Pediatric emergency medicine trisk 0260 0260

FIGURE 10.1 Etiologic types of shock. The size of each circle is proportional to the incidence
of each shock type. Although distinct etiologies are evident, there is considerable overlap in the
clinical presentation and underlying pathophysiology between categories.

Blood pressure is determined by both cardiac output and SVR and is generally
used as a clinical surrogate for tissue perfusion. While low blood pressure will
reduce oxygen and nutrient delivery to tissues, the absence of hypotension in
children should not be taken to mean that organ perfusion is adequate, since
efforts to compensate for changes in cardiac output and SVR may initially
preserve blood pressure. Early signs of shock with a normal blood pressure,
referred to as compensated shock, include tachycardia, mild tachypnea, slightly
delayed capillary refill (more than 2 to 3 seconds), cool extremities, orthostatic
changes in blood pressure or pulse, decreased urine output, and subtle changes in
mental status (e.g., mild irritability or sleepiness). In some cases of distributive
shock, such as sepsis or anaphylaxis, a fall in SVR due to peripheral vasodilation
may lead to the findings of “bounding” pulses, flash capillary refill, and widened
pulse pressure. In addition to these clinical signs, biochemical changes such as an