Neurological complications after cardiac surgery: anesthetic considerations based on outcome evidence

Analysis of influencing factors for postoperative brain injury in patients with cardiac surgery

OBJECTIVE

To identify risk factors in people with heart disease prior to undergoing cardiac surgery and to provide a prediction model.

METHODS

106 patients who underwent cardiac surgery were selected by convenience sampling method. Case-control study design was used to divide them into control and observation groups according to whether there was postoperative brain injury. General demographic data, perioperative surgery, postoperative recovery, past medical history and preoperative conditions, laboratory test indicators were collected. Univariate and multivariate Logistic regression analyses were performed to select influencing factors. A nomogram model for predicting postoperative brain injury was established.

RESULTS

Univariate Logistic regression analysis showed that age, female, stroke, diabetes mellitus, perioperative administration of dexmedetomidine, intraoperative use of cardiopulmonary bypass were related factors for postoperative brain injury(p < 0.05). Multivariate Logistic regression analysis showed that females, history of stroke, and intraoperative use of cardiopulmonary bypass were risk factors, and perioperative administration of dexmedetomidine was protective factor(p < 0.05). Nomogram model was established with an AUC of 0.847 and accuracy of 84.7%.

CONCLUSION

Preoperative stroke history and females are risk factors for brain injury after coronary artery bypass grafting under cardiopulmonary bypass, and perioperative use of dexmedetomidine is protective factor.

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.

Machine Learning Model for Predicting Risk Factors of Prolonged Length of Hospital Stay in Patients with Aortic Dissection: a Retrospective Clinical Study

The length of hospital stay (LOS) is crucial for assessing medical service quality. This study aimed to develop machine learning models for predicting risk factors of prolonged LOS in patients with aortic dissection (AD). The data of 516 AD patients were obtained from the hospital's medical system, with 111 patients in the prolonged LOS (> 30 days) group based on three quarters of the LOS in the entire cohort. Given the screened variables and prediction models, the XGBoost model demonstrated superior predictive performance in identifying prolonged LOS, due to the highest area under the receiver operating characteristic curve, sensitivity, and F1-score in both subsets. The SHapley Additive exPlanation analysis indicated that high density lipoprotein cholesterol, alanine transaminase, systolic blood pressure, percentage of lymphocyte, and operation time were the top five risk factors associated with prolonged LOS. These findings have a guiding value for the clinical management of patients with AD.

Leveraging Hypotension Prediction Index to Forecast LPS-Induced Acute Lung Injury and Inflammation in a Porcine Model: Exploring the Role of Hypoxia-Inducible Factor in Circulatory Shock

Acute respiratory distress syndrome (ARDS) is a critical illness in critically unwell patients, characterized by refractory hypoxemia and shock. This study evaluates an early detection tool and investigates the relationship between hypoxia and circulatory shock in ARDS, to improve diagnostic precision and therapy customization. We used a porcine model, inducing ARDS with mechanical ventilation and intratracheal plus intravenous lipopolysaccharide (LPS) injection. Hemodynamic changes were monitored using an Acumen IQ sensor and a ForeSight Elite sensor connected to the HemoSphere platform. We evaluated tissue damage, inflammatory response, and hypoxia-inducible factor (HIF) alterations using enzyme-linked immunosorbent assay and immunohistochemistry. The results showed severe hypotension and increased heart rates post-LPS exposure, with a notable rise in the hypotension prediction index (HPI) during acute lung injury (p = 0.024). Tissue oxygen saturation dropped considerably in the right brain region. Interestingly, post-injury HIF-2α levels were lower at the end of the experiment. Our findings imply that the HPI can effectively predict ARDS-related hypotension. HIF expression levels may serve as possible markers of rapid ARDS progression. Further research should be conducted on the clinical value of this novel approach in critical care, as well as the relationship between the HIF pathway and ARDS-associated hypotension.

Neurological outcomes in minimally invasive mitral valve surgery: risk factors analysis from the Mini-Mitral International Registry

OBJECTIVES

The aim of this study was to examine the incidence and predictors of stroke after minimally invasive mitral valve surgery (mini-MVS) and to assess the role of preoperative CT scan on surgical management and neurological outcomes in the large cohort of Mini-Mitral International Registry.

