HCA 100 RAI Comprehensive Resource To Help You Ace Exams Includes Frequently Tested Questions With ELABORATED 100% Correct COMPLETE SOLUTIONS Guaranteed Pass First Attempt!! Current Update!!

HCA 100 RAI Comprehensive Resource To Help You Ace Exams Includes Frequently Tested Questions With ELABORATED 100% Correct COMPLETE SOLUTIONS Guaranteed Pass First Attempt!! Current Update!! 1. The diagnosis of perioperative MI in a cardiac surgery patient can be made by which of the following: A. Widespread ST depression on the postoperative ECG. B. New Q waves or LBBB on the postoperative ECG or new wall motion abnormalities on echocardiogram. C. Any troponin I or CK-MB elevation postoperatively. D. ST elevation on the post operative ECG. - Correct Answer: B. The diagnosis of perioperative MI is often difficult to make after cardiac surgery because biomarkers (Troponin I, CK-MB) are usually elevated secondary to the surgical procedure, and ST elevation (the ECG sign of myocardial injury) can occur secondary to low graft flow or postoperative pericarditis. The Society of Thoracic Surgeons recommends the following definition of perioperative MI: 1) CKMB or troponin elevations five times the 99th percentile of the normal reference range during the first 72 h following CABG, plus 2) New pathological Q waves or new LBBB, or angiographically documented new graft or native coronary artery occlusion, or imaging evidence of new loss of viable myocardium. ST depression is associated with myocardial ischemia or with non-ST elevation MI. 2. Low cardiac output following cardiac surgery is common and can be due to all of the following EXCEPT: A. Cardiac tamponade. B. Postoperative arrhythmias. C. Reduced preload due to bleeding or increased capillary permeability. D. Reduced afterload due to hypothermia. E. Use of CPB and cardioplegia during surgery. - Correct Answer: D. Hypothermia causes peripheral vasoconstriction which increases afterload. A reduced afterload would cause vasodilation and allow the ventricle to eject against a lower resistance and therefore increases LV function and often increases cardiac output. Cardiac output is determined by four things: heart rate, preload, afterload, and contractility. A low cardiac output postoperatively can be caused by a heart rate that is too fast or too slow, low preload, high afterload, decreased contractility, or a combination of these factors. The use of CPB and cardioplegic arrest during surgery contributes to myocardial stunning which decreases LV contractility and can cause low cardiac output postoperatively. In addition, CPB alters coagulation factors and platelet function which contributes to the risk of bleeding as well as initiating an inflammatory response that causes increased capillary permeability and fluid shifts into the interstitial space - all of which contribute to reduced preload and low cardiac output. Postoperative arrhythmias, including bradycardia and tachycardias, can decrease cardiac output. Cardiac tamponade compresses the heart and causes decreased filling of the ventricles, resulting in decreased cardiac output. 3. Which of the following is the most common post operative cardiac arrhythmia following any kind of cardiac surgery: A. Ventricular tachycardia. B. Second or third degree AV block. C. Atrial fibrillation. D. Sinus bradycardia. - Correct Answer: C. Atrial fibrillation (AF) occurs in up to 40% of patients after CABG, up to 50% after valve surgery, and up to 60% after CABG plus valve surgery. Most atrial fibrillation occurs on postoperative day 2 or 3, and is associated with increased morbidity and prolonged hospital stay. Risk factors for developing post operative atrial fibrillation include advanced age, previous history of AF, mitral valvular disease, increased left atrial size, cardiomegaly, long bypass and aortic cross-clamp times, previous cardiac surgery, COPD, obesity, and severe RCA stenosis. Nonsustained ventricular tachycardia is common after cardiac surgery but not as common as AF. VT is thought to be reperfusion-induced, but hypokalemia and hypomagnesemia can also contribute. Heart block is more common after valve surgery because both the aortic and mitral valves are close to the conduction system. Heart block can be related to direct surgical injury and edema of the conduction system. 4. Your patient who is day 2 post CABG has developed the rhythm seen here. He is unstable with a BP in the 80s systolic, SOB, and diaphoretic. Which of the following would be the most appropriate therapy for an unstable patient with this rhythm: (AFIB WITH RVR) A. Immediate defibrillation B. Amiodarone. C. Digoxin. D. Adenosine. E. Synchronized cardioversion. - Correct Answer: E. This is atrial fibrillation with a rapid ventricular response and the patient is hemodynamically unstable. Cardioversion is recommended as first line therapy for hemodynamically unstable AF. Defibrillation is appropriate for ventricular fibrillation or pulseless VT, not for atrial fibrillation. Digoxin might be appropriate for rate control in a patient with heart failure, but it takes time to work, and in an unstable patient cardioversion is the therapy of choice, then drug therapy to prevent recurrences. Amiodarone can be effective in terminating atrial fibrillation and may also slow the ventricular response, but it takes time to work and is not the first drug recommended for an unstable patient. Adenosine is a good drug for terminating AV nodal reentry tachycardia or accessory pathway tachycardias but it is not indicated for treating atrial fibrillation or flutter. 