Seema P. Deshpande

Perioperative Management of Adult Surgical Patients on Extracorporeal Membrane Oxygenation Support

XTRACORPOREAL MECHANICAL support devices are used as an adjunct in the management of critically ill patients who are refractory to more conventional modes of therapy. Extracorporeal membrane oxygenation (ECMO) is one such device that has been used mainly in the management of patients in cardiogenic shock or respiratory failure who failed therapy on maximal ventilator settings and maximal pharmacologic support. ECMO has the advantage of being rapidly deployable, both at the bedside and in the operating room, and can be initiated without the need for general anesthesia. ECMO has been used as a bridging device to recovery or to more definitive therapy. In patients who are awaiting lung transplantation, ECMO has been used as a bridge to transplant when decompensation occurs and also as an adjunct in physical rehabilitation before transplant. The science and instrumentation of ECMO are direct outgrowths of the development of cardiopulmonary bypass (CPB) technology that reached its full potential in support of cardiac surgery in the latter half of the 20th century. This is a fascinating history in itself and has been reviewed thoughtfully at key points by physician-scientists directly involved in the process. 1-3 Over the last decade, the design and reliability of components of the ECMO circuit have improved markedly from earlier iterations, and clinical teams have gained experience with a multidisciplinary approach to the management of patients on ECMO. These advancements have led to more prolonged and widespread use of ECMO as an alternative for support in patients with otherwise nonsurvivable respiratory or cardiopulmonary failure. Outcomes also have improved from what is reported in the older medical literature. With the increase in the use of ECMO, anesthesiologists have become more involved in the perioperative management of these critically ill patients, and an understanding of the physiologic changes that occur in patients on ECMO is essential for perioperative management. In addition, a number of issues remain controversial, mainly regarding risk/benefit differentials in pediatric versus older age groups, end-stage versus acute disease, and the timing and duration of therapy. This review addresses the practical clinical problems during the perioperative management of adult patients on ECMO. TYPES OF ECMO Three major configurations of ECMO are available. Venovenous (VV) ECMO is used in the management of patients with refractory pulmonary failure and stable cardiovascular status. Venoarterial (VA) ECMO is used in patients with refractory cardiogenic shock or cardiorespiratory failure. The third configuration, arteriovenous (AV) ECMO, also known as the “artificial lung,” can be used in patients with acute lung injury presenting with stable cardiovascular status. In this review, the term “inflow cannula” refers to the cannula that carries blood from the patient into the ECMO system, and “outflow cannula” refers to the cannula that carries oxygenated blood from the ECMO system back to the patient. In VV ECMO, the inflow and outflow ECMO cannulae run in and out of the venous system in the patient. In VA ECMO, the inflow cannula is from the patient’s venous system, but the outflow cannula runs into the arterial system. Conversely, in AV ECMO, the inflow cannula is from the patient’s arterial system with the outflow cannula from the oxygenator running into the patient’s venous system. AV ECMO differs from VA and VV ECMO in that the AV ECMO circuit does not incorporate a pump to maintain blood flow in the circuit. Blood flow in this type of circuit is a function of systemic blood pressure, cardiovascular stability, the resistance of the membrane oxygenator, the size and length of the conducting circuit, and blood viscosity. Adequate blood pressure and cardiovascular stability are required to maintain blood flow in this form of circuit. Commonly used inflow cannulation sites during VV and VA ECMO are the femoral vein, the inferior vena cava, the superior vena cava, and the right atrium. Outflow during VV ECMO may be into any of these sites. In patients on VA ECMO, inflow usually is into the femoral artery, axillary artery, ascending aorta, or the pulmonary artery. Inflow during AV ECMO may

Anesthetic Management of Robotically Assisted Totally Endoscopic Coronary Artery Bypass Surgery (TECAB)

Over the last decade, TECAB has matured into a reproducible technique associated with low incidence of both mortality and morbidity, as well as superior quality of life, when compared with open CABG surgery. However, TECAB also is associated with important and specific challenges for the anesthesiology team, particularly with regard to the physiologic stresses of OLV, placement of special catheters, and induced capnothorax. As the technology supporting robotic surgery evolves and familiarity with, and confidence in, TECAB increases, the authors anticipate increasingly widespread use of these procedures in an increasingly fragile and problematic patient population who will require the support of a skilled and vigilant anesthesiology team.

