Introduction to Perioperative Echocardiography

Perioperative echocardiography has become an essential tool in the anesthetic management of the cardiac surgical patient. Moreover, echocardiographic skills and knowledge can be applied to patients irrespective of the nature of surgical procedure. Consequently, this text begins with a discussion about transesophageal echocardiography (TEE) and other echocardiographic modalities. Because in recent years cardiac anesthesia has increasingly been associated with the use of TEE, this introduction will also serve to present the TEE examination of the normal patient with normal heart structures. Throughout this book, TEE will be employed to illustrate various cardiac pathologies and the anesthetic manipulations required to manage patients with a variety of cardiac conditions. In fact, TEE imagery will be integrated into the discussion and explanations of anesthetic management much in the way that echographic images are employed in routine anesthetic practice. Although it is not the authors' intention to write a definitive text of perioperative echocardiography, it is hoped that the reader will become sufficiently familiar with this valuable tool to appreciate how echocardiographic imagery can be mated with clinical knowledge and clinical experience to effectively manage the cardiac surgery patient or any patient perioperatively.

Perioperatively, TEE has been employed to help anesthesiologists, surgeons, and cardiologists answer questions related to the structure and function of the heart. TEE assists in a number of ways including:

1. Identify the source of hemodynamic instability: TEE can detect areas of myocardial ischemia, poor ventricular function, and inadequate volume load secondary to pericardial tamponade or hypovolemia.

2. Determine hemodynamic parameters: TEE can be used to determine stroke volume (SV) and cardiac output (CO) and can also be used to assess pulmonary arterial and intraventricular pressures.

3. Examine and confirm structural diagnoses: TEE perioperatively can detect new pathology perhaps missed on previous examinations including: patent foramen ovale, atheromatous aorta, or undiagnosed valvular heart disease. More likely, however, perioperative TEE will confirm the patient's previous cardiac diagnoses.

4. Guide and confirm adequacy of surgical interventions: TEE is essential in determining the adequacy of valvular repair/replacement and in detecting any unexpected surgical complications.

5. Postoperative hemodynamic instability: Echocardiography will readily determine causes of postoperative hemodynamic instability secondary to pericardial tamponade, left, right or biventricular failure, pulmonary embolism, aortic dissection, and other catastrophic perioperative events.

Throughout this text, echocardiography will be integrally linked to perioperative anesthetic management and its use in each of the ways described above illustrated.

TEE was introduced in the operating rooms in the mid to late 1980s. By the mid 1990s it had increasingly become a "routine" part of perioperative management.1 The National Board of Echocardiography (NBE) was subsequently established to credential and "certify" individuals in perioperative TEE. TEE is the echocardiographic modality most commonly associated with cardiac anesthesiologists. Anesthesiologists have subsequently expanded the use of TEE in the noncardiac surgical suites and in the intensive care unit (ICU) (Figures Intro–1, Intro–2 and Video Intro–1).