Page 337 - Feline Cardiology

348 Section J: Pericardial Diseases

Box 22.1. Procedure for pericardiocentesis in cats

1. Approach from the left or right side—each direction has 3. Perform a sterile prep of the skin.
advantages and drawbacks; in the example here, the cat Infiltrate the skin, intercostal muscles, and parietal
is in right lateral recumbency, allowing an approach to the pleura with local anesthetic (2% lidocaine, 1 ml) and
pericardium from the left side unless echocardiography repeat surgical preparation.
suggests the fluid pocket is larger on the right side. Mild 4. Use an 18–20 gauge over-the-needle catheter system or
sedation can be achieved with 0.3 mg/kg butorphanol a 19 gauge butterfly needle in a cat. Make two small side
and 0.3 mg/kg midazolam IV or IM, if necessary. An holes near the tip of the catheter to avoid blockages during
electrocardiogram should be monitored during the aspiration.
procedure to monitor for ventricular ectopy (which can 5. Attach the catheter to a 12–20 cc syringe via an extension
occur if the epicardium is abraded). tube and a three-way stopcock. If a butterfly needle is
Note: The direction of approach for pericardiocentesis used, you can attach it directly to a three-way stopcock and
is primarily driven by location of the largest fluid pocket syringe.
and personal experience. Some clinicians prefer to perform 6. Slowly advance the catheter or butterfly needle through
the procedure from the right believing there is less risk of the skin toward the pericardium while maintaining slight
lacerating a coronary artery. Others prefer to approach from negative pressure via the syringe. Once a flashback of
the left because deoxygenated blood in the right ventricle fluid is noted, advance the catheter over the needle into
can easily be mistaken for the “port wine” appearance of the pericardial space and remove the needle while the
the classic hemorrhagic pericardial effusion. Therefore, extension tube is connected to the catheter (or advance
when performing the procedure from the left, the clinician the butterfly cautiously toward the opposite scapula). It
knows quickly whether the sample is blood from the left is important to keep in mind that an initial flashback will
ventricle (oxygenated and bright red in color), or pericardial be pleural effusion if the patient has both pleural and
fluid (“port wine” (dark red) in color). As long as the pericardial effusions present. Therefore, the needle/catheter
pericardiocentesis is performed from the apex of the heart will need to be advanced further for a second flashback,
revealing fluid that often is different in appearance.
and the needle is directed toward the opposite shoulder, 7. Pericardial fluid is often less sanguineous in cats
Pericardial Diseases 2. Shave the left (or right) thorax after the ideal location compared to dogs, but if the appearance is bloody, place
the risk of coronary laceration is low, whether one performs
the procedure from the right or left thorax.
an aliquot of fluid in an activated clotting time tube to
confirm that it is not blood. Pericardial effusion should not
for the procedure is determined by echocardiography. In
clot, whereas blood from a great vessel or cardiac puncture
many cats, the fluid pocket is small and echocardiographic
will clot.
guidance during the procedure is helpful.

equilibration of atrial and ventricular diastolic pressures
and loss of the normal reduction in caval pressure asso-
ciated with inspiration. Right-sided heart failure is the
most common abnormality noted on physical examina-
tion. This disease likely is extremely rare in the cat, and
has not yet been reported.

REFERENCES

Boldface font indicates key references.
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