1c value of ≥10% (n=8). Cerebral monitoring was performed with near-infrared spectroscopy and transcranial Doppler. Measurement periods were defined as follows: Before anesthesia induction (period 1), 10 min after anesthesia induction (period 2), during cannulation (period 3), 10 min after cardiopulmonary bypass (period 4), at 32°C temperature during cardiopulmonary bypass (period 5), at 36°C temperature during cardiopulmonary bypass (period 6), and at the end of the operation (period 7).

Results

There was a significant difference in the near-infrared spectroscopy values in the cannulation period for both right (p<0.001) and left (p=0.002) sides and the mean transcranial Doppler flow velocity (p=0.002) in Group 4, compared to Group 1. The heart rate was found to be significantly lower in Group 4 in the cannulation period. The near-infrared spectroscopy values and transcranial Doppler blood flow velocity decreased in Group 4 in all measurement periods.

Conclusion

The results of our study show that, in patients with severe diabetes undergoing open heart surgery, heart rate decreases in the cannulation period due to possible autonomic neuropathy, and cerebral blood flow and oxygenation decrease. For these patients, particularly in the cannulation period, perfusion of both cerebral and other organs should be closely monitored and necessary interventions should be performed.

Effect of Ulinastatin Combined With Dexmedetomidine on Postoperative Cognitive Dysfunction in Patients Who Underwent Cardiac Surgery

Background: Recent studies have shown that early diagnosis and intervention promote the patient's good prognosis. For patients who underwent cardiac surgery and require extracorporeal circulation support, the incidence of postoperative cognitive dysfunction (POCD) is higher than in other types of surgery due to greater changes in brain perfusion compared with normal physiological conditions. Recent studies have confirmed that the use of ulinastatin or dexmedetomidine in the perioperative period effectively reduces the incidence of POCD. In this study, ulinastatin was combined with dexmedetomidine to assess whether the combination of the two drugs could reduce the incidence of POCD.

Methods: One hundred and eighty patients with heart valve replacement surgery undergoing cardiopulmonary bypass from August 2017 to December 2018 were enrolled, with age 60–80 years, American Society of Anesthesiologists (ASA) grades I–III, education level above elementary school, and either gender. According to the random number table method, patients were grouped into ulinastatin + dexmedetomidine (U+D) group, ulinastatin (U) group, dexmedetomidine (D) group, and normal saline (N) control group. Group U was pumped 20,000 UI/kg immediately after induction and the first day after surgery, group D continued to pump 0.4 μg/kg/h from induction to 2 h before extubation, group U+D dexmedetomidine 0.4 μg/kg/h + ulinastatin 20,000 UI/kg, and group N equal volume of physiological saline. The patients were enrolled with Mini-Mental State Examination (MMSE) before surgery. The cognitive function was assessed by Montreal Cognitive Assessment (MoCA) on the first day before surgery and on the seventh day after surgery. Inflammatory factors, such as S100β protein, interleukin (IL)-6, matrix metalloproteinase (MMP)-9, and tumor necrosis factor (TNF)-α, were detected in peripheral blood before anesthesia (T0), immediately after surgery (T1), and immediately after extubation (T2).

Results: One hundred and fifty-four patients enrolled in this study. Compared with group N, the incidence of POCD in group U+D was the lowest (P < 0.05), followed by group U and group D. Group U+D had the lowest concentration of inflammatory factors at the T1 and T2 time points, followed by group U and group D.

Conclusions: Both ulinastatin and dexmedetomidine can reduce the perioperative inflammatory response and the incidence of POCD in patients with heart valve surgery, and their combination can better reduce the incidence of POCD.

Neuroprotective Effect of Low Mean Arterial Pressure on Postoperative Cognitive Deficit Attenuated by Prolonged Coronary Artery Bypass Time: A Meta-Analysis

Introduction

The true influence of the low mean arterial pressure (low MAP) during coronary artery bypass grafting (CABG) on the development of postoperative cognitive deficit (POCD) remains controversial. We aimed to perform a meta-analysis and meta-regression to determine the effect of low MAP on POCD, as well as moderator variables between low MAP and POCD.

