A Prospective Observational Study of Seizures After Cardiac Surgery Using Continuous EEG Monitoring

Effective management of nonconvulsive status epilepticus following cardiac surgery: a case report

BACKGROUND

Epileptic seizures following adult cardiovascular surgery occur in 0.9-3% of patients, with the condition in 3-12% of these patients progressing to status epilepticus (SE). SE is a severe condition that significantly impacts prognosis and necessitates early diagnosis and treatment. However, the diagnosis of nonconvulsive status epilepticus (NCSE) is challenging due to its subtle clinical symptoms. Herein, we report a case of NCSE that was diagnosed early by aggressive electroencephalogram (EEG) and treated effectively following cardiac surgery, resulting in discharge without sequelae.

CASE PRESENTATION

A 44-year-old man with a history of meningitis-induced intellectual disability since childhood underwent aortic valve replacement and grafting of the ascending aorta for a bicuspid aortic valve, severe aortic regurgitation, and ascending aortic dilatation. We observed repeated tonic-clonic seizures on the day of surgery and the following day when the sedation was reduced. On the first postoperative day, an EEG revealed sharp, high-amplitude waves during the tonic-clonic seizure and 2-Hz rhythmic delta activity after motor symptoms disappeared. Based on these findings, the patient was diagnosed with NCSE. Under EEG monitoring, we initially used propofol at 4 mg/kg/h, but owing to a decrease in blood pressure, we achieved deep sedation and burst suppression by combining propofol at 1.5 mg/kg/h with midazolam at 0.18 mg/kg/h. We also administered levetiracetam and fosphenytoin as antiseizure medications. Levetiracetam was administered at 1000 mg/day and fosphenytoin at 20.5 mg/kg, followed by maintenance at 7.2 mg/kg/day. The patient's consciousness improved upon cessation of sedation on postoperative day 6. Postoperative magnetic resonance imaging revealed no abnormalities. Fosphenytoin was discontinued, and the patient was discharged on postoperative day 32 without any sequelae. The patient continues to take levetiracetam orally at a dose of 1000 mg/day and has been followed up in the outpatient clinic for 4 years without any seizure recurrence.

CONCLUSION

Postoperative seizures following cardiac surgery may occur with NCSE, even after visible seizures have ceased. This case highlights the importance of thorough EEG monitoring in cases of prolonged disturbance of consciousness, indicating that early diagnosis and treatment of NCSE can improve the prognosis.

Review of Noninvasive Neuromonitoring Modalities in Children II: EEG, qEEG

Critically ill children with acute neurologic dysfunction are at risk for a variety of complications that can be detected by noninvasive bedside neuromonitoring. Continuous electroencephalography (cEEG) is the most widely available and utilized form of neuromonitoring in the pediatric intensive care unit. In this article, we review the role of cEEG and the emerging role of quantitative EEG (qEEG) in this patient population. cEEG has long been established as the gold standard for detecting seizures in critically ill children and assessing treatment response, and its role in background assessment and neuroprognostication after brain injury is also discussed. We explore the emerging utility of both cEEG and qEEG as biomarkers of degree of cerebral dysfunction after specific injuries and their ability to detect both neurologic deterioration and improvement.

Neurologic complications after cardiopulmonary bypass - A narrative review

Neurologic complications, associated with cardiac surgery and cardiopulmonary bypass (CPB) in adults, are common and can be devastating in some cases. This comprehensive review will not only consider the broad categories of stroke and neurocognitive dysfunction, but it also summarises other neurological complications associated with CPB, and it provides an update about risks, prevention and treatment. Where appropriate, we consider the impact of off-pump techniques upon our understanding of the contribution of CPB to adverse outcomes.

The Impact of Nonconvulsive Status Epilepticus after Cardiac Surgery on Outcome

Neurological complications after heart surgery are associated with tremendous morbidity and mortality. Nonconvulsive status epilepticus (NCSE), which can only be verified by EEG, may cause secondary brain damage. Its frequency and its impact on outcomes after cardiac surgery is still unclear. We collected the neurological files and clinical data of all our patients after heart surgery who, in the course of their ICU stay, had been seen by a neurologist who ordered an EEG. Within 18 months, 1457 patients had cardiac surgery on cardiopulmonary bypass. EEG was requested for 89 patients. Seizures were detected in 39 patients and NCSE was detected in 11 patients. Open heart surgery was performed in all 11 NSCE patients, of whom eight showed concomitant brain insults. None had a history of epilepsy. Despite the inhibition of seizure activity with antiseizure medication, clinical improvement was only noted in seven NCSE patients, three of whom were in cerebral performance category 2 and four in category 3 at hospital discharge. The four patients without neurological benefit subsequently died in the ICU. The occurrence of NCSE after open cardiac surgery is significant and frequently associated with brain injury. It seems prudent to perform EEG studies early to interrupt seizure activity and mitigate secondary cerebral injury.

Seizures and risks for recurrence in critically ill patients: an observational cohort study

Background

To assess the frequency and clinical characteristics of seizures in adult critically ill patients, to identify predictors of recurrent seizures not transforming into status epilepticus and to characterize their effects on course and outcome.

Methods

ICU patients at a Swiss academic medical center with seizures not transforming into status epilepticus from 2015 to 2020 were included. Recurrent seizures and associated clinical characteristics were primary, death, and return to premorbid neurologic function were secondary outcomes.

Results

Two hundred of 26,370 patients (0.8%) with a median age of 65 years had seizures during ICU stay. Seizure semiology was described in 82% (49% generalized; 33% focal) with impaired consciousness during seizures in 80% and motor symptoms in 62%. Recurrent seizures were reported in 71% (36% on EEG) and associated with longer mechanical ventilation (p = 0.031), higher consultation rate by neurologists (p < 0.001), and increased use of EEG (p < 0.001) when compared to single seizures. The use of EEG was not associated with secondary outcomes. Acidosis at seizure onset and prior emergency operations were associated with decreased odds for seizure recurrence (OR 0.43; 95% CI 0.20–0.94 and OR 0.48; 95% CI 0.24–0.97). Epilepsy had increased odds for seizure recurrence (OR 3.56; 95% CI 1.14–11.16).

Conclusions

Seizures in ICU patients are infrequent, but mostly recurrent, and associated with higher resource utilization. Whenever seizures are observed, clinicians should be vigilant about the increased risk of seizures recurrence and the need for antiseizure treatment must be carefully discussed. While known epilepsy seems to promote recurrent seizures, our results suggest that both acidosis and previous emergency surgery seem to have protective/antiseizure effects.

Trial registration

Clinicaltrials.gov (No. NCT03860467).

Cerebral monitoring in surgical ICU patients

PURPOSE OF REVIEW

To give an overview of cerebral monitoring techniques for surgical ICU patients.

RECENT FINDINGS

As the burden of postsurgical neurological and neurocognitive complications becomes increasingly recognized, cerebral monitoring in the surgical ICU might gain a relevant role in detecting and possibly preventing adverse outcomes. However, identifying neurological alterations in surgical ICU patients, who are often sedated and mechanically ventilated, can be challenging. Various noninvasive and invasive techniques are available for cerebral monitoring, providing an assessment of cortical electrical activity, cerebral oxygenation, blood flow autoregulation, intracranial pressure, and cerebral metabolism. These techniques can be used for the diagnosis of subclinical seizures, the assessment of sedation depth and delirium, the detection of an impaired cerebral blood flow, and the diagnosis of neurosurgical complications.

SUMMARY

Cerebral monitoring can be a valuable tool in the early detection of adverse outcomes in surgical ICU patients, but the evidence is limited, and clear clinical indications are still lacking.

