Marc E. Stone

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.

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.

Perioperative Management of a Patient With a Nonpulsatile Left Ventricular-Assist Device Presenting for Noncardiac Surgery

A 55-year-old man supported by a VentrAssist LVAD (Ventracor Limited, Chatswood, Australia) presented for debridement and myocutaneous flap closure of a stage IV sacral decubitus ulcer in the prone position. The device had been implanted as a bridge to transplantation approximately 2 months previously, and the patient was hemodynamically stable. Additional procedures at the time of VAD implantation had included mitral valve replacement, aortic valve replacement, and coronary artery bypass graft surgery to the right coronary distribution. The postoperative course had been complicated by renal failure, anemia, and prolonged respiratory failure for which he had previously undergone tracheostomy, and he was chronically in atrial fibrillation. Medications included heparin infusion, hydromorphone, levetiracetam, cefazolin, levocarnine, quetiapine, darbopoeitin, and insulin. Physical examination revealed a cachectic male weighing 55 kg and measuring 165 cm tall. The driveline of the LVAD exited the abdomen at the left upper quadrant. There was an indwelling right femoral arterial pressure cannula and a 7.5F triple-lumen catheter in the right internal jugular vein. An 8.0 cuffed Shiley tracheostomy tube was present. The patient was transported to the operating room by the anesthesia team and a dedicated VAD nurse. Hemodynamic monitoring was used in transport, and the device was powered by battery packs. Upon arrival to the operating room, the VAD was returned to main AC power. Intraoperative monitoring included an electrocardiogram, pulse oximetry (SpO2), invasive arterial pressure, central venous pressure, transesophageal echocardiography (TEE), and cerebral oximetry (SctO2). In addition to the anesthesia team assigned to the case, a cardiac anesthesiologist and the VAD nurse were present intraoperatively. In addition to infusions of epinephrine and vasopressin, nitric oxide was available in the room, although the tank was not opened as a cost-containment effort. Vital signs on operating room arrival were heart rate of 70 beats/min, mean arterial pressure of 60 to 70 mmHg, central venous pressure of 14 mmHg, SpO2 of 100%, and left SctO2 of 70% and right of 60%. A thorough denitrogenation was accomplished through the tracheostomy, and induction of general anesthesia proceeded smoothly with midazolam (2 mg), fentanyl (250 g), etomidate (8 mg), and vecuronium (10 mg). Anesthesia was maintained with isoflurane in oxygen and additional boluses of vecuronium. After anesthetic induction in the supine position, TEE examination by a cardiac anesthesiologist revealed a dilated and severely hypokinetic left ventricle (LV), a well-functioning right ventricle (RV), absence of tricuspid regurgitation, a well-functioning mitral bioprosthesis, and an intact bioprosthetic aortic valve that was not opening. The inflow cannula to the LVAD could not be visualized in the left ventricular apex (likely because it is quite short with this particular device), but color-flow mapping revealed no apparent turbulence suggesting obstruction to inflow. Outflow from the device in the ascending aorta was visualized, but the outflow cannula itself could not be. Once the baseline TEE examination was completed, the patient was then turned from the supine to the prone position, with careful placement of abdominal and chest bolsters. The patient initially tolerated this position without significant change in arterial or airway pressures. By comparison to the baseline examination in the supine position, the TEE examination in the prone position revealed relatively decreased right ventricular function (Videos 1 and 2 [supplementary videos are available online]). Unfortunately, within just a few minutes (and before skin incision), the airway pressures suddenly increased, SctO2 decreased bilaterally, there was an abrupt loss of the capnogram tracing, and LVAD output rapidly decreased from 6.1 L/min to 3.8 L/min. The patient was immediately returned to the supine position. Attempted manual ventilation revealed significantly decreased lung compliance. Suctioning of the tracheostomy evacuated bloody secretions along with a large clot. Once the bloody plug had been removed, ventilatory parameters, LVAD flows, and SctO2 returned to their previously stable baseline values. Discussion with the surgeons resulted in the procedure being performed in the right lateral decubitus position to allow for better access to the airway during the surgery. The TEE examination revealed that the right-ventricular function had returned to baseline. The airway required suctioning multiple times throughout the procedure for bloody airway secretions, but LVAD flow rates remained steady at approximately 5.7 LPM throughout the remainder of the surgery. The SpO2 monitoring did function intermittently and indicated no oxygen desaturations during those periods. The SctO2 was reliable throughout the case and was stable. At the conclusion of the operation, the patient was transported back to the cardiothoracic ICU by the anesthesiologists, surgeons, and the LVAD nurse with the device running on battery power. DISCUSSION

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.

