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Approximately 70% of patients who develop perioperative pulmonary edema do so in the first hour after surgery, and the greatest onset occurs during the first 30 minutes. Causes include the following:

Volume overload

Cessation of positive-pressure ventilation with subsequent increase in preload

Anesthetic -induced myocardial depression

Postoperative hypertension

Arrhythmias and conduction abnormalities

Incidence

Up to 84% of patients who undergo surgery exhibit abnormalities of cardiac rate or rhythm in the perioperative period. Only 5% of these abnormalities are clinically significant.

The incidence of arrhythmias is highest during surgery that lasts longer than 3 hours, during neurosurgical or thoracic surgery, and during endotracheal intubation.

Metabolic abnormalities are the most common cause of arrhythmia (i.e., hypoxia, hypercarbia, hypokalemia, hyperkalemia). Therapy is aimed at reversal of these abnormalities.

Electrocautery used during surgery can affect the performance of cardiac pacemakers and implanted cardiac defibrillators (AICD)

The electromagnetic interference generated by electrocautery may be “sensed” by a pacemaker as intrinsic cardiac electrical activity and inhibit cardiac pacemaker activity. This inhibition may be prevented by temporarily programming the pacemaker to a fixed rate mode. In the operating room, placing a pacemaker magnet on the pacemaker during the surgical procedure will make the pacemaker operate in a fixed rate mode.

An AICD may interpret the electromagnetic interference of electrocautery as ventricular tachycardia or ventricular fibrillation, which would trigger the AICD to deliver a

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defibrillating shock. This may be prevented by turning off the AICD immediately prior to surgery and turning on the AICD on completion of the surgical procedure.

Valvular heart disease

Critical aortic stenosis is associated with an increased risk of perioperative cardiac complications.

These patients typically cannot increase cardiac output because an outflow obstruction is present at the site of the aortic valve.

Therefore, any hemodynamic changes that could result in a need for increased cardiac output (e.g., vasodilatation) should be avoided.

Aortic or mitral regurgitation. Operative risk is related to the status of left ventricular function rather than to the degree of valvular regurgitation.

Mitral stenosis. Volume status and heart rate are key factors in the perioperative period.

Tachycardia decreases diastolic filling time and may result in pulmonary edema.

Small fluid shifts may result in marked hemodynamic abnormalities.

Prosthetic heart valves. Patients with prosthetic heart valves are at risk for valve thrombosis and thromboembolic complications if anticoagulants are withheld for an excessive period preoperatively.

For most patients, anticoagulants can be discontinued up to 3 days before surgery and restarted 2–3 days after surgery without thromboembolic complications.

Patients with caged-disk prosthetic mitral valves have a high risk of valve thrombosis when they are not receiving anticoagulation.

For these patients, warfarin anticoagulation should be stopped 3 days before surgery and replaced with full -dose intravenous heparin, which is stopped 12 hours before surgery.

Once hemostasis is stable after surgery (usually at 12–24 hours postoperatively), heparin therapy is resumed. Warfarin therapy is started again once oral intake is begun.

Hypertrophic cardiomyopathy. Patients with hypertrophic cardiomyopathy with left ventricular outflow tract obstruction are at risk for worsening of left ventricular outflow tract obstruction in the perioperative period. Factors that may lead to worsening of the left ventricular outflow tract gradient include excessive preload or afterload reduction, which may occur with volume depletion or vasodilator therapy. Perioperative catecholamine release may directly act on the left ventricular outflow tract to increase myocardial contractility and increase the outflow tract gradient.

D Approaches to reduction of perioperative cardiac risk

Perioperative beta blocker therapy

Data from small clinical trials suggest that beta blockers decrease the risk of cardiac complications in the perioperative period.

An observational study has found that perioperative beta blockers have their greatest benefit in preventing cardiac complications in patients at increased cardiac risk, i.e., those having three or more of the following clinical features: (a) ischemic heart disease, (b) cerebrovascular disease, (c) renal insuficiency, (d)diabetes mellitus, (e) undergoing high-risk surgery.

The American College of Cardiology/American Heart Association 2006 Update on Perioperative Beta Blocker Therapy recommends that beta blockers be continued in patients already receiving beta blockers and initiated in patients undergoing vascular surgery who are estimated to be at high cardiac risk as determined by the presence of ischemia on preoperative testing. This guideline states that beta blockers are probably recommended for patients who undergo vascular surgery with a history of coronary artery disease or who have multiple coronary artery disease risk factors and for patients with multiple cardiac risk factors who undergo intermediate -risk or high-risk surgical procedures. Beta blockers may be considered for patients who undergo intermediate -risk or highrisk surgical procedures who have a single clinical cardiac risk factor and may also be considered for patients who undergo vascular surgery who have no cardiac risk factors.

