Preoperative and Intraoperative Care

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CHAPTER 1 Preoperative and Intraoperative Care

Robert E. Roses, Suhail K. Kanchwala, Patrick M. Reilly

Case Study

A 72-year-old male presents to a surgeon’s office after being diagnosed with a symptomatic right inguinal hernia. He notes progressive enlargement of the hernia over the course of several months and complains of associated discomfort. He reports a history of hypertension and a myocardial infarction (MI) at the age of 65 years. He takes aspirin and two antihypertensive medications. He smoked heavily for 40 years until the age of 60 years. On physical examination, a large, reducible, mildly tender right inguinal hernia is noted. He appears well otherwise.

He is sent for preoperative testing, including a chest radiograph and an electrocardiogram (ECG), and he is referred to a cardiologist for a preoperative assessment of his cardiac risk. At the cardiologist’s instruction, he undergoes a radionuclide stress test, which reveals no reversible myocardial perfusion defects. The cardiologist classifies the patient’s cardiac risk as intermediate and recommends perioperative adrenergic blockade and a postoperative ECG. The patient undergoes an uneventful inguinal hernia repair under regional anesthesia with conscious sedation.

PREOPERATIVE CARE

Indications for surgery must be weighed against the risks associated with the planned procedure. Principles that guide this evaluation and preoperative planning are the subject of the first part of this chapter.

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.

TABLE 1-1 Recommendations for Preoperative Screening Tests

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Additional Considerations

An aging population and advances in perioperative care with associated improvements in outcomes have lessened the number of absolute contraindications to surgical intervention. Patients with significant comorbidities, however, require a more extensive preoperative evaluation and, sometimes, preoperative interventions. Cardiovascular disease and pulmonary disease in particular often mandate special preoperative consideration.

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).
B. Interventions that may decrease pulmonary complications include preoperative smoking cessation, the use of epidural anesthesia, bronchodilator therapy, and aggressive postoperative pulmonary toilet and rehabilitation.

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.
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Figure 1-1 American College of Cardiology (ACC)/American Heart Association (AHA) 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery. The scope of the preoperative cardiac evaluation is determined by the clinical scenario and cardiac risk factors. HR, heart rate.

(Modified from Fleisher LA, Beckman JA, Brown KA, et al: ACC/AHA 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines [Writing Committee to Revise the 2002 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery]. Circulation 116: e418–e499, 2007.)

Preparation for Surgery

I. Fasting: The American Society of Anesthesiologists (ASA) recommends a minimum interval of 2 hours without clear liquids and 6 hours without solid foods or unclear liquids before surgery. In practice, patients are generally instructed to abstain from eating after midnight the evening before surgery and to take important routine medications (e.g., antihypertensive agents) with a sip of water on the day of surgery.
II. Antibiotic Prophylaxis: Systemic administration of antibiotics before surgery significantly decreases the incidence of surgical site infections. The timing of antibiotic administration has proven to be critical; antibiotics should be administered before, but no more than 1 hour before, skin incision. The choice of antibiotics administered should reflect the nature of the procedure to be undertaken. Procedures may be classified as clean, clean-contaminated, contaminated, or dirty, and the risk of infection may be predicted based on this classification (Table 1-2). Antibiotic prophylaxis is generally unnecessary for clean cases except those involving placement of prosthetic material. Antibiotic prophylaxis should be given before class II, III, and IV procedures. Class III and IV procedures require coverage for aerobic and anaerobic infection. In the case of class IV procedures, antibiotics are often continued into the postoperative period as dictated by signs of ongoing infection (e.g., fever, tachycardia, and leukocytosis).
III. Deep Vein Thrombosis Prophylaxis: Acute deep vein thrombosis (DVT) and pulmonary embolism are major sources of perioperative morbidity and mortality. Virchow described the major factors that contribute to the pathogenesis of venous thrombosis (Virchow’s triad [see text box]). Although the surgical patient is vulnerable to all of these, an increasingly aged, obese, and sedentary population, and the widespread use of central venous catheters have contributed further to the incidence of DVT. Little consensus exists regarding appropriate prophylaxis against DVT in surgical patients; however, perioperative use of sequential compression devices has been widely adopted for this purpose. These devices should be applied before the administration of anesthesia because induction may be associated with significant vasodilation and venous stasis. In patients deemed high risk, there may be a role for preoperative administration of subcutaneous heparin and even placement of a prophylactic inferior vena cava (IVC) filter.

TABLE 1-2 Classification of Surgical Wounds

Category Definition Risk of Infection
Clean (class I) Respiratory, gastrointestinal, or genitourinary tract not entered 1%–3%
Clean-contaminated (class II) Gastrointestinal or respiratory tract entered without significant spillage 5%–8%
Contaminated (class III) Spillage from gastrointestinal tract or entrance into genitourinary or biliary tract in the presence of infected urine or bile
Fresh traumatic wound		 20%–25%
Dirty (class IV) Acute bacterial infection encountered, delayed treatment of a traumatic wound
Traumatic wound with retained devitalized tissue, foreign body, or fecal contamination		 30%–40%

Virchow’s triad:

1. Venous stasis
2. Endothelial injury
3. Hypercoagulability

IV. Preparation of Blood Products: Before procedures associated with a risk of significant surgical bleeding, a type and screen should be obtained to determine a patient’s blood type (A, B, AB, or O) and to detect preformed antibodies to red blood cell–associated antigens. If the planned procedure is associated with a relatively high (>10%) likelihood of bleeding requiring transfusion, blood should be crossmatched for immediate use. If large-volume transfusion is anticipated, fresh frozen plasma (FFP) should be prepared in addition to packed red blood cells (pRBCs). Generally, 2 units of FFP should be prepared for every 5 units of pRBCs because large-volume transfusion of pRBCs alone is associated with coagulopathy resulting from dilution of clotting factors.

