Heparin Rebound: An In-Depth Review.

The common conception of "heparin rebound" invokes heparin returning to circulation in the postoperative period after apparently adequate intraoperative reversal with protamine. This is believed to portend increased postoperative bleeding and provides the rationale for administering additional empiric doses of protamine in response to prolonged coagulation tests and/or bleeding. However, the relevant literature of the last 60+ years provides only a weak level of evidence that "rebounded" heparin itself is a significant etiology of postoperative bleeding after cardiac surgery with cardiopulmonary bypass. Notably, many of the most frequently cited heparin rebound investigators ultimately concluded that although exceedingly low levels of heparin activity could be detected by anti-Xa assay in some (but not all) patients postoperatively, there was no correlation with actual bleeding. An understanding of the literature requires a careful reading of the details because the investigators lacked standardized definitions for "heparin rebound" and "adequate reversal" while studying the phenomenon with significantly different experimental methodologies and laboratory tests. This review was undertaken to provide a modern understanding of the "heparin rebound" phenomenon to encourage an evidence-based approach to postoperative bleeding. Literature searches were conducted via PubMed using the following MeSH terms: heparin rebound, heparin reversal, protamine, platelet factor 4, and polybrene. Relevant English language articles were reviewed, with subsequent references obtained from the internal citations. Perspective is provided for both those who use HepCon-guided management and those who do not, as are practical recommendations for the modern era based on the published data and conclusions of the various investigators.

Accurate protamine:heparin matching (not just smaller protamine doses) decreases postoperative bleeding in cardiac surgery; results from a high-volume academic medical center.

BACKGROUND: A multidisciplinary Quality Assurance/Performance Improvement study to identify the incidence of "heparin rebound" in our adult cardiac surgical population instead detected a thromboelastometry pattern suggestive of initial protamine overdose in 34% despite Hepcon-guided anticoagulation management. Analysis of our practice led to an intervention that made an additional lower-range Hepcon cartridge available to the perfusionists. METHODS: One year later, an IRB-approved retrospective study was conducted in >500 patients to analyze the effects of the intervention, specifically focusing on the impact of the initial protamine dose accuracy and 18-h mediastinal chest tube drainage (MCTd). RESULTS: No differences were observed between group demographics, surgical procedures, duration of CPB or perioperative blood product transfusion. Both groups were managed using the same perfusion and anesthesia equipment, strategies, and protocols. The median initial protamine dose decreased by 19% (p < .001) in the intervention group (170 [IQR 140-220] mg; n = 295) versus the control group (210 [180-250] mg; n = 257). Mean 18-h MCTd decreased by 13% (p < .001) in the intervention group (405.15 ± 231.54 mL; n = 295) versus the control group (466.13 ± 286.73 mL; n = 257). Covariate-adjusted mixed effects model showed a significant reduction of MCTd in the intervention group, starting from hour 11 after surgery (group by time interaction p = .002). CONCLUSION: Though previous investigators have associated lower protamine doses with less MCTd, this study demonstrates that more accurately matching the initial protamine dose to the remaining circulating heparin concentration reduces postoperative bleeding.

EACTA/SCA Recommendations for the Cardiac Anesthesia Management of Patients With Suspected or Confirmed COVID-19 Infection: An Expert Consensus From the European Association of Cardiothoracic Anesthesiology and Society of Cardiovascular Anesthesiologists With Endorsement From the Chinese Society of Cardiothoracic and Vascular Anesthesiology.

The European Association of Cardiothoracic Anaesthesiology (EACTA) and the Society of Cardiovascular Anesthesiologists (SCA) aimed to create joint recommendations for the perioperative management of patients with suspected or proven severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection undergoing cardiac surgery or invasive cardiac procedures. To produce appropriate recommendations, the authors combined the evidence from the literature review, reevaluating the clinical experience of routine cardiac surgery in similar cases during the Middle East Respiratory Syndrome (MERS-CoV) outbreak and the current pandemic with suspected coronavirus disease 2019 (COVID-19) patients, and the expert opinions through broad discussions within the EACTA and SCA. The authors took into consideration the balance between established procedures and the feasibility during the present outbreak. The authors present an agreement between the European and US practices in managing patients during the COVID-19 pandemic. The recommendations take into consideration a broad spectrum of issues, with a focus on preoperative testing, safety concerns, overall approaches to general and specific aspects of preparation for anesthesia, airway management, transesophageal echocardiography, perioperative ventilation, coagulation, hemodynamic control, and postoperative care. As the COVID-19 pandemic is spreading, it will continue to present a challenge for the worldwide anesthesiology community. To allow these recommendations to be updated as long as possible, the authors provided weblinks to international public and academic sources providing timely updated data. This document should be the basis of future task forces to develop a more comprehensive consensus considering new evidence uncovered during the COVID-19 pandemic.