Tranexamic acid after cardiopulmonary bypass does not increase risk of postoperative seizures: a retrospective study

OBJECTIVE

To evaluate the effects of administering tranexamic acid (TXA) after cardiopulmonary bypass, instead of after anesthesia induction, on postoperative seizures and blood transfusion requirements.

METHODS

Adult patients who underwent valve surgery and/or coronary artery bypass grafting at West China Hospital between July 1, 2011 and December 31, 2016 were retrospectively analyzed. Patients either received TXA after bypass (n = 2062) or not (n = 4236). Logistic regression and propensity score matching analysis were performed to assess effects of TXA on postoperative seizures and blood product requirements in hospital.

RESULTS

Among 6298 patients, seizures occurred in 2.4% (102/4236) in the no-TXA group and 2.7% (56/2062) in the TXA group (P = 0.46). The number of patients receiving any blood products was greater in the no-TXA group (57.3%, 2428/4236) than in the TXA group (53.1%, 1095/2062) (P < 0.01), and the volume of blood products was also greater in the no-TXA group (1.5 vs. 1.0 units, P < 0.01). TXA was not associated with increased incidence of postoperative seizures (adjusted OR 1.16, 95% CI 0.83-1.62) but was associated with lower incidence of a requirement for blood products (adjusted OR 0.82, 95% CI 0.73-0.92). Similar results were obtained after patients from the two groups were matched based on propensity scoring. TXA was associated with reduced requirements for fresh frozen plasma, platelets and cryoprecipitate, but not red blood cells.

CONCLUSIONS

Administering TXA after bypass may reduce requirements for blood products without increasing risk of seizures following cardiac surgery.

Tranexamic acid evidence and controversies: An illustrated review

Tranexamic acid (TXA) is an antifibrinolytic agent commonly used for the treatment or prevention of bleeding. Indications for TXA are diverse, including heavy menstrual bleeding, trauma, postpartum hemorrhage, traumatic brain injury, and surgical site bleeding. Despite decades of use and a robust body of evidence, hesitancy using TXA persists in many clinical settings. This illustrated review describes the history, pharmacology, and practical considerations of TXA use. We also describe the major landmark randomized controlled trials of TXA and their implications. Finally, we review the evidence around common controversies surrounding TXA such as the risk of thrombosis, prescription along with combined hormonal contraceptives, and use in patients with gross hematuria.

Epileptic seizure discharges in patients after open chamber cardiac surgery-a prospective prevalence pilot study using continuous electroencephalography

Purpose

Patients undergoing cardiac surgery often develop delirium which increases the risk of postoperative morbidity and leads to a reduced quality of life. Retrospective studies show a higher incidence of delirium in patients with seizures. However, these studies do not systematically detect subclinical seizures, so the incidence of seizures after cardiac surgery remains speculative. The objective of this study is to determine the prevalence of electrographic seizures after elective open-chamber cardiac surgery.

Methods

This prospective, blinded, monocentric, observational study investigated patients scheduled for elective open-chamber valve reconstruction or replacement. Anaesthesia, surgery and postoperative treatment were standardized and not influenced by the presented observation. After surgery, all patients arrived at the ICU, and EEG monitoring started within the first hour. EEG recording was continuously performed for up to 24 h, and the results were independently analysed by two blinded EEG board-certified neurologists.

Results

100 patients were included. Abnormal EEG patterns were present in 33% of patients, and 9% of all patients showed electrographic seizures. The main EEG activity at the beginning of each recording was suppressed or showed a burst-suppression pattern, and at the end of recording, all patients had an alpha/theta rhythm. An association between electrographic seizures and delirium was found (p_χ2 < 0.01).

Conclusion

This study reveals a surprisingly high incidence of abnormal EEG patterns and electrographic seizures in patients undergoing open-chamber cardiac surgery. As electrographic seizures are associated with the incidence of delirium, this finding is a relevant phenomenon in the post-cardiac surgery ICU population.

