Principles of Surgery, Companion Handbook

Chapter 11 Surgical Complications

Principles of Surgery Companion Handbook

OPERATIVE RISK

Cardiac Risk One means of estimating cardiac risk is to use Goldman's cardiac risk index (Table 11-1). The focus of the Goldman classification is the history of a previous myocardial infarction. If more than 6 months has elapsed between the cardiac infarction and the proposed operation, then there is a 6 percent risk. If a transmural infarct has occurred less than 3 months before operation, the risk of cardiac death is between 16 and 37 percent. Significant peripheral vascular disease should alert the surgeon to consider the cardiac risk. A cardiac stress test is indicated to identify those patients at coronary risk. The most sensitive examination of cardiac risk is the inability to perform a bicycle exercise for 2 min and achieve a heart rate higher than 100 beats/min.

TABLE 11-1 COMPUTATION OF MULTIFACTORIAL INDEX SCORE TO ESTIMATE CARDIAC RISK IN NONCARDIAC SURGERY

For patients in congestive failure, the use of calcium channel blockers or beta blockers, digitalization with cardiac glycosides, and diuresis are part of the therapeutic armamentarium. Patients with rapid atrial fibrillation should have their heart rates controlled. If the cardiac rhythm cannot be returned to normal sinus rhythm, cardioversion should be considered.

Pulmonary Risk The patient at pulmonary risk can be identified by simple functional tests such as walking up a flight of steps or blowing out a match with unpursed lips from a distance of 8 to 10 in. If arterial blood gases are drawn while the patient is on room air, a PCO₂ greater than 45 mmHg suggests a diffusion defect. Other identifiable risk factors include a maximum breathing capacity of less than 50 percent of predicted or a 1-s forced expiratory volume (FEV₁) of less than 2 L. The most sensitive test for patients undergoing thoracotomy is the exercise oxygen consumption (VO₂).

Because most lung damage is a result of smoking or industrial pollution, cessation of smoking is essential for patients who are to undergo long elective procedures, and an 8-week preoperative cessation provides maximal benefit.

Renal Risk Renal abnormalities are reflected in the blood urea nitrogen (BUN) and creatinine levels. Reversible causes of renal insufficiency should be identified and corrected. Aminoglycosides should be avoided in these patients for bowel preparation. In the postoperative period, if severe hyperkalemia supervenes with electrocardiographic (ECG) changes, calcium should be administered intravenously, followed shortly thereafter by 50% dextrose, 10 units of insulin, and intravenous bicarbonate. Essential amino acids and hypertonic dextrose solution, given as total parenteral nutrition (TPN) may lower the potassium level.

Hepatic Risk Hepatic dysfunction is best estimated by the Child-Pugh criteria. In cirrhotic patients, the mortality accompanying noncardiac surgery is less than 5 percent for Class A patients, 5–10 percent for Class B patients, and between 25 and 50 percent or higher for Class C patients. When the blood ammonia concentration is higher than 150 ng/dL, an 80 percent mortality can be expected. The same pertains to albumin levels below 2.0 g/dL. In patients with ascites, the conversion of uncontrollable ascites to ascites that can be controlled with medication improves the operative risk. Spironolactone, furosemide, and restriction of salt may reduce the ascites.

Nutritional-Immunologic Defects Malnourished patients experience a higher complication rate. A weight loss of more than 15 percent over the previous 3–4 months, a serum albumin level of less than 3.0 g/dL, anergy to injected skin test antigens, and a serum transferrin level of less than 200 mg/dL are critical. Malnourished patients may require TPN preoperatively.

DIABETES MELLITUS

Pathophysiology Anesthesia may affect carbohydrate metabolism. Hyperglycemia may be increased by an accelerated breakdown of liver glycogen with the formation of lactic acid. The stress of an operation aggravates hyperglycemia because of increased levels of epinephrine, growth hormone, and glucocorticoids. These may require larger doses of insulin in patients undergoing operative procedures. Treatment is directed at preventing ketoacidosis, hyperosmolar nonketotic coma, decreased cardiac output, electrolyte imbalance, and decreased wound healing.

Management Diabetic patients should have preference on the operative schedule to minimize the effects of fasting and ketosis. Preoperative medication should be kept to a minimum because these patients are more sensitive to narcotics and sedatives. The choice of anesthesia should not be influenced by the presence of diabetes.

Patients with mild diabetes frequently do not require insulin or dietary control. The cornerstone of all diabetic management is the dietary or parenteral intake. The goal of a dietary or parenteral fluid regimen is to keep the patient free of acetonuria without excessive hyperglycemia. Patients with well-controlled diabetes taking oral agents should continue the use of these drugs until the day before the operation. Patients who take tolbutamide usually require insulin during and immediately after a major operation.

Insulin Therapy Several protocols for the administration of insulin have been proposed. One popular method is shown in Table 11-2. Severe hyperglycemia in patients undergoing major operations is best managed with intravenous regular insulin (Table 11-3).

TABLE 11-2 INSULIN INFUSION PROTOCOL IN MAJOR SURGERY IN DIABETIC PATIENTS

TABLE 11-3 CONTINUOUS INSULIN INFUSION GUIDELINES

GENERAL CONSIDERATIONS

The response to surgical procedures includes antidiuresis, an increase in extravascular volume, fever, and tachycardia. These are caused by the release of cytokines and other agents. Urine output falls, normally because of the release of antidiuretic hormone. A tendency to hyponatremia is present in the immediate postoperative period. Diuresis usually begins on the second or fourth postoperative day and coincides with the decreased secretion of aldosterone. Ileus of the colon and stomach persists for 2–5 days after an open abdominal procedure but for a considerably shorter period after minimally invasive surgery. Wound pain can be severe for approximately 48–72 h, and postoperative fatigue may be prolonged.

