Page 179 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

eline Head,
Neck and
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A Manual of Canine and F
Thoracic Surger
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BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery
BSA
OPERATIVE TECHNIQUE 12.1
VetBooks.ir Needle thoracocentesis

PATIENT PREPARATION AND POSITIONING
A generous area around the site for needle insertion is clipped and surgically prepared. Local anaesthetic may be
infiltrated under the skin at the site of needle insertion if desired. Sternal recumbency is usually the easiest position for
the animal and the most efficient for drainage. Alternatively, a sitting position or lateral recumbency may be used.
Thoracocentesis is usually performed on conscious animals. Sedation, or occasionally general anaesthesia, may be
required in fractious animals.
ASSISTANT

One person is required to restrain the patient. It is useful, but not essential, to have another person available to perform
drainage of the pleural space with the syringe, allowing the surgeon to concentrate solely on needle placement.

ADDITIONAL INSTRUMENTS
Butterfly needle or over-the-needle catheter (18–22 G); extension tubing;
three-way tap; syringe (10–50 ml). A needle size that is appropriate for the
size of animal is selected, e.g. 20–22 G for cats and small dogs; 18–20 G for
medium to large dogs. A measuring bowl is helpful if a large amount of fluid
is present.

Thoracocentesis equipment. If an over-the-needle catheter is used
instead of a butterfly cannula a separate e tension tube is also re uired.

SURGICAL TECHNIQUE
Approach
The seventh or eighth intercostal space is recommended unless radiography or ultrasonography indicates otherwise. If
fluid and air are present within the pleural cavity the needle is inserted approximately half way up the chest wall. If only
fluid is present, it is more efficient to insert the needle in the ventral third of the thorax, whereas the dorsal third is
appropriate if just air is present. To avoid the intercostal vessels and nerve, which lie on the caudal aspect of each rib,
the needle is introduced close to the cranial rib border.

Surgical manipulations
1 Advance the needle slowly in a slightly ventral direction (approximately 45 degrees to the body wall), with the
bevel of the needle facing the lung (to reduce the risk of iatrogenic lung laceration).
2 Once the needle is felt to penetrate the pleura, apply gentle suction using the preattached syringe and extension
tubing. The extension tubing allows the needle in the patient to move independently from the syringe, reducing
the risk of lung laceration and minimizing the risk of the needle becoming dislodged from its desired position.
If an over-the-needle catheter is used, withdraw the stylet once the pleural cavity is entered, followed by
prompt attachment of the extension tubing and syringe. Redirection of the catheter after the stylet has been
removed tends to result in kinking and obstruction of the catheter.
3 Drainage of both sides of the thorax is recommended to ensure complete evacuation of the pleural space.

WARNING PRACTICAL TIP

A negative finding does not rule out a pleural effusion Fluid in the pleural cavity may be present in ‘pockets’
and it is worth trying both sides and different sites if
the expected amount of fluid is not forthcoming. If
available, ultrasonography may help to identify specific
areas of fluid accumulation and guide needle placement
POSTOPERATIVE CARE

Radiography should be performed after thoracocentesis to document change and confirm absence of iatrogenic injury.

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