Relative cerebral hyperperfusion during cardiopulmonary bypass is associated with risk for postoperative delirium: a cross-sectional cohort study

Inhaled NO at a crossroads in cardiac surgery: current need to improve mechanistic understanding, clinical trial design and scientific evidence

Inhaled nitric oxide (NO) has been used in pediatric and adult perioperative cardiac intensive care for over three decades. NO is a cellular signaling molecule that induces smooth muscle relaxation in the mammalian vasculature. Inhaled NO has the unique ability to exert its vasodilatory effects in the pulmonary vasculature without any hypotensive side-effects in the systemic circulation. In patients undergoing cardiac surgery, NO has been reported in numerous studies to exert beneficial effects on acutely lowering pulmonary artery pressure and reversing right ventricular dysfunction and/or failure. Yet, various investigations failed to demonstrate significant differences in long-term clinical outcomes. The authors, serving as an advisory board of international experts in the field of inhaled NO within pediatric and adult cardiac surgery, will discuss how the existing scientific evidence can be further improved. We will summarize the basic mechanisms underlying the clinical applications of inhaled NO and how this translates into the mandate for inhaled NO in cardiac surgery. We will move on to the popular use of inhaled NO and will talk about the evidence base of the use of this selective pulmonary vasodilator. This review will elucidate what kind of clinical and biological barriers and gaps in knowledge need to be solved and how this has impacted in the development of clinical trials. The authors will elaborate on how the optimization of inhaled NO therapy, the development of biomarkers to identify the target population and the definition of response can improve the design of future large clinical trials. We will explain why it is mandatory to gain an international consensus for the state of the art of NO therapy far beyond this expert advisory board by including the different major players in the field, such as the different medical societies and the pharma industry to improve our understanding of the real-life effects of inhaled NO in large scale observational studies. The design for future innovative randomized controlled trials on inhaled NO therapy in cardiac surgery, adequately powered and based on enhanced biological phenotyping, will be crucial to eventually provide scientific evidence of its clinical efficacy beyond its beneficial hemodynamic properties.

Target flow deviations on the cardiopulmonary bypass cause postoperative delirium in cardiothoracic surgery-a retrospective study evaluating temporal fluctuations of perfusion data

OBJECTIVES

Postoperative delirium (POD) is common, costly and associated with long-term morbidity and increased mortality. We conducted a cohort study to assess the contribution of cardiopulmonary bypass (CPB) to the development of POD by means of algorithm-based data processing.

METHODS

A database was compiled from 3 datasets of patients who underwent cardiac surgery between 2014 and 2019: intensive care unit discharge files, CPB protocols and medical quality management records. Following data extraction and structuring using novel algorithms, missing data were imputed. Ten independent imputations were analysed by multiple logistic regression with stepwise deletion of factors to arrive at a minimal adequate model.

RESULTS

POD was diagnosed in 456/3163 patients (14.4%). In addition to known demographic risk factors and comorbidities like male sex, age, carotid disease, acute kidney failure and diabetes mellitus, cardiopulmonary parameters like total blood volume at the CPB [adjusted odds ratio (AOR) 1.001; confidence interval (CI) 1.1001-1.002] were independent predictors of POD. Higher values of the minimal blood flow were associated with a lower risk of POD (AOR 0.993; CI 0.988-0.997). Flow rates at least 30% above target did emerge in the minimal adequate model as a potential risk factor, but the confidence interval suggested a lack of statistical significance (AOR 1.819; 95% CI: 0.955-3.463).

CONCLUSIONS

CPB data processing proved to be a useful tool for obtaining compact information to better identify the roles of individual operational states. Strict adherence to perfusion limits along with tighter control of blood flow and acid-base balance during CPB may help to further decrease the risk of POD.

The effect of relative cerebral hyperperfusion during cardiac surgery with cardiopulmonary bypass to delayed neurocognitive recovery

OBJECTIVE

Delayed neurocognitive recovery (dNCR) remains a common complication after surgery and the incidence of it is determined 30-80% after cardiac surgery with cardiac bypass (CPB) in eldery patients. Many researchers have identified that neuropsychological complications emerge from insufficient cerebral perfusion. Relative cerebral hyperperfusion also disrupts cerebral autoregulation and might play a significant role in dNCR development. The aim of this study is to determine hyperperfusion in the middle cerebral artery during CPB influence to dNCR development and brain biomarker glial fibrillary acidic protein (GFAP) impact in diagnosing dNCR.