FEVER

Pathophysiology Thermoregulation is controlled by the anterior hypothalamus. Various pathophysiologic mechanisms, such as pyrogens, are responsible for the generation of fever. These may arise from infectious agents, antigen-antibody complexes, steroids, and other inorganic substances. All pyrogens appear to evoke a common mediator, endogenous pyrogen or interleukin-1 (IL-1), a monokine produced by leukocytes. Fever per se usually is not a significant physiologic problem unless core temperature is elevated above 105°F (40.5°C).

Perioperative Fever Fever on the first postoperative night is usually ascribed to atelectasis, but other causes should not be disregarded. A delayed transfusion reaction can cause a fever.

Malignant Hyperthermia This is a rare anesthetic complication that occurs in about 1 in 100,000 general anesthetic procedures. It consists of a rapid rise in body temperature, usually during the initiation of a general anesthetic or the administration of succinylcholine. A family history of complications associated with anesthetics is a warning of this possibly lethal complication. Once the syndrome unfolds, dantrolene is administered intravenously. Support measures include positive-pressure ventilation with 100% oxygen and control of acidosis and electrolyte imbalance, cooling blankets, monitoring of urine output, and treatment of possible myoglobinuria.

Time Relationships of Fever Fever within 24 h is usually caused by atelectasis or failure to clear pulmonary secretions. High fevers with systemic symptoms such as rigors are associated with severe wound complications. Fever at 24–48 h is usually attributed to respiratory complications. Fever after 48–72 h is usually caused by thrombophlebitis or wound infection. Less common infectious complications include pneumonitis, acute cholecystitis, idiopathic postoperative pancreatitis, and drug allergy.

WOUND COMPLICATIONS

Wound Infection

Predisposing Factors Wound contamination occurs in the operating room, but not all wounds harboring bacteria become infected. Staphylococcus aureus is the most frequently involved offending organism. Enteric organisms frequently contaminate wounds when bowel operations are performed. Hemolytic streptococci are responsible for 3 percent of wound infections. Occasionally, “surgical scarlet fever” may complicate these infections. Other less common pathogens include enterococci, Pseudomonas, Proteus, and Klebsiella.

The incidence of wound infection developing in clean, atraumatic, and uninfected wounds is between 3 and 4 percent. The figure rises to over 10 percent when the bronchus, gastrointestinal tract, or oropharynx has been entered during the procedure. With breaks in surgical technique, it rises to over 16 percent, and in operations involving perforated viscera, the rate is reported to be as high as 28 percent. In the latter situation, consideration should be given to delayed primary closure of the skin.

The rate of wound infection rises in patients over age 65. Diabetes is not an independent risk when adjusted to age. Obesity doubles the infection rate.

Prevention Wound infection rates can be minimized by (1) skin preparation, (2) bowel preparation, (3) prophylactic antibiotics, (4) meticulous technique, (5) temperature maintenance, and (6) appropriate drainage. Bowel preparation decreases wound infection. Mechanical preparation is a most effective modality, but a variety of antibiotic regimens should be included. Systemic antibiotics should be given immediately before the incision is made and serum levels maintained throughout the operative procedure. Wounds requiring drainage are more likely to become infected, but it cannot be concluded that the drains are responsible for the infection.

Management Management depends on the extent of destruction and the type of wound infection. A simple collection of purulent material is treated by opening the incision to provide adequate drainage. This is insufficient in severe clostridial myositis or necrotizing fascitis where radical debridement is necessary. Clostridial myositis is manifest by crepitus, which also may be present in necrotizing fascitis. The patient is more sick than expected than with a simple wound infection. A Gram stain may identify some of the offending organisms. In the absence of specific information, the wound should be cultured and the patient placed on a combination of antibiotics. Diabetic patients are prone to Fournier's gangrene, which is a form of necrotizing fascitis in the perineum or groin.

Wound Hematomas

Wound hematomas are caused by inadequate hemostasis. Anticoagulation, fibrinolysis, polycythemia vera, myeloproliferative disorders, and decreased or inadequate clotting factors all contribute to hematoma formation. Hematomas provide a good culture medium for bacteria and frequently become infected. When the hematomas are discovered early in the postoperative course, the patient should be returned to the operating room and, under sterile conditions, the wound opened and the hematoma evacuated. If discovered late, the patient can be managed expectantly if there is no evidence of contamination. If drainage is required, a closed-suction drainage system is preferable.

Wound Seromas

These are lymph collections usually associated with large surgical areas such as axillary dissection and groin dissection. They are best managed with closed-suction drains if they are sterile and open drainage if they have become infected.

Wound Dehiscence

By definition, dehiscence is a separation within the fascial layer of the abdomen, whereas evisceration indicates extrusion of peritoneal contents through the fascial separation. Old age, malnutrition, hypoproteinemia, morbid obesity, malignancy, immunologic deficiency, uremia, diabetes, coughing with increased abdominal pressure, and remote infections are all contributory factors. Ascites also increases the incidence of wound disruption. Vitamin C is essential for collagen synthesis, and patients who are subclinically scorbutic have an eightfold increase in the incidence of wound dehiscence. Zinc is a cofactor for enzymatic processes, and zinc deficiencies also have been implicated in the formation of a dehiscence. Chemotherapeutic agents also inhibit wound healing.

Clinical Manifestations Dehiscence without evisceration is detected by the appearance of salmon-colored fluid draining from the wound. This usually occurs about the fourth or fifth day. Evisceration is evidenced by intestine on the abdominal wall.

