Shock
Cardiogenic Shock
Nursebob© 9/25/2005
Cardiogenic shock is the impaired ability of the heart to pump. The usual cause is myocardial infarction. However, there are some noncoronary causes such as cardiomyopathy, valvular heart abnormalities, cardiac tampanade, or cardiac arrhythmias. These patients would generally have poor cardiac output. Clinically they will have tissue hypoxia resulting in oliguria, cyanosis, altered mentation, and cool extremities. There’ll be a state of adequate blood volume but failure to put it in circulation. They may have systolic hypotension less than 90 mm or 30 mm below baseline. There will be a low cardiac index usually less than 2.2. The wedge pressure is usually elevated greater than 18.
The key management of cardiogenic shock is the early assessment, identification and treatment. The cause must be identified and treated before the cardiogenic shock can be treated. This could be myocardial infarction, dysrhythmis, cardiac tampanade or other cardiac insult. The cause must be treated before cardiogenic shock can be corrected.
The patient may require intraaortic balloon pump therapy, ventricular assistive device, or might ultimately require cardiac transplant.
Management of Cardiogenic Shock (Ann Intern Med 1999; 131:47-59)
The airway should be thoroughly assessed an established early on. Ventilation may be required. It is important to identify and correct any arrhythmias that may be present. Other conditions that might mimic cardiogenic shock should be excluded. Among these are pulmonary embolus, sepsis, aortic dissection, ruptured aortic aneurysm, and pericardial tampanade.
The patient’s volume status must be established. Inadequate preload is a prerequisite to successful process and patient. The hands-on clinical assessment may often be inaccurate. Central venous pressures and pulmonary artery wage pressures should be measured. (Ann Int Med 1988; 109:826-34)
The insertion of pulmonary artery catheter it is frequently required. But plated volume must be replaced. In the absence of clinical evidence of pulmonary edema, an immediate the challenge is indicated. Often, a small volume of fluid can mean the difference between inadequate left ventricular filling pressures and pulmonary edema. (Circulation 1969; 40:653-9) Thus, frequent small volume (250 ml) normal saline boluses are preferred in cardiogenic shock resuscitation.
In the patient has mild cardiogenic shot with a preserve blood pressure build new dobutamine maybe the drug of choice. (Ann Intern Med 1983; 99:490) It is usually given to 2.5-20 micrograms per kg per minute. However if a patient as a moderate to severe cardiogenic shock, dopamine might be the drug of choice. (Circulation 1977; 55:375-81) for those patients to fail to respond to dopamine, Levophed (norepinephrine) may be used. It is usually reserved for patients failing to respond to welcoming.
Vasodilators are rarely used in the treatment of cardiogenic shot. Nipride may be used only if cardiogenic shock is accompanied by an inappropriately high after load, mitral regurgitation, acute aortic regurgitation, or acute ventricular septal defect. (J Am Coll Cardiol, 1995; 26:668-74) If the patient has an inappropriately high praise of nitroglycerin may be used.
Intra-aortic balloon pump is usually indicated for cardiogenic shock that does not respond promptly to pharmacologic therapy. It may be used with a right ventricle infarction and shock is not responding to volume infusion. (Circulation 1990; 82:664-707) IABP may be used for refractory postinfarction angina for stabilization before and during angiography. It is often used as a bridge to the surgical correction of mechanical complications of acute myocardial infarct. It may be used for intractable recurrent tachycardia accompanied by hemodynamic compromise. Intra-aortic balloon pumps can enhance diastolic coronary artery but the oldest reducing ischemia to a bruised myocardium.
As with any other shock, the cause of cardiogenic shock must be explored before treatment can begin. Approximately eight percent of patients with cardiogenic shock will have a surgically correctable condition such as mitral regurgitation, or ventricular septal rupture. (Circulation, 1995; 91:873-81) some other causes may include ventricular aneurysm, ventricular septal defect, or a ruptured ventricle. (Chest 1989; 95:292-98)
Coronary cardiac catheterization should be considered for all patients with cardiogenic shock after myocardial infarction. Angioplasty shock results in a better hospital and one year post survival rate. (Am Heart J, 1995; 130:459-64) There are some other emergent surgical interventions which must be done for patients with cardiogenic shock under certain conditions; among these are capillary muscle rupture, acute ventricular septal defect, left ventricular aneurysm with heart failure, intractable ventricular tachycardia, and, failure with cardiogenic shock after angioplasty. (Circulation 1990; 82:664-707)
Right ventricular infarctions that might result in cardiogenic shock usually occur with right coronary artery occlusion and are more frequent in inferior infarctions. On physical exam the patient may have hypotension, clear lungs, elevated jugular venous pressure, Kussmaul’s sign (jugular venous distention with inspiration) the right atrial pressure may be greater than 10 mm, and may be within five mm of the wage pressure. (NEJM 1994; 330:1211-1217)
REFERENCES:
American Heart Journal 1995; 130:459-64)
Annals of Internal Medicine 1988; 109:826-34)
Annals of Internal Medicine 1999, 131:47-59
Chest 1989; 95:292-98
Circulation 1990; 82:664-707
Circulation, 1995, 91:873-81
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