METHODS

Clinical, operative and in-hospital outcomes in patients undergoing mini-MVS between 2015 and 2021 were collected. Univariable and multivariable analyses were used to identify predictors of stroke. Finally, the impact of preoperative CT scan on surgical management and neurological outcomes was assessed.

RESULTS

Data from 7343 patients were collected. The incidence of stroke was 1.3% (n = 95/7343). Stroke was associated with higher in-hospital mortality (11.6% vs 1.5%, P < 0.001) and longer intubation time, ICU and hospital stay (median 26 vs 7 h, 120 vs 24 h and 14 vs 8 days, respectively). On multivariable analysis, age (odds ratio 1.039, 95% confidence interval 1.019-1.060, P < 0.001) and mitral valve replacement (odds ratio 2.167, 95% confidence interval 1.401-3.354, P < 0.001) emerged as independent predictors of stroke. Preoperative CT scan was made in 31.1% of cases. These patients had a higher risk profile and EuroSCORE II (median 1.58 vs 1.1, P < 0.001). CT scan influenced the choice of cannulation site, being ascending aorta (18.5% vs 0.5%, P < 0.001) more frequent in the CT group and femoral artery more frequent in the no CT group (97.8% vs 79.7%, P < 0.001). No difference was found in the incidence of postoperative stroke (CT group 1.5, no CT group 1.4%, P = 0.7).

CONCLUSIONS

Mini-MVS is associated with a low incidence of stroke, but when it occurs it has an ominous impact on mortality. Preoperative CT scan affected surgical cannulation strategy but did not led to improved neurological outcomes.

A comprehensive review of cerebral oximetry in cardiac surgery

BACKGROUND

Patients who undergo cardiac surgery are at increased risk of stroke, postoperative cognitive decline, and delirium. These neurocognitive complications have led to increased costs, intensive care unit stays, morbidity, and mortality. As a result, there is a significant push to mitigate any neurological complications in cardiac surgery patients. Near-infrared spectroscopy to measure regional cerebral oxygen saturations has gained consideration due to its noninvasive and user-friendly nature. Cerebral oximetry desaturations during cardiac surgery have been linked to an array of adverse clinical outcomes. However, the most effective intraoperative interventions to protect this vulnerable patient population have yet to be ascertained.

AIM OF STUDY

To provide a comprehensive summary of the intraoperative management for cerebral oximetry desaturations during cardiac surgery. The review highlights clinical outcomes from cerebral oximetry use to quantify the importance of identifying cerebral desaturations during cardiac surgery. The review then interrogates possible interventions for cerebral oximetry desaturations in an effort to determine which interventions are most efficacious and to enlighten possible areas for further research.

METHODS

A narrative review of randomized controlled trials, observational studies, and systematic reviews with metanalyses was performed through August 2021.

RESULTS

There is significant heterogeneity among patient populations for which cerebral oximetry monitoring has been studied in cardiac surgery. Further, the definition of a clinically significant cerebral desaturation and the assessment of neurocognitive outcomes varied substantially across studies. As a result, metanalysis is challenging and few conclusions can be drawn. Cerebral oximetry use during cardiac surgery has not been associated with improvements in neurocognitive outcomes, morbidity, or mortality to date. The evidence to support a particular intervention for an acute desaturation is equivocal.

CONCLUSIONS

Future research is needed to quantify a clinically significant cerebral desaturation and to determine which interventions for an acute desaturation effectively improve clinical outcomes.

Infection…what else? The usefulness of procalcitonin in children after cardiac surgery

Objectives

Procalcitonin is a useful biomarker for predicting bacterial infection after cardiac surgery. However, sometimes procalcitonin rises following cardiac surgery without a confirmation of bacterial infection. The aim was to analyse procalcitonin levels in children without a bacterial infection after cardiac surgery.

Study design

This is a prospective, observational study of children <18 years old admitted to the pediatric intensive care unit after cardiac surgery.