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.

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.

Case 6-2010: Noncardiac surgery in patients with a left ventricular assist device.

ENTRICULAR ASSIST DEVICES (VADs) are being implanted with greater frequency in patients with circulatory failure. These devices can be used for short-term support in hopes that the patient’s myocardium will recover, longerterm as a “bridge” to heart transplantation, or even as permanent solutions to end-stage heart failure, so-called “destination therapy.” As a result of expanded usage, these patients increasingly are presenting for noncardiac surgery. 1 Two cases of patients with left ventricular assist devices (LVADs) undergoing noncardiac surgery are presented. The discussion reviews the different types of devices, their pathophysiology, and the unique perioperative considerations when dealing with these challenging cases. CASE PRESENTATIONS* Case 1: Thoracoscopy A 58-year-old woman with an LVAD for idiopathic dilated cardiomyopathy was scheduled for left thoracoscopy for persistent pleural effusion. Past medical history included New York Heart Association class IV congestive heart failure, which had been managed medically for 10 years, with several months of worsening symptoms. She also had a history of migraines, obesity, mild asthma, and insulin-dependent diabetes mellitus. Her past surgical history included automated implantable cardioverter-defibrillator (ICD) placement, total abdominal hysterectomy with bilateral salpingo-oophorectomy, 3 caesarean sections, and tonsillectomy, all without anesthetic complications. Nine days earlier, she had a Heartmate II LVAD (Thoratec Corporation, Pleasanton, CA) implanted as a bridge to transplant. The original surgery included LVAD insertion, patent foramen ovale closure, and a DeVega tricuspid valve annuloplasty, which proceeded without complications. Intraoperative transesophageal echocardiography (TEE) performed immediately after LVAD implantation showed adequate left ventricular (LV) decompression, no valvular abnormalities, and adequate right ventricular (RV) function. Initial pulmonary artery pressure before LVAD placement was 32/15 mmHg, with minimal change after LVAD insertion. Postoperatively, the patient had been doing well except for some difficulty optimizing her international normalized ratio (INR) with warfarin. A left-sided pleural effusion was noted that did not resolve despite chest tube drainage, and the decision was made to perform a thoracoscopy and pleurodesis. Medications at the time of thoracoscopy included metoprolol, insulin glargine, furosemide, esomeprazole, docusate, and nebulized albuterol/ipratropium. Heparin infusion was stopped the morning of the scheduled thoracoscopy. The patient was allergic to amoxicillin/clavulanate, torsemide, and cefdinir. Vital signs immediately before the induction of anesthesia in

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.

Trends in the Management of Patients With Left Ventricular Assist Devices Presenting for Noncardiac Surgery: A 10-Year Institutional Experience.

In our institution, the vast majority of patients presenting for noncardiac surgery (NCS) while supported by a left ventricular assist device (LVAD) are now cared for by noncardiac-trained anesthesiologists as the result of a decade of educational intervention to effect this transition. This represents a significant departure from the published experiences of other institutions. With institutional review board approval, we queried the database of our anesthesia record keeping system (CompuRecord) to determine various aspects of the perioperative management of these patients from July 1, 2003, through June 30, 2013, during which time 271 NCS procedures were performed on adult patients supported by LVADs. Over the entire study period (2003-2013), anesthetic care was provided by a cardiac anesthesiologist 47% of the time and by a noncardiac anesthesiologist 53% of the time. However, by the time period 2012-2013, 88% of the NCS procedures were staffed by a noncardiac anesthesiologist. Despite the prevalence of continuous flow devices in this series, the use of invasive blood pressure monitoring decreased dramatically by the later years of the study. Vasoactive and inotropic medications were rarely required intraoperatively. No intraoperative cardiac arrests, thromboembolic complications, or device malfunctions occurred. Our conclusion is that NCS procedures on LVAD-supported patients can be safely managed by educated noncardiac anesthesiologists.

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.