Preoperative Evaluation for Thoracic Surgery

The goal of the preoperative evaluation for thoracic surgery is to assess and implement measures to decrease perioperative complications and prepare high-risk patients for surgery. Major respiratory complications, such as atelectasis, pneumonia, and respiratory failure, occur in 15% to 20% of patients and account for most of the 3% to 4% mortality rate. Development of pulmonary complications has been associated with higher postoperative mortality rates. Strategies aimed at preventing postoperative difficulties have the potential to reduce morbidity and mortality, decrease hospital stay, and improve resource use. One lung ventilation leads to a significant derangement of gas exchange, and hypoxemia can develop due to increased intrapulmonary shunting. Recent advances in anesthetic management, monitoring devices, improved lung isolation techniques, and improved critical care management have increased the number of patients who were previously considered inoperable. In addition, there is a growing tendency to offer surgery to patients with significant lung function impairment; hence a higher incidence of intraoperative gas-exchange abnormalities can be expected. The anesthesiologist must also consider the risks of denying or postponing a potentially curative operation in patients with lung cancer. Detailed consideration of the information provided by preoperative testing is essential to successful outcomes following thoracic surgery.

Use of Partial Venovenous Cardiopulmonary Bypass in Percutaneous Hepatic Perfusion for Patients with Diffuse, Isolated Liver Metastases: A Case Series

OBJECTIVES Diffuse isolated liver metastases are the dominant mode of tumor progression in a number of cancers and present a major treatment challenge for oncologists. An experimental treatment, percutaneous hepatic perfusion (PHP), utilizes partial venovenous cardiopulmonary bypass to allow administration of high-dose chemotherapy directly and solely to the liver with filtration of chemotherapeutic agents from the blood prior to its return to the systemic circulation, thereby minimizing toxic systemic effects. The following case series describes the management of 5 patients with metastatic melanoma undergoing serial PHPs. DESIGN A single-center experience from a national multi-center random-assignment trial comparing PHP to best alternative care (BAC) in patients with diffuse melanoma liver metastases. SETTING A tertiary care hospital. PARTICIPANTS Five patients with metastatic melanoma to the liver. INTERVENTION Five patients underwent a total of fifteen PHPs using a venovenous bypass circuit with hemofiltration, receiving hepatic intra-arterial melphalan, 3 mg/kg of ideal body weight, for 30 minutes with a total of 60 minutes of hemofiltration. MEASUREMENTS AND MAIN RESULTS Five patients tolerated the procedure well with transient hemodynamic and metabolic changes. CONCLUSIONS In patients with diffuse isolated liver metastases, PHP is a safe and well-tolerated procedure that can be performed more than once and is associated with marked anti-tumor activity in some patients.

Intra-abdominal Hypertension and Postoperative Kidney Dysfunction in Cardiac Surgery Patients

OBJECTIVE To determine the incidence of intra-abdominal hypertension (IAH) in adult cardiac surgery patients and its association with postoperative kidney dysfunction. DESIGN Prospective cohort study. SETTING Single tertiary-care university hospital. PARTICIPANTS Forty-two adult patients having cardiac surgery with cardiopulmonary bypass. INTERVENTIONS Intra-abdominal pressure (IAP) was measured preoperatively, immediately after surgery, and at the following time points after surgery: 3 hours, 6 hours, 12 hours, and 24 hours. Urine neutrophil gelatinase-associated lipocalin (NGAL) levels were measured as a marker of kidney dysfunction at the following time points: prior to surgery, immediately after surgery, 4 to 6 hours after surgery, and 16-to-18 hours after surgery. MEASUREMENTS AND MAIN RESULTS Two hundred fifty-two IAPs were measured, and 90 (35.7%) showed IAH. Thirty-five of 42 patients (83.3%) had IAH at 1 time point or more. Peak urine NGAL levels were lower in patients with normal IAP (mean difference = -130.6 ng/mL [95% CI = -211.2 to -50.1], p = 0.002). There was no difference in postoperative kidney dysfunction by risk, injury, failure, loss of kidney function, and end-stage kidney disease (RIFLE) criteria in patients with normal IAP (mean difference = -31.4% [95% CI = -48.0 to 6.3], p = 0.09). IAH was 100% sensitive for predicting postoperative kidney dysfunction by RIFLE criteria, but had poor specificity (54.8%). CONCLUSIONS IAH occurs frequently during the perioperative period in cardiac surgery patients and may be associated with postoperative kidney dysfunction.

