1. Risk of surgery. Patients with ischemic heart disease undergoing surgery are at greater risk for perioperative myocardial infarction. This risk is significantly greater in patients with a recent infarction. Stable angina pectoris is not thought to increase the risk of surgery, but unstable angina does. A prior myocardial infarction also increases risk, particularly if the infarction has occurred 3 to 6 months before the surgery. Patients who have undergone coronary revascularization have a substantially lower risk for postoperative myocardial infarction. A number of factors contribute to the risk for postoperative death, including decompensated congestive heart failure, arrhythmias, and obstructive lung disease.
2. Preoperative testing. The precise role of stress testing, nuclear scanning, and ambulatory electrocardiography in the preoperative setting is not clear. Such testing may be helpful in selected patients, and a decision regarding their utility can be reached in conjunction with cardiology consultation. Nonetheless, patients with unstable angina or a recent myocardial infarction should not undergo elective surgery until their risk can be modified with appropriate medical and surgical management.
3. Drug therapy. For patients taking long-acting nitrates, the drug should be given on the morning of surgery; cutaneous nitrate preparations can be continued postoperatively until the patient resumes oral intake. Likewise, beta blockers and calcium channel blockers should be restarted as soon as possible postoperatively. Decisions to give cardioactive and vasoactive medication on the day of surgery should be fully discussed and sanctioned by the anesthesiologist.
4. Postoperative testing. Postoperative surveillance for the development of cardiac ischemia or myocardial infarction is required for patients at high risk for these complications. Although creatine kinase levels are usually elevated in these patients because of the muscle trauma associated with surgery, serial electrocardiograms and determination of creatine kinase isoenzymes are useful in the detection of interval ischemia.
C. Congestive heart failure. Patients with decompensated congestive heart failure and, to a lesser extent, those with a history of cardiac failure are at greatest risk in the postoperative setting. Therefore, it is important to assess the patient's intravascular volume status, and elective surgery should be postponed until any existing cardiac failure is controlled. Patients should be maintained on their usual program of medications, including diuretics and ACE inhibitors, throughout the perioperative period. Digitalization before surgery is reasonable in patients with a known congestive cardiomyopathy, and in patients with a history of atrial fibrillation.
D. Valvular heart disease. The risks of surgery in patients with valvular heart disease depend on the valve affected and on the nature and severity of the valvular lesion. Hemodynamically significant aortic stenosis is the most serious lesion, followed by hypertrophic cardiomyopathy (the latter being considered a relative contraindication to epidural or spinal anesthesia). Mild to moderate mitral lesions or aortic insufficiency is usually well tolerated, although hemodynamically significant valvular disease (New York Heart Association class 3 or 4) of any type creates major risks. When it is present, cardiology consultation and monitoring from 13 to 48 hours is prudent.
E. Pulmonary disease. Chronic obstructive lung disease and asthma are the two forms of pulmonary disease seen most frequently in the preoperative setting.
1. Risk of surgery. The risk of pulmonary complications can be attributed to various factors, both pulmonary and nonpulmonary. Minor pulmonary complications (atelectasis, bronchitis) are increased in patients who smoke or who have chronic cough or abnormal spirometry values. However, the risk for severe postoperative pulmonary complications (pneumonia, respiratory failure) is increased mainly in those patients with marked impairment in lung function (FEV-i <1.5 L). Among the nonpulmonary factors that contribute to the risk for postoperative complications are age, obesity, longer duration of anesthesia, excessive sedation, poor patient effort, and the type of surgery. Respiratory dysfunction is less severe after orthopedic than after intraabdominal or thoracic surgery.
2. Bronchodilator therapy. Patients who are taking bronchodilators on a long-term basis before surgery should be given their standard dose the night before surgery, and bronchodilator therapy should be administered postoperatively either systemically or by nebulizer.
3. Incentive spirometry and mobilization are helpful in preventing postoperative atelectasis or pneumonia.
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If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.