Methods

The Web of Science, PubMed database, Scopus and the Cochrane Library database (up to June 2018) were searched and retrieved articles systematically reviewed. Only randomized controlled trials (RCTs) comparing maintenance of low MAP (<80 mmHg) and high MAP (>80 mmHg) during cardiopulmonary bypass (CPB) were included in our final review. Statistical analysis of the risk ratio (RR) and corresponding 95% confidence interval (CI) was used to report the overall effect. The overall effect and meta-regression analysis were done using Mantel-Haenszel risk ratio (MHRR) and the corresponding 95% confidence interval (CI).

Results

A total of 731 patients in three RCTs were included in this study. POCD occurred in 6.4% of all cases. Maintenance of low MAP did not reduce the occurrence of POCD (MHRR 1.012 [95% CI 0.277-3.688]; Z=0.018; P=0.986; I²=66%). Shorter CPB time reduced the occurrence of POCD regardless of group assignment (MH log risk ratio -0.519 [95% CI -0.949 - -0.089]; Z= -2.367; P=0.017).

Conclusion

POCD is a common event among CABG patients. The neuroprotective effect of low MAP on POCD was attenuated by the prolonged CPB time.

Urinary metabolomics reveals kynurenine pathway perturbation in newborns with transposition of great arteries after surgical repair

INTRODUCTION

Transposition of the great arteries (TGA) is a cyanotic congenital heart defect that requires surgical correction, with the use of cardiopulmonary-bypass (CPB), usually within 3 weeks of life. The use of CPB in open heart surgery results in brain hypoperfusion and in a powerful systemic inflammatory response and oxidative stress.

OBJECTIVE

We aimed to develop a novel untargeted metabolomics approach to detect early postoperative changes in metabolic profile following neonatal cardiac surgery.

METHODS

We studied 14 TGA newborns with intact ventricular septum undergoing arterial switch operation with the use of CPB. Urine samples were collected preoperatively and at the end of the surgery and were analyzed using an untargeted metabolomics approach based on UHPLC-high resolution mass spectrometry.

RESULTS

Since post surgery metabolic spectra were heavily contaminated by metabolites derived from administered drugs, we constructed a list of drugs used during surgery and their related metabolites retrieved from urine samples. This library was applied to our samples and 1255 drugs and drug metabolites were excluded from the analysis. Afterward, we detected over 39,000 unique compounds and 371 putatively annotated metabolites were different between pre and post-surgery samples. Among these metabolites, 13 were correctly annotated or identified. Metabolites linked to kynurenine pathway of tryptophan degradation displayed the highest fold change.

CONCLUSIONS

This is the first report on metabolic response to cardiac surgery in TGA newborns. We developed an experimental design that allowed the identification of perturbed metabolic pathways and potential biomarkers of brain damage, limiting drugs interference in the analysis.

Association of Changes in Plasma Neurofilament Light and Tau Levels With Anesthesia and Surgery: Results From the CAPACITY and ARCADIAN Studies

Importance

Anesthesia and surgery are believed to act on the central nervous system by a fully reversible mechanism innocuous to nerve cells. Evidence that neurological sequelae may follow would challenge this belief and would thereby suggest a need to reassess theories of the mechanism of anesthetic action or the response of the central nervous system to surgery.

Objective

To measure 2 biomarkers of neurological injury (neurofilament light and tau) in plasma in a series of timed collections before and after anesthesia and surgery.

Design, Setting, and Participants

These 2 related observational studies (CAPACITY and ARCADIAN) recruited patients 60 years and older who were undergoing general anesthesia for surgeries performed within a tertiary hospital. Blood samples were taken immediately before surgical anesthesia was administered and then sequentially after surgery at 30-minute, 6-hour, 24-hour, and 48-hour intervals. Sampling took place from January 2014 to August 2015. Data analysis took place from October 2016 to February 2017.

Main Outcomes and Measures

Plasma neurofilament light and tau.

Results

A total of 30 patients were enrolled (13 from the CAPACITY study and 17 from the ARCADIAN study). The mean (SD) age was 69.1 (7.0) years, and 18 members (59%) of the participant group were female; 22 (73%) were undergoing joint arthroplasty. Mean neurofilament light increased at each measurement from a combined baseline mean (SD) of 22.3 (20.4) pg/mL to a maximal combined mean (SD) level of 35.1 (28.7) pg/mL, a maximum increase of 67% (95% CI, 45%-89%; P < .001), at 48 hours postoperatively. The level of tau increased significantly from baseline at every measurement, from a combined baseline mean (SD) of 3.1 (1.3) pg/mL to a maximal combined mean (SD) of 10.8 (9.5) pg/mL, a peak increase of 257% (95% CI, 154%-361%; P < .001), at 6 hours postoperatively. After 6 hours, the mean level began to return to baseline but remained elevated after 48 hours.