Treatment In some instances, if there is no evisceration, the patient can be treated expectantly and a ventral hernia accepted. Patients with evisceration should be returned to the operating room for closure of the wound.

COMPLICATIONS OF THE GENITOURINARY SYSTEM

Urinary Retention

Postoperative urinary retention occurs more frequently in males than in females. The incidence after major abdominal surgery ranges from 4–5 percent but after anorectal surgery may be greater than 50 percent. Stress, pain, spinal anesthesia, and various anorectal reflexes conspire to cause increased alpha-adrenergic stimulation that prevents release of the musculature around the bladder neck. Prazosin hydrochloride has been shown to significantly reduce postoperative urinary retention.

Patients experiencing urinary retention experience urgency, discomfort, and fullness, and an enlarged bladder can be percussed. Straight catheterization is undertaken initially and then usually repeated once. If the catheterization is required more than twice, a Foley catheter is placed and left to drain for 2–7 days.

Acute Renal Failure

Acute renal failure is frequently caused by inadequate resuscitation. It is also a consequence of transfusion reaction, in which case the patient should be treated with diuresis and alkalinization of the urine. A second important cause of acute renal failure is the use of nephrotoxic drugs such as aminoglycosides, vancomycin, amphotericin B, and occasionally high doses of penicillin.

Pathology Prerenal dysfunction is characterized by a BUN-to-creatinine ratio of 20:1 or greater. This is commonly observed with dehydration or under resuscitation. Another type of prerenal azotemia is a complication of liver disease known as the hepatorenal syndrome. This is due to hypovolemia and also maldistribution of blood flow. Recovery from hepatorenal syndrome depends on recovery from the intrinsic liver disease. Renal dysfunction also may be caused by the intrinsic damage of acute tubular necrosis, pigment nephropathy, and drug nephrotoxicity. There is a prolonged diminished renal perfusion in the face of sustained hypotension that results in ischemia of the renal parenchyma. The use of large amounts of radiocontrast medium causes reversible renal failure due to intrinsic damage. Another cause is the showering of atheromatous emboli during aortic surgery.

Postrenal failure is rare in the surgical setting but can result from ureteral clots or stones. It also can be caused by benign prostatic hypertrophy. Foley catheterization is the treatment of choice.

Prevention of Acute Renal Failure For patients with chronic urinary tract infection, specific antibiotics based on the culture should be used. Patients with benign prostatic hypertrophy should be treated with preemptive balloon dilatation or transurethral resection. A patient with inadequate urinary output should not be subjected to a general anesthesia unless the situation represents an emergency. In low-flow states, mannitol, bicarbonate, and diuresis induced by furosemide should be used. If there is any question regarding the volume status, central venous pressure monitoring is indicated.

Manifestations Acute renal failure presents in the postoperative period with oliguria and a urine output of 0.4–0.5 mL/kg/h in an adult. The diagnosis of acute tubular necrosis is made by measurement of the urinary sodium and potassium levels and osmolality. A fractional excretion of sodium (FENa) greater than 1 indicates intrinsic renal damage.

Management The management of renal failure is divided into two periods; the first is when the diagnosis is uncertain, and the second is when the diagnosis has been made. If the patient is oliguric and thought to be hypovolemic, a volume challenge is in order. Once adequate volume status has been established, furosemide or mannitol can be given to increase urinary output. “Renal dose dopamine” also may be used in conjunction with diuretics.

When the patient has been diagnosed with established renal failure, it is important to avoid overhydration, avoid toxic ionic damage such as hyperkalemia, provide nutritional support, and attempt to manage the patient without dialysis. Dialysis is undertaken in patients with acute renal failure for critical ionic excesses such as hyperkalemia and BUN concentrations that are higher than 100 mg/dL. Dialysis has an annual mortality of 5–10 percent.

RESPIRATORY COMPLICATIONS

Pathophysiology Respiratory complications are among the most common complications of surgery and the most lethal, responsible for 5–35 percent of postoperative deaths. Upper abdominal and thoracic incisions result in a significant decrease in vital capacity and functional residual capacity in the first 24 h after an operation. Postoperative pain also alters the mechanics of respiration.

A number of risk factors predispose the patient to the development of pulmonary complications. These include smoking, advanced age, obesity, chronic obstructive pulmonary disease, and cardiac disease.

Atelectasis

Atelectasis is the collapse of alveoli with ongoing perfusion of blood resulting in a perceptible increase in the shunt fraction. It may be due to a loss of surfactant allowing secretions to accumulate in the collapsed alveolus. Lung inflation in the postoperative period prevents and reverses atelectasis. This can be accomplished by coughing and deep breathing, chest percussion and postural drainage, incentive spirometry, intermittent positive-pressure breathing, and continuous positive airway pressure. Three groups of medications have been applied: expectorants, detergents and mucolytics, and bronchodilators.

Pneumonitis

Pneumonitis is a nosocomial infection that is seen with increasing frequency on surgical services. The organisms involved include Pseudomonas, Serratia, Klebsiella, Proteus, Enterobacter, and Streptococcus. There is an emerging predominance of gram-negative organisms. Fungal pneumonia is uncommon, but with the increasing use of antibiotic regimens, it is likely to increase.

Clinical Manifestations These include fever, productive cough, dyspnea, pleuritic chest pain, and purulent sputum.

Management Management depends on indentifying the responsible organism and treating it with antibiotic therapy. Given the increasing incidence of gram-negative nosocomial infections in the intensive care setting, antibiotic therapy with an aminoglycocide and an antipseudomonal penicillin should be initiated when the diagnosis is made.

