Shock is defined as cellular hypoxia, regardless of shock type (ie, cardiogenic, hypovolemic, distributive, metabolic, hypoxemic). When practitioners are presented with a “shocky” patient (tachycardic, hypotensive, poor perfusion), they need to rule out cardiogenic shock (eg, myocardial failure secondary to dilated cardiomyopathy), as the other types of shock generally require IV fluid therapy as part of the primary intervention to volume resuscitate the patient.
Using the entire shock dose of IV fluids in emergency medicine is no longer considered a standard of care. Traditional shock dose is extrapolated from the total blood volume of the patient (dogs, 60–90 mL/kg; cats, 60 mL/kg). A patient rarely requires replacement of its entire blood volume with crystalloid fluids. Instead of immediately using a whole shock dose, using smaller, repeated aliquots of IV crystalloids (over 20–30 minutes) is recommended.
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Hint: Simply adding 0 to the dog’s weight in pounds results in a conservative shock bolus, equating to a 22 mL/kg bolus (eg, 70 lb + 0 = 700 mL).
The use of one-quarter to one-third of a shock bolus of a balanced, maintenance crystalloid over 20 minutes can be implemented in shocky patients, followed by frequent reassessment of perfusion parameters: Has heart rate or mentation improved? Has capillary refill time or pulse quality improved?
If minimal to no clinical response is seen, repeated aliquots are indicated until appropriate volume resuscitation has occurred.