DESIGNS AND METHODS

This prospective - case control study included patients undergoing elective coronary artery bypass grafting or/and valve surgery with CPB. For cognitive evaluation 101 patients completed Addenbrooke's cognitive examination - ACE-III. To determine mild cognitive dysfunction, cut - off 88 was chosen. Mean BFV was monitored with transcranial Doppler ultrasonography (TCD) and performed before surgery, after induction of anaesthesia, during CPB and after surgery. Preoperative BFV was converted to 100% and used as a baseline. The percentage change of cerebral blood flow velocity during CPB was calculated from baseline. Patients with decreased blood flow velocity were included for further investigation. To measure glial fibrillary acidic protein, blood samples were collected after anaesthesia induction, 24 and 48 h after the surgery. According to the ACE-III test results, patients with relative hyperperfusion were divided into two groups: with Delayed neurocognitive recovery and without dNCR (non-dNCR group).

RESULTS

101 patients were examined, 67 (69.1%) men and 29 (29.9%) women, age 67.9 (SD 9.2) Increased percentage of BFV was determined for 40 (39.60%) patients. There were no differences in sex, haematocrit, paCO2, aortic cross-clamping or CPB time between the two groups. Percentage change of BFV was 105.60% in the non-dNCR group and 132.29% in the dNCR group, p = .033. Patients who developed dNCR in the early post-surgical period were significantly older, p < .001 and had a lower baseline of BFV, p = .004. GFAP concentration significantly increased in the dNCR group 48 hours after surgery, compared to the non-dNCR group, p = .01.

CONCLUSIONS

Relative hyperperfusion during CPB may cause dNCR. Elderly patients are sensitive to blood flow velocity acceleration during CPB. GFAP concentration increased 48 h after surgery in dNCR group but did not have any connection with risk factors.

Effect of cerebral oxygen saturation monitoring in patients undergoing superficial temporal anterior-middle cerebral artery anastomosis for ischemic Moyamoya disease: a prospective cohort study

Objective

Regional cerebral oxygen saturation (rSO2) is linked with blood pressure. This study evaluated the influence of perioperative rSO2 monitoring on the prognosis of ischemic Moyamoya disease (MMD) patients undergoing anastomosis surgery.

Methods

In this prospective cohort, patients with unilateral ischemic MMD of Suzuki stage ≥3 were included. The decision of rSO2 was made by the clinician and the patient. The rSO2 group maintained intraoperative rSO2 levels through the modulation of blood pressure, inhaled oxygen concentration, carbon dioxide in arterial blood, and red blood cell transfusion. The non-rSO2 group used conventional anesthesia practices. Perioperative mean arterial pressure (MAP), rSO2 values, neurological complications, and postoperative results were assessed.

Results

A total of 75 eligible patients were categorized into a rSO2 monitoring group (n = 30) and a non-rSO2 monitoring group (n = 45). For the rSO2 group, the preoperative rSO2 was significantly lower on the affected side (P < 0.05). After anastomosis, this value notably increased (P = 0.01). A moderate relationship was observed between perioperative rSO2 and MAP before, during, and after surgery, with correlation coefficients (r) of 0.536, 0.502, and 0.592 (P < 0.05). Post-surgery MAP levels differed between the groups, with the rSO2 group showing decreased levels compared to pre-surgery and the non-rOS2 group displaying elevated levels. Notably, the rSO2 group reported shorter hospitalizations and decreased neurological complications. Patients with a hypertension history found postoperative MAP influencing hospital stay duration.

Conclusion

Perioperative rSO2 surveillance enhanced cerebral perfusion and minimized postoperative complications in ischemic MMD patients. Thus, rSO2 monitoring is advocated for MMD patients undergoing vascular anastomosis.

Influence of cardioplegic solution on incidence of delirium after CABG surgery: Use of Calafiore blood cardioplegia versus HTK - Bretschneider - solution in a single-center retrospective analysis from 2017 to 2021

BACKGROUND

Purpose of the present study is an evaluation of postoperative incidence for delirium after coronary artery bypass surgery (CABG). Study addressed whether application of Histidine-Tryptophan-Ketoglutarate (HTK) solution (Bretschneider) or blood cardioplegia (Calafiore) is associated with increased of postoperative delirium cases.