Aspiration

This occurs when large amounts of particulate-laden acid contents of the stomach enter the tracheobronchial tree. This should be removed as expeditiously as possible by suction. If untreated, the results resemble pulmonary edema. Chest radiographs demonstrate progression of local damage and infiltration. In over 50 percent of patients who suffer aspiration, a resulting pneumonia occurs.

Management The only effective treatment of aspiration is prevention by emptying the stomach and neutralization of gastric contents. Treatment of the early phase of aspiration includes removal of the debris and lavage of the upper airway. Endotracheal intubation is usually necessary to initiate treatment and to clear the tree. Bronchodilating agents may be helpful, and positive-pressure ventilation (PPV) is often necessary.

Pulmonary Edema

This is the transudation of fluid into the alveolus. The most common causes in surgical patients are fluid overload or myocardial insufficiency secondary to infarction or ischemia. Additional causes include sepsis, valvular dysfunction, neurogenic stimulation, and hepatic failure. There are two time frames for the manifestation of pulmonary edema. The first occurs during resuscitation with overly aggressive fluid therapy. The second occurs in the postoperative period when fluid mobilization is taking place. The patient presents with dyspnea at rest, tachypnea, and air hunger. There may be changes in the mental status and disorientation. Wheezing and signs of bronchospasm may be audible. There may be distended neck veins, cyanosis, and peripheral pitting edema.

Management Management depends on addressing the inciting cause, oxygen therapy, positioning the patient in the upright position, and diuretics.

Fat Embolism Syndrome

This is a common pathologic finding after trauma, particularly trauma involving the long bones. The incidence of fat embolism ranges from 26 percent in patients with single fracture to 44 percent in patients with multiple fractures. This syndrome of pulmonary dysfunction, coagulopathy, and neurologic disturbances associated with increasing circulating fat globules is uncommon. It has been reported in approximately 9 percent of patients with femoral and tibial fractures.

Clinical Manifestations Over three-quarters of the patients manifest some degree of respiratory insufficiency, usually occurring soon after injury but occasionally as long as 48–72 h thereafter. Chest radiographs reveal bilateral alveolar infiltrates. Central nervous system manifestations may include disorientation and confusion. The skin demonstrates a characteristic petechial rash in the axilla, neck, and skin folds. Fever and tachycardia are common. The examination of urine for the presence of fat globules is not specific.

Management The patient is treated for the clinical manifestations. Treatment includes adequate fluid resuscitation, transfusion, oxygen, and other supportive measures. There is little support for the use of steroids, and the effects of heparin are debatable. Other modalities include low-molecular-weight dextran to reduce the blood viscosity and platelet adhesion.

Acute Respiratory Distress Syndrome (ARDS)

By definition, this is the clinical situation in which the patient is incapable of maintaining adequate oxygenation, adequate ventilation, adequate tissue delivery, or some combination of these defects. The syndrome is characterized by atelectasis, reduced pulmonary compliance, and refractory hypoxemia. The most widely accepted definition of ARDS is a syndrome that includes (1) lung injury, acute in nature, (2) bilateral infiltrates on frontal chest radiograph, (3) PaO₂/FIO₂ less than 200, and (4) pulmonary capillary wedge pressure less than 19 mmHg with no evidence of congestive failure. The etiology is unknown, but abnormal cytokine response to injury has been invoked. There may be some activation of the complement cascade, activation of the thromboxane-leukotriene pathway, disorders in nitric oxide production, degranulation of neutrophils, and production of increased permeability factors by macrophages. This results in a ventilation-perfusion mismatch.

A newly described concept of ventilator lung injury is termed volutrauma, which is different from barotrauma and results in the maldistribution of inspired tidal volume secondary to positive high-pressure ventilation and a heterogeneous nature of lung injury in ARDS. Barotrauma, on the other hand, is simply extra-alveolar air.

Management Current mechanical ventilation strategies have emphasized the need to reduce volutrauma. These include (1) early use of positive end-expiratory pressure (PEEP), (2) pressure-limited ventilation with plateau pressures of less than 35 cmH₂O, (3) permissive hypercapnia, and (4) use of inhalational nitric oxide. Initial experience with the use of nitric oxide has suggested a response rate of 60–70 percent. Partial liquid ventilation or perfluorocarbon-assisted gas ventilation has been applied.

CARDIAC COMPLICATIONS

Myocardial Infarction

Perioperative myocardial infarction probably is the leading cause of death in the elderly after noncardiac surgery. The presence of coronary artery disease increases the incidence from a control level of 0.1–0.7 percent to 1 percent after operation. The most widely used criteria to estimate cardiac risk is that originally suggested by Goldman (see Table 11-1). The history is important in evaluating the risk of myocardial infarction. A history of dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, peripheral edema, and angina should lead the surgeon to obtain a more detailed history on the cardiac evaluation. A preoperative ejection fraction of less than 0.35 is associated with a 75 percent incidence of perioperative myocardial infarction.

Clinical Manifestations Most cases occur during the first 3 postoperative days, and the most important precipitating factor is shock. Chest pain occurs in only 21 percent of patients. Dyspnea, cyanosis, tachycardia, and arrhythmia are all manifestations. The ECG may provide the diagnosis, but it is not an unequivocal finding. Determination of the CPK-MB isoenzyme is the most precise method for detection for myocardial necrosis after operation.

Management Preoperatively, patients with signs of cardiac insufficiency should be digitalized. Routine digitalization is not indicated, however. Treatment of a developed myocardial infarction consists of relief of pain and anxiety using morphine and sedation. Patients are treated with oxygen to relieve hypoxia. The patient should be managed in an intensive care setting. Cardiac shock is treated by vasopressor agents.

