CHAPTER 1 Preoperative and Intraoperative Care
PREOPERATIVE CARE
Preoperative Evaluation
All patients undergo a general evaluation before elective surgery, the primary aim of which is to identify and quantify comorbidities that may influence surgical outcomes. The scope of this evaluation is dictated by a number of factors, including patient age and medical history and the risks associated with the planned procedure. Frequently ordered preoperative tests include: an ECG; a chest radiograph; hemoglobin, creatinine, and glucose levels; a urinalysis; a pregnancy test; and coagulation studies. Not all of these are essential in all cases and some recommendations regarding their use are detailed in Table 1-1.
Additional Considerations
I. Cardiovascular Disease
A. Approximately 30% of surgical patients have cardiac disease. A number of risk stratification tools (e.g., the Cardiac Risk Index and American College of Cardiology/American Heart Association [ACC/AHA] Guidelines) are in use and take into account various clinical predictors, functional status, and planned procedure type to identify those patients who will benefit from a more extensive cardiac evaluation (Fig. 1-1). The preoperative history and physical examination should elicit signs and symptoms of coronary artery disease, valvular disease, congestive heart failure (CHF), and cardiac arrhythmias. Patients who have suffered from a recent MI (within 6 months) are at a substantially elevated risk for a perioperative MI. The timing of surgery for these patients must be given special consideration because this risk lessens with time.
B. Patients at elevated cardiac risk who have not undergone recent coronary revascularization (i.e., within the previous 5 years) are often referred for noninvasive testing (e.g., an echocardiogram and a stress test). Patients deemed high risk sometimes require coronary angiography to determine whether they can benefit from revascularization (i.e., coronary artery bypass or angioplasty) before elective surgery. Additionally, the cardiac evaluation can influence anesthetic choice and intraoperative monitoring strategies. Finally, β-blockers are often administered to decrease myocardial oxygen demand and reduce the risk of perioperative cardiac events in patients at elevated risk.
II. Pulmonary Disease
A. Patients with significant pulmonary disease, specifically chronic obstructive pulmonary disease (COPD) and pulmonary hypertension, are at increased risk for postoperative complications, including respiratory failure (requiring mechanical ventilation > 48 hours), atelectasis, bronchospasm, and pneumonia. Pulmonary function tests (PFTs) are frequently obtained in patients with known pulmonary disease as well as in older patients (>60 years of age) with pulmonary symptoms or an extensive smoking history. Although poor pulmonary function may preclude pulmonary resection, guidelines are less definitive with regard to nonthoracic procedures. Pulmonary evaluation in nonthoracic surgical patients may, however, influence management (e.g., operative vs. nonoperative approach), choice of anesthesia (e.g., epidural vs. general), and surgical approach (palliative vs. curative).
III. Review of Medications: A thorough review of the patient’s current medications is of critical import. Insulin, steroids, and anticoagulants are a few examples of widely prescribed agents that necessitate special consideration before surgery. In general, short-acting insulin preparations are substituted for long-acting ones or other antihyperglycemic agents. Long-term steroid therapy should be continued through the perioperative period, and administration of perioperative “stress-dose” steroids should be given consideration. When possible, aspirin and clopidogrel (Plavix) should be withheld for 7 to 10 days before surgery. Likewise, warfarin (Coumadin) should be withheld for several days before surgery to allow the international normalized ratio (INR) to fall to 1.5 or less.
