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Unit VI Promoting Health in Patients With Circulatory or Perfusion Disorders
Treatment Medications for patients with CAD are often prescribed with the goals of (a) stopping the aggregation of blood components to the injured endothelium, (b) controlling factors that led to damage of the endothelium, and (c) relieving symptoms (Table 30.2). Patients with stable angina at low risk for ACS are often prescribed aspirin and nitroglycerin along with medications to reduce risk factors, such as antihypertensives, antidiabetic agents, and cholesterol-lowering medications. Aspirin prevents thrombus formation in the coronary artery. Nitroglycerin, a vasodilator, is used to manage anginal epi- sodes, both at home and in the hospital. Nitroglycerin can be administered as sublingual tabs, as a spray or powder, intra- venously, through transdermal patches, as an ointment, and by mouth with extended-release capsules. During anginal episodes, the sublingual and IV routes are preferred to restore blood flow promptly. Blood pressure should be monitored carefully due to the adverse effect of hypotension. Headaches can also occur and are best treated with nonopioid analgesics such as acetaminophen. Treatment of ACS in the acute care setting includes aspirin, supplemental oxygen for oxygen sat- urations less than 94%, nitroglycerin, and morphine or other opioid for pain management and can be referred to by the acronym MONA. Morphine can be given for angina pain in patients not responsive to nitroglycerin, but its use can be associated with hypotension, nausea, and vomiting. The use of oxygen has been a cornerstone of supportive care but there is some evidence that it may cause complications, such as vaso- constriction, when given to patients with an oxygen saturation higher than 93%. The use of oxygen should be evaluated on a case by case basis. Beta blockers, additional anticoagulants, and possibly calcium channel blockers are also prescribed in ACS management. Treatment for nonobstructive CAD is being studied. Statins, angiotensin-converting enzyme (ACE) inhibitors, and beta blockers may be beneficial.
receives monitored anesthesia care (MAC), a catheter with a small balloon on its tip is advanced under fluoroscopy through a suitable artery, commonly the femoral or radial, to the area with atherosclerotic plaque. The balloon is inflated and deflated to open the lumen of the artery. During this time, patients may experience chest pain due to vessel occlu- sion. Once the lumen is open, a stent may be advanced to the location to hold the artery open and maintain adequate blood flow. Stent options include bare metal stents, drug-eluting stents to prevent clots, or bioabsorbable stents. Patients fre- quently return from the procedure with a vascular closure device, such as an angioseal, applied to the access site to main- tain hemostasis. This allows early ambulation. If no closure device is applied, strict bedrest for 6 to 8 hours is required until hemostasis is achieved. Figure 30.3 illustrates stent placement within the artery. Bleeding at the insertion site, abrupt vessel closure, dysrhythmias, and ruptured arteries are uncommon but potential complications from PCI (see Genetic Connec- tions: Pharmacogenetics and Clot Prevention). Care of the patient receiving a PCI is outlined in Chapter 28. Pharmacogenetics and Clot Prevention Anticoagulants and antiplatelets such as warfarin or clopidogrel are prescribed after percutaneous coronary intervention (PCI). Patient responses to standard doses can vary greatly. Some patients need very low doses to reach therapeutic levels, whereas others require very high doses. Pharmacogenetics is the study of how a person’s genes affect responses to medications. With scientific advances, genetic testing can now be used to determine responsiveness. In the case of warfarin, some patients are genetically fast metabolizers, which can result in an increased risk of clotting and the need for higher or more frequent doses. In contrast, slow metabolizers have an increased risk of bleeding and require lower or less frequent doses. Patients who are fast or slow metabolizers may also respond similarly to other types of medications. Pharmacogenetic testing is not widely used due to availability, clinician knowledge, and regulatory and reimbursement issues, but it may be valuable. Genetic Connections A more invasive surgical treatment is coronary artery bypass grafting (CABG) . With CABG, blockages in coronary arteries are bypassed using other arteries from the chest or arm or veins from the legs. In the traditional CABG, patients undergo general anesthesia. A large inci- sion through the sternum is made, and a cardiopulmonary bypass (CPB) is begun through large catheters in the vena cava or right atrium and aorta. A CPB provides continuous
Safety Alert
Medication Safety Alert: Nitroglycerin
Nitroglycerin is a treatment for angina. Patients should be instructed to take this medication as prescribed, typically one tablet or spray under the tongue not to exceed three doses taken 5 minutes apart. If the symptom of angina (chest pain) is not relieved with three doses or if the pain worsens, they should be instructed to call emergency personnel. In addi- tion, patients using medications such as sildenafil citrate (i.e., Revatio, Viagra) should be educated on the increased risk of hypotension with coadministration with nitroglycerin.
Percutaneous coronary intervention (PCI) , formerly referred to as percutaneous transluminal coronary angio- plasty (PTCA) , is the procedure most commonly performed to relieve symptoms caused by atherosclerotic changes in the coronary vessels. During this procedure, after the patient
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