Outcome impact of different tranexamic acid regimens in cardiac surgery with cardiopulmonary bypass (OPTIMAL): Rationale, design, and study protocol of a multicenter randomized controlled trial

Tranexamic acid (TxA) reduces perioperative blood transfusion in cardiac surgery; however, the optimal dose of TxA remains unknown. METHODS AND RESULTS: This large-scale, double-blind, randomized controlled trial with a 1-year follow-up enrolls patients undergoing elective cardiac surgery with cardiopulmonary bypass. Patients are randomly assigned 1:1 into either the high-dose TxA group (intravenous bolus [30 mg/kg] after anesthesia followed by intravenous maintenance [16 mg/kg/h] throughout the operation, and a pump prime dose of 2 mg/kg) or the low-dose TxA group (intravenous bolus and maintenance are 10 mg/kg and 2 mg/kg/h, respectively, and a pump prime dose of 1 mg/kg). The primary efficacy end point is the rate of perioperative allogeneic red blood cell (RBC) transfusion defined as the number (%) of patients who will receive at least 1 RBC unit from operation day to discharge. The primary safety end point is the 30-day rate of the composite of perioperative seizures, renal dysfunction, myocardial infarction, ischemic stroke, deep vein thrombosis, pulmonary embolism, and all-cause mortality. The secondary end points are perioperative allogeneic RBC transfusion volume, the non-RBC blood transfusion rate, postoperative bleeding, reoperation rate, mechanical ventilation duration, intensive care unit stay, hospital length of stay, total hospitalization cost, each component of composite primary safety end point, and the 6-month/1-year follow-up mortality and morbidity. We estimated a sample size of 3,008 participants. CONCLUSIONS: The study is designed to identify a TxA dose with maximal efficacy and minimal complications. We hypothesize that the high dose has superior efficacy and noninferior safety to the low dose.

Antifibrinolytics and cardiac surgery: The past, the present, and the future

Cardiac surgery is usually associated with significant blood loss, which often necessitates blood transfusion. In order to decrease the risks associated with the latter, pharmacological as well as nonpharmacological strategies have been used to reduce blood loss. Among the pharmacological approaches, antifibrinolytic drugs are the mainstay. Aprotinin, which was the first ubiquitously used drug, fell into disrepute only to re-emerge after much debate. The decline of aprotinin paved the way for the lysine analogs. However, we must be aware with the side effects of these drugs as well as the dose modification required in special situations. Nonsaccharide glycosaminoglycans have been under investigation to overcome the drawbacks of the lysine analogs. It remains to be seen whether these drugs can replace the traditional antifibrinolytics.

Bleeding Management Practices of Australian Cardiac Surgeons, Anesthesiologists and Perfusionists: A Cross-Sectional National Survey Incorporating the Theoretical Domains Framework (TDF) and COM-B Model

Purpose

Excessive bleeding is an acknowledged consequence of cardiac surgery, occurring in up to 10% of adult patients. This clinically important complication leads to poorer patient outcomes. Clinical practice guidelines are available to support best practice however variability in bleeding management practice and related adverse outcomes still exist. This study had two objectives: 1) to gain insight into current bleeding management practice for adult cardiac surgery in Australia and how that compared to guidelines and literature; and 2) to understand perceived difficulties clinicians face implementing improvements in bleeding management.

Methods

A national cross-sectional questionnaire survey was utilized. Perspectives were sought from cardiac surgeons, cardiac anesthesiologists and perfusionists. Thirty-nine closed-ended questions focused on routine bleeding management practices to address pre and intra-operative care. One open-ended question was asked; “What would assist you to improve bleeding management with cardiac surgery patients?” Quantitative data were analysed with SPSS. Qualitative data were categorized into the domains of the Theoretical Domains Framework; the domains were then mapped to the COM-B model.