MATERIALS AND METHODS

In a retrospective, single center evaluation a total number of 273 patients were enrolled in the study from January 2017 to October 2021. There were 124 patients assigned to the Calafiore group blood cardioplegic solution (BCC) and 149 patients were included in the Bretschneider group (HTK). The primary endpoint was the postoperative delirium rate in its frequency of occurrence. Definition of the dilirium status was performed using the Confusion Assessment Method in the Intensive Care Unit (CAM-ICU) score during the first three postoperative days. Secondary endpoints were the time intervals of intensive care duration of stay, mechanical ventilation, total extracorporeal circulation, ischemia and reperfusion. Serum levels of the electrolytes Sodium, Potassium, ionized Calcium, and Chloride were monitored.

RESULTS

Although no significant difference in delirium status between the groups were noticed, on third postoperative day, delirium rate dependent on cardioplegia solution used (HTK 12.0%; BCC 3.0%; p = .024) and duration of intensive care stay differed (HTK 4.5 vs. BCC 3.0 days; p = .001). Although Ischemic time (HTK 73.0 vs. BCC 83.0 min; p < .001) and reperfusion time (HTK 35.0 vs. Calafiore 24.0 min; p < .001) were extended in the BCC group less cases of delirium were diagnosed. Serum sodium levels after HTK cardioplegic infusion were decreased (HTK 129.68 vs. BCC 138.96 mmol/l; p < .001). The significant difference persists up to the hundredth extracorporeal circulation circuit min (p = .005).

CONCLUSION

The present data suggest an impact of the cardioplegic solution used upon postoperative delirium rates. Optimization of cardiac arrest protocols is needed. Present data encourage further prospective studies regarding the impact of cardioplegic solutions on electrolyte imbalance for postoperative delirium rates in CABG surgery.

Risk factors for postoperative delirium after cardiac surgical procedures with cardioplegic arrest

OBJECTIVES

The pathophysiology of delirium after cardiac surgery is complex. The present study aims to determine perioperative risk factors and construct a scoring system for postoperative delirium based on the type of surgery.

METHODS

Three hundred patients undergoing coronary artery bypass grafting (CABG; n = 150) or valve and/or aortic surgery ± CABG (n = 150) were retrospectively evaluated.

RESULTS

The incidence of delirium (32%) was similar in subgroups (28.7% and 33.33%, P = 0.384). Delirium patients were older [71.3 (standard deviation: 8.5) vs 66.6 (standard deviation: 9.5), P < 0.001; 70.0 (standard deviation: 9.6) vs 62.5 (standard deviation: 12.6), P < 0.001] and required more packed red blood cell units [2.1 (standard deviation: 2.1) vs 4.2 (standard deviation: 4.0), P < 0.001; 2.4 (standard deviation: 3.3) vs 5.4 (standard deviation: 5.9), P < 0.001] and fresh frozen plasma units [6.1 (standard deviation: 2.9) vs. 8.0 (standard deviation: 4.2), P < 0.001; 6.3 (standard deviation: 3.4) vs 10.8 (standard deviation: 7.2), P < 0.001] in CABG and valve/aortic subgroups, respectively. Delirium was associated with longer operation time [298.3 (standard deviation: 98.4) vs 250.6 (standard deviation: 67.8) min, P < 0.001], cardiopulmonary bypass (CPB) time [171.5 (standard deviation: 54.9) vs 140.98 (standard deviation: 45.8) min, P < 0.001] and cardiac arrest time [112 (standard deviation: 35.9) vs 91.9 (standard deviation: 28.6), P < 0.001] only in the valve/aortic group (versus non-delirium). Multivariate regression analysis identified an association between delirium and age [odds ratio: 1.056 (95% confidence interval: 1.002-1.113), P = 0.041], CPB time [odds ratio: 1.1014 (95% confidence interval: 1.004-1.025), P = 0.007], fresh frozen plasma transfusion [odds ratio: 1.127 (95% confidence interval: 1.006-1.262), P = 0.039] and atrial fibrillation [odds ratio: 4.801 (95% confidence interval: 1.844-12.502), P < 0.001] after valve/aortic surgery (area under the curve 0.835, P < 0.001) and between delirium and age [odds ratio: 1.089 (95% confidence interval: 1.023-1.160), P = 0.007] and ventilation time [odds ratio: 1.068 (95% confidence interval: 1.026-1.113), P = 0.001] after isolated CABG (area under the curve 0.798, P < 0.001). The cross-validation of the results by k-fold logistic regression revealed for the entire patient cohort an overall average accuracy of the prediction model of 0.764, with a false-positive rate of 0.052 and a false-negative rate of 0.18.

