Principles of surgery
BOX 1-11 -.
Review of Cardiovascular and Respiratory Systems
1. Consult patient’s primary care physician,
2. Defer major elective surgery until 6 months after
3. Check if patient is using anticoagulants (including
4. Use anxiety reduction protocol.
5. Have nitroglycerin available; use prophylactically if
physician advises. ,
6. Administer supplemental oxyqen,
7. Provide profound local anesthesia.
8. Consider nitrous oxide.
9. Monitor vital signs and maintain verbal contact.
’10. Possible limitation of epinephrine used to 0.04 mg.
11. Consider referral to oral and maxillofacial surgeon.
Angina, MI, or both and therefore should be managed as previously described. Routine office surgical procedures may be safely performed in patients less than 6 months after CABG surgery if their recovery has been
uncomplicated and anxiety is kept to a minimum.
Coronary’ angioptasty. The introduction of balloontipped catheters into narrowed coronary arteries for the purpose of reestablishing adequate blood flow and stenting arteries open is becoming commonplace. If the angloplasty has been successful (based on cardiac stress testing), oral surgery can proceed soon thereafter, with the same precautions as those used for angina patients.
Cerebrovascular accident (stroke). Patients who have had a erebrovascular accident are always susceptible to further neurovascular accidents. They are generally placed on anticoagulants and, if ypertensive, are taking blood pressure-lowering agents. If such a patient equires surgery, clearance by the patient’s physician is desirable, as is a delay until significant hypertensive tendencies have been controlled.The patient’s baseline neurologic status should be assessed and documented preoperativeIy. The patient should be treated by a nonpharmacologlc anxiety reduction protocol and have vital signs carefully monitored during surgery. If pharrnacolog.c sedation isnecessary, low concentrations of nitrous oxide can he used. Techniques to manage patients taking anticoagulants are discussed later in this chapter.
Dysehythmias. Patients who are ‘prone to or who have cardiac dysrhythmias usually have a history of ischemic heart disease requiring ‘dental management modifications. Many advocate limiting the total amount of epinephrine administration to 0.0-1 mg. However, in addition, they may have been placed on anticoagulants or have a permanent cardiac pacemaker. Pacernarers pose no contraindications to oral surgery, and no evidence exists showing the need for antlbiotic prophylaxis in patients with pacemakers. Electrical equipment, such as electrocautery and microwaves, should not be used near the palicnt. As with other medically compromised patients, vital signs should be carefully monitored.
Heart abnormalities predisposed toward infective endocarditis. The internal cardiac surface. or endocarditis, can be predisposed toward infection when abnormalities of its surface allow pathologic bacteria to attach and multiply. A complete description of this process and
recommended means of preventing it are discussed in Chapter 16.
Congestive heart failure (hypertrophic cardiomyopathv). Congestive heart failure occurs when a diseased myocardium is unable to deliver the cardiac output demanded by the body or when excessive demands are, placed on a normal myocardium. The heart begins, to have an increased end-diastolic volume that, in the case of the normal myocardium, increases Contractility
through the Frank-Starling mechanism. However, as the normal or diseased myocardium further dilates, ‘it becomes a less efficient pump, causing blood to back up into the pulmonary, hepatic, and mesenteric vascular
beds. This eventually leads to ‘pulmonary edema, hepatic dysfunction, and compromised intestinal nutrient absorption.The lowered cardiac output ,causes generalized weakness, and impaired renal clearance of excess fluid
leads to vascular overload.
Symptoms of congestive heart failure include orthopedist, paroxysmal nocturnal dyspnea, and ankle edema.Orthopnea is a respiratory disorder that exhibits shortness of breath when the patient is in the supine position.
Orthopnea usually.occurs as a result of the redistribution of blood ‘pooled in the lower extremity when a patient assumes the supine position (as when sleeping). The heart’s ability to handle the increased cardiac preload is overwhelmed, and blood backs up in the pulmonary circulation, producing pulmonary edema. Patients with orthopnea usually sleep with their upper body supported on several pillows.
Paroxysmal nocturnal dyspnea is a symptom of congestive heart failure that is similar to orthopnea. The patient has respiratory difficulty 1 or 2 hours after assuming a supine position. The disorder occurs when pooled
blood and interstitial fluid reabsorbed into the vasculature from the legs are redistributed centrallv, overwhelming the heart and producing pulmonary edema. Patients suddenly wake awhile after laying down to sleep feeling short of breath and frequently desiring to open a window
to breathe cool air.
Lower extremity edema usually appears as a swelling of the foot, the ankle, or both that is caused by an increase in interstitial fluid, Usually till’ fluid collects as a result of any problem that increases venous pressure, forcing increased amounts of plasma to remain in the tissue spares of the feet. The edema is detected by pressing a finger into the swollen area for a few seconds: if an indentation in the soft tissue is left after the finger is removed, pedal edema is present, Other symptoms of congestive heart failure include weight gain, dyspnea on exertion, and general weakness.
Patients with congestive heart failure who are under a phvsician care usually are on low-sodium diets to red use fluid retention and are” receiving diuretics to reduce intravascular volume cardiac glycosides, such as digoxin, to improve cardiac efficiency and sometimes after load .