Conclusions and Relevance

Neurofilament light is a specific marker of axonal injury and has been shown to indicate neuronal damage in a number of diseases. Tau proteins are an integral component of axonal integrity, and increased tau indicates neuronal damage. The increases in both neurofilament light and tau over 48 hours after surgery suggest that general anesthesia and surgery may be associated with neuronal damage in the short term. Further investigations will be required to study any association with clinical outcomes. These preliminary findings demand that we question the prevailing assumption that anesthesia and surgery are innocuous, transient, and without injurious changes to the central nervous system.

Cerebral Small Vessel, But Not Large Vessel Disease, Is Associated With Impaired Cerebral Autoregulation During Cardiopulmonary Bypass: A Retrospective Cohort Study

BACKGROUND

Impaired cerebral blood flow (CBF) autoregulation during cardiopulmonary bypass (CPB) is associated with stroke and other adverse outcomes. Large and small arterial stenosis is prevalent in patients undergoing cardiac surgery. We hypothesize that large and/or small vessel cerebral arterial disease is associated with impaired cerebral autoregulation during CPB.

METHODS

A retrospective cohort analysis of data from 346 patients undergoing cardiac surgery with CPB enrolled in an ongoing prospectively randomized clinical trial of autoregulation monitoring were evaluated. The study protocol included preoperative transcranial Doppler (TCD) evaluation of major cerebral artery flow velocity by a trained vascular technician and brain magnetic resonance imaging (MRI) between postoperative days 3 and 5. Brain MRI images were evaluated for chronic white matter hyperintensities (WMHI) by a vascular neurologist blinded to autoregulation data. "Large vessel" cerebral vascular disease was defined by the presence of characteristic TCD changes associated with stenosis of the major cerebral arteries. "Small vessel" cerebral vascular disease was defined based on accepted scoring methods of WMHI. All patients had continuous TCD-based autoregulation monitoring during surgery.

RESULTS

Impaired autoregulation occurred in 32.4% (112/346) of patients. Preoperative TCD demonstrated moderate-severe large vessel stenosis in 67 (25.2%) of 266 patients with complete data. In adjusted analysis, female sex (odds ratio [OR], 0.46; 95% confidence interval [CI], 0.25-0.86; P = .014) and higher average temperature during CPB (OR, 1.23; 95% CI, 1.02-1.475; P = .029), but not moderate-severe large cerebral arterial stenosis (P = .406), were associated with impaired autoregulation during CPB. Of the 119 patients with available brain MRI data, 42 (35.3%) demonstrated WMHI. The presence of small vessel cerebral vascular disease was associated with impaired CBF autoregulation (OR, 3.25; 95% CI, 1.21-8.71; P = .019) after adjustment for age, history of peripheral vascular disease, preoperative hemoglobin level, and preoperative treatment with calcium channel blocking drugs.

CONCLUSIONS

These data confirm that impaired CBF autoregulation is prevalent during CPB predisposing affected patients to brain hypoperfusion or hyperperfusion with low or high blood pressure, respectively. Small vessel, but not large vessel, cerebral vascular disease, male sex, and higher average body temperature during CPB appear to be associated with impaired autoregulation.

Toward Understanding Cerebral Blood Flow during Cardiopulmonary Bypass: Implications for the Central Nervous System

Factors and Their Influence on Regional Cerebral Blood Flow during Nonpulsatile Cardiopulmonary Bypass. By Govier AV, Reves JG, McKay RD, Karp RB, Zorn GL, Morawetz RB, Smith LR, Adams M, and Freeman AM. Ann Thorac Surg. 1984; 38:609-13. Reprinted with permission.In this study, we examined the relationship of regional cerebral blood flow (CBF) to mean arterial pressure, systemic blood flow, partial pressure of arterial carbon dioxide (PaCO2), nasopharyngeal temperature, and hemoglobin during hypothermic nonpulsatile cardiopulmonary bypass (CPB). Regional CBF was determined by clearance of xenon 133 in 67 patients undergoing coronary bypass grafting procedures. There was a significant decrease in regional CBF (55% decrease) during CPB, with nasopharyngeal temperature and PaCO2 being the only two significant factors (p < 0.05). In a subgroup of 10 patients, variation of pump flow between 1.0 and 2.0 L/min/m2 did not significantly affect regional CBF. We conclude that cerebral autoregulation is retained during hypothermic CPB. Under the usual conditions of CPB, variations in flow and pressure are not associated with important physiologic or detrimental clinical effects.