CONCLUSIONS

Age, CPB time, ventilation, transfusion and atrial fibrillation are differently associated with delirium depending on the operative characteristics. Optimization of intraoperative parameters and use of risk calculators may enable early institution of pharmacotherapy and improve overall outcome after cardiac surgery.

Neuromonitoring and Neurocognitive Outcomes in Cardiac Surgery: A Narrative Review

Neurocognitive dysfunction after cardiac surgery can present with diverse clinical phenotypes, which include postoperative delirium, postoperative cognitive dysfunction, and stroke, and it presents a significant healthcare burden for both patients and providers. Neurologic monitoring during cardiac surgery includes several modalities assessing cerebral perfusion and oxygenation (near-infrared spectroscopy, transcranial Doppler and jugular venous bulb saturation monitoring) and those that measure cerebral function (processed and unprocessed electroencephalogram), reflecting an absence of a single, definitive neuromonitor. This narrative review briefly describes the technologic basis of these neuromonitoring modalities, before exploring their use in clinical practice, both as tools to predict neurocognitive dysfunction, and with a bundle of interventions designed to optimize cerebral oxygen supply, with the aim of reducing postoperative delirium and cognitive dysfunction following cardiac surgery.

Delirium and depression in cardiac surgery: A comprehensive review of risk factors, pathophysiology, and management

BACKGROUND

Mental health and wellbeing continue to gain more attention as they are inextricably associated with clinical outcomes, particularly quality of life. Many medical ailments and major surgeries affect patients' mental health, including depression and delirium.

AIMS

The objective of this manuscript was to comprehensively review and critically examine the literature pertaining to cardiac surgery, depression, and delirium.

METHODS

This is a narrative review article. We performed our search analysis by using the following key words: "Cardiac Surgery", "Depression", "Delirium", "Clinical outcomes", and "Mental Health". Search analysis was done on MedLine PubMed, accessing indexed peer-reviewed publications.

RESULTS

Cardiac Surgery is a life-altering intervention indicated to improve morbidity and mortality in patients with cardiovascular diseases. Psychiatric conditions before and after cardiac surgery worsen patient prognosis and increase mortality rate. Specifically, preoperative depression increases postoperative depression and is associated with impaired functional status, slow physical recovery, and an increased readmission rate.

DISCUSSION

Although the exact pathophysiology between depression and cardiovascular disease (CVD) is unknown, several pathways have been implicated. Unmanaged depression can also lead to other psychological conditions such as delirium. Like depression, the exact association between delirium and CVD is not well understood, but believed to be multifactorial.

CONCLUSION

Herein, we provide a comprehensive review of the links between depression, delirium, and cardiovascular surgery. We critically examine the current data that pertains to the pathophysiology of these debilitating mental health issues in the context of cardiac surgery. Finally, we summarize the various treatment options available for managing depression and delirium in the cardiac surgery patient population.

Extended neuromonitoring in aortic arch surgery : A case series

BACKGROUND

Aortic arch repair for aortic dissection is still associated with a high mortality rate. Providing adequate means of neuromonitoring to guide cerebral hemodynamics is advantageous, especially during selective anterior cerebral perfusion (SACP).

OBJECTIVE

We aimed to investigate an easy multimodal neuromonitoring set-up consisting of processed electroencephalography (EEG), near infrared spectroscopy (NIRS), and transcranial doppler sonography (TCD).

MATERIAL AND METHODS

We collected intraoperative data from six patients undergoing surgery for aortic dissection. In addition to standard hemodynamic monitoring, patients underwent continuous bilateral NIRS, processed EEG with bispectral index (BIS), and intermittent transcranial doppler sonography of the medial cerebral artery (MCA) with a standard B‑mode ultrasound device. Doppler measurements were taken bilaterally before cardiopulmonary bypass (CPB), during CPB, and during SACP at regular intervals.

