Page 167 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

surgical treatment, for example in cases of spontaneous necessary. Minimizing the risk of nosocomial infection is
pneumothorax (see Chapter 14). Chest drains are also very important and chest drainage is performed using
VetBooks.ir the lungs to re-expand and allow removal of residual fluid sterile during drainage and replaced regularly. A dressing
gloves and a sterile syringe. The ends of the bungs are kept
placed at the end of all thoracotomy procedures to enable
over the chest drain insertion site is changed daily and the
or air in the postoperative period (see Chapter 11).
thorax is bandaged. The personnel involved in these tasks
Three main types of chest drain are available:
must wash their hands thoroughly before and after dealing
• Small-bore, 20 cm long, multi-fenestrated 14 G wire- with the patient. Prophylactic antibiotics are not routinely
guided chest drains made of polyurethane can be prescribed following placement of a chest drain because
placed in a closed chest using a modified Seldinger this does not reduce the incidence of infection. However, a
technique under light sedation (with or without the sample of chest fluid and/or the tip of the chest drain can be
addition of local anaesthetic infiltration and/or a local submitted for culture at the time of drain removal and any
intercostal nerve block) infection identified is treated with an antibiotic course based
• Polyvinylchloride (PVC) chest drains (16–30 Fr) can be on the results of sensitivity testing.
used for closed chest insertion. General anaesthesia is
recommended for insertion using the trochar or a Continuous drainage
‘mini-thoracotomy’ approach. General anaesthesia
removes the stress of manual restraint for these more Continuous drainage of the pleural space is indicated if the
invasive chest drain placements, allows intubation of rate of fluid or air accumulation is so rapid that frequent
the animal (and therefore direct provision of oxygen) intermittent drainage cannot alleviate the animal’s respira-
and enables manual positive pressure ventilation tory signs. It is also used when continuous subatmospheric
• Silicone chest drains (16–30 Fr) are soft and flexible, pressure is required within the pleural space to enable seal-
and are introduced into the open chest using forceps ing of a small airway leak. Continuous drainage is best
during a thoracotomy procedure. Three to five side provided by means of an underwater seal, which may be
holes must be created in the end of the tube with sterile attached to a suction device. Various commercial systems
scissors before insertion. The holes should not exceed are available that comprise three connected chambers
one-third of the tube diameter or the drain may fracture (Figure 12.1):
at the site of the hole.
• The collection chamber acts as a reservoir for
The optimal size of chest drain is unknown because suctioned chest fluid
there have been no studies directly comparing large- and • The underwater seal chamber (water trap) enables
small-bore chest drains. A study evaluating placement of unidirectional removal of air from the chest
29 small-bore wire-guided drains into a closed chest for • The vacuum regulator chamber (suction control) limits
management of pleural disease in dogs and cats showed the amount of pressure that can be generated by the
suction device. Negative pressure exerted on the pleural
that they were easy and quick (<10 minutes) to place, were
associated with only minor complications and the perfor- cavity by the suction device is limited to <10–20 cmH 2O.
mance of the chest drain was satisfactory (Valtolina and
Adam antos, 2009). It therefore seems sensible to select a
small-bore wire-guided chest drain for closed chest inser- Patient Atmosphere Suction
tion unless a specific reason exists (e.g. a chest drain >20
cm in length is needed for a large- or giant-breed dog, or
the viscosity of the fluid is expected to be extremely high)
to justify the increased pain and invasiveness of placing a
large-bore chest drain.
Whichever method of chest drain placement is used,
careful preparation of the equipment that may be needed is
essential to eliminate delays. Appropriate monitoring of the
patient under sedation or anaesthesia is critical. Needle
thoracocentesis just prior to sedation or anaesthesia for
chest drain placement will minimize respiratory compro-
mise caused by pleural space disease. All chest drains
should have a radiopaque marker strip running along their
length so that thoracic radiographs taken following place-
ment can document their position. If the most distal side
hole includes a portion of the radiopaque marker strip its
position can be visualized on the radiograph.
Techniques for placing a closed chest drain are com-
pared in the BSAVA Manual of Canine and Feline Surgical
Principles. Techniques for placing a 14 G wire-guided tube
in a closed chest and a silicone larger-bore tube into an
open chest are detailed in Operative Techniques 12.2 and
12.3, respectively.

Intermittent drainage
Collection chamber Water trap Suction control
In most situations intermittent thoracic drainage with a
syringe is sufficient. The chest is drained at regular inter- Three-chamber underwater seal system.
vals, usually every 1–4 hours, but more frequently if 12.1

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