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CHAPTER SUMMARY FROM THE PHARMACOTHERAPY HANDBOOK
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For the chapter in the Wells Handbook, please go to Chapter 12. Shock.
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KEY CONCEPTS
Plasma does not have to be lost from the body for hypovolemic shock to occur.
Patients may die of hypovolemic shock despite having normal serum electrolyte concentrations.
Although the Starling’s equation of fluid transport is useful for understanding the factors involved in fluid shifting between compartments, it is not a practical tool for use in the clinical setting.
Patients may have complications and death as a result of reperfusion injury as well as the initial insult.
The clinical presentation of patients with hypovolemic shock can vary substantially, depending on concomitant disease states, medications, and cause of hypovolemia.
The initial monitoring of a patient with suspected intravascular depletion always should include vital signs, urine output, mental status, and physical examination.
The need for intravenous (IV) (vs oral) rehydration in children often is overestimated.
Crystalloid (sodium-containing) solutions should be used for most forms of circulatory insufficiency that are associated with hemodynamic instability.
Neither crystalloids nor colloids have the oxygen-carrying properties of red blood cells.
Vasoactive medications should not be considered for hypovolemic shock until fluid resuscitation has been optimized.
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This chapter discusses the assessment and management of hypovolemic shock. Other forms of shock such as obstructive (eg, cardiac tamponade), distributive (eg, spinal cord injury, septic or anaphylactic shock), and left ventricular dysfunction (eg, myocardial infarction, arrhythmia) often are considered separately from hypovolemic shock because fluid loss from the body is not necessary for their occurrence. Although these forms of shock are not discussed in detail, it is important to note that intravenous (IV) fluid administration (in conjunction with vasoactive medications) is a mainstay of therapy because circulating volume is decreased. In this regard, adequate fluid resuscitation to maintain circulating blood volume is a common principle in managing all forms of shock.
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Because shock is not a reportable category by state and federal agencies that track causes of death, the incidence is unknown. Estimates of deaths due to shock are complicated by differences in definitions and classification systems. Part of the problem is defining when progressive circulatory insufficiency results in the loss of normal compensatory responses by the body, which could reverse the processes leading to irreversible organ dysfunction. This loss of appropriate compensation varies from patient to patient and is not always readily apparent during the initial patient presentation. Therefore, forms of hypovolemic shock, such as hemorrhagic shock, are subsumed by more readily identifiable categories of death, such as accidental injuries and homicides. Crude and conservative estimates of death due to hypovolemic shock are available for some of its forms. More than 39 deaths per 100,000 standard population occur each year in the United States due to unintentional injuries that frequently involve bleeding,1 and more than 600 deaths each ...