RESULTS

Of the patients four survived without neurological deficits while two suffered fatal outcomes. Of the survivors two suffered from transient postoperative delirium. Multimodal monitoring led to a change in CPB flow or cannula repositioning in three patients. Left-sided mean flow velocities of the MCA decreased during SACP, as did BIS values.

CONCLUSION

Monitoring consisting of BIS, NIRS, and TCD may have an impact on hemodynamic management in aortic arch operations.

Cerebral microemboli in mini-sternotomy compared to mini- thoracotomy for aortic valve replacement: a cross sectional cohort study

Background

Recently adopted mini-thoracotomy approach for surgical aortic valve replacement has shown benefits such as reduced pain and shorter recovery, compared to more conventional mini-sternotomy access. However, whether limited exposure of the heart and ascending aorta resulting from an incision in the second intercostal space may lead to increased intraoperative cerebral embolization and more prominent postoperative neurologic decline, remains inconclusive. The aim of our study was to assess potential neurological complications after two different minimal invasive surgical techniques for aortic valve replacement by measuring cerebral microembolic signal during surgery and by follow-up cognitive evaluation.

Methods

Trans-cranial Doppler was used for microembolic signal detection during aortic valve replacement performed via mini-sternotomy and mini-thoracotomy. Patients were evaluated using Addenbrooke’s Cognitive Examination Revised Test before and 30 days after surgical procedure.

Results

A total of 60 patients were recruited in the study. In 52 patients, transcranial Doppler was feasible. Of those, 25 underwent mini-sternotomy and 27 had mini-thoracotomy. There were no differences between groups with respect to sex, NYHA class distribution, Euroscore II or aortic valve area. Patients in mini-sternotomy group were younger (60.8 ± 14.4 vs.72 ± 5.84, p = 0.003), heavier (85.2 ± 12.4 vs.72.5 ± 12.9, p = 0.002) and had higher body surface area (1.98 ± 0.167 vs. 1.83 ± 0.178, p = 0.006). Surgery duration was longer in mini-sternotomy group compared to mini-thoracotomy (158 ± 24 vs. 134 ± 30 min, p < 0.001, respectively). There were no differences between groups in microembolic load, length of ICU or total hospital stay. Total microembolic signals count was correlated with cardiopulmonary bypass duration (5.64, 95%CI 0.677–10.60, p = 0.027). Addenbrooke’s Cognitive Examination Revised Test score decreased equivalently in both groups (p = 0.630) (MS: 85.2 ± 9.6 vs. 82.9 ± 11.4, p = 0.012; MT: 85.2 ± 9.6 vs. 81.3 ± 8.8, p = 0.001).

Conclusion

There is no difference in microembolic load between the groups. Total intraoperative microembolic signals count was associated with cardiopulmonary bypass duration. Age, but not micorembolic signals load, was associated with postoperative neurologic decline.

Trial registry number

clinicaltrials.gov, NCT02697786 14.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01509-8.

Perioperative Vascular Biomarker Profiling in Elective Surgery Patients Developing Postoperative Delirium: A Prospective Cohort Study