INTRAOPERATIVE CONSIDERATIONS

All surgical procedures require the coordinated effort of a team of surgeons, anesthesiologists, and support staff. The second part of this chapter focuses on intraoperative factors that influence surgical outcomes.

Anesthesia

Numerous anesthetic approaches exist; each has advantages and disadvantages. In choosing the most appropriate approach, the surgeon and anesthesiologist must consider several factors, including procedure type and length, anticipated blood loss, and patient comorbidities.

I. General: General anesthesia is defined as any form of anesthesia during which the patient no longer maintains consciousness. Induction of anesthesia is typically achieved with a combination of intravenous paralytics and sedatives, followed by maintenance with inhalational agents (e.g., halothane, desfluorane, or isoflurane).
II. Regional: Regional anesthesia involves the delivery of an anesthetic agent to specific sensory nerves (e.g., epidural, interscalene, and pudendal blocks). Epidural anesthesia, in particular, is frequently administered during major abdominal and thoracic procedures, and may be used in conjunction with general anesthesia. Initiation of epidural anesthesia in the operating room may result in improved postoperative pain control and a more rapid recovery.
III. Local: Most commonly used as an adjunct for postoperative pain control, local anesthetics can be used as a primary method of anesthesia for minor procedures.

Airway

Airway management is a critical component of all anesthetic approaches. Deep sedation and the use of paralytics in conjunction with general anesthesia require ventilatory support. Endotracheal (ET) intubation is the most common method of securing the airway. ET tubes are inserted beyond the vocal cords and are equipped with a distal cuff. Inflation of the cuff protects against aspiration of gastrointestinal secretions and provides a seal to allow for ventilation. In contrast, laryngeal mask airways (LMAs) are equipped with a cuff that fits over the glottic opening (Fig. 1-2). LMAs are an alternative to ET tubes and are particularly useful for shorter procedures involving deep sedation. Because LMAs are more easily displaced and provide less protection against aspiration than do ET tubes, they should not be used for long procedures in which ventilatory support is necessary.

image

Figure 1-2 Laryngeal mask airway.

(From Cameron JL [ed]: Current Surgical Therapy, 8th ed, Philadelphia, Mosby, 2004.)

Patient Preparation

After the induction of anesthesia, a variety of steps must be taken to prepare the patient for the operation. These may include the following:

I. Urinary catheterization
II. Placement of electrocautery grounding pads
III. Intravenous line placement
IV. Invasive monitoring (e.g., Swan-Ganz and arterial catheterization)
V. Placement of a nasogastric or orogastric tube
VI. Patient positioning and application of the sterile preparation
VII. Application of drapes
VIII. Time-out for safety

Urinary Catheterization

A urinary catheter should be placed before any procedure anticipated to take longer than 3 hours to allow for bladder decompression and urine output monitoring. The former is particularly important in laparoscopic cases, which require placement of a suprapubic port to prevent bladder injuries. Urinary catheterization is associated with several complications, the most prevalent of which is urinary tract infection (UTI). Strict adherence to sterile technique may limit infection rates, although duration of catheterization is the dominant predisposing factor for the development of UTIs. Rates of infection are estimated to be 4% to 7% per day of indwelling catheterization.

Is the anticipated operative time more than 3 hours?

Gastric Decompression

Gastric decompression prevents gastric distention during intubation and enhances visualization during abdominal procedures. Either orogastric or nasogastric tubes may be used for these purposes. Orogastric tubes should be removed at the time of extubation. When a need for postextubation gastric decompression is anticipated, a nasogastric tube should be inserted.

Will your patient require postoperative gastric decompression?

Patient Positioning and Sterile Preparation

The patient is positioned to optimize visualization of the surgical field. Common positions include supine, prone jackknife (face down with the hips flexed), lateral decubitus, and Trendelenburg (head of the table tilted down). Pressure points should be padded to limit the incidence of pressure necrosis.

A variety of antiseptic solutions are commonly in use, including povidone-iodine (Betadine), alcohol, and chlorhexidene. The efficacy of betadine depends on the release of the active iodine from a carrier molecule. This requires several minutes after application; therefore, betadine should be allowed to dry before incision. The sterile preparation is typically applied in concentric circles, starting around the incision site and expanding outward. Three coats of preparation are applied before the application of sterile drapes.

Time–out for Safety

In an effort to minimize the small but devastating incidence of wrong-site, wrong-procedure, and wrong-person surgeries, hospitals have adopted the time-out for safety. Before incision, operating room personnel (including the surgeon, anesthesiologist, and nursing staff) confirm the patient’s identity, the procedure type, and the operative site.

Dressing the Wound

At the conclusion of a procedure, a sterile dressing should be applied to the wound before removal of the sterile drapes. Theoretically, this dressing prevents bacterial colonization of the wound during the initial 24 to 48 hours of healing, allowing for epithelialization and limiting the risk of infection. Before application of the dressing, excess antiseptic solution should be washed off with sterile saline. In general, the dressing should be secured without the use of excessive tape, which may be irritating to the skin.

SUGGESTED READINGS

Fleisher LA, Beckman JA, Brown KA, et al. ACC/AHA 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines [[Writing Committee to Revise the 2002 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery]. Circulation. 2007;116:e418-e499.

Marino PL. The ICU Book, 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2007.

Nierman E, Zakrewski K. Recognition and management of preoperative risk. Rheum Dis Clin North Am. 1999;25:587.

Weintraub SL, Wang Y, Hunt JP, O’Leary JP. Principles of preoperative and operative surgery. In: Townsend CM, editor. Sabiston Textbook of Surgery: The Biologic Basis of Modern Surgical Practice. 17th ed. Philadelphia: Saunders; 2004:221-241.

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