Arrhythmias

In cardiac procedures, the incidence of arrhythmias is approximately 50 percent, whereas thoracic surgical procedures have an incidence of about 20 percent and arrhythmias occur in about 2 percent of other operative procedures. Arrhythmias may be caused by hypokalemia or hyperkalemia, hypercalcemia, and hypomagnesemia. Digitalis may predispose surgical patients to serious dysrhythmias, and digitalis toxicity can result in supraventricular-atrial flutter with varying blocks. Hypercapnia and thyrotoxicosis are also precipitating causes.

Management of Preexisting Arrhythmias Cardiac glycosides can be used to control the ventricular rate in patients with supraventricular tachycardia. Reversal causes arrhythmia such as electrolyte disturbance, drug toxicity, and hypoxia should be controlled. Intravenous lidocaine may be used. For significant conduction defects, cardiac pacing should be considered.

Management of New-Onset Arrhythmias The patient's hemodynamic status should be assessed. Management depends on the ventricular rate, the site of origin of the arrhythmia (atrial or ventricular), the need for cardioversion, and identifying and correcting the underlying causes. In hypotensive patients with acute tachyrhythmia, cardioversion should be performed using an initial pulse of 100 J. If this is not successful, it should rapidly increase to 360 J. If bradycardia is present, the patient should be treated with atropine.

Paroxysmal Supraventricular Tachycardia This may be caused by hypoxia, myocardial ischemia or infarction, or congestive failure. The primary treatment is adenosine 6 mg intravenously, which may be repeated after 1–2 min with 12 mg. If the arrhythmia persists, verapamil intravenously is indicated but should be used with caution.

Atrial Fibrillation This is particularly common after pulmonary resection. Direct current cardioversion is indicated when the patient is hemodynamically unstable. Verapamil may be used to convert, and digitalis glycoside is also helpful once the heart rate is decreased. When atrial fibrillation supervenes in a patient on digitalis, quinidine or procainamide is usually successful.

Sustained Supraventricular Tachycardia This may be the result of digitalis toxicity, and the medication should be discontinued and potassium supplemented if the serum level is low.

Atrial Flutter This can be associated with mitral or tricuspid valve disease or sustained pulmonary hypertension. The heart rate is controlled with electric shock, and once the heart rate is controlled, digitalis maintenance therapy is indicated.

Ventricular Tachycardia This is the most dangerous arrhythmia and cannot be tolerated for an extended period of time. The underlying cause is usually intrinsic disease of the heart, including cardiomyopathy or coronary artery disease. Treatment is similar to that used for ventricular fibrillation and incorporates electric shock therapy and lidocaine. Refractory cases have been treated successfully with bretylium.

Ventricular Fibrillation This is usually fatal and due to ischemia. Direct current countershock is used initially. Epinephrine may be administered, and lidocaine therapy or bretylium also should be used. Arterial blood gases should be used to guide the resuscitation.

Hypertension

There is controversy about whether hypertension represents a dangerous preoperative situation. It is not clear that these patients are at increased risk for cardiac morbidity and mortality. Preoperative hypertension does increase the risk of perioperative blood pressure lability, which in turn may contribute to the incidence of stroke, arrhythmia, and myocardial ischemia. In patients with mild to moderate hypertension, several factors may call for delay of an operative procedure. These include ECG changes of myocardial ischemia, new-onset dysrhythmias, emergence of left ventricular hypertrophy on ECG, new onset of unstable angina pectoris, congestive heart failure, a recent neurologic deficit, and a new onset of high-grade hypertensive retinopathy.

In patients who are taking antihypertensive medications, they should be continued until the day of surgery. If hypertension develops during anesthetic induction or postoperatively, the adequacy of ventilation, hydration, and fluid status should be established. If the hypertension reaches alarming heights, sodium nitroprusside or nitroglycerin can be used. Diuretic therapy may be required to diminish the intravascular volume. Preoperative medication should be resumed as soon as possible.

HYPERCOAGUlABLE STATES

Acquired Hypercoagulable States

Lupus anticoagulant factors interfere with heparin monitoring. The presence of these antibodies is associated with an increased risk of arterial and venous thrombosis. Patients with this factor should receive prophylactic anticoagulation before and immediately after surgery and also sequential compression boots against thromboembolism. Heparin-induced thrombocytopenia is a form of a consumptive platelet activation. It is idiosyncratic and not dose-dependent. Mild thrombocytopenia occurs 2–4 days after heparin exposure and may occur earlier if the patient had previously received heparin. A more severe syndrome includes profound hyperthrombocytopenia associated with multiple small-vessel thrombosis. In this circumstance, the mortality is significant. A diagnosis can be made based on measurement of antibody. Discontinuation of heparin results in lower morbidity and mortality if the syndrome is detected early.

Inherited Thrombotic Disorders

Antithrombin III deficiency is an autosomal dominant inherited trait associated with recurrent thrombosis in about 60 percent of patients and pulmonary embolism in up to 40 percent. Treatment is with heparin. These patients undergoing operation should be given fresh frozen plasma to raise the level of antithrombin III. Protein C deficiency also causes unexplained venous thrombosis as a result of a deficiency of a protein that is an inhibitor of the procoagulant system. Since the levels of this protein are affected by warfarin, anticoagulation therapy is usually sufficient. Protein S deficiency is also associated with increased thrombosis, and patients may require treatment for acute thrombotic disease that is often widely disseminated.