Background: Postoperative delirium (POD) ranks among the most common complications in surgical patients. Blood-based biomarkers might help identify the patient at risk. This study aimed to assess how serum biomarkers with specificity for vascular and endothelial function and for inflammation are altered, prior to or following surgery in patients who subsequently develop POD. Methods: This was a study on a subcohort of consecutively recruited elective non-cardiac as well as cardiac surgery patients (age > 60 years) of the single-center PROPDESC trial at a German tertiary care hospital. Serum was sampled prior to and following surgery, and the samples were subjected to bead-based multiplex analysis of 17 serum proteins (IL-3, IL-8, IL-10, Cripto, CCL2, RAGE, Resistin, ANGPT2, TIE2, Thrombomodulin, Syndecan-1, E-Selectin, VCAM-1, ICAM-1, CXCL5, NSE, and uPAR). Development of POD was assessed during the first five days after surgery, using the Confusion Assessment Method for ICU (CAM-ICU), the CAM, the 4-‘A’s test (4AT), and the Delirium Observation Scale (DOS). Patients were considered positive if POD was detected at least once during the visitation period by any of the applied methods. Non-parametric testing, as well as propensity score matching were used for statistical analysis. Results: A total of 118 patients were included in the final analysis; 69% underwent non-cardiac surgery, median overall patient age was 71 years, and 59% of patients were male. In the whole cohort, incidence of POD was 28%. The male gender was significantly associated with the development of POD (p = 0.0004), as well as a higher ASA status III (p = 0.04). Incidence of POD was furthermore significantly increased in cardiac surgery patients (p = 0.002). Surgery induced highly significant changes in serum levels of almost all biomarkers except uPAR. In preoperative serum samples, none of the analyzed parameters was significantly altered in subsequent POD patients. In postoperative samples, CCL2 was significantly increased by a factor of 1.75 in POD patients (p = 0.03), as compared to the no-POD cohort. Following propensity score matching, CCL2 remained the only biomarker that showed significant differences in postoperative values (p = 0.01). In cardiac surgery patients, postoperative CCL2 serum levels were more than 3.5 times higher than those following non-cardiac surgery (p < 0.0001). Moreover, after cardiac surgery, Syndecan-1 serum levels were significantly increased in POD patients, as compared to no-POD cardiac surgery patients (p = 0.04). Conclusions: In a mixed cohort of elective non-cardiac as well as cardiac surgery patients, preoperative serum biomarker profiling with specificity for vascular dysfunction and for systemic inflammation was not indicative of subsequent POD development. Surgery-induced systemic inflammation—as evidenced by the significant increase in CCL2 release—was associated with POD, particularly following cardiac surgery. In those patients, postoperative glycocalyx injury might furthermore contribute to POD development.

Decrease of Coronal Optic Nerve Sheath Diameter is Associated With Postoperative Cognitive Decline in Patients Undergoing Carotid Endarterectomy

OBJECTIVE

Patients undergoing carotid endarterectomy (CEA) have a significant possibility of developing postoperative cognitive decline (POCD). POCD after surgery could be result from cerebral hypotension induced by cross-clamping or postoperative hyperperfusion. Optic nerve sheath diameter (ONSD) exhibits an excellent correlation with invasive intracranial pressure monitoring, Here, the authors explored the risk factors of POCD in patients undergoing CEA, paying close attention to ONSD to test the hypothesis that decrease of coronal ONSD was related to the incidence of POCD.

DESIGN

Observational retrospective review.

SETTING

Single tertiary academic center.

PARTICIPANTS

One hundred sixteen patients undergoing CEA from January 1, 2019 to December 31, 2019.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

A multivariate logistic regression, scatter diagrams, and a receiver operating curve were used to evaluate the ability to predict POCD though the change in coronal ONSD. This study ultimately enrolled 84 patients and the incidence of POCD within postoperative two days was 28.6%. Decrease of coronal ONSD (odds ratio [OR], 0.438; 95% confidence interval [CI] 0.217-0.881; p = 0.021) and total intravenous anesthesia (TIVA) (OR, 25.541, 95% CI 2.100-310.614, p = 0.011) were independent risk factors for POCD. Changes in coronal ONSD had an area under the curve to distinguish POCD of 0.716 (95% CI 0.531-0.902). Using a cutoff of 0.05 cm, changes of coronal ONSD had a sensitivity of 66.7% and specificity of 66.7%.

CONCLUSIONS

Decrease of coronal ONSD, measured by ultrasonography and TIVA, were associated with POCD. Change in coronal ONSD was a moderate predictor of incidence of POCD.

[Near-infrared spectroscopy : Technique, development, current use and perspectives]

Near-infrared spectroscopy (NIRS) has been available in research and clinical practice for more than four decades. Recently, there have been numerous publications and substantial developments in the field. This article describes the clinical application of NIRS in relation to current guidelines, with a focus on pediatric and cardiac anesthesia. It discusses technical and physiological principles, pitfalls in clinical use and presents (patho)physiological influencing factors and derived variables, such as fractional oxygen extraction (FOE) and the cerebral oxygen index (COx). Recommendations for the interpretation of NIRS values in connection with influencing factors, such as oxygen transport capacity, gas exchange and circulation as well as an algorithm for cardiac anesthesia are presented. Limitations of the method and the lack of comparability of values from different devices as well as generally accepted standard values are explained. Technical differences and advantages compared to pulse oxymetry and transcranial Doppler sonography are illuminated. Finally, the prognostic significance and requirements for future clinical studies are discussed.

