Page 354 - Fluid, Electrolyte, and Acid-Base Disorders in Small Animal Practice

344 FLUID THERAPY

increased hydrostatic pressure, diuresis, and loss of tested regularly for accuracy. Mistakes in fluid administra-
administered electrolytes in urine). It is the method most tion still can occur as a consequence of human error or
commonly used for medical patients at the Ohio State equipment failure. For practices that do not routinely
University Veterinary Teaching Hospital. use electronic fluid pumps, several management practices
Whenever possible, intravascular volume deficits may assist in accurately and safely delivering fluid therapy.
should be replaced before anesthesia and surgery. Ideally, A strip of adhesive tape can be attached to the bottle and
such patients also should be rehydrated depending on the marked appropriately to provide a quick visual estimate of
urgency of their underlying condition. During induction the volume of fluid received (Figure 14-5). In the
and maintenance of anesthesia, prevention of Buretrol system (Baxter, Deerfield, Ill.), a reservoir allows
hypovolemia, and maintenance of renal perfusion are a predetermined volume of fluid to be delivered over a
essential. Induction of diuresis in this setting may be an given period (Figure 14-6). This approach prevents infu-
important factor in prevention of intraoperative acute sion of excessive volumes of fluid to small animals. The
renal failure. A basal fluid administration rate of 5 to technical aspects of fluid therapy are discussed in detail
10 mL/kg/hr is recommended during anesthesia and in Chapter 15.
surgery. During major surgery (e.g., exploratory laparot-
omy, thoracotomy), fluid administration at twice this HOW MUCH FLUID SHOULD
basal rate is recommended. Fluid therapy during anesthe- BE GIVEN?
sia and surgery is discussed in more detail in Chapter 17.
Most administration sets designed for adult human The purpose of fluid therapy is to increase tissue perfu-
patients deliver 10 to 20 drops/mL, whereas pediatric sion, repair fluid deficits, supply daily fluid needs, and
35
administration sets deliver 60 drops/mL. This informa- replace ongoing losses. It has been emphasized: “the
tion is used to calculate the drip rate: aim of therapy is not to administer fluids but to induce
Adult administration set: positive fluid balance.” 31
COMPONENTS OF FLUID THERAPY
mL=hr 1hr=60 min 10 drops=mL
The volume requirements of patients with fluid-respon-
or sive shock syndromes can vary widely. Ultimately, the goal
of reestablishing widespread effective tissue perfusion
ðmL=hrÞ=6 ¼ drops=min should dictate the volume of fluid administered. In gen-
eral, the same cardiovascular parameters used to charac-
Pediatric administration set: terize the patient’s shock syndrome should return to
normal or to the extent they are able to do so given the
mL=hr 1hr=60 min 60 drops=mL limitations of the patient’s underlying disease condition.
For example, a severely dehydrated dog with tachycardia,
or pale mucous membranes, prolonged capillary refill time,

mL=hr ¼ drops=min

Fluid orders should be written so that the volume to be
administered is recorded as mL/day, mL/hr, and
drops/min. This allows personnel to detect errors in
calculations. The clinician should not assume that the ani-
mal has received the volume of fluid ordered, and the vol-
ume actually received should be noted in the record by
nursing personnel. All additives should be clearly listed
on the bottle, and adhesive labels for this purpose are
available (Figure 14-3). Infusion pumps are available
for clinical use (e.g., Heska, Baxter) and provide a highly
accurate record of the volume infused (Figure 14-4).
These pumps also have alarm systems that can alert per-
sonnel when flow is obstructed. The availability of afford-
able electronic fluid pumps has resulted in widespread
incorporation of such equipment into veterinary practice. Figure 14-3 Adhesive label for fluid additives. (From Chew DJ.
Although use of infusion pumps makes fluid administra- Parenteral fluid therapy. In: Sherding RG, editor. The cat: diseases
tion safer and more accurate, the equipment must be used and clinical management. New York: Churchill Livingstone,
appropriately, maintained in good working order, and 1989: 50.)