Shock, a syndrome in which clinical deterioration can occur quickly, requires careful analysis and rapid treatment. Broad definitions for shock include inadequate cellular energy production or the inability of the body to supply cells and tissues with oxygen and nutrients and remove waste products. Shock may result from a variety of underlying conditions and can be classified into the broad categories of septic, hemorrhagic, obstructive, and hypovolemic shock.1-3 Regardless of the underlying cause, all forms of shock share a common concern: inadequate perfusion.1,2 Perfusion (ie, flow to or through a given structure or tissue bed) is imperative for nutrient and oxygen delivery, as well as removal of cellular waste and byproducts of metabolism. Lack of adequate perfusion can result in cell death, morbidity, and, ultimately, mortality.
Related Article: The Many Types of Shock
Hypovolemic shock is one of the most common categories of shock seen in clinical veterinary medicine.4 In hypovolemic shock, perfusion is impaired as a result of an ineffective circulating blood volume. During initial circulating volume loss, there are a number of mechanisms to compensate for decreases in perfusion, including increased levels of 2,3-Bisphosphoglycerate, resulting in a rightward shift in the oxyhemoglobin dissociation curve and a decreased blood viscosity. When approximately 30% of blood volume is lost, however, compensatory mechanisms may fail, resulting in organ dysfunction. Causes of hypovolemia include hemorrhage (surgery, trauma, neoplasia, anticoagulant rodenticide ingestion); fluid loss from vomiting, diarrhea, or renal disease; severe burns; and third-space losses (eg, edema, ascites).1,2