Beta blocker therapy should be titrated to achieve a heart rate of 60–70 beats per minute in the perioperative period.

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Anticipation of fluid shifts in the patient with left ventricular dysfunction or fixed cardiac output

Major vascular surgery in the patient with left ventricular dysfunction Surgery in the patient with a recent MI or unstable angina

G

Bacterial endocarditis prophylaxis (Tables 3-4, 3-5, 3-6, 3-7, 3-8) is indicated for procedures associated with bacteremia for patients with

Prosthetic heart valves

Rheumatic or other acquired valvular abnormalities

Mitral valve prolapse with mitral regurgitation

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TABLE 3-4 Cardiac Conditions Associated with Endocarditis

Endocarditis prophylaxis recommended

High-risk category

Prosthetic cardiac valves, including bioprosthetic and homograft valves Previous bacterial endocarditis

Complex cyanotic congenital heart disease (e.g., single ventricle states, transposition of the great

arteries, tetralogy of Fallot)

Surgically constructed systemic pulmonary shunts or conduits

Moderate-risk category

Most other congenital cardiac malformations (other than above and below) Acquired valvar dysfunction (e.g., rheumatic heart disease)

Hypertrophic cardiomyopathy

Mitral valve prolapse with valvar regurgitation or thickened leaflets

Endocarditis prophylaxis not recommended

Negligible-risk category (no greater risk than the general population)

Isolated secundum atrial septal defect

Surgical repair of atrial septal, ventricular septal defect, or patent ductus arteriosus (without residua beyond 6 months)

Previous coronary artery bypass graft surgery Mitral valve prolapse without valvar regurgitation Physiologic, functional, or innocent heart murmurs

Previous Kawasaki disease without valvar dysfunction Previous rheumatic fever without valvar dysfunction

Cardiac pacemakers (intravascular and epicardial) and implanted defibrillators

From Dajani AS, Taubert K, Wilson W, et al. Prevention of bacterial endocarditis: recommendations by the American Heart Association. JAMA. 1997;277:1794–1801.

TABLE 3-5 Dental Procedures and Endocarditis Prophylaxis

Endocarditis prophylaxis recommended*

Dental extractions

Periodontal procedures including surgery, scaling and root planing, probing, and recall maintenance

Dental implant placement and reimplantation of avulsed teeth

Endodontic (root canal) instrumentation or surgery only beyond the apex Subgingival placement of antibiotic fibers or strips

Initial placement of orthodontic bands but not brackets Intraligamentary local anesthetic injections

Prophylactic cleaning of teeth or implants where bleeding is anticipated

Endocarditis prophylaxis not recommended

Restorative dentistry (operative and prosthodontic) with or without retraction cord‡ Local anesthetic injections (nonintraligamentary)

Intracanal endodontic treatment; postplacement and buildup Placement of rubber dams

Postoperative suture removal

Placement of removable prosthodontic or orthodontic appliances Taking of oral impressions

Fluoride treatments Taking of oral radiographs

Orthodontic appliance adjustment Shedding of primary teeth

*Prophylaxis is recommended for patients with highand moderate-risk cardiac conditions.

This includes restoration of decayed teeth (filling cavities) and replacement of missing teeth.

‡Clinical judgment may indicate antibiotic use in selected circumstances that may create significant bleeding.

From Dajani AS, Taubert K, Wilson W, et al. Prevention of bacterial endocarditis: recommendations by the American Heart Association. JAMA. 1997;277:1794–1801.

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TABLE 3-6 Other Procedures and Endocarditis Prophylaxis

Endocarditis prophylaxis recommended

Respiratory tract

Tonsillectomy or adenoidectomy

Surgical operations that involve respiratory mucosa

Bronchoscopy with a rigid bronchoscope

Gastrointestinal tract*

Sclerotherapy for esophageal varices

Esophageal stricture dilation

Endoscopic retrograde cholangiography with biliary obstruction

Biliary tract surgery

Surgical operations that involve intestinal mucosa

Genitourinary tract

Prostatic surgery

Cystoscopy

Urethral dilatation

Endocarditis prophylaxis not recommended

Respiratory tract

Endotracheal intubation

Bronchoscopy with a flexible bronchoscope, with or without biopsy

Tympanostomy tube insertion

Gastrointestinal tract

Transesophageal echocardiography

Endoscopy with or without gastrointestinal biopsy

Genitourinary tract

Vaginal hysterectomy

Vaginal delivery

Cesarean section

In uninfected tissue:

Urethral catheterization

Uterine dilatation and curettage

Therapeutic abortion

Sterilization procedures

Insertion or removal of intrauterine devices

Other

Cardiac catheterization, including balloon angioplasty

Implanted cardiac pacemakers, implanted defibrillators, and coronary stents

Incision or biopsy of surgically scrubbed skin

Circumcision

*Prophylaxis is recommended for high-risk patients; it is optional for medium-risk patients.