Asymmetric cerebral edema presenting with severe neurologic impairment and seizures after cardiac and thoracic interventions

INTRODUCTION

A syndrome of focal neurologic deficits with characteristic imaging features, acute encephalopathy, and seizures after cardiac and thoracic interventions has been previously briefly reported in the literature. In a retrospective observational study, we aim to identify the prevalence and characteristics of this syndrome, in addition to discussing the possible underlying pathophysiology.

METHODS

In a retrospective study, we reviewed records of consecutive adult patients (≥18 years old) who underwent cardiac and thoracic procedures at a single institution between September 2014 to September 2019 and found to have evidence of focal cerebral edema following their procedure. We included and reported clinical course of patients who developed post-operative neurologic dysfunction and underwent magnetic resonance imaging (MRI) showing (1) asymmetric cerebral edema with (2) cortical diffusion restriction and (3) T2 cortical or subcortical hyperintensity and (4) no proximal vascular occlusion.

RESULTS

Three out of 107 patients (2.8%) met our inclusion criteria. These represented one male and two females with age at presentation of 63, 81 and 69, respectively. All patients developed severe neurologic impairment on the same day following their procedure (sternotomy with valve or bypass surgery in 2 patients; esophageal dilatation procedure in 1 patient). All patients underwent MRI of the brain and vessel imaging qualifying our inclusion criteria. Two patients improved neurologically prior to discharge, and one patient expired after family elected to withdraw care.

CONCLUSION

We present a series of cases with a rare syndrome after cardiac and thoracic interventions. Although the exact mechanism of this syndrome remains unclear, we believe it to be related to relative cerebral hyperperfusion and cerebral dysautoregulation following anesthesia and thoracic manipulation. Future studies should focus on understanding the true prevalence and pathophysiology of this syndrome.

Risk Factors for Delayed Neurocognitive Recovery According to Brain Biomarkers and Cerebral Blood Flow Velocity

Background and Objectives: The aim of this study is to identify risk factors for the development of delayed neurocognitive recovery (dNCR). Methods: 140 patients underwent neurocognitive evaluations (Adenbrooke, MoCa, trial making, and CAM test) and middle cerebral artery (MCA) blood flow velocity (BFV) measurements, one day before cardiac surgery. BFV was re-evaluated after anesthesia induction, before the beginning, middle, end, and after cardiopulmonary bypass (CPB) and postsurgery. To measure glial fibrillary acidic protein (GFAP) and neurofilament heavy chain (Nf-H), blood samples were collected after anesthesia induction, 24 and 48 h after the surgery. Neurocognitive evaluation was repeated 7-10 days after surgery. According to the results, patients were divided into two groups: with dNCR (dNCR group) and without dNCR (non-dNCR group). Results: 101 patients completed participation in this research. GFAP increased in both the non-dNCR group (p < 0.01) and in the dNCR group (p < 0.01), but there was no difference between the groups (after 24 h, p 0.342; after 48 h, p 0.273). Nf-H increased in both groups (p < 0.01), but there was no difference between them (after 24 h, p = 0.240; after 48 h, p = 0.597). MCA BFV was significantly lower in the dNCR group during the bypass (37.13 cm/s SD 7.70 versus 43.40 cm/s SD 9.56; p = 0.001) and after surgery (40.54 cm/s SD 11.21 versus 47.6 cm/s SD 12.01; p = 0.003). Results of neurocognitive tests correlated with CO₂ concentration (Pearson's r 0.40, p < 0.01), hematocrit (r 0.42, p < 0.01), MCA BFV during bypass (r 0.41, p < 0.01), and age (r -0.533, p < 0.01). The probability of developing dNCR increases 1.21 times with every one year of increased age (p < 0.01). The probability of developing dNCR increases 1.07 times with a decrease of BFV within 1 cm/s during bypass (p = 0.02). Conclusion: Risk factors contributing to dNCR among the tested patients were older age and middle cerebral artery blood flow velocity decrease during bypass.

