The Obstetric Patient for Cardiac Surgery

Cardiac disease is the second leading cause of morbidity and mortality in pregnancy behind peripartum hemorrhage. In developed countries, a majority of cardiac disease in pregnancy is secondary to congenital heart defects, whereas in developing countries, mitral stenosis secondary to rheumatic fever prevails as the leading cause of cardiac disease during pregnancy. There is added workload on the heart during pregnancy due to the increased blood volume and cardiac output of the parturient. In patients with preexisting cardiac disease, this added workload may lead to decompensated congestive heart failure. Alternatively, such physiologic changes may unmask an unknown cardiac lesion in an unsuspecting patient. Medical management is always the first-line treatment of the pregnant patient with decompensated heart failure. However, if medical management has failed, cardiac surgery with cardiopulmonary bypass may be necessary. Due to the unique maternal physiology and the presence of not only one but also two patients, anesthesia, cardiac surgery, and cardiopulmonary bypass come with specific challenges, hemodynamic goals, and ethical dilemmas.

Anesthesia for Lung Transplantation

Since the first human procedure in 1963, lung transplantation has become the gold standard treatment of a variety of end-stage lung diseases. With over 4000 lung transplants performed in 2015 and steadily improving survival rates over the past three decades, anesthetic management of patients undergoing lung transplant can significantly contribute to patient outcomes. Anesthesia care for lung transplantation can be both complex and clinically challenging. Anesthesiologists taking part in these procedures need to have specific skills regarding thoracic and cardiac anesthesia. There are both technical and physiological challenges, such as achieving adequate lung isolation and oxygenation, interpretation and use of transesophageal echocardiography, and the management of respiratory and myocardial impairments. This chapter provides an overview of these perioperative anesthetic management considerations utilizing a problem-based format.

Mediastinal Mass Excision

Mediastinal masses are rare tumors of the thoracic cavity. Although not all types require surgical intervention, resection of these masses provides a clinical challenge for the anesthesiologist due to both local mass effects, such as airway and vascular compression, and systemic effects, including paraneoplastic syndromes. A common example includes myasthenia gravis associated with thymoma. Preoperative assessment includes viewing imaging, obtaining a thorough history, performing a focused physical examination, and reviewing laboratory values. Medically optimizing comorbid conditions prior to excision, if possible, may reduce perioperative morbidity and mortality. Intraoperative considerations include planning for postoperative analgesia, establishing an airway, selection of invasive and noninvasive monitors, choosing intravenous access sites commensurate with tumor size and location, judicious fluid administration, and ventilator management. Postoperative considerations include intensive care unit transport, analgesia, and airway maintenance.

Percutaneous Mitral Valve Procedures

As the population ages, more patients are presenting with symptomatic mitral valve disease that requires risk-prohibitive cardiac surgery. In the last decade, advances in valve technology have generated valves that can be inserted via a minimally invasive percutaneous approach. Nonetheless, patients must fulfill specific criteria in order to be considered for a percutaneous mitral intervention. From an anesthesiologist’s perspective, these cases are unique as they require both a detailed understanding of complex patient physiology and the need to be planned as fast-track procedures. Echocardiography is the cornerstone to success for these procedures, and typically a separate team of echocardiographers may be involved in the conduct of the case. This review discusses patient selection, complications of the procedure, and perioperative considerations for this technique.

Air Embolism on Cardiopulmonary Bypass

The danger associated with air embolism in cardiac surgery has been well established for over 125 years. In the first volume of Annals of Surgery, published in 1885, long preceding the era of cardiac surgery and the use of extracorporeal circulatory techniques, Dr. Nicholas Senn alluded to the ensuing calamity caused by air embolism: “I intend on this occasion to call your attention to one of the most dreaded and, I may add, one of the most uncontrollable causes of sudden death—I allude to air-embolism.”1,2 Since the advent of modern cardiac surgery, much attention has been focused on the prevention of air embolism by cardiac surgeons, anesthesiologists, and perfusionists alike. Indeed, all three team members are critically responsible for the safe conduct of thousands of cardiac surgical procedures occurring on a daily basis worldwide. While the morbidity and mortality of massive air embolism is exceedingly high, most believe that with appropriate training and unwavering vigilance during clinical practice, almost all massive air emboli can be prevented.3

