Page 411 - Fluid, Electrolyte, and Acid-Base Disorders in Small Animal Practice

Monitoring Fluid Therapy and Complications of Fluid Therapy 401

and 0.9% saline are fluids of choice for the subcutaneous is not performed. Inflammation at the venipuncture site
route. Acetated polyionic solutions (Plasma-Lyte 148, may indicate infection or phlebitis caused by movement
Plasma-Lyte A, and Normosol-R) appear to cause severe ofthecatheterortherigidmaterialofthecatheter(Teflon).
discomfort when administered subcutaneously. The In a study in which Violon catheters (Insyte, Becton
author has observed excessive vocalization and other Dickinson, Franklin Lakes, N.J.) were placed after strict
painful behavior after subcutaneous administration of aseptic skin preparation, catheter dwell time could be
Plasmalyte 148. These effects may be associated with extended up to 10 days with peripheral catheters and lon-
the acetate itself because the p. 6 of this solution is com- ger with jugular catheters. 57 These catheters become very
parable with that of lactated Ringer’s solution and is flexible and soft when warmed to body temperature, and
greater than that of 0.9% sodium chloride. Dextrose- catheter replacement every 72 hours is not necessary when
containing solutions should not be administered via this using these methods. Reduced inflammation associated
route. Abscess formation and cellulitis also may be with Violon catheters appears to result in minimal discom-
complications of this route if aseptic technique is not fort for the animal, and rarely do dogs and cats attempt to
followed carefully. remove the catheter. At the Ontario Veterinary College,
catheters only are removed when inflammation or fever
Intraosseous of unknown origin occurs, or if the catheter is grossly
contaminated. Such catheter tips are submitted for cul-
The bone marrow of the femur and humerus occasionally
ture, and rarely (approximately one annually) is bacterial
is more easily accessed than small collapsed veins in neo-
contamination identified. Inflammation of the catheter
natal and pediatric small animal patients. Strict aseptic
insertionsitetendstooccurat72hoursinpatientswithvas-
technique is required to avoid infection resulting in 57
culitis (e.g., immune-mediated hemolytic anemia). Vas-
abscess formation and sepsis. This procedure is painful,
and lidocaine should be infiltrated through the skin, sub- culitis may also predispose to thrombosis (e.g., immune-
cutaneous tissue, and to the periosteum before mediated hemolytic anemia, pancreatitis). Jugular vein
attempting catheter placement. Iatrogenic injury to the catheterization should be avoided if possible in such
regional nerves also may occur. Although this route is fre- animals,butmanyrequire frequentbloodsampling orpar-
enteralnutritionorboth,oftennecessitatingacentralcath-
quently advocated for our very young and small patients,
eter. Heparin administration may reduce the potential for
this is rarely performed at the Ontario Veterinary College
thrombosis.
because placement of a 2-inch peripheral intravenous
Extravasation of fluids can be a serious complication if
catheter into the jugular vein is preferred. However,
the fluid is hyperosmolar (e.g., amino acids, >5% dextrose
where intravascular access cannot be obtained and
in electrolyte solutions), contains vasoconstrictive drugs
intraosseous access is required, the EZ-IO Intraosseous
(e.g., epinephrine, norepinephrine), or contains certain
Infusion system (Vidacare—distributed by MILA Inter-
chemotherapeutic agents. To reduce or prevent phlebitis
national, Erlanger, Ky.) is suggested as this technology
associated with hyperosmolar solutions, a central vein
allows clinicians to access the intraosseous space quickly
should be used to deliver these solutions. If a peripheral
and relatively painlessly. This technique is also useful for
vein must be used, a 24- to 22-gauge catheter rather than
fluid delivery in severely hypovolemic animals with col-
20- to 18-gauge catheter should be selected. A minimum
lapsed veins.
catheter length of 2 inches should be selected where pos-
Intraperitoneal sible, unless the patient is very small. Unlike the standard
approach, where a subcutaneous tunnel before venipunc-
This route is rarely used, but relatively rapid absorption of ture is recommended, it is important that the short (<2
crystalloid solutions occurs from this site. 70 Concerns inches) catheter be placed directly through the skin and
using this route include pathologic conditions of the into the vein at a minimal angle to avoid excessive
abdomen and the risk of peritonitis should contamination tunneling before the catheter enters the vein. This will
occur. Solutions containing acetate (e.g., Plasma-Lyte, ensure that the whole length of the catheter enters the
Normosol products) should be avoided because they vein, reducing the chance of the catheter backing out
appear to be very painful when introduced into the abdo- of the vein, resulting in leakage of the hyperosmolar solu-
men. Lactated Ringer’s solution and 0.9% saline are tion (these should be considered for short-term use only).
advised for this route. The catheter must besecuredwelltopreventmovement of
theskinanddislodgementofthecatheter.Wherelooseskin
Intravenous isaproblem,a2-inch,22-or20-gaugecatheterisessential.
The most common route for fluid administration is the Hyperosmolar solutions should be administered slowly
intravenous route. Catheters are placed in peripheral veins through small bore catheters to avoid displacement from
(e.g., saphenous, cephalic) or a jugular vein. Strict aseptic the vein. The area of catheter placement routinely should
technique is required (see Chapter 15). Complications be assessed each time the veterinarian or technician
may occur if surgical preparation of the venipuncture site examines the patient. The bandage does not have to be