POSTOPERATIVE PAROTITIS

This may be a serious complication that is associated with a high mortality related mainly to the primary disease. Seventy-five percent of patients with this disorder are over the age of 70 and have undergone major operative procedures. The causes include poor oral hygiene, dehydration, and the use of anticholinergic drugs. Most infections are from staphylococci.

The interval between operation and onset of symptoms varies from hours to weeks. The patient usually presents with pain in the parotid region, and the gland is slightly swollen and tender. There is often associated and overlying cellulitis. Eventually, abscess formation can occur, and a significant enlargement can result in airway obstruction. Prophylaxis includes adequate hydration and good oral hygiene aided by methods to stimulate salivary flow. Prophylactic antibiotics have no value.

When considering the diagnosis, pus should be expressed from Stensen's duct. While awaiting the results, a broad-spectrum antibiotic that acts against staphylococci is initiated. If the disease persists or progresses and there is a suggestion of fluctuance, incision and drainage, often of multiple sites, are indicated.

COMPLICATIONS OF SURGERY OF THE GASTROINTESTINAL TRACT

Ileus and Partial Small Bowel Obstruction

Ileus is defined as nonmechanical obstruction that prevents normal postoperative progression of the return of bowel function. It is thought to arise from a neuroinhibition that interferes with coordinated intrinsic bowel wall motor activity. The small bowel does not manifest ileus postoperatively and continues to function unless there is an inflammatory process. Gastric ileus can persist from 24–48 h, whereas colonic ileus may last 3–5 days. Ileus increases with manipulation, inflammation, peritonitis, and large amounts of blood left in the peritoneal cavity. Blood in the retroperitoneum also produces ileus, as does hypokalemia, hypocalcemia, hyponatremia, and hypomagnesmia. Opiates and phenothiazines contribute to the delay in resolution of ileus.

Failure to pass contrast medium beyond a fixed point is pathognomonic of intestinal obstruction. Ileus and mechanical obstruction may be difficult to distinguish. If ileus persists postoperatively, a long tube may be effective in reversing the process without operation. The long tube, however, is generally contraindicated in the face of mechanical obstruction.

Anastomotic Leaks and Fistulas

Factors that increase the likelihood of an anastomotic leak following an intestinal procedure include emergency procedures, poorly prepared patients, inadequately resuscitated patients, prolonged intraoperative hypotension, and hypothermia. The three major etiologic factors are poor surgical technique, distal obstruction, and inadequate proximal decompression.

Duodenal Stump Blowout The incidence of duodenal stump blowout following gastric resection has been reported to be approximately 1 percent with a mortality of 0.6 percent. Duodenal stump leakage occurs most commonly after operations for duodenal ulcer, particularly emergency procedures to stop hemorrhage. Specific measures can be taken to avoid this complication. When the duodenal closure is difficult, a catheter duodenostomy may be used to develop a controlled fistula. Duodenal blowout is more likely to occur between the second and seventh postoperative days, manifested by sudden pain, temperature elevation, and general deterioration. Adequate drainage must be instituted immediately and is best accomplished with at large sump catheter passed down to the duodenal stump region.

INTESTINAL LEAKS AND FISTULAS

Leakage of intestinal anastomoses is manifest by fever, leukocytosis, unexplained ileus, and a complicated postoperative course. Computed tomography (CT) is usually diagnostic. Percutaneous drainage often is effective in reversing sepsis.

If the leak is small, or if previous drains were placed in the region of the anastomosis, nasogastric suction, antibiotics, and TPN may contain the leakage without further need of operative intervention. If the patient is in jeopardy, reexploration is indicated, at which time the anastomosis should not be resutured. It must be completely resected and redone, or the two ends of the bowel should be separated and diversion performed.

A fistula is an anastomotic leak that has developed a pathway to the skin. Typical presentation includes fever, ileus, leukocytosis, and malaise. On the fourth or fifth postoperative day, there is increased wound pain and redness leading to drainage of purulent material from the wound followed by leakage of intestinal contents. The treatment plan for patients with enterocutaneous fistulas is to allow the fistula to close spontaneously, if possible; operative intervention is reserved for patients in whom spontaneous healing does not occur.

Therapy of an Established Fistula The initial management of an established fistula is a period of stabilization of the patient, attempting to raise the albumin level to 3.0 mg/dL while giving the patient nothing by mouth. A sump-type drain is placed around the skin, and the skin and its edges are protected. Generally, TPN is administered, but enteral nutrition is also effective in some patients. After the patient is stabilized, the site of the fistula is identified by a fistulogram, and it is determined whether there is any distal obstruction. In the absence of distal obstruction, spontaneous closure usually occurs within 5 weeks of adequate nutritional support. Somatostatin has been used to promote closure, but there is no demonstration of speeding up of the process. A determination must be made as to whether an operation is indicated. If closure does not occur spontaneously, an operation is performed, at which time all adhesions are taken down and all abscesses drained. Resection and end-to-end anastomosis yield the lowest incidence of failure and the lowest incidence of complications. Ancillary procedures at the time of resection and operation include gastrostomy and feeding jejunostomy in some patients. After the procedure has been performed successfully, feeding is usually delayed for about a week.

Colocutaneous Fistulas These are generally the result of colonic anastomotic leaks, particularly in patients with acute diverticulitis. In contrast to enterocutaneous fistulas, fluid and electrolyte abnormalities are rare, and spontaneous closure occurs in about 75 percent of patients. The lack of spontaneous closure by 5 weeks is an indication for surgical repair, at which time the definitive operation involves resection of the fistula and affected segment with primary anastomosis and temporary diversion of the fecal stream by colostomy if necessary.