Preoperative Evaluation of the Cardiac Surgical Patient

Patients undergoing cardiac surgery are at elevated risk for perioperative complications; however, certain risk factors may be modifiable. Preoperative evaluation performed in advance of surgery provides an opportunity for the perioperative anesthesiologist to intervene to reduce risk. Performing a focused history and physical examination informs the selection of appropriate preoperative tests. Risk assessment via tools specific to cardiac surgery provide a detailed risk profile. Certain diseases common to cardiac surgical patients deserve particular focus during assessment. Poorly controlled diabetes mellitus and resultant hyperglycemia are modifiable risk factors. Undiagnosed obstructive sleep apnea is common and associated with postoperative complications. Concurrent carotid artery disease presents a management conundrum requiring multidisciplinary planning. Preoperative anemia is common; when due to iron deficiency, it is easily treated to improve outcomes. In addition to gathering information about the patient, the goal of preoperative evaluation is to identify ways to reduce risk and improve outcome from surgery in a resource-efficient manner.

Aortic Arch Repair (Circulatory Arrest)

Aortic arch repair is a technically challenging surgery that requires collaboration between the anesthesiology, cardiac surgery, and perfusion teams. To accomplish a total aortic arch repair, blood flow to the brain and the rest of the body has to be interrupted. The most common aortic arch pathologies encountered for surgery are aortic arch aneurysms followed by aortic dissections. The need for hypothermia and circulatory arrest during aortic arch surgeries leads to unique implications for anesthetic management. Therefore, adequate knowledge of the planned surgery and specific surgical and nonsurgical cerebral protection techniques are necessary. Furthermore, an understanding of intraoperative neurophysiologic and temperature monitoring at deep hypothermia as well as postbypass coagulopathy management are needed in these challenging cases.

Aortic Stenosis in Noncardiac Surgery

Aortic stenosis is the most common valvular lesion in patients older than 65 years, occurring in 2%–9% of patients. It is estimated that the number of patients with aortic stenosis who will need surgery will increase dramatically as the world’s population ages. Treatment of aortic stenosis includes surgical aortic valve replacement, transcatheter aortic valve replacement, balloon valvuloplasty, or medical management. Aortic stenosis is associated with significant perioperative risk in noncardiac surgery. Hemodynamic changes from anesthesia medications and the surgical procedure can result in decreased coronary perfusion, myocardial ischemia, arrhythmias, heart failure, or even death. General or regional anesthesia can be administered safely to asymptomatic patients with significant aortic stenosis if hemodynamics are maintained in the perioperative period.

Fast-Track Recovery

Fast-track cardiac care (FTCC) encompasses the entire spectrum of perioperative care for the cardiothoracic surgical patient. From the preoperative assessment to postoperative care, the main goal is to expedite recovery while minimizing the inherent risks associated with cardiac surgery. The practice of prolonged mechanical ventilation due to high-dose narcotic anesthesia has evolved to early protocolized extubation pathways facilitated by multimodal anesthesia. The goal of the postoperative care phase is focused on reducing or completely bypassing the intensive care unit and ultimately decreasing hospital length of stay. Yet, here is where FTCC seems unable to achieve its goals due to multifactorial barriers. An integral part of successful FTCC is constant reevaluation of the patient through each of the perioperative phases (pre-, intra-, and postoperatively).

Transfusion Dilemma/Coagulation TEG

The healthcare team is presented with a unique challenge when providing bloodless surgery to patients of the Jehovah’s Witness faith who refuse allogenic transfusions based on religious beliefs. The Jehovah’s Witness faith interprets New and Old Testament passages of the Bible, including Genesis 9:4, as God commanding against “eating blood,” thus preventing believers from receiving transfusions of blood products. When it comes to complex cardiac surgery, where blood loss and coagulopathy are common, the physician and patient must establish a plan for blood conservation and optimization of hemoglobin preoperatively. Knowledge of management options during the preoperative period as well as treatment options for blood loss is imperative to honor patient autonomy and avoid ethical dilemmas.