Perioperative Medicine

INTRODUCTION

The practice of anesthesiology historically focused on the care of an individual patient undergoing surgery. The specialty has an impressive track record for improving quality and safety in patient care (also see Chapter 46 ). Although anesthesia practice continues to evolve, patients undergoing major surgery still experience adverse outcomes related to their physiologic reserve and the metabolic and inflammatory response to the surgical intervention. The focus on the nonoperative care of patients undergoing major surgery has led to the concept of perioperative medicine. Two leaders in the field have stated that “Perioperative Medicine is the future of anesthesia, if our specialty is to thrive.” Others acknowledge the importance of perioperative medicine as a means to promote value-based, patient-centered care. ^,

The evolution of perioperative medicine has come a long way, and yet is still in its infancy. Other medical specialties have also experienced exponential growth and a distinct area of focus, including the evolution of interventional radiology within radiology and hospital-based medicine in internal medicine.

One estimate of the average number of operations that an average American will undergo in an 85-year lifetime is nine procedures. Of these, three were non–operating room procedures (e.g., colonoscopy), three were outpatient procedures (e.g., cataracts, minor orthopedic surgery), and three were inpatient procedures. The most common operating room procedures in men were coronary angioplasty (percutaneous transluminal coronary angioplasty [PTCA]), wound debridement, and groin hernia; for women, the most common operating room procedures were cesarean section, cholecystectomy, and lens and cataract procedures. As such, the preoperative, intraoperative, and postoperative anesthesia and surgical management is a major health concern. This chapter will describe the emerging domain of perioperative medicine, which spans the period beginning with preoperative assessment and nonsurgical patient optimization, the surgical procedure itself, and subsequent care until the patient returns to their primary care and other longitudinal providers after recovery from surgery.

THE PERIOPERATIVE MEDICINE CONSULTANT

The perioperative medicine consultant, who may someday be called a “perioperativist”, is a physician specifically trained to optimize patient health in order to improve postoperative outcomes. Although there is overlap with many medical subspecialties, perioperative medicine is a distinct medical discipline with a unique focus on preparing patients for the stress of surgery, anesthesia, and recovery throughout the postoperative period. ^, Although it is possible that physicians from surgical or medical disciplines could provide this care, the anesthesiologist is uniquely suited for this role ( Box 42.1 ). The core training focuses on the immediate perioperative period; however, the expansion of anesthesia care to include optimization of patient care for long-term outcome improvement represents a natural extension of the specialty.

IMPROVING PERIOPERATIVE OUTCOMES AND OPERATIONALIZING PERIOPERATIVE MEDICINE

For many decades, the immediate perioperative period was the focus for improving patient safety and outcomes. As safety vastly improved in the intraoperative and immediate postoperative period, the focus widened to include in-hospital complications and then the first 30 days after surgery. Most recently, clinical advances have afforded the ability to focus even further to include outcomes at 1 year after surgery and beyond. Those advances have enabled perioperative care teams to study and focus more and more on the patient from a holistic perspective, including functional capacity, social interactions, pain interference, sleep disturbances, and more. This expanded focus involves three distinct phases of care: prehabilitation, immediate perioperative care, and recovery/rehabilitation.

When considering the work of the perioperative medicine consultant, one metaphor relates the perioperative period to traversing a dangerous mountain. The novice traveler, the patient in this metaphor, has a better chance of safe passage (good outcome) if assisted by someone more familiar with the trail, the perioperative consultant ( Fig. 42.1) . The ascent is focused on prehabilitation and medical optimization for surgery, as the current focus of perioperative medicine is largely on the preoperative period. However, the descent (postoperative period) is more dangerous, as the most serious outcomes, including death, are more likely to occur in this phase of care. Future studies will need to focus on helping vulnerable patients safely descend from the stressful summit of surgery and anesthesia. A timeline of the perioperative management of the conditions discussed here will be provided at the end of this chapter.

VALUE-ADDED PREOPERATIVE SCREENING AND TESTING

Indications for preoperative testing are evolving. Campaigns such as the American Board of Internal Medicine (ABIM) Foundation’s Choosing Wisely and the United Kingdom’s National Institute for Health and Care Excellence (NICE) guidelines emphasize selection of testing that is evidence based and that supports a value-based care paradigm. Risk prediction tools have become more readily accessible, refined, and patient-specific. This has resulted in a shift away from routine preoperative testing toward a balanced, systems-based approach targeting the identification of modifiable factors. The current American Society of Anesthesiologists Practice Advisory for the preanesthesia evaluation recommends that preoperative testing be based on patient risk factors and surgical severity, as opposed to the provision of routine screening in the absence of clinical indications. Examples of routine testing to be avoided include electrocardiograms (ECGs) in asymptomatic patients simply based on age or medical history (e.g., hypertension), chest x-rays in asymptomatic patients with normal physical examination, and urinalysis.

Instead, a history and physical examination that is focused through the lens of the perioperative specialist serves as the basis of the preoperative evaluation. Those foundational elements are enhanced when used alongside validated screening tools to identify relevant, potentially modifiable clinical conditions such as the STOP-BANG for obstructive sleep apnea, preoperative nutrition screening (PONS) for malnutrition, or a clinical frailty scale. ^, Results generated by this multifaceted examination can direct necessary preoperative testing, focused upon identification and diagnosis of modifiable medical conditions that affect perioperative outcomes. The result is an appropriate use of preoperative testing in a select population, including tests such as cardiac biomarkers, hemoglobin A _1C , and studies to determine the etiology of anemia.

This increase in optimization-focused testing is counterbalanced by a reduction in ubiquitous testing in all patients where no such opportunity to affect outcomes or change perioperative management is likely to occur (also see Chapter 13 ).

MEDICAL MANAGEMENT OF THE MOST COMMON COMORBIDITIES