Neuroprotection against stroke and encephalopathy after cardiac surgery

Cerebral ischemia in the perioperative period is a major risk factor for stroke, encephalopathy, and cognitive decline after cardiothoracic surgery. After coronary artery bypass grafting, both stroke and encephalopathy can result in poor patient outcomes and increased mortality. Neuroprotection aims to lessen the severity and occurrence of further injury mediated by stroke and encephalopathy and to aid the recovery of conditions already present. Several pharmacological and non-pharmacological methods of neuroprotection have been investigated in experimental studies and in animal models, and, although some have shown effectiveness in protection of the central nervous system, for most, clinical research is lacking or did not show the expected results. This review summarizes the value and need for neuroprotection in the context of cardiothoracic surgery and examines the use and effectiveness of several agents and methods with an emphasis on clinical trials and clinically relevant neuroprotectants.

Large-vessel occlusion stroke after cardiothoracic surgery: Expanding time windows offer new salvage opportunities

OBJECTIVES

Ischemic stroke due to large-vessel occlusion (LVO) is a complication after cardiothoracic surgery (CTS). Recently published endovascular stroke trials have major implications for treating LVO strokes; we evaluated our experience in patients undergoing CTS.

METHODS

Our prospective institutional CTS database was reviewed between July 2013 and April 2018 for ischemic strokes. Patients with LVO were identified and their course and outcomes analyzed.

RESULTS

A total of 5947 patients were reviewed; 148 (2.48%) had a cerebrovascular complication; 92.5% were ischemic. Of these 10.9% had an LVO. Prolonged aortic crossclamp was associated with LVO (odds ratio, 1.012 for every minute of prolonged aortic crossclamp time; confidence interval, 1.001-1.023) and remained significant in patients with ejection fraction >45%; prolonged cardiac bypass time was only associated with LVO in patients with ejection fraction >45% (odds ratio, 1.012 for every minute of prolonged cardiac bypass time; confidence interval, 1.003-1.021). Patients fell into 2 categories: detection of neurologic deficit in the stable postoperative patient or detection of deficit on emergence from anesthesia. Seven patients met criteria for emergent revascularization, with median National Institutes of Health Stroke Scale score 15, and shorter times from last seen well to deficit detection compared with patients not meeting criteria (P = .032). Median National Institutes of Health Stroke Scale day 7 score improved to 5. There was a trend toward better modified Rankin Scale scores at 3 months in patients who underwent thrombectomy.

CONCLUSIONS

LVO complicates a small proportion of patients after CTS and may be more likely with prolonged aortic crossclamp and cardiac bypass times. Both early and late window endovascular stroke treatment has the potential to positively modify the complication profile of CTS. Greater awareness of this treatment option is needed.

Effects of Isolated Impaired Fasting Glucose on Brain Injury During Cardiac Surgery Under Cardiopulmonary Bypass

Objective: To evaluate the effects of isolated impaired fasting glucose (IIFG) on brain injury in patients undergoing cardiopulmonary bypass (CPB) surgery. Methods: Patients with rheumatic heart valve disease who underwent elective mitral valve replacement were included and divided into control and IIFG groups. Pre-, intra-, and postoperative blood glucose levels, serum insulin levels, insulin resistance index (HOMA-IR), lactic acid levels, and neuron-specific enolase (NSE) and S100B levels were measured. The cerebral oxygen extraction ratio (OER) was calculated. Cognitive function was assessed via the Mini-Mental State Examination (MMSE). Results: HOMA-IR levels were higher in the IIFG group than the control group 30 min after the beginning of CPB, at the termination of CPB, and 2 h after the termination of CPB. Cerebral OER and lactic acid increased intraoperatively in both groups, especially in the IIFG group. NSE and S100B levels were higher in the IIFG group than in the control group at the termination of CPB, 2 h after the termination of CPB, and at 24 h postoperatively. The MMSE scores did not significantly differ between the two groups. Delirium occurred in two patients in the IIFG group, and one in the control group. No other signs and symptoms of brain injuries were detected in either group. Conclusions: The increased postoperative NSE and S100B levels in the IIFG group compared with controls may be associated with severe insulin resistance and stress hyperglycemia. However, the IIFG group did not have clinical manifestations of brain injuries, including cognitive impairment.

