Page 388 - Clinical Small Animal Internal Medicine

356 Section 5 Critical Care Medicine

patient’s disease process might make one catheterization induration. Sloughing of the skin and the perivascular
VetBooks.ir site preferred over another. An example is the parvoviral tissue can then follow. If the catheter is a central line, it
may not be immediately evident that the position of the
enteritis patient with voluminous diarrhea; a hind leg
catheter should not be the first choice, as it would prob-
can result in mediastinal or pleural fluid accumulation
ably become soiled in short order. catheter has changed. Infiltration of fluid in this instance
The area selected for placement should be clipped and that can be severe enough to cause dyspnea.
aseptically prepared, taking care not to abrade the skin, The key to preventing catheter‐related complications
as this can increase the rate of catheter‐related complica- is vigilance. Place catheters away from joints and avoid
tions. In addition to preparing the patient, staff members using rigid materials, like a butterfly catheter, for pro-
should also wash their hands and wear gloves. Once the longed infusion. Inspect the catheter site frequently.
catheter is seated within the vein, it is flushed with sterile Before infusing drugs, aspirate the catheter for blood (a
saline. There has been no proven benefit to using hep- “flash”) and then flush with saline to ensure proper place-
arinized saline in lieu of sterile saline as a catheter flush. ment and patency of the catheter.
Peripheral catheters are secured to the limb with medical Catheter foreign bodies occur when a portion of the
tape. It is common to suture central lines in place and catheter becomes free within a vessel and lodges (most
then to protect them further with a bandage. Catheter commonly) in the heart or a pulmonary artery. Catheter
sites should be kept clean and dry and inspected at least foreign bodies may occur when catheters are accidently
daily for evidence of inflammation. cut during removal or when a through‐the‐needle cath-
eter is cut off by the introducer needle. It can also occur
when an over‐the‐needle catheter is partially advanced
Catheter‐Related Complications
and then replaced on the needle while seated within a
Catheter‐related complications are common but can be vein. Infrequently, the shaft of a catheter can become
minimized with relative ease. Any material used for an disconnected from the catheter hub. These types of
intravenous catheter will cause some inflammation mishaps can be associated with serious complications,
within a vessel so it is important to diligently assess cath- including cardiac perforation, endocarditis, pulmonary
eter sites for indication of not only infection but also embolism, sepsis, and arrhythmias. Options for manage-
thrombophlebitis. Catheter sites should be inspected ment of catheter foreign bodies include surgical retrieval,
daily for swelling, pain, or induration of the vessel. An endovascular retrieval, or leaving the catheter in situ. In
indurated vessel will feel firm and ropey when palpated. human medicine, attempted retrieval of the foreign body
It is also important to monitor patient response when is preferred. Successful retrieval of intravascular foreign
infusing medications. As catheter integrity degrades, the bodies using endovascular techniques has been reported
animal may object when drugs are infused. in five dogs, a goat, and a horse.
The possibility of infection or thrombophlebitis should Air emboli occur when air is introduced into the vas-
be suspected in any patient who has an intravenous cath- cular system through a catheter. This can be seen when a
eter and develops signs of infection or exhibits a reaction central line is advanced into the thoracic cavity and the
to injections that were previously well tolerated. A change in pressure draws air into the system. More com-
patient who develops a low‐grade fever in hospital with- monly, air can be introduced through incorrectly pre-
out another potential nidus of infection or inflammation pared IV lines or when air is injected into rigid fluid
should have all catheter sites promptly inspected. While containers to speed an infusion. Small emboli are usually
in the past it has been recommended that catheters be clinically silent. Large air emboli can result in a dramatic
removed after 72 hours to prevent infection, multiple increase in pulmonary vascular resistance followed by
studies have shown that the rate of infection does not pulmonary edema formation and dyspnea. If a large
increase if catheters are allowed to remain in place for enough bolus of air is delivered, the right ventricular out-
longer periods of time and that it is more important to flow tract can be obstructed. If a central line is in place
keep the area clean and the catheter dressing unsoiled. when an air emboli occurs, aspirating the air out of the
Infiltration occurs when a catheter moves out of a vein heart is the best choice for treatment.
into the surrounding tissue. Any fluids or drugs adminis-
tered through the catheter are therefore infiltrated into
that area instead of being delivered to the vein. Most Body Fluid Compartments
commonly, infiltration is identified by swelling and
tenderness at the catheter site. If vesicant medications Body Water Distribution
are administered perivascularly, the term used is extrava-
sation. The sequelae of extravasation can be more severe Approximately 60% of body weight is water. This
and may include heat, pain, redness, swelling, and percentage can change based on age, gender or body