should be infused antegrade or retrograde, and timing of infusion (intermittent or continuous). Most cardiac surgery programs use a combination of the myocardial protection techniques discussed here.
arms, such as the cephalic or basilic, make poor bypass conduits because of their calibre and high incidence of aneurysm formation. Lesser saphenous vein located on the posterior aspect of the lower leg may be used, but may be small calibre and difficult to harvest. Cadaveric and synthetic bypass grafts have also been attempted but are not commonly used due to poor patency rates. Because of long-term patency, the left IMA is most commonly used to bypass the left anterior descending (LAD) artery. The right IMA may also be used to bypass the LAD, artery as well as the right coronary artery. When multiple grafts are required, single or bilateral IMA grafts in combination with other arterial conduit and saphenous vein grafts can be used to accomplish complete revascularization (Fig. 25-1). Many authors recommended complete arterial revascularization in young patients in hopes of avoiding additional revascularizations later in life.
develop collateral circulation before pacing is started. Stimulation is gradually introduced by a stimulated pulse synchronized to every other cardiac cycle. Long-term survival after cardiomyoplasty has been reported as high as 50% at 8 years.27 Although cardiomyoplasty is not a replacement for cardiac transplantation, it may have a limited role in patients who would not be candidates for transplantation.
established care map or “roadmap.” In the operating room, patients receive lower doses of opioids with the aim of extubation within 1 or 2 hours after arrival in the intensive care unit. The patient is kept sedated with short-acting agents such as propofol or midazolam intravenous infusions. When the patient is hemodynamically stable and bleeding is under control, the patient can be extubated. As a result, cardiac surgery patients may stay in the intensive care unit as little as 8 to 12 hours, thus freeing up critical care beds and reducing costs to the patient. Patients who are “fast tracked” in rapid recovery programs are discharged 3 to 5 days after surgery. Nurse practitioners or physician assistants in collaboration may manage cardiac surgery patients with the physician. Atrial arrhythmias and pulmonary complications are the most common variances that keep patients in hospital longer than planned by the care map.
and phenylephrine may be used A variety of vasodilating agents such as sodium nitroprusside, nitroglycerin, and angiotensin-converting enzyme inhibitors may be used to reduce afterload in low cardiac output syndrome as well as hypertension. Intra-aortic balloon pump therapy is frequently used in patients with severe cardiac dysfunction that is not adequately supported with medications alone.
Table 25-1 ▪ INOTROPES AND VASODILATOR INTRAVENOUS INFUSIONS COMMONLY USED AFTER CARDIAC SURGERY | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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surgery. Contributing factors of atrial fibrillation (AF) may include electrolyte or metabolic disturbances, increased circulating catecholamines, volume overload, hypoxia, and myocardial ischemia or MI. Although atrial tachyarrhythmias may occur any time during the first few days to weeks after cardiac surgery, they frequently peak around the second or third day postoperative. Atrial fibrillation after cardiac surgery may be associated with important complications including stroke, renal dysfunction, and prolonged hospitalization.38 Risk factors for postoperative AF include advanced age, history of congestive heart failure or AF, chronic obstructive lung disease, male sex, history of rheumatic heart disease, prolonged aortic cross-clamp time, and bicaval cannulation.39 The onset of tachyarrhythmias is often preceded by frequent premature atrial contractions. Medications commonly used to control the ventricular response in AF and flutter include diltiazem (either intravenous drip or orally), digoxin, and β-blockers (orally or by intravenous drip, such as esmolol). Medications used to promote conversion of AF include procainamide, amiodarone, and sotalol. While multiple medications have been studied, β-blockers have been the only medication consistently shown across clinical studies that reduce the frequency of postoperative AF.40 β-Blockers should be considered early during the postoperative course, especially if the patient was on β-blockers preoperatively. Although β-blockers, atrial pacing, antiarrhythmic medications, or a combination of these therapies may reduce the incidence or duration of AF, optimal strategies are still being defined.41
▪ Figure 25-5 Recording of a burst of rapid atrial pacing used to overdrive and convert this atrial flutter to sinus rhythm. Arrows denote atrial pacing spikes. |