Page 8 - 2013 AAHA/AAFP Fluid Therapy Guidelines for Dogs and Cats

2013 AAHA/AAFP Fluid Therapy Guidelines for Dogs and Cats

Fluid Therapy in the Sick Patient high risk of fluid overload include those with heart disease, renal
First, determine the initial rate and volume based on whether the disease, and patients receiving fluids via gravity flow. 16
patient needs whole body rehydration or vascular space volume Cats require very close monitoring. Their smaller blood vol-
expansion. Next, determine the fluid type based on replacement and ume, lower metabolic rate, and higher incidence of occult cardiac
maintenance needs as described in the following sections. Fluid ther- disease make them less tolerant of high fluid rates. 7,18
apy for disease falls into one or more of the following three categories:
the need to treat changes in volume, content, and/or distribution. Changes in Fluid Volume
Typically, the goal is to restore normal fluid and electrolyte sta-
tus as soon as possible (within 24 hr) considering the limitations
of comoribund conditions. Once those issues are addressed, the Examples of Common Disorders
rate, composition, and volume of fluid therapy can be based on Causing Changes in Fluid Volume
ongoing losses and maintenance needs. Replace the deficit as well Dehydration from any cause
as normal and abnormal ongoing losses simultaneously (e.g., con- Heart disease
tinued vomiting/diarrhea as described below in the “Changes in Blood loss
Fluid Volume” section). Accurate dosing is essential, particularly
in small patients, to prevent volume overload.
The physical exam will help determine if the patient has whole
Monitor Response to Fluid Therapy body fluid loss (e.g., dehydration in patients with renal disease),
Individual patients’ fluid therapy needs change often. Monitor for vascular space fluid loss (e.g., hypovolemia due to blood loss),
a resolution of the signs that indicated the patient was in need of or hypervolemia (e.g., heart disease, iatrogenic fluid overload).
fluids (Table 1). Monitor for under-administration (e.g., persistent Acute renal failure patients, if oliguric/anuric, may be hypervol-
increased heart rate, poor pulse quality, hypotension, urine output), emic, and if the patient ispolyuric they may become hypovolemic.
and overadministration (e.g., increased respiratory rate and effort, Reassessment of response to fluid therapy will help refine the
peripheral and/or pulmonary edema, weight gain, pulmonary determination of which fluid compartment (intravascular or
crackles [a late indicator]) as described in Table 1. Patients with a extravascular) has the deficit or excess.

TABLE 2
Determining the Route of Fluid Administration

Patient parameter Route of fluid administration

Gastrointestinal tract is functional and no contraindications exist Per os
(e.g., vomiting)

Anticipated dehydration or mild fluid volume disturbances in an Subcutaneous. Caution: use isotonic crystalloids only. Do not use
outpatient setting dextrose, hypotonic (i.e., D5W), or hypertonic solutions.

Subcutaneous fluids are best used to prevent losses and are not
adequate for replacement therapy in anything other than very
mild dehydration
Hospitalized patients not eating or drinking normally, anesthetized IV or intraosseous
patients, patients who need rapid and/or large volume fluid
administration (e.g., to treat dehydration, shock, hyperthermia,
or hypotension)

Critical care setting. Used in patients with a need for rapid and/ Central IV
or large volume fluid administration, administration of hypertonic
fluids and/or monitoring of central venous pressure

D5W, 5% dextrose in water.

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