Each year, tens of millions of patients in the United States undergo a surgical procedure requiring general or regional (spinal or epidural) anesthesia. An increasing number of these patients are over age 65 or have significant comorbid medical disease. However, operative mortality and morbidity have declined due to improvements in surgical, anesthetic, and monitoring techniques. The traditional preoperative roles of the medical consultant or primary care provider include evaluating the severity and stability of medical conditions, assessing the risk of medical complications, determining whether further preoperative risk stratification testing is indicated, and recommending measures to reduce the risk of perioperative complications. The consultant may also be asked to manage medical aspects of patients' postoperative care, including evaluation and treatment of medical complications.
et al. The impact of pre-operative comprehensive geriatric assessment on postoperative outcomes in older patients undergoing scheduled surgery: a systematic review. Anaesthesia. 2014 Jan;69(Suppl 1):8–16.
PHYSIOLOGIC EFFECTS OF ANESTHESIA & SURGERY
In general, decisions about anesthetic techniques and agents, intraoperative monitoring, and other aspects of care within the operating room should be left to the anesthesiologist. However, the medical consultant should understand the physiologic effects of anesthesia and surgery. Both general and neuraxial (spinal or epidural) anesthetic agents usually cause peripheral vasodilatation, and many of the commonly used general anesthetic regimens also decrease myocardial contractility. These effects often result in transient mild hypotension or, less frequently, prolonged or more severe hypotension. The decrease in tidal volume and functional residual capacity caused by general and regional anesthesia can close small airways and lead to atelectasis. Epinephrine, norepinephrine, and cortisol levels increase during surgery and remain elevated for 1–3 days. Serum antidiuretic hormone levels may be elevated for up to 1 week postoperatively, which can lead to hyponatremia. Anesthesia and surgery may be associated with both hypercoagulability, mediated by increases in plasminogen activator-1, factor VIII, and platelet reactivity, as well as inflammation due to increased levels of tumor necrosis factor, interleukins 1 and 6, and C-reactive protein.
et al. Neuraxial blockade for the prevention of postoperative mortality and major morbidity: an overview of Cochrane systematic reviews. Cochrane Database Syst Rev. 2014 Jan 25;1:CD010108.
EVALUATION OF THE ASYMPTOMATIC PATIENT
Patients without significant medical problems—especially those under age 50—are at very low risk for perioperative complications. Their preoperative evaluation should include a history and physical examination. Special emphasis is placed on obtaining a careful pharmacologic history and assessment of functional status, exercise tolerance, and cardiopulmonary symptoms and signs in an effort to reveal previously unrecognized disease that may require further evaluation prior to surgery. In addition, a directed bleeding history (Table 3–1) should be taken to uncover coagulopathy that could contribute to excessive surgical blood ...