Fluid therapy: Choosing the best solution for each patient - Veterinary Medicine
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Fluid therapy: Choosing the best solution for each patient
Which intravenous solution is best in a patient with metabolic acidosis and a low sodium concentration? In a patient experiencing hypercoagulability and thrombosis? This emergency clinician helps you select the right fluid for each patient and discusses an efficient way to help hypoalbuminemic patients.


VETERINARY MEDICINE


As a general rule, the serum albumin concentration should be raised to at least 2 g/dl with fresh frozen plasma or HSA. Administering fresh frozen plasma can help restore some of the intravascular albumin, but it is largely inefficient on a ml/kg basis when compared with HSA. Plasma is better suited to replenish clotting factors and antithrombin and should be used in conjunction with a synthetic colloid such as hetastarch to maintain oncotic pressure. A volume of 20 ml/kg plasma will raise the serum albumin concentration by 0.5 g/dl, provided no ongoing protein loss is present.11

Chronic hypoalbuminemia results when the body's interstitial albumin pool becomes depleted and can no longer maintain intravascular albumin concentrations and oncotic pressure. The albumin contained in an infusion of fresh frozen plasma will replenish the interstitial albumin stores before an increase in serum albumin is detected. But in many cases, this can be costly and can deplete a hospital's resources of plasma. Instead, a more efficient means of restoring both interstitial and intravascular albumin is to administer HSA.

HSA has been used with success in a variety of critically ill dogs.12 It is a potent colloid and is effective in restoring serum and interstitial albumin in patients with acute or chronic hypoalbuminemia for the short term, but in animals with chronic hypoalbuminemia, the underlying cause of decreased albumin production or increased loss must also be addressed for the best long-term outcome.

HSA also helps retain fluid within the vascular space.11 Like other colloids, HSA can also pull fluid from the interstitium into the vascular space, so it may be helpful in treating interstitial edema. Carefully monitor the animal for signs of intravascular volume overload such as tachypnea, orthopnea, chemosis, or fulminant pulmonary edema.

Pretreat animals with 1 mg/kg intramuscular diphenhydramine, and then give 2 ml/kg HSA over four hours. Monitor for clinical signs of a reaction, including urticaria, angioneurotic edema, hypotension, salivation, and vomiting. Rare reports of delayed reactions and systemic vasculitis and polyarthritis have been observed in dogs about 14 days after albumin infusion.13 All patients had clinical signs of gastrointestinal inflammation or septic peritonitis at the time of albumin infusion. Treat vasculitis and polyarthritis with 1 mg/kg prednisone given orally twice a day for two weeks and then tapered over two additional weeks. Although the potential for a reaction exists, the benefits of albumin supplementation can outweigh this small risk and can improve overall outcome.

CONCLUSION

Intravenous fluid therapy is undoubtedly one of the mainstays of treatment of both acute and chronic illnesses. The fluid armamentarium available to veterinary practitioners has evolved dramatically over the past decades to include a variety of crystalloid and colloidal fluids. Similar to choosing an antibiotic to treat the most likely bacterial infection, a fluid should be chosen to treat a specific disease entity. Even in situations in which a specific diagnosis has not yet been made, the fluid should be chosen after careful consideration of an animal's acid-base, electrolyte, dehydration, and oncotic pressure status. It is not necessary to stock every crystalloid or colloid available. However, having a combination of replacement and maintenance crystalloids along with a colloid to choose from can decrease morbidity and mortality in your most critically ill patients.

Elisa M. Mazzaferro, MS, DVM, PhD, DACVECC
Wheat Ridge Veterinary Specialists
3695 Kipling St.
Wheat Ridge, CO 80033

This article is adapted from Dr. Mazzaferro's 2006 CVC East proceedings paper.


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Source: VETERINARY MEDICINE,
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