Postgastrectomy Syndromes

Dumping Dumping is the result of loss of the pyloric valve that allows hyperosmolar material to rapidly enter the small intestine. This results in physiologic changes including the release of vasoactive substances. There is also loss of plasma volume as the small intestine secretes actively to dilute the hyperosmolar contents. Rapid absorption of glucose and secretion of insulin and the rapid entry of glucose and potassium into the cell result in hypokalemia.

The manifestations result in early postprandial bloating, borborygmus, cramps, light-headedness, palpitations, sweating, and hypotension. Carbohydrate-rich foods are more likely to provoke dumping and should be avoided. In severe cases, octreotide may relieve the symptoms. If the patient remains symptomatic, a Billroth II anastomosis should be converted to a Billroth I anastomosis. If this strategy fails, an interposed 6-cm reversed loop of jejunum may slow the transit of hypertonic solution into the small bowel.

Postvagotomy Diarrhea Most patients have increased bowel movements after truncal vagotomy. In about 5–20 percent of patients, diarrhea is troublesome, and in 1–2 percent, it is disabling. Treatment is difficult. In patients who are incapacitated, a 10-cm reversed jejunal loop 100 cm distal to the ligament of Treitz has been advocated.

Afferent Loop Syndrome This is a mechanical problem peculiar to gastroenterostomy reconstruction after gastrectomy. There is disturbance of flow from the afferent loop into the efferent loop. The afferent loop syndrome can be acute or chronic. In the chronic form, as the afferent loop becomes obstructed, bile, pancreatic juice, and duodenal secretions are suddenly regurgitated into the stomach. In the acute form, as the secretion increases, a perforation can occur.

The manifestations include sudden pain and cramps relieved by projectile vomiting of clear bile. The diagnosis can be made on the basis of an upper gastrointestinal series showing a massively distended afferent loop. Operation is required for relief of this symptom and in most instances consists of anastomosing the afferent loop into a Roux-en-Y efferent loop downstream. A vagotomy is carried out to reduce the propensity for marginal ulcer.

Alkaline Reflux Gastritis In patients in whom there is constant reflux of bile into the stomach, the symptoms consist of continual burning epigastric pain. Eating is associated with an increase in pain rather than relief, and vomiting may be present. Endoscopy reveals a great amount of bile emanating from the afferent loop, and there is a diffuse, beefy-red gastritis.

The most effective treatment is a combination of cholestyramine and sucralfate. If medication does not relieve the symptoms, a Roux-en-Y may be corrective.

Stomal Complications

An enteral stomal therapist is an essential member of the team. The stoma should be placed through the rectus muscle a sufficient distance from the umbilicus and the anterosuperior iliac spine. There should be no tension on the bowel as it is brought up through the fascia, and the bowel should be fixed to the fascia to prevent it from falling back into the abdomen. The fascial opening should be adequate. The stoma should not be placed in a skin crease or at the belt line.

Recurrence of Disease The incidence of complications for ileostomies is about 4 percent in patients with ulcerative colitis and up to 30 percent in patients with Crohn's disease. Crohn's disease may result in peristomal fistulas. Antibiotics should be administered, and there is little advantage to resiting the stoma because the Crohn's disease usually leads to recurrence.

Stomal Necrosis and Retraction Inadequate vascularization of the stoma can lead to ischemia or necrosis in the immediate postoperative period. The development of duskiness should prompt an evaluation to determine the extent of involvement. If necrosis is superficial to the fascia, no immediate action is required, but stricture usually results. If the necrosis extends below the fascia, immediate exploration and reconstruction are indicated.

Skin Complications Skin complications are usually a result of siting and the inability to obtain an appropriate seal around the stoma. The critical issue for healing of peristomal skin is the placement of a stomadhesive that can be left in place for 5–7 days. Bulk formers such as metamucil also thicken ileostomy contents so that they will be more manageable. When the breakdown is severe, the patient may require placement of a sump tube within the ileostomy.

Stomal Stricture This is usually a late complication. Primary maturation of the stoma has drastically reduced the development of serositis. A superficial stricture of the stoma can be dilated, and at times, an operation under local anesthesia can relax the skin. If the stricture is at the fascial level, the fascia must be enlarged and the bowel fixed to a newly enlarged opening.

Peristomal Hernias and Prolapse In occasional circumstances, a local procedure can reduce the hernia. In the majority of patients, the entire stoma must be repositioned. The fascial defect of the peristomal hernia should be closed to ensure that a ventral hernia does not occur.

METABOLIC COMPLICATIONS

Syndrome of Inappropriate Secretion of Antidiuretic Hormone (SIADH)

This is perhaps the most common metabolic complication after surgery and is especially frequent in the elderly. If unrecognized, it may result in central nervous system damage, seizures, and even death. The development of this syndrome is augmented by the tendency to overhydrate patients postoperatively.

If the serum sodium concentration falls below 125 mEq/L, fluid restriction is all that is necessary because the syndrome generally corrects itself. If, however, the serum sodium level is significantly reduced, 3% saline solution is the treatment of choice. This is particularly true if the patients are confused and somnolent. Mannitol should be used in this situation to provoke a diuresis of excess water.

Disorders of Thyroid Metabolism

Thyroid Storm This is an infrequent occurrence seen in patients in whom thyrotoxicosis is unrecognized before the induction of anesthesia and surgery. Tachycardia, fever, and changing mental status are the predominant symptoms. Treatment consists of propranolol or other beta blockers to stabilize the cardiovascular system. Propylthiouracil and potassium iodide are given to decrease T₃ and T₄ release.

