Thoracentesis is a procedure to remove fluid or air from the pleural space for diagnostic or therapeutic purposes. It requires inserting a needle between the ribs to drain fluid. The document outlines the materials, steps, and potential complications of performing thoracentesis on dogs, cats, and horses. Diagnostic thoracentesis is indicated for animals showing respiratory distress and reduced breath sounds to identify the cause of pleural effusion. Analysis of drained pleural fluid can help determine the underlying disease process.

1. ADDIS ABABA UNIVERSITY COLLEGE OF VETERINARY MEDICINE AND
AGRICULTURE
INDIVIDUAL PRESENTATION ON THORACENTESIS; SITE AND MATERIALS
BY:
Akinaw Wagari
Instructor: Tilaye D. (DVM, MSc, Assistant Prof.)
Mar, 6/2015
Bishoftu, Ethiopia

2. 1. INTRODUCTION
• Thoracentesis is an invasive procedure to remove fluid or air from the pleural space for
diagnostic or therapeutic purposes. The procedure was first described in 1852.
• Diagnostic thoracocentesis is indicated in any animal with increased respiratory effort (or signs
of respiratory distress) and reduced breath sounds.
• If air or fluid is discovered with this procedure in an animal with respiratory difficulty, you
should immediately proceed to therapeutic thoracocentesis.

3. Cont…
When the findings of thoracic auscultation or percussion are suggestive of pleural effusion,
thoracocentesis can be performed to:
• Confirm the presence of pleural effusion
• Provide a specimen for examination which provide a diagnosis or guide the therapeutic
plan
• Therapeautically drain a large volume of pleural fluid

4. 2. DIAGNOSTIC THORACOCENTESIS
Materials needed:
• 3 ml syringe with a 22 ga 1” needle (25 ga 5/8” is OK for thin cats).
Procedure:
• Position the animal in whatever position it is most comfortable – do not stress it by forcing it
to lie in lateral recumbency! For most animals this will mean doing the procedure with the
animal standing or in sternal recumbency.
• Try to avoid letting it sit during the procedure, as this will make it more difficult to identify
landmarks.

5. Cont…
• If you suspect pneumothorax, you will want to aspirate the ‘highest’ accessible portion of the
chest at around the 7th or 8th interspace.
• If you suspect that fluid is in the pleural space, go in at the junction of the middle and ventral
thirds, near the costachondral junction.
• If for some reason an animal with pleural fluid seems to prefer to lie on its side, try to get it
into sternal recumbency first, since fluid will gravitate to the lowest part of the chest.

6. A cadaver in lateral recumbency, with the hair clipped and each rib marked with an overlay of red
ink.

7. Walking his fingers cranialy from one interspace to the next

8. Advancing the needle through the skin

9. A person having thoracentesis

10. 3. HOW TO PERFORM A CANINE OR FELINE THORACENTESIS
What you need?
Fortunately, a thoracentesis does not require much in terms of equipment:
 Stethoscope
 Clippers
 Surgical scrub solution
 Alcohol (in spray bottle)
 A butterfly needle or appropriately sized hypodermic needle (16–21 gauge)
 A three-way stopcock (ideally)
 Sterile gloves

11. Cont…
Extension set
• A 10- to 60-mL syringe, depending on anticipated amount of air or effusion
• Appropriate sterile collection tubes (for cytologic and culture sample collection)
• Oxygen
Preparing cat for thoracentesis

12. Cont…
• A thoracentesis should be performed cranial to the rib, as the blood vessels and nerves lie caudal
to the rib (“hiding” behind the rib).
• Thoracentesis should be performed at the 7th to 9th intercostal space to avoid the heart (3th–5th
ICS) or liver (caudal to the 9th ICS).
Advancing the needle into the pleural space

13. Complications
• Complications from thoracentesis are generally rare.
• Iatrogenic pneumothorax or laceration. Although rare, hematoma, pneumothorax,
arterial laceration, hypotension, re-expansion pulmonary edema or vagal reaction can
occur with thoracentesis.
• The fluid can give an indication of prognosis; in the cat prognosis is generally poor for
all diagnoses except pyothorax (an exudate with degenerate neutrophils and
intracellular bacteria).

14. 4. EQUINE THORACOCENTESIS
Equipment
 Sedation as necessary
 Clippers and materials to perform a surgical scrub
Ultrasonography if available
Local anaesthetic and a 23G 3cm needle
Sterile gloves
Number 15 scalpel blade
Cannula, 3-way tap and extension set
EDTA tube, plain tube and sterile vial for culture

15. Procedure
• The site for thoracocentesis can be identified using anatomical landmarks; 7-8th intercostal
space on the left or 6-7th intercostal space on the right midway between the shoulder and the
elbow.
• The horse should be sedated and the area clipped and scrubbed. Local anaesthetic should be
administered into the subcutis, intercostal musculature and parietal pleura using a 23 gauge, 3
cm needle.

16. Cont…
Pleural fluid analysis
• Analysis of the pleural fluid may in turn help you to determine the underlying disease
process and develop a therapeutic plan.
• Pleural fluid in healthy horses normally contains less than 5,000 nucleated cells/l and less
than 25g/l total protein. Levels greater than 10,000 nucleated cells/l and 35g/l total protein
should be considered abnormal.

17. 5. CONCLUSIONS
• Thoracentesis is a procedure to remove fluid from the space between the lungs and the chest
wall called the pleural space. It is done with a needle (and sometimes a plastic catheter) inserted
through the chest wall.
• Ultrasound pictures are often used to guide the placement of the needle. This pleural fluid may
be sent to a lab to determine what may be causing the fluid to build up in the pleural space.
• Normally only a small amount of pleural fluid is present in the pleural space. A buildup of
excess pleural fluid (pleural effusion) may be caused by many conditions, such as infection,
inflammation, heart failure, or cancer.

18. I