Results

Survey responses from 159 Anesthesiologists, 39 cardiac surgeons and 86 perfusionists were included (response rate 37%). Four of the recommendations queried in this survey were reported as routinely adhered to < 50% of the time, 9 queried recommendations were adhered to 51–75% of the time and 4 recommendations were routinely followed >76% of the time.

Conclusion

There is a wide variation in peri-operative bleeding management practice among cardiac anaesthesiologists, surgeons and perfusionists in Australian cardiac surgery units. Conceptualizing factors believed necessary to improve practice with the TDF and COM-B model found that bleeding management could be improved with a standardized approach including; point of care diagnostic assays, a bleeding management algorithm, access to concentrated coagulation factors, cardiac surgery specific bleeding management education, multidisciplinary team agreement and support, and an overarching national approach.

Efficacy and tolerance of early administration of tranexamic acid in patients with cirrhosis presenting with acute upper gastrointestinal bleeding: a study protocol for a multicentre, randomised, double-blind, placebo-controlled trial (the EXARHOSE study)

INTRODUCTION

The management of acute upper gastrointestinal bleeding (UGIB) is challenging in patients with cirrhosis, as it is responsible for severe complications and high mortality rates. Tranexamic acid (TXA) may help control the bleeding by counterbalancing cirrhosis-related hyperfibrinolysis. Still, there is a lack of unbiased data to conclude on its efficacy. The aim of this study is to evaluate the efficacy of TXA in the early treatment of acute UGIB in patients with cirrhosis.

METHODS AND ANALYSIS

This study is a multicentre, randomised, double-blind, placebo-controlled trial, for adult patients with cirrhosis presenting with an acute UGIB and allocated to one of two arms: TXA or placebo (saline). Physicians from emergency mobile services, emergency departments (EDs) or intensive care units (ICUs) can include patients. Besides study intervention, standard care for UGIB will be performed as recommended. Intervention will consist an intravenous infusion of 10 mL of TXA (1 g) or saline, immediately followed by three identical intravenous infusions over 8 hours each (total dose of 4 g of TXA or 40 mL of placebo over 24 hours). Main analyses will be conducted in intention to treat on every patient included, then in modified intention to treat on patients with underlying lesion of portal hypertension visualised by endoscopy. The main objective is to show efficacy of TXA until day 5 on a composite criterion (bleeding control, rebleeding episodes and mortality). Secondary objectives aim at showing the efficacy of TXA on each individual component of the main outcome measure and others at 6 weeks and later (transjugular intrahepatic portosystemic shunt procedure, cirrhosis-specific complications, length of stay in ICU and in hospital, safety and tolerance of TXA, liver transplantation). Included patients will be followed up to 1 year after inclusion.500 patients will be necessary to show a reduction in the prevalence of the primary outcome from 30% to 18% with a bilateral alpha risk of 5% and a power of 80%.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Comité de Protection des Personnes Ile-de-France 1 (CPP-IDF1). Results will be disseminated via publications in peer-review medical journals and scientific forums.

PROTOCOL VERSION

This protocol is based on the latest version, as established on 11 October 2017 and validated by the IRB CPP Ile-de-France 1.

TRIAL REGISTRATION NUMBER

NCT03023189.

The role of EEG recordings in children undergoing cardiac surgery for congenital heart disease

BACKGROUND

Neurological dysfunction may occur after corrective cardiac surgery using cardio-pulmonary bypass (CPB) with or without circulatory arrest. Different neurophysiological monitoring systems have been employed to detect neurological complications and possible brain injury in infants and children during and after cardiac surgery. The value of Elecetroencephalogram (EEG) in infants and children at risk for neurological sequelae has not been systematically studied.

METHODS

Sequential performance of two EEGs before and after cardiac surgery at a tertiary University Hospital to screen for possible brain injury after cardiac surgery in neonates and children undergoing CPB surgery. In addition, a complete neurological examination and assessment by a physiotherapist was performed.

