Page 626 - Cardiac Nursing

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602 PA R T I V / Pathophysiology and Management of Heart Disease
established care map or “roadmap.” In the operating room, pa- Willebrand factor. DDAVP also increases factor VIII C levels,
tients receive lower doses of opioids with the aim of extubation which shorten the partial prothrombin time. In the past, apro-
within 1 or 2 hours after arrival in the intensive care unit. The pa- tinin had been used extensively to limit bleeding especially in redo
tient is kept sedated with short-acting agents such as propofol or operations, the safety of aprotinin came under scrutiny. An obser-
midazolam intravenous infusions. When the patient is hemody- vational study by Mangano et al. 32 of 4,374 patient undergoing
namically stable and bleeding is under control, the patient can be revascularization found a doubling of the risk of renal failure
extubated. As a result, cardiac surgery patients may stay in the in- (95% CI), 55% increased risk of MI or heart failure (p 0.001),
(
tensive care unit as little as 8 to 12 hours, thus freeing up critical and 181% increase in risk of stroke or encephalopathy (p
(
care beds and reducing costs to the patient. Patients who are “fast 0.001). In a retrospective analysis by Shaw et al., 33 patients who
tracked” in rapid recovery programs are discharged 3 to 5 days af- received aprotinin had higher mortality rate and larger increase in
ter surgery. Nurse practitioners or physician assistants in collabo- serum creatinine than those who received Aminocaproic or no an-
ration may manage cardiac surgery patients with the physician. tifibrinolytic agent.
Atrial arrhythmias and pulmonary complications are the most Protamine also may be administered intravenously in patients
common variances that keep patients in hospital longer than who had inadequate reversal of heparin or in those with heparin
planned by the care map. rebound. Protamine must be administered as a slow intravenous
infusion to prevent hypotension. Patients with insulin-dependent
Early Complications After diabetes or allergy to fish are more likely to have allergic reactions
Cardiac Surgery to protamine. If postoperative bleeding continues and coagula-
tion tests are normal, bleeding may be mechanical or may result
Cardiovascular from suture line or venous bleeding. Adequate control of hyper-
Cardiovascular dysfunction or low cardiac output syndrome can tension with sodium nitroprusside may also help control bleed-
occur after cardiac surgery. Low cardiac output syndrome may be ing. If coagulopathies were corrected and bleeding continues,
related to reduced preload, increased afterload, arrhythmias, car- mediastinal re-exploration is advised to decrease the risk of car-
diac tamponade, or myocardial depression with or without my- diac tamponade.
ocardial necrosis. Excessive bleeding can occur secondary to coag-
ulopathy, uncontrolled hypertension, or inadequate hemostasis. Cardiac Tamponade. Cardiac tamponade is a life-threatening
Perioperative MI and pericarditis can occur as a result of cardiac emergency that may occur immediately postoperative. Compres-
surgery. sion of the right heart with blood and/or clot decreases left ven-
tricular preload and consequently, cardiac output that results in
Postoperative Bleeding. Pleural and mediastinal tubes are causes hemodynamic deterioration. 34 Cardiac tamponade is sus-
attached to water-seal and 20-cm suction to drain mediastinal pected as a cause of low cardiac output if right and left heart pres-
shed blood. Although blood may clot in these chest tubes, they sures increase and equalize. Physical exam findings, hemodynamic
should not be stripped because stripping may cause excessive suc- parameters, and diagnostic tests for tamponade include: decreased
30
tion, which may increase bleeding or cause damage to grafts. Ex- cardiac index, mediastinal drainage that may increase as well as
cessive postoperative bleeding (mediastinal drainage of more than decrease or stop, radiography shows widening of the cardiac sil-
500 mL for the first hour after surgery or drainage, totaling houette, neck vein distention, a pulsus paradoxus is noted by ar-
200 mL/h thereafter) usually is mechanical in nature and caused terial line or by auscultation, or narrow pulse pressure is present.
by bleeding from suture lines, but it may be caused by the pres- Although tachycardia is a sign of classic tamponade, the cardiac
ence of pericardial adhesions from an earlier surgery or to a coag- surgical patient may be unable to generate a compensatory
ulopathy. Postoperative bleeding is usually venous rather than ar- tachycardia because of heart block or previously administered
terial. Coagulopathies may occur in patients with prolonged CPB -blockers or calcium-channel blockers. Echocardiography provides
times or excessive intraoperative bleeding. If patients are bleeding rapid confirmation of pericardial fluid and tamponade physiology,
excessively, coagulation panels should be obtained immediately to facilitating intervention with echo-guided pericardiocentesis, or
evaluate for coagulopathy. Coagulopathies caused by depletion of open pericardial drainage in the operating room.
factors should be treated with administration of depleted factors,
such as fresh-frozen plasma, platelets, and cryoprecipitate. Auto- Myocardial Depression. Myocardial depression (impaired
transfusion may be used to replace red blood cells, but filtered myocardial contractility) may be reversible or irreversible after car-
blood lacks adequate clotting factors. In an observational study of diac surgery. If a patient is not acidotic or hypoxemic and has ev-
8004 coronary artery bypass patients, 31 having a lower nadir idence of decreased cardiac contractility, myocardial cell dysfunc-
hematocrit is associated with increased risk of developing low out- tion or necrosis is suspected. Treatment of low cardiac output
put heart failure and that risk was increased further with transfu- secondary to myocardial dysfunction first involves treatment of
sion of packed red blood cells as a significant independent predic- hypoxemia, acidosis, heart rate and rhythm abnormalities, de-
tor of low output heart failure (adjusted odds ratio, 1.27; 95% CI, creased preload, and increased afterload. If a patient continues to
1.00 to 1.61; p 0.047). have a low cardiac output after these maneuvers, inotropes or in-
Pharmacologic means of controlling postoperative hemorrhage tra-aortic balloon pump therapy is instituted. A variety of in-
include a variety of nonhematogenous therapies. Aminocaproic otropes and vasoactive medications may be employed postopera-
acid is an antifibrinolytic medication that inhibits conversion of tively (Table 25-1). Dobutamine, dopamine, epinephrine,
plasminogen to plasmin. Desmopressin (DDAVP) may be infused norepinephrine, and milrinone intravenous infusions are fre-
intravenously in patients with severe platelet dysfunction after quently used for inotropic support of myocardial depression after
prolonged CPB or uremia. DDAVP shortens bleeding time and cardiac surgery. If the patient’s cardiac index is normal to high and
improves platelet function by increasing circulating levels of von hypotension is related to vasodilation, pressers such as vasopressin