What is the MOST common cause of preload disorders in children?
A. Distributive shockB. Hypovolemic shock from vomiting and diarrhea
C. Congestive heart failure
D. Severe anemia
Answer. B. Hypovolemic shock from vomiting and diarrhea
Preload is the
amount of blood that the heart receives to distribute to the body. In addition
to heart rate, afterload, and cardiac contractility, preload determines cardiac
output. In children, the most common cause of decreased preload is hypovolemia,
usually from vomiting and diarrhea. Distributive shock secondary to sepsis,
neurogenic spinal shock, or anaphylaxis is a less common cause of preload
reduction. Acute anemia may also be associated with decreased preload.
Congestive heart failure is a frequent complication in children with congenital
heart disease. Increased preload results in elevation of left atrial pressure
leading to pulmonary edema and decreased oxygenation.