Frailty and anesthesia - risks during and post-surgery

Frailty is a state of decreased physiologic reserve and resistance to stressors. Its prevalence increases with age and is estimated to be 26% in those aged above 85 years. As the population ages, frailty will be increasingly seen in surgical patients receiving anesthesia. Here, we evaluate the instruments which have been developed and validated for measuring frailty in surgical patients and summarize frailty tools used in 110 studies linking frailty status with adverse outcomes post-surgery. Frail older people are vulnerable to geriatric syndromes, and complications such as postoperative cognitive dysfunction and delirium are explored. This review also considers how frailty, with its decline of organ function, affects the metabolism of anesthetic agents and may influence the choice of anesthetic technique in an older person. Optimal perioperative care includes the identification of frailty, a multisystem and multidisciplinary evaluation preoperatively, and discussion of treatment goals and expectations. We conclude with an overview of the emerging evidence that Comprehensive Geriatric Assessment can improve postoperative outcomes and a discussion of the models of care that have been developed to improve preoperative assessment and enhance the postoperative recovery of older surgical patients.

[Perioperative stroke in heart valve surgery: pathogenesis, clinical findings, diagnosis, prevention, treatment]

AIM

To study risk factors, characteristics of clinical symptoms and diagnosis, and possibilities of prevention of perioperative stroke and other clinical types of cerebral dysfunction in main types of heart valve surgery.

MATERIAL AND METHODS

The study included 83 patients, aged 63 (54; 70) years, undergoing heart valve surgery with cardiopulmonary bypass.

RESULTS

Postoperative cerebral dysfunction was diagnosed in 37.3% of cases, including perioperative stroke in 3.6% of cases. In cases of aortic stenosis, the frequency of perioperative stroke was 9.5%. The cardioembolic subtype of perioperative ischemic stroke in cardiac valve surgery was most likely. The risk factors of the symptomatic delirium of the early postoperative period are: age over 75 years, preoperative frontal dysfunction, duration of artificial respiratory care more than 20 hours after the surgery.

CONCLUSION

The results suggest the efficacy of preventive use of cytoflavin for reducing the frequency and severity of perioperative stroke and symptomatic delirium of the early postoperative period in heart valve surgery with cardiopulmonary bypass.

Cerebrovascular autoregulation monitoring and patient-centred outcomes after cardiac surgery: a systematic review

BACKGROUND

Impaired cerebrovascular autoregulation (CVAR) is observed in up to 20% of cardiac surgical patients. This systematic review aims to evaluate the association between impaired CVAR, measured by current monitoring techniques, and patient-centred outcomes in adults following cardiac surgery.

METHODS

MEDLINE, EMBASE, PubMed, MEDLINE In-Process and Cochrane Library were systematically searched through 8 December 2017. Studies were included if they assessed associations between CVAR and patient-centred outcomes in the adult cardiac surgical population. The primary outcome of this systematic review was mortality. Secondary outcomes were stroke, delirium and acute kidney injury. Risk of bias was systematically assessed, and the GRADE methodology was used to evaluate the quality of evidence across outcomes.

RESULTS

Eleven observational studies and no randomised controlled trials met the inclusion criteria. Due to methodological heterogeneity, meta-analysis was not possible. There was a high risk of bias within individual studies and low quality of evidence across outcomes. Of the included studies, one assessed mortality, five assessed stroke, four assessed delirium, and three assessed acute kidney injury. No reliable conclusions can be drawn from the one study assessing mortality. Interpretation of studies investigating CVAR and stroke, delirium and acute kidney injury was complicated by the lack of standardisation of monitoring techniques as well as varying definitions of impaired CVAR.

CONCLUSIONS

There is a paucity of high quality evidence for CVAR monitoring and its associations with outcome measures in post-cardiac surgical patients, highlighting the need for future studies.

Lidocaine dose-response effect on postoperative cognitive deficit: meta-analysis and meta-regression

INTRODUCTION

The true influence of the perioperative intravenous lidocaine on the development of postoperative cognitive deficit (POCD) in coronary artery bypass grafting (CABG) remains controversial. The principal aim is to undertake a meta-regression to determine whether moderator variables mediate the relationship between lidocaine and POCD. Areas covered: We searched the Web of Science, PubMed database, Scopus and the Cochrane Library database (up to June 2017) and systematically reviewed a list of retrieved articles. Our final review includes only randomized controlled trials (RCTs) that compared infusion of lidocaine and placebo during cardiopulmonary bypass (CPB). Mantel-Haenszel risk ratio (MH RR) and corresponding 95% confidence interval (CI) was used to report the overall effect and meta-regression analysis. A total of 688 patients in five RCTs were included. POCD occurred in 34% of all cases. Perioperative lidocaine reduces POCD (MH RR 0.702 (95% CI: 0.541-0.909). Younger age, male gender, longer CPB and higher concentration of lidocaine significantly mediate the relationship between lidocaine and POCD in favour of the neuroprotective effect of lidocaine. Expert commentary: The neuroprotective effect of lidocaine on POCD is consistent in spite of longer CPB time. A higher concentration of lidocaine strengthened the neuroprotective effect of lidocaine.

Cardiopulmonary Bypass for a Patient With Congenital Hyperinsulinemia

Congenital hyperinsulinism is a clinical syndrome of pancreatic β-cell dysfunction characterized by failure to suppress insulin secretion in the presence of hypoglycemia. Here, we describe the concerns, the techniques used to ameliorate these potential problems, and the outcomes for a child with this condition undergoing cardiopulmonary bypass for correction of an atrial septal defect.

Non-invasive assessment of cerebral oxygenation: A comparison of retinal and transcranial oximetry

BACKGROUND

To investigate the correlation between cerebral (SO2-transcranial), retinal arterial (SaO2-retinal) and venous (SvO2-retinal) oxygen saturation as measured by near-infrared spectroscopy (NIRS) and retinal oximetry respectively.

METHODS

Paired retinal and cerebral oxygen saturation measurements were performed in healthy volunteers. Arterial and venous retinal oxygen saturation and diameter were measured using a non-invasive spectrophotometric retinal oximeter. Cerebral oxygen saturation was measured using near-infrared spectroscopy. Correlations between SO2-transcranial and retinal oxygen saturation and diameter measurements were assessed using Pearson correlation coefficients. Lin's concordance correlation coefficient (CCC) and Bland-Altman analysis were performed to evaluate the agreement between SO2-transcranial as measured by NIRS and as estimated using a fixed arterial:venous ratio as 0.3 x SaO2-retinal + 0.7 x SvO2-retinal. The individual relative weight of SaO2-retinal and SvO2-retinal to obtain the measured SO2-transcranial was calculated for all subjects.

RESULTS

Twenty-one healthy individuals aged 26.4 ± 2.2 years were analyzed. SO2-transcranial was positively correlated with both SaO2-retinal and SvO2-retinal (r = 0.44, p = 0.045 and r = 0.43, p = 0.049 respectively) and negatively correlated with retinal venous diameter (r = -0.51, p = 0.017). Estimated SO2-transcranial based on retinal oximetry showed a tolerance interval of (-13.70 to 14.72) and CCC of 0.46 (95% confidence interval: 0.05 to 0.73) with measured SO2-transcranial. The average relative weights of SaO2-retinal and SvO2-retinal to obtain SO2-transcranial were 0.31 ± 0.11 and 0.69 ± 0.11, respectively.

CONCLUSION

This is the first study to show the correlation between retinal and cerebral oxygen saturation, measured by NIRS and retinal oximetry. The average relative weight of arterial and venous retinal oxygen saturation to obtain the measured transcranial oxygen saturation as measured by NIRS, approximates the established arterial:venous ratio of 30:70 closely, but shows substantial inter-individual variation. These findings provide a proof of concept for the role of retinal oximetry in evaluating cerebral oxygenation.