Results

1,042 children were included, 996 (95.6%) without a bacterial infection. From them, severe complications occurred in 132 patients (13.3%). Procalcitonin increased differentially depending on the type of complication. Patients who presented a poor outcome (n = 26, 2.6%) had higher procalcitonin values in the postoperative period than the rest of patients (<24 hours: 5.8 ng/mL vs. 0.6 ng/mL; 24–48 hours, 5.1 ng/mL vs. 0.8 ng/mL, and 48–72 hours, 5.3 ng/mL vs. 1.2 ng/mL), but these values remained stable over time (p = 0.732; p = 0.110). The AUC for procalcitonin for predicting poor outcome was 0.876 in the first 24 hours. The cut-off point to predict poor outcome was 2 ng/mL in the first 24 hours (sensitivity 86.9%, specificity 77.3%). Patients with bacterial infection (n = 46) presented higher values of procalcitonin initially, but they decreased in the 48–72 hours period (<24 hours: 4.9 ng/mL; 24–48 hours, 5.8 ng/mL, and 48–72 hours, 4.5 ng/mL).

Conclusions

A procalcitonin value<2 ng/mL may indicate the absence of infection and poor outcome after cardiac surgery. The evolution of the values of this biomarker might help to discern between infection (where procalcitonin will decrease) and poor outcome (where procalcitonin will not decrease).

Effect of Deliberate Hypotension on Regional Cerebral Oxygen Saturation During Functional Endoscopic Sinus Surgery: A Randomized Controlled Trial

Background: Deliberate hypotension can reduce bleeding and improve visualization of the surgical field during functional endoscopic sinus surgery (FESS). However, hypotension may cause brain hypoperfusion and subsequent ischemic injuries, such as delayed awakening, stroke, postoperative delirium, and postoperative cognitive dysfunction. Near-infrared spectroscopy (NIRS) can be used to monitor real-time regional cerebral oxygen saturation (rSO₂) levels to estimate brain perfusion. The present study aimed to evaluate the change in rSO₂ induced by deliberate hypotension during FESS, and assess the impact of deliberate hypotension on the surgical process.

Material and Methods: A randomized controlled trial was registered with the Chinese clinical trial registry (ChiCTR2000039846). A total of 40 patients were enrolled and randomly divided into the control and intervention groups, and finally, 39 patients were analyzed. Deliberate hypotension was induced in the intervention group using nicardipine and esmolol, whereas the control group received general anesthesia without deliberate hypotension. We recorded mean arterial pressure (MAP), saturation of pulse oximetry (SpO₂), rSO₂, and heart rate (HR) before induction of anesthesia (T0), immediately after induction of anesthesia (T1), at the beginning of the operation (corresponding with the establishment of deliberate hypotension) (T2), 10 min (T3) and 20 min (T4) after the operation began, at the end of the operation (corresponding with the end of deliberate hypotension) (T5), and 5 min (T6) and 15 min (T7) after the operation. The partial pressure of end-tidal carbon dioxide (PetCO₂) was recorded at T1, T2, T3, T4, T5, and T6. The duration of surgery, intraoperative blood loss, tracheal extubation time, and the number of patients that experienced cerebral desaturation events (CDEs) were recorded. The surgical field was estimated postoperation based on the Fromme score.

Results: A 30% decrease from the baseline MAP resulted in a decrease of intraoperative bleeding, improvement in the quality of the surgical field, and the shortening of the duration of surgery during FESS in the intervention group compared with the control group. In addition, rSO₂ was reduced and no CDEs were experienced in the intervention group. Linear regression analysis demonstrated a correlation between the decline in rSO₂ and that in MAP.

Conclusions: A decrease in MAP to a certain level will cause a decrease of rSO₂ in patients undergoing FESS under general anesthesia. Based on our findings, we recommend that the deliberate hypotensive target indicated by MAP be reduced by 30%, while PetCO₂ is maintained at 35–40 mmHg and HR is maintained at about 60 beats per minute during FESS.