RESULTS

Over a 4-year period, in 313 patients (age: 54.2 ± 55.7 months; normal initial EEG) after cardiac surgery CPB (duration of surgery: 146.0 ± 58.9 min; aortic cross clamp time: 34.1 ± 19.1 min), a 19-channel EEG recording was performed 2.4 ± 1.8 days prior to and 11.6 ± 5.3 days after cardiac surgery. An abnormal EEG was detected in only 8 of 313 patients (2.5%; focal slowing: 1, generalised slowing: 5, epiletiform discharges: 2) after cardiac surgery, while the EEG was normal in the remaining 305 patients (97.5%). In 1 patient, an intra-cerebral pathology was seen on MRI (ischemic); in 5 patients, follow-up EEGs were performed, which revealed normalized findings. None of the 8 patients demonstrated new focal neurological deficits on physical examination, but 33 (9.7%) children demonstrated minor abnormalities (e.g., subtle motor asymmetry, increase in muscle tone, etc.), which were unrelated to abnormal EEG findings.

CONCLUSIONS

According to the used protocol, pathological EEG findings were very infrequent in our study cohort. The routine and indiscriminative recording of EEGs in children before and after corrective or palliative cardiac surgery for congenital heart disease using CPB is not recommended. Further intra-operative neuromonitoring methods with immediate intervention should be evaluated.

Continuous electroencephalography in a mixed non-neurological intensive care population, an observational study

PURPOSE

Continuous electroencephalography (cEEG) improves monitoring of the brain in unconscious patients, but implementation at ICU is difficult. The present investigation shows a way to introduce cEEG at an anesthesiological ICU and discusses the first experiences.

MATERIALS AND METHODS

The study analyzed the feasibility of cEEG, assessed the interpretable cEEG time, importance of automatic seizure detection, the incidence of seizures, the predominant background EEG activity, incidence of delirium and mortality.

RESULTS

Fifty-three cEEGs of 50 patients with a median interpretable length of 24 hours [IQR 20 to 42 hours] were recorded. One patient had status epilepticus, while 5 patients had non-convulsive seizures. Automated seizure detection recognized the status epilepticus and 3 of 10 non-convulsive seizures, however, detected 42 false positive seizures. Predominant background EEG activity was alpha (9%), theta (17%), delta (26%), burst-suppression (17%), and suppressed background activity (30%). EEG activity correlated neither with dosage of analgo-sedative drugs nor with incidence of delirium or mortality.

CONCLUSION

Continuous electroencephalography recording is feasible and manageable. Automatic seizure detection was often false negative/positive; therefore, the interpretation of the cEEG should be supported by EEG-trained neurologists. Background EEG activity was not associated with outcome parameters, which suggests that background activity is a poor outcome predictor.

Tranexamic acid-associated seizures: Causes and treatment

Antifibrinolytic drugs are routinely used worldwide to reduce the bleeding that results from a wide range of hemorrhagic conditions. The most commonly used antifibrinolytic drug, tranexamic acid, is associated with an increased incidence of postoperative seizures. The reported increase in the frequency of seizures is alarming, as these events are associated with adverse neurological outcomes, longer hospital stays, and increased in‐hospital mortality. However, many clinicians are unaware that tranexamic acid causes seizures. The goal of this review is to summarize the incidence, risk factors, and clinical features of these seizures. This review also highlights several clinical and preclinical studies that offer mechanistic insights into the potential causes of and treatments for tranexamic acid–associated seizures. This review will aid the medical community by increasing awareness about tranexamic acid–associated seizures and by translating scientific findings into therapeutic interventions for patients. ANN NEUROL 2016;79:18–26

Antifibrinolytic Therapy for Cardiac Surgery

Antifibrinolytic therapy reduces bleeding and chest tube drainage output in cardiac surgical patients but is associated with potential side effects. Two phase-II studies with new compounds were terminated prematurely. There is increasing evidence of adverse side effects with tranexamic acid.