Tuesday, December 14, 2010

Preoperative Evaluation for Cardiac Surgery..Simple Notes

Preoperative Evaluation for Cardiac Surgery

improved risk-adjusted mortality for CABG of less than 2% for the general population

particular attention should be paid to the patient's risk for 
   -endocarditis, 
    -the presence of aortic insufficiency, 
    -the presence of vascular disease, and 
    -the neurologic status.
    -conduit ..vein/arteial.. Ima for mastectomy

    -contraindications to the use of an intra-aortic balloon pump, which include aortic insufficiency, severe peripheral vascular insufficiency, abdominal aortic aneurysm, or significant atherosclerosis

 
Examination of the head, eyes, ears, throat, and teeth for infection is helpful in the assessment of an individual's risk of endocarditis in valvular surgery. Inspection of the patient's skin is helpful in detecting and preventing infection (e.g., the presence of tinea pedis on the lower extremities increases the risk of lower extremity cellulitis). Identifying the presence of an aortic regurgitation murmur is important because regurgitation can worsen during cardiopulmonary bypass and acute left ventricular distention may develop.

Basic laboratory testing prior to cardiac surgery should include 
    -a complete blood count, anemia tdk blh, ec hemodilusi intraop 
    -coagulation screen,   
    -chemistry profile, f hepar/renal u obat anest
    -electrolitr, ... U risk arythmia 
    -stool hematest, 
    -evaluation of ventricular function, and 
    -assessment of coronary anatomy via cardiac catheterization
    -nutrisi, albumin <2.5...dikoreksi skt 1wk, ec risk sepsis/resp failure Myocard consumtion naik .     -chf     -as     -lm disease Kl plu transfusi preop... Individuals with mitral regurgitation and heart failure should receive preoperative afterload reduction with angiotensin-converting enzyme (ACE) inhibitors or intravenous sodium nitroprusside to maintain systolic blood pressures in the 90 to 100 mm Hg range.   While patients with aortic stenosis and hemodynamically significant cerebral or renovascular disease should not receive the latter therapies, intra-aortic balloon counterpulsation (IABP) may be useful in such subgroups. Intra-aortic balloon support can also be used in the setting of acute mitral regurgitation due to papillary muscle rupture as well as in infarct-related ventricular septal defect. Preoperative IABP use in high-risk patients decreases mortality and shortens ICU stay due to enhanced hemodynamic performance Right ventricular dysfunction caused by increased pulmonary vascular resistance should be treated with inotropes that have vasodilator properties such as dobutamine (5 µg/kg/min) and milronone (5 µg/kg/min). Intravenous nitrates, prostacyclin (0.5–2.0 ng/kg/min), and nitric oxide (10–20 ppm) are also effective agents for lowering pulmonary vascular resistance with resultant improvement in right ventricular function (COPD), -prolonged weaning from mechanical ventilation postoperatively is common if FEV1 is less than 65% of VC or if FEV1 is less than 1.5 L. CABG patients with severe COPD are more likely to develop ventilatory failure and have higher mortality rates than those with mild-to-moderate or no COPD (death: 19% vs. 4% vs. 2%, p = .02). -Preoperative screening of arterial oxygen concentration on room air can provide guidance in respiratory management postoperatively.  -preoperative spirometry and perioperative bronchodilators remains unclear in stable patients and cannot be recommended on a routine basis The postoperative hypermetabolic state requires increased nutrition in order to facilitate wound healing and to meet corporal metabolic demands.  -patients who are malnourished preoperatively should receive at least 2 to 4 weeks of intensive nutritional bolstering prior to elective surgery, and all patients should resume an oral diet within 24 hours after uncomplicated surgery. Since perioperative stroke may limit the ability of some patients to protect their airway, a swallowing evaluation is mandatory in this subset of patients.  -Early enteral feeding is warranted in those individuals who have no contraindications to feeding. Low body mass index (<20 kg/m2) and hypoalbuminemia (<2.5 g/dL) are independently associated with increased risk of morbidity and mortality after cardiac surgery. -Patients with decreased albumin levels are at increased risk for bleeding, renal failure, prolonged ventilatory support, and reoperation.  -obesity is not associated with increased mortality, patients with high percent body fat and poor aerobic capacity are at higher risk for sternal wound infection (OR = 2.3; p<.001), saphenous vein harvest site infection, and atrial arrhythmias -Preoperative temporary transvenous pacemaker wire insertion is recommended in patients with hemodynamic instability and high-grade heart block (third degree or Mobitz II).  -Permanent epicardial pacing lead implantation should be done intraoperatively for patients undergoing tricuspid valve replacement with a mechanical prosthesis, due to the contraindication of passing a transvenous lead through the latter. HIt ..white clot syndrm... Immune... Vein arterial pulmonal trombois...Hit igG -penurunan tc >50%, at >30% bl ada gjl pdarahan/trombosis
-pd pts dg heparin (ufh/lmwh), min 5d-14d
-risk ; heparinisasi in 3bln
-if stopped.. Tc naik within days n pdarahan/tromosis within 1bln
Treathment
-delay 3bln
-warfarin initiation should be done in the presence of lepirudin or argatroban due to warfarin's association with limb gangrene