5. The risk of sternal wound infection is increased by which of the following: A. Early extubation and pneumonia. B. Hypoglycemia and advanced age. C. Prolonged CPB and renal dysfunction. D. Diabetes and obesity. - Correct Answer: D.Major risk factors for sternal wound infection include diabetes and obesity. Diabetes is a risk factor because hyperglycemia impairs the immune system. Patients with diabetes have impaired chemotaxis (the process that draws white blood cells to the site of an infection) and phagocytosis (the process of ingestion of bacteria by white blood cells). Obesity results in increased force applied to the incision which affects the collagen fibers and inhibits healing. Patient factors that increase risk include: Diabetes mellitus, obesity, COPD, advanced age, and protein calorie malnutrition. Surgical factors that increase risk include: prolonged cardiopulmonary bypass time, prolonged intubation time, reoperation or surgical re exploration. and use of both internal mammary arteries. 6. Diabetes increases the risk for postoperative complications in patients undergoing cardiac surgery. Which of the following are appropriate statements about glycemic control in diabetic patients: A. Insulin administration should begin in the ICU and be maintained for 12 hours. B. Intermittent subcutaneous administration of insulin is as effective as continuous insulin infusion in maintaining tight glycemic control. C. Intraoperative glycemic control is not necessary. D. Serum glucose level should be maintained 180 mg/dL using continuous IV infusion that begins in the OR and is maintained for at least 24 hours postoperatively. - Correct Answer: D.The Society of Thoracic Surgeons guidelines on blood glucose management in cardiac surgery patients state the following for diabetic patients : - Glycemic control is best achieved with continuous insulin infusions rather than intermittent subcutaneous insulin injections or intermittent IV insulin boluses. - All patients with diabetes undergoing cardiac surgical procedures should receive an insulin infusion in the operating room, and for at least 24 hours postoperatively to maintain serum glucose levels 180 mg/dL. 7. A complication seen in patients who have received a CABG using the LIMA or a radial artery graft that is not seen with saphenous vein grafts is: A. Graft aneurysm. B. Bleeding at graft suture lines. C. Graft spasm. D. Acute MI due to graft thrombosis. - Correct Answer: C. Arterial conduits, such as the LIMA, RIMA, or radial artery are prone to spasm because of their thicker arterial walls. All grafts can thrombose or bleed at suture lines, and aneurysm formation is more common in veins harvested from the arms. IMA grafts have excellent long term patency and are preferred conduits in most patients. 8. You are caring for a CABG patient who received a radial artery graft to the RCA. Which of the following drugs do you expect to administer to prevent spasm of the graft: A. Beta blockers. B. Nitroprusside. C. Amiodarone. D. Nitrates or calcium channel blockers. - Correct Answer: D. Arterial grafts are prone to vasospasm because of their thick muscular wall. Calcium channel blockers and nitroglycerin are arterial dilators and can be used to prevent graft spasm. Beta blockers can leave alpha vasoconstrictor receptors unopposed and are not indicated for preventing arterial spasm. Nitroprusside is a potent arterial dilator but it is used as an afterload reducer and for managing hypertension, not for preventing arterial spasm. Amiodarone is an antiarrhythmic used for managing atrial fib and ventricular arrhythmias. 9. Your patient has received a mechanical valve to replace his severely stenotic aortic valve. You know the following to be true: A. Infective endocarditis only occurs with biological valves. B. Mechanical valves do not require anticoagulation but biological valves do. C. Mechanical valves are more durable but require lifelong anticoagulation, while biological valves do not. D. Biological valves have a lower rate of structural failure than mechanical valves. - Correct Answer: C. Mechanical valves are manufactured from manmade materials and usually have a tilting disk or bileaflet design. Biological valves are made from living tissue and include porcine or bovine tissue, or are transplanted from other humans (homografts) or from the same patient (autografts). Mechanical valves have a very low rate of structural failure but require life-long anticoagulation therapy, usually with warfarin. Bioprosthetic valves usually do not require long term anticoagulation unless there are other risk factors (like atrial fibrillation), but have a higher rate of structural failure requiring a second valve replacement within 10-15 years. Infective endocarditis occurs with equal frequency on mechanical and bioprosthetic valves during the first postoperative year, but bioprosthetic valves have a higher risk after 18 months. 10. Prosthetic heart valves are associated with all of the following complications EXCEPT: A. High incidence of renal failure. B. Hemolytic anemia. C. Bleeding. D. Systemic embolization. E. Endocarditis. - Correct Answer: A.Prosthetic valves are not directly associated with an increased risk of renal failure, although renal failure can occur for several reasons following any type of cardiac surgery. Systemic embolization can occur with both mechanical and biological valves as a result of thrombosis, vegetations, or left atrial thrombus (especially in the presence of atrial fibrillation). The risk is twice as high with valves in the mitral position than those in the aortic position. Bleeding risk is higher with mechanical valves because of the need for chronic anticoagulation. Infective endocarditis occurs with equal frequency on mechanical and bioprosthetic valves during the first postoperative year, but bioprosthetic valves have a higher risk after18 months. Hemolytic anemia due to mechanical damage to RBCs can occur with mechanical valves.