Intra-operative hyperoxia and the risk of delirium in elderly patients after cardiac surgery

Delirium is a common complication after cardiac surgery. The aim of our study was to determine the impact of hyperoxia episodes occurring during cardiopulmonary bypass (CBP) on the rate of delirium episodes in the postoperative period. 93 patients, aged ≥ 65, who underwent elective cardiac surgery (CBP <90 minutes) were enrolled. The occurrence of delirium episodes was examined every 12 hours for three days after surgery. Eleven patients (11.8%) developed postoperative delirium (POD (+)) and 83 did not (POD (-)). More incidences of severe hyperoxia (PaO2 ≥ 26.6kPa) during CBP were observed in the POD (+) group: 64% had ≥ 2 episodes of hyperoxia, 27% ≥ 3, and 18% ≥ 4, while in the POD (-) group: 42%, 13% and 1%, respectively (P=0.02). Patients in the POD (+) group had a higher maximum PaO₂ during CBP than the POD (-) group (37 ± 5.8 vs 31.6 ± 6.6 kPa; P=0.01) and a higher mean PaO₂ (30.1 ± 4.5 vs 26.1 ± 5.6 kPa; P=0.01). The optimal maximum PaO₂ cut-off point for the occurrence of delirium was 33.2 kPa (AUC 0.72, P=0.001, sensitivity 75%, specificity 38%). We conclude that CBP hyperoxia episodes may be a risk factor associated with the occurrence of postoperative delirium.

The influence of blood flow velocity changes to postoperative cognitive dysfunction development in patients undergoing heart surgery with cardiopulmonary bypass

BACKGROUND

The aim of this study was to compare blood flow velocity changes in the middle cerebral artery before, during and after heart surgery with cardiopulmonary bypass for patients with and without postoperative cognitive dysfunction.

MATERIALS AND METHODS

A total of 100 patients, undergoing elective coronary artery bypass grafting or/and valve surgery enrolled in the study. A neurocognitive test evaluation included Adenbrooke, Mini-Mental State Examination and Trial Making test before and 7-10 days after surgery. Middle cerebral artery mean blood flow velocity was evaluated 1 day before the surgery, after anaesthesia induction, before cardiopulmonary bypass, at the beginning, ending and after cardiopulmonary bypass, and post surgery in intensive care unit. Blood samples for glial fibrillary acidic protein were measured after anaesthesia induction, 24 hours and 48 hours after surgery. According to neurocognitive tests results patients were divided in to two groups: patients with and without postoperative cognitive dysfunction.

RESULTS

Of the 100, 86 patients completed investigation. After induction, blood flow velocity of the middle cerebral artery was lower in postoperative cognitive dysfunction group (41.2; min 27.91, max 49.47) than in the H group (41.2, min 21.9, max 84.3) p = 0.034, and during cardiopulmonary bypass, blood flow velocity of the middle cerebral artery was lower in the postoperative cognitive dysfunction group (37.35, min 26.6, max 44.02) than the H group (42.3, min 20.1, max 86.5), p = 0.001. After the surgery, blood flow velocity of the middle cerebral artery was lower in the postoperative cognitive dysfunction group (40.7, min 29.7, max 50.4) than in the H group (45.3, min 34.12, max 59.88), p = 0.05. Results of cognitive tests had weak correlation (rho, 0.391) with middle cerebral artery's blood flow velocity after anaesthesia induction (p = 0.001) and during bypass (p = 0.018). The receiver operating characteristic analysis showed that the blood flow velocity of the middle cerebral artery during bypass (area under the curve = 0.735) was a fair predictor for postoperative cognitive dysfunction (p = 0.001). No significant correlations were found among glial fibrillary acidic protein, middle cerebral artery blood flow velocity, and cognitive tests results.

CONCLUSION

Middle cerebral artery's blood flow velocity was decreased after anaesthesia induction and during cardiopulmonary bypass for patients with postoperative cognitive dysfunction comparing with their blood flow velocity preoperatively. Blood flow velocity during bypass has diagnostic value for postoperative cognitive dysfunction. Brain biomarker glial fibrillary acidic protein is not helpful in diagnosing postoperative cognitive dysfunction.