Postoperative Neurocognitive Disorders in Cardiac Surgery: Investigating the Role of Intraoperative Hypotension. A Systematic Review

Perioperative neurocognitive disorders remain a challenging obstacle in patients after cardiac surgery, as they significantly contribute to postoperative morbidity and mortality. Identifying the modifiable risk factors and mechanisms for postoperative cognitive decline (POCD) and delirium (POD) would be an important step forward in preventing such adverse events and thus improving patients’ outcome. Intraoperative hypotension is frequently discussed as a potential risk factor for neurocognitive decline, due to its significant impact on blood flow and tissue perfusion, however the studies exploring its association with POCD and POD are very heterogeneous and present divergent results. This review demonstrates 13 studies found after structured systematic search strategy and discusses the possible relationship between intraoperative hypotension and postoperative neuropsychiatric dysfunction.

Neurological outcome after minimally invasive coronary artery bypass surgery (NOMICS): An observational prospective cohort study

Background/Objectives

Endoscopic coronary artery bypass grafting (Endo-CABG) is a minimally invasive CABG procedure with retrograde arterial perfusion. The main objective of this study is to assess neurocognitive outcome after Endo-CABG.

Methods/Design

In this prospective observational cohort study, patients were categorised into: Endo-CABG (n = 60), a comparative Percutaneous Coronary Intervention (PCI) group (n = 60) and a healthy volunteer group (n = 60). A clinical neurological examination was performed both pre- and postoperatively, delirium was assessed postoperatively. A battery of 6 neurocognitive tests, Quality of life (QoL) and the level of depressive feelings were measured at baseline and after 3 months. Patient Satisfaction after Endo-CABG was assessed at 3-month follow-up. Primary endpoints were incidence of postoperative cognitive dysfunction (POCD), stroke and delirium after Endo-CABG. Secondary endpoints were QOL, patient satisfaction and the incidence of depressive feelings after Endo-CABG.

Results

In total, 1 patient after Endo-CABG (1.72%) and 1 patient after PCI (1.67%) suffered from stroke during the 3-month follow-up. POCD in a patient is defined as a Reliable Change Index ≤-1.645 or Z-score ≤-1.645 in at least two tests, and was found in respectively 5 and 6 patients 3 months after Endo-CABG and PCI. Total incidence of POCD/stroke was not different (PCI: n= 7 [15.9%]; Endo-CABG: n= 6 [13.0%], p = 0.732). ICU delirium after Endo-CABG was found in 5 (8.6%) patients. QoL increased significantly three months after Endo-CABG and was comparable with QoL level after PCI and in the control group. Patient satisfaction after Endo-CABG and PCI was comparable. At follow-up, the level of depressive feelings was decreased in all groups.

Conclusions

The incidence of poor neurocognitive outcome, including stroke, POCD and postoperative ICU delirium until three months after Endo-CABG is low and comparable with PCI.

Trial registration

Registered on ClinicalTrials.gov (NCT02979782)

Severe low cerebral oximetry in difficult cardiopulmonary bypass weaning of low body-weight infant: a case report and literature review

Background

For infants undergoing complex cardiac surgery, hemodynamic management after cardiopulmonary bypass (CPB) is challenging because of severe myocardial edema, vasomotor dysfunction and weak tolerance to a change in blood volume. More importantly, the lack of availability of equipment for advanced monitoring, such as transesophageal echocardiography or transthoracic echocardiography, restricts the accurate assessment of hemodynamics.

Case presentation

This is a case of severe hypotension and non-detectable pulse oxygen saturation (SpO₂) after CPB in a low-weight infant who had normal blood pressure and oxygen saturation before surgery. Epinephrine and milrinone were administered with cerebral oximetry monitoring rather than blood pressure measurements because cerebral oximetry was more responsive to treatment than blood pressure. Under the guidance of cerebral oximetry, the infant was successfully weaned from CPB and recovered after surgery without adverse neurological events.

Conclusions

For infants who develop refractory hypotension and failure in SpO₂ monitoring during the CPB weaning period, cerebral oximetry provides an index for assessing brain perfusion and valuable guidance for appropriate inotropic treatment.