Myxedema Coma This is an extremely rare complication that occurs in patients who are chronically hypothyroid and are provoked by the stress of an operation. The manifestations include hypoventilation, hypothermia, bradycardia, and seizures or coma. The treatment consists of warming, hydration, assisted ventilation, and the administration of L-thyroxine intravenously.

Adrenal Insufficiency

This may occur as a result of previous administration of steroids or the destruction or exhaustion of the adrenal glands during an operative procedure. Adrenal insufficiency complicates other forms of severe illness such as sepsis, shock, or trauma and can result in unexplained hypotension that will end fatally unless treated. It is manifest by fever, abdominal pain, hypotension, light-headedness, palpitations, and changes in mental status. There is associated hypoglycemia, hyponatremia, and occasionally hypokalemia. The cortisol level should be measured, and treatment consists of 200 mg hydrocortisone intravenously. The hydrocortisone should be continued in divided doses over 24 h and then tapered to a maintenance dose.

Liver Failure

Patients with cirrhosis, alcoholic hepatitis, or fatty infiltration are prone to develop liver failure postoperatively. Patients who develop shock are more at risk. The manifestations include somnolence, jaundice, diminished urine output, and ascites. Liver function tests reveal an elevated bilirubin level, a decreased albumin level, and a lengthening of the prothrombin time. Spontaneous bacterial peritonitis must be ruled out in these patients.

Treatment consists of correction of the electrolyte abnormalities; administration of neomycin, cathartics, or lactulose orally or by enema; and provision of nutritional support. A modified low-aromatic, high-branched-chain-amino-acid formulation is appropriate. A high cardiac output with low peripheral resistance usually complicates hepatic failure. Hemodynamic support should be initiated with dopamine and alpha-adrenergic agents to restore peripheral resistance.

PSYCHIATRIC COMPLICATIONS

There is an increased incidence of postoperative psychiatric complications in older patients. In some series, delirium has been diagnosed in up to 20 percent of elderly patients on the intensive care unit. “Postoperative psychosis” cannot be considered a distinct clinical entity, and no single factor has been shown to be responsible.

Clinical Manifestations The duration of the latent interval between surgical treatment and psychological disturbance may be days to weeks. In the recovery room, patients usually exhibit a lack of concern about the operation and an absence of affective response. After 24 h, the patient responds with concerns and emotions that have been conspicuously absent in the immediate postoperative period. The manifestations of this disorder are extremely variable. Fear can be accompanied by depression, elation, and overactivity. There may be acute delirium with confusion and disorientation or merely a vague change in perception or mood. Delirium may begin with an inappropriate remark or a dramatic outburst.

Depressive reactions are the second most important psychosis noted in several series. The patient is characteristically uncooperative in an active way or may be listless. It is not rare for a schizophrenic reaction to have its onset in the surgical patient. The incidence of postoperative psychosis is not related to the duration of preoperative hospital stay. By contrast, emergency operation often results in reactions marked by acute anxiety, nightmares, insomnia, and irritability.

Management There is a need to integrate psychological treatment with management of the surgical problem. Verbal communication between the surgeon and the patient is the best means of overcoming emotional or mental difficulty. Consultation with a psychiatrist is indicated in the case of any acute and severe emotional disturbance. This referral should be candidly discussed between the surgeon and the patient. A number of drugs including tranquilizers and S1 antagonists have been helpful in the treatment of postoperative psychological complaints.

Delirium Tremens and Other Forms of Delirium

A relatively normal-appearing patient may undergo withdrawal from alcohol or narcotics in the postoperative period. This is potentially fatal if not corrected. The patient is typically hyperactive with irritability, delusions, hallucinations, restlessness, and agitation. Prophylactic lorazepam should be administered in the perioperative period to patients with severe alcoholic histories who are candidates for delirium tremens.

Special Surgical Situations

Pediatric Surgery In children, severe anxiety states may be precipitated by the shock of operation. This occurs most frequently in the 1–2-year-old group. Postoperative reactions consist of disobedience, temper tantrums, defiance, and destructive behavior. Moderate and severe reactions may require medications.

Surgery in the Aged Elderly patients are more prone to becoming emotionally disturbed when confronted with new situations. Severe depression is not uncommon subsequent to an operation in older patients. These patients should be encouraged to maintain human contact and prevent withdrawal.

Gynecologic and Breast Surgery Removal of the breast and a variety of gynecologic procedures may be accompanied by severe depression. Routine counseling lowers the postoperative psychiatric morbidity significantly.

Cancer Surgery Cancer patients are exposed to two major threats, disease and extensive surgical treatment. They are concerned with death during the operation and the threat of disease throughout the postoperative years. Postoperative depression is related to anticipated interference with valued activities. A colostomy may suggest to patients that they will be rejected socially. Some patients suffer a sense of isolation, guilt, and abandonment.

Cardiac Surgery Severe psychiatric disturbances have been observed to occur with considerable frequency after open-heart surgery. They do resolve rapidly after the patient is transferred from the intensive care unit to the standard hospital ward. The incidence of psychosis is greater in males, older patients, and those expressing minimal preoperative anxiety. Children generally react well to open-heart surgery.

Dialysis and Transplantation Patients undergoing dialysis become extremely dependent and emotionally attached to the staff. A large number of psychological syndromes have been described in patients undergoing transplantation. This is particularly true of patients of who have had living donors provide the transplanted organ.

For a more detailed discussion, see Fischer JE, Fegelman E, and Johannigman J: Surgical Complications, chap. 11 in Principles of Surgery, 7th ed.

Books@Ovid

Copyright © 1998 McGraw-Hill

Seymour I. Schwartz

Principles of Surgery Companion Handbook