In the PURSUIT trial, patients who received the glycoprotein IIb/IIIa inhibitor eptifibatide within 30 days of CABG did not experience higher rates of bleeding, probably due to the short half-life of the drug. 
However, the CURE trial showed that the antiplatelet agent clopidogrel was beneficial in patients with acute coronary syndromes undergoing PCI but was associated with a concomitant increased risk of major bleeding.34 Though clopidogrel can decrease mortality, it may potentially pose serious problems with major perioperative bleeding (clopidogrel vs. placebo .The median time between discontinuation of clopidogrel and CABG was 5d
Limited data are available regarding the use of fibrinolytic agents prior to CABG. However, in a subgroup analysis of the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries trial (GUSTO I), patients who underwent PCI or CABG after receiving fibrinolytics had a lower rate (0%) of intracranial hemorrhage than those treated with repeat fibrinolysis (1.3%) or medical therapy (0.5%) (p = .046)

Hypercoaguable Disorders
In general, warfarin therapy can be switched to LMWH 3 to 5 days prior to cardiac surgery. 
Anticoagulation using UFH as a bridge should be resumed as soon as the bleeding risks associated with cardiac surgery have been stabilized, usually within 2 to 3 days postoperatively. 
The patients at highest risk for venous thrombosis are those within 3 months of an episode of thrombosis and those with conditions that predispose to the highest risk of thrombosis, such as antithrombin deficiency

Atrial Fibrilasi
10% to 40% of patients after CABG and in up to 65% of patients undergoing combined CABG and valve surgery.42–45
24 to 48 hours after surgery, considered benign and self-limited, 
associated with prolonged hospitalization, hemodynamic instability, and thromboembolization. 
the risk of stroke increases 3-fold 
(25% to 80%) spontaneously convert to sinus rhythm within 24 hours.

The mechanism 
-multiple wavelet reentry in the atria, 
-rapid firing of an atrial focus, and less likely 
-atrial ischemia.Preoper

predictors 
- age, history of hypertension, male sex, and a previous history of atrial fibrillation and congestive heart 
- aortic cross-clamp time, pulmonary vein venting, respiratory disease, and prolonged ventilation

-The prophylactic use of beta-blocker therapy decreases the incidence of post–CABG atrial fibrillation by as much as 70% to 80%.
-amiodarone in decreasing the incidence of postoperative atrial fibrillation when started one week prior to surgery and continued until hospital discharge.
-Sotalol, a class III antiarrhythmic 
-prophylactic continuous atrial overdrive pacing via temporary epicardial wires or from the right atrium

Carotid Artery Diseases
 -Approximately 1% to 6% of persons develop neurologic complications after cardiac surgery.
-Cerebral microembolization from the arterial tree during CABG is likely the most common culprit. 
-atherosclerosis of the ascending aorta is an independent predictor of long-term neurologic insult and mortality.
-patients undergoing CABG, the incidence of carotid artery disease can be as high as 22% (3% in unselected populations), depending on multiple factors including screening method, age, diabetic status, the presence of left main disease or left ventricular dysfunction, female sex, and a history of smoking or prior cerebrovascular attacks
-perioperative stroke risk is believed to be highest (>5%) in patients with more than 80% unilateral stenosis, bilateral stenoses of at least 50%, and unilateral occlusion with at least a 50% carotid artery lesion on the contralateral side.
Consequently, all patients who fall into one of these categories should be considered for combined carotid endarterectomy (CEA) and CABG. 
-Several authors report operative mortalities between 0% and 5%, and perioperative neurologic and myocardial events of approximately 3%.89–93 At 5 years, over 85% of these patients are stroke free 
-combined CABG/CEA is recommended in symptomatic patients with carotid artery stenosis. 
-Although perioperative myocardial infarction and mortality are generally higher with combined CABG/CEA than with CABG alone, the former is still preferred in this group. 
-no demonstrated difference in mortality or morbidity whether CEA is done before or during CABG.
-Carotid artery stenting can also be. performed in close proximity to CABG. Potential advantages of carotid artery stenting include minimizing the need for systemic heparinization prior to CABG. At present, stenting can be safely performed 4 weeks prior to CABG. Thus carotid artery stenting might be advantageous in patients with stable carotid and coronary disease, in elderly patients who are at high risk for thoracotomy, and in patients who have concomitant carotid artery disease and single-vessel left anterior descending artery disease for which minimally invasive surgery is planned. .



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