Prophylaxis is optional for high-risk patients.

From Dajani AS, Taubert K, Wilson W, et al. Prevention of bacterial endocarditis: recommendations by the American Heart Association. JAMA. 1997;277:1794–1801.

Most congenital cardiac defects

Surgically constructed systemic-pulmonary shunts

Hypertrophic obstructive cardiomyopathy

Prior history of bacterial endocarditis

III The Surgical Patient with Chronic Lung Disease

Chronic lung disease is common and affects surgical patients of all ages and diagnoses. It has multiple causes and, when severe, increases the risk of surgery. The disease may be symptomatic (in the form of dyspnea) or totally asymptomatic. In addition, an acute infectious process may be superimposed on a chronic disorder. P.74

TABLE 3-7 Prophylactic Regimens for Dental, Oral, Respiratory Tract, or Esophageal Procedures

IM, intramuscularly; IV, intravenously.

*Total child's dose should not exceed the adult dose.

Cephalosporins should not be used in individuals with an immediate-type hypersensitivity reaction (urticaria, angioedema, or anaphylaxis) to penicillins.

From Dajani AS, Taubert K, Wilson W, et al. Prevention of bacterial endocarditis: recommendations by the American Heart Association. JAMA. 1997;277:1794–1801.

A Assessment of pulmonary risk

History

A history of pulmonary symptoms and disorders should alert the physician that further intervention and evaluation may be necessary.

Dyspnea

Sputum production

Chronic cough

Exercise intolerance

Prior medical conditions

Recurrent bronchitis or pneumonia

Chronic obstructive pulmonary disease (COPD)

Emphysema

Systemic disease with potential pulmonary involvement

Previous lung surgery

Exposure to environmental toxins

Cigarette smoking , the most common cause of chronic lung disease, is toxic to the respiratory epithelium and cilia and results in impaired transport of mucus, with consequent impaired resistance

to infection.

Physical examination. Abnormal findings follow.

Anatomic abnormalities (e.g., scoliosis or chest wall abnormalities)

Findings on auscultation of the chest (e.g., decreased breath sounds, wheezing, and rhonchi or rales)

Signs of inadequate oxygenation (e.g., cyanosis, finger clubbing, and use of accessory muscles for breathing)

Chest radiograph. Abnormal findings include blebs, pneumonitis, consolidation, pleural effusion, and hyperaeration with flattening of the diaphragm.

Laboratory studies

Arterial blood gases provide information on the adequacy of ventilation and oxygenation. Abnormal laboratory values include hypoxemia and hypercarbia.

Secondary polycythemia may also be seen in patients with chronic hypoxia.

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TABLE 3-8 Prophylactic Regimens for Genitourinary/Gastrointestinal (Excluding Esophageal) Procedures

IM, intramuscularly; IV, intravenously.

*Total child's dose should not exceed the adult dose.

No second dose of vancomycin or gentamicin is recommended.

From Dajani AS, Taubert K, Wilson W, et al. Prevention of bacterial endocarditis: recommendations by the American Heart Association. JAMA. 1997;277:1794–1801.

Pulmonary function tests. The correlation between preoperative pulmonary function tests and postoperative complication rates is controversial. No single pulmonary function test absolutely contraindicates an operation; however, abnormal results on several pulmonary function tests are thought to be associated with an increased probability of postoperative pulmonary complications.

In the absence of symptoms or significant history, routine preoperative spirometry is not indicated in extrathoracic surgery.

Preoperative spirometry and arterial blood gases may be considered in patients with

Planned thoracic procedures , with or without pulmonary resection

Productive cough and dyspnea

A history or physical findings of cardiopulmonary disease

A history of more than 20 pack -years of cigarette smoking

Abnormal chest radiograph findings

Morbid obesity

The ASA risk classification , when greater than class I or II, in combination with other risk factors, may predict the occurrence of pulmonary complications.

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For patients with planned thoracic surgery ,

Specific criteria have been published for the minimum pulmonary function necessary to tolerate varying degrees of pulmonary resection (Table 3-9).

Pulmonary function tests may be repeated after bronchodilator therapy to assess improvement after