Poor Left Ventricular Function Is Not a Contraindication for Robotic Totally Endoscopic Coronary Artery Bypass Grafting

Robotic technology has enabled performance of totally endoscopic coronary artery bypass grafting (TECABG). Published series on TECABG were primarily performed in low-risk patients, and little is known about the outcome after totally endoscopic coronary surgery in patients with severely impaired left ventricular function. We report successful endoscopic placement of a left internal mammary artery bypass graft to the left anterior descending artery using the daVinci robotic system in a patient with a severely reduced left ventricular ejection fraction.

Prostacyclins in Cardiac Surgery: Coming of Age

Prostacyclin (prostaglandin I2 [PGI2]) is an eicosanoid lipid mediator produced by the endothelial cells. It plays pivotal roles in vascular homeostasis by virtue of its potent vasodilatory and antithrombotic effects. Stable pharmacological analogues of PGI2 are used for treatment of pulmonary hypertension and right ventricular failure. PGI2 dose dependently inhibits platelet activation induced by adenosine-5′-diphosphate, arachidonic acid, collagen, and low-dose thrombin. This property has led to its use as an alternative to direct thrombin inhibitors in patients with type II heparin-induced thrombocytopenia (HIT) undergoing cardiac surgery. The aims of this review are the following: (1) to review the pharmacology of PGI2 and its derivatives, (2) to present the evidence for their use in pulmonary hypertension and right heart failure, and (3) to discuss their utility in the management of HIT in cardiac surgery.

Pro: Robotic Surgery Is the Preferred Technique for Coronary Artery Bypass Graft (CABG) Surgery

OBOTICALLY ASSISTED totally endoscopic coronary artery bypass (TECAB) surgery represents the most advanced procedural development in the field of minimally invasive coronary artery surgery. TECAB surgery is an innovative surgical procedure that utilizes robotic technology to perform the entire coronary revascularization endoscopically in the closed chest. Robotic coronary artery surgery encompasses utilization of robotic assistance in varying degrees from robotically-assisted minimally invasive direct coronary artery bypass (MIDCAB) procedures to TECAB. MIDCAB procedures involve harvesting of the internal mammary artery (IMA) robotically with the coronary anastomoses being performed through a small minithoracotomy under direct visualization. In TECAB procedures, IMA harvesting as well as the coronary anastomoses are performed in a closed chest with robotic assistance through small ports, making this procedure truly minimally invasive.

Totally Endoscopic Coronary Artery Bypass Grafting is Feasible in Morbidly Obese Patients

Development of robotic technology has enabled totally endoscopic coronary artery bypass grafting (TECAB) procedures. With complete preservation of sternal and thoracic stability, this operation would be an interesting option for obese patients, who are known to be at higher risk for deep sternal wound infection. We describe a case of successful totally endoscopic left internal mammary artery to left anterior descending artery bypass grafting using the da Vinci telemanipulation system in a patient who was morbidly obese. The patient underwent a so called staged hybrid coronary intervention with percutaneous angioplasty and placement of a stent to the right coronary artery.

Totally endoscopic robotic coronary artery bypass surgery.

Purpose of review To assess the current status and methods of robotic totally endoscopic coronary artery bypass (TECAB) surgery and discuss important anesthetic considerations. Recent findings Technological and surgical advances in robotics have led to the evolution of TECAB surgery from a single-vessel procedure to quadruple-vessel bypass. TECAB is now a reproducible technique, with a low incidence of mortality and morbidity and superior quality of life. Although early cohorts of patients are still being observed for long-term outcomes, initial and midterm outcomes are comparable to those of conventional coronary artery bypass. TECAB is also associated with specific challenges for the anesthesiologist. Summary TECAB surgery is a feasible alternative to open coronary artery bypass surgery in selected patient populations. Appropriate patient selection, team training, and stepwise application of the procedure are crucial. TECAB is associated with a unique set of challenges, requiring a skilled operative team. As robotic technology and surgical expertise evolve, this technology will find wider application in an increasing high-risk patient population that will require the support of a skilled anesthesiology team.