Which of the following is true about cardiogenic shock?

Choice A rationale Bleeding leads to a decrease in the total intravascular volume, which is the defining characteristic of hypovolemic shock, not cardiogenic shock. In hypovolemic shock, the heart is typically healthy but lacks the volume necessary to pump. In contrast, cardiogenic shock occurs when the heart itself is damaged or dysfunctional, making it unable to circulate the existing blood volume. Bleeding reduces preload, whereas cardiogenic shock usually involves an elevated preload. Choice B rationale Neurogenic, septic, and anaphylactic shocks are subcategories of distributive shock, which is characterized by abnormal distribution of blood flow due to excessive vasodilation. Cardiogenic shock is its own distinct category focused on pump failure. While both lead to tissue hypoxia, the underlying mechanisms are opposites; distributive shock involves a container that is too large, while cardiogenic shock involves a pump that has lost its mechanical or electrical efficiency. Choice C rationale Cardiogenic shock is physiologically defined by the heart's inability to maintain adequate cardiac output due to a primary cardiac dysfunction. Systolic dysfunction involves a reduced ability of the heart to contract and eject blood, often following a myocardial infarction. Diastolic dysfunction involves impaired filling due to stiffness or pressure. Both lead to decreased stroke volume, increased pulmonary capillary wedge pressure, and systemic tissue hypoperfusion despite an adequate or even excessive intravascular volume. Choice D rationale Hypovolemia refers to a state of low extracellular fluid or blood volume. This is the primary cause of hypovolemic shock. Cardiogenic shock is actually often associated with fluid overload or "relative" hypervolemia because the failing heart cannot move blood forward, leading to backup in the pulmonary or systemic circulation. Therefore, treating cardiogenic shock with aggressive fluid resuscitation can be dangerous, as it may worsen pulmonary edema and further strain the failing myocardium.