Anesthesia teams managing pacemakers and ICDs for the perioperative period: enhanced patient safety and improved workflows.

PURPOSE OF REVIEW: There have been both technological and philosophical advances over the last decade regarding pacemakers and implanted cardioverter defibrillators (ICDs). Collectively, these devices are currently referred to as cardiac implantable electronic devices (CIEDs). Technological advances include the introduction of leadless pacemakers, subcutaneous defibrillators and cardiac event recorders, enhancements regarding compatibility of CIEDs for MRI scanning, the ability to interrogate devices remotely, and improved programming modes that preserve battery life. Philosophical advances have been mainly in the area of perioperative management of CIED patients. RECENT FINDINGS: Current practice recommendations now acknowledge that not every patient requires a formal interrogation of their CIED before and after surgery (as was previously recommended). The response to magnet application is standardized across manufacturer's platforms, and it is known that sources of electromagnetic interference remote from the CIED and its leads do not usually cause any interference with device function. SUMMARY: Educated anesthesia teams can independently manage the vast majority of CIED patients perioperatively with magnet application alone. Furthermore, this portends enhanced patient safety and improved workflows in the perioperative period.

Novel approaches to spinal cord protection during thoracoabdominal aortic interventions.

PURPOSE OF REVIEW: Spinal cord ischemia after thoracoabdominal aortic interventions is a devastating complication because it significantly worsens the perioperative morbidity and mortality. Long-term outcome is also affected because of medical complications which are directly related to the neural deficits. Paraplegia has significant medical, social, and financial aspects. Limited mobility, the need for assistance in activities of daily living, makes paraplegia an important target for prevention. An understanding of spinal cord blood supply, risk factors for spinal ischemia, and strategies for spinal cord rescue in this setting can help minimize the negative outcome effects of this important complication. RECENT FINDINGS: The vascular supply of the spinal cord is via an extensive collateral arterial network with multiple auxiliary arterial supplies. Risk factors for spinal cord ischemia include extensive aortic repair, prior aortic repair, spinal cord malperfusion on clinical presentation, systemic hypotension, acute anemia, prolonged aortic clamping, and vascular steal. Spinal rescue strategies include systemic hypothermia, endovascular aortic repair, permissive systemic hypertension, cerebrospinal fluid drainage, pharmacologic neuroprotection, and intensive neuromonitoring. SUMMARY: The progression of spinal cord ischemia after thoracoabdominal aortic interventions can frequently be arrested before irreversible infarction results. This spinal cord rescue depends on the early detection and immediate multimodal intervention to maximize spinal cord oxygen supply. The devastating outcomes associated with spinal infarction in this setting offset the risks and knowledge gaps currently associated with contemporary interventions.

Current management of von Willebrand disease and von Willebrand syndrome.

PURPOSE OF REVIEW: Anesthesiologists frequently care for patients with altered hemostasis and coagulation. Where a clear history of familial and personal bleeding exists, a thoughtful plan can be developed in advance to manage the issue perioperatively. However, in some cases, it may not be known that the patient has a disorder until excessive bleeding is noted during or after surgery. Recognition of the issue and appropriate targeted therapy are the keys to successful management. RECENT FINDINGS: With an estimated prevalence approaching 1% of the population, von Willebrand disease (vWD) is the most common hereditary bleeding diathesis, but the estimated prevalence of acquired vWD (often termed von Willebrand syndrome or vWS) is now believed to be significantly higher, especially in patients with malignancies, autoimmune diseases, cardiac valvular lesions, and in patients on mechanical circulatory support devices. Acquired vWD may also occur with certain medications. SUMMARY: The mainstay of the diagnosis of vWD is laboratory testing. Preoperative clinical assessment and a high level of suspicion are often effective to alert the anesthesiologist to the possibility of vWS, thus allowing for appropriate testing and potential prophylaxis in elective situations, as well as appropriately targeted therapy of unexpected bleeding when a hemostatic derangement was not anticipated preoperatively.

Current perioperative management of the patient with a cardiac rhythm management device.

The safe and effective perioperative management of the patient with a cardiac rhythm management device (ie, pacemaker and/or implantable cardioverter defibrillator) is based entirely on the avoidance of adverse outcomes, including damage to the device, the leads, or the site of lead implantation that might prevent the device from functioning as intended. An important management principle is the potential reprogramming of such a device in the perioperative period to avoid transient interruption of device function or the delivery of inappropriate electrophysiological therapy (eg, unnecessary defibrillation or pacing). Given the large numbers of patients worldwide currently implanted with these devices, the anesthesia practitioner should become electively familiar with the current technology. This article describes the current status of cardiac rhythm management devices and discusses recommended perioperative management.

Cerebral air embolism recognized by cerebral oximetry.

Absolute cerebral oximetry is useful in clinical settings to identify "catastrophic events" that may occur during the course of surgeries that would otherwise have gone unrecognized. This study reports a case in which cerebral desaturation occurred after commencing cardiopulmonary bypass. Consequently, the source of air entrainment was discovered and therapeutic measures implemented.

Current status of mechanical circulatory assistance.

Mechanical circulatory support has become an increasingly used management strategy for patients with both acute and chronic ventricular failure. This article briefly reviews the current state of mechanical circulatory support with a focus on indications, contraindications, and complications of currently available devices. Perioperative considerations for ventricular assist device implantation are discussed, including the decision-making process underlying the use of univentricular versus biventricular support, specific anesthetic considerations, and the role of transesophageal echocardiography where ventricular assist devices are concerned. The anesthetic considerations for the patient already supported by a ventricular assist device presenting for noncardiac surgery are also reviewed. The work concludes with a discussion of the rationale behind the next generation of continuous flow devices currently in human clinical trials.

Intracardiac thrombosis and acute right ventricular failure following complex reoperative cardiac surgery with aprotinin and deep hypothermic circulatory arrest.

Although coagulopathy and bleeding are common in the setting of cardiac surgery, a growing number of case reports in the literature suggest that hypercoagulability may also result in significant morbidity and mortality. We present a case of apparent hypercoagulability with formation of thrombus in the cardiac chambers following reoperative cardiac surgery using cardiopulmonary bypass, aprotinin, and deep hypothermic arrest. A review of those hypercoagulable disorders with reported impact on cardiac surgery and a discussion follow the case presentation.

Anesthetic consideration for descending thoracic aortic aneurysm repair.

Anesthesia for surgery of the aorta poses some of the most difficult challenges for anesthesiologists. Major hemodynamic and physiologic stresses and sophisticated techniques of extracorporeal support are superimposed on patients with complex medical disease states. In this review, etiologies, natural history, and surgical techniques of thoracic aortic aneurysm are presented. Anesthetic considerations are discussed in detail, including the management of distal perfusion using partial cardiopulmonary bypass. Considerations of spinal cord protection, including management of proximal hypertension, cerebral spinal fluid drainage, and pharmacological therapies, are presented.

Repair of thoracic aneurysms, with special emphasis on the preoperative work-up.

The anesthetic approach to the patient with a thoracic aortic aneurysm depends on the urgency of repair. Symptomatic patients with leaking aneurysms require urgent intervention, and there is generally little time to perform more than the most basic preoperative assessment. For elective repair, however, one must consider nearly every organ system. Many of the specific issues are inherent to the underlying pathophysiology that has resulted in aneurysm formation, and some stem from the requirements of the surgical procedure itself. A thorough knowledge of the extent and location of the aneurysm, the functional status of the heart, and the coronary artery anatomy are critical. Most patients aged older than 40 years undergo coronary angiography preoperatively, as do younger patients with specific risk factors for myocardial ischemia. Respiratory failure is one of the most common sequelae of these procedures, and a thorough preoperative pulmonary work-up is mandatory. Neurologic deficits are not uncommon postoperatively, and pre-existing deficits in the central nervous system must be sought. Coagulopathy is common in the immediate postoperative period, and preoperative assurance of hemostatic competence is important. Computed tomography scans and magnetic resonance imaging are the mainstay of diagnosis, although the adjunctive use of echocardiography provides important information. Routine preoperative laboratory studies include complete blood count, chemistries, coagulation profile, and indices of renal function; an electrocardiogram, and chest radiograph. Close communication with the surgeon regarding the operative procedure, cannulation strategy (where applicable), and planned evoked potential monitoring is necessary to ensure appropriate perioperative management. Prophylactic antibiotics and antifibrinolytics are routine.

Perioperative management of von Willebrand disease: a review for the anesthesiologist.

von Willebrand disease (VWD) is the most common hereditary bleeding disorder in humans, with an estimated prevalence of 0.5% to 1%. Patients with VWD are at increased risk of perioperative bleeding complications. This review provides an evidence-based overview of VWD and its management during the perioperative period.

The anesthetic considerations in patients with ventricular assist devices presenting for noncardiac surgery: a review of eight cases.

IMPLICATIONS: The number of patients supported by ventricular assist devices (VADs) that present for noncardiac surgery is increasing in our institution. Our recent experience with eight such patients is reported, along with a review of the most commonly implanted VADs and the anesthetic implications and considerations for VAD-supported patients undergoing noncardiac surgery.