In hypodynamic or ‹“ ‹“cold’ ‘ septic shock, seen more frequently in the elderly, there are two causes for reduced cardiac output. First, the myocardial depressant factor decreases the cardiac index.
Second, in progressive sepsis, there are increases in pulmonary capillary resistance. These factors cause a significant decrease in cardiac output and present clinically like right-sided congestive heart failure. Cold septic shock has a very high mortality.
Describe the Killip classification of pump dysfunction in acute myocardial infarction.
The Killip classification is based on clinical criteria that correlate the degree of pump dysfunction with acute mortality in patients with myocardial infarction.
‚ Class I has no evidence of left ventricular failure and has a 5% mortality.
‚ Class II has bibasilar rates, an S3 gallop or heart failure by chest x-ray, and a 15-20% mortality.
‚ Class III patients are in pulmonary edema. These patients have a 40% mortality.
‚ Class IV patients are in cardiogenic shock defined by: (1) systolic blood pressure 90 mmHg, (2) peripheral vasoconstriction, (3) oliguria, and (4) pulmonary vascular congestion. Class IV patients have a mortality of 80%.
How significant is a loud holosystolic murmur in a patient with shock and an acute myocardial infarction?
Loud holosystolic murmurs with myocardial infarction indicates either papillary muscle rupture or an acute ventricular septal defect (VSD). These may be indistinguishable, but acute VSD usually occurs with an anteroseptal myocardial infarction and has an associated palpable thrill. Papillary rupture often does not have a thrill and is usually seen in inferior myocardial infarctions. These frequently cause shock on the basis of much reduced forward blood flow and can be differentiated by echocardiography or Swan-Ganz catheterization. Both require emergent cardiothoracic surgery for early repair. In some patients, the murmur may be soft or inaudible.
What are the signs and symptoms of massive pulmonary embolism?
Massive pulmonary embolism causes shock on the basis of reduced cross-sectional area of the pulmonary outflow tract. Shock occurs when the cross-sectional area is reduced by 50% or more. In an acute situation, the right ventricle can increase its systolic pressure only to a maximum of about 40 mmHg. This pressure is inadequate to overcome the increased resistance, blood flow is reduced, and shock develops. Massive pulmonary embolism presents with the following signs and symptoms: