Page 397 - Small Animal Internal Medicine, 6th Edition

CHAPTER 23 Clinical Manifestations and Diagnostic Tests of Pleural Cavity and Mediastinal Disease 369

muscles, and pleura at the seventh ICS. The dorsoventral
orientation is one half to two thirds the distance from the
VetBooks.ir costochondral junction to the thoracolumbar musculature.
This distance should correspond to the level where the ribs
are maximally bowed.
The length of tube to be advanced into the chest must
be determined from thoracic radiographs or by external
landmarks on the animal. The tube should extend from
the tenth ICS to the first rib. The fenestrations in the
tube must not extend outside the point of exit from the
pleural cavity.
A stab incision is made through the skin at the tenth ICS.
A purse-string suture is then placed around the opening but
is not tied. Some chest tubes made for humans contain a
stylet. Smaller chest tubes are inserted with the aid of curved
hemostats. The tip of the tube is grasped with the tip of the FIG 23.6
hemostats with the tube parallel to the body of the clamps After an assistant pulls the skin forward, an incision can be
(see Fig. 23.5, B). made through the skin at the seventh intercostal space and
The tube, with the stylet or hemostats, is then tunneled blunt dissection is used to reach the pleura. A chest tube
subcutaneously from the tenth to the seventh ICS. If hemo- can be popped into the pleural space with minimal trauma
stats are used, the tips are directed away from the animal’s to the underlying lung. When the skin is released, the tube
will course through a subcutaneous tunnel to prevent air
body (see Fig. 23.5, C). Once the tip reaches the seventh leaks around the tube.
ICS, the stylet or hemostats are raised perpendicular to the
chest wall. The palm of the hand is placed over the end of
the stylet or the hemostat handles, and the tube is thrust
through the body wall with one rapid motion (see Fig. 23.5, is too tight can greatly decrease chest wall compliance and
D). Once the tube has entered the pleural space, it is quickly can increase the work of breathing in these compromised
advanced forward until a predetermined length has entered animals. The hose clamp is placed on the tube between
the chest while the stylet or hemostats are withdrawn (see the animal and the three-way valve to further protect
Fig. 23.5, E). against pneumothorax whenever suction is not being
An alternative technique can be used to minimize trauma applied to the tube. An Elizabethan collar is always placed
to the lungs caused when the tube is thrust through the on the animal because a single bite through the tube can
body wall. In this technique, after the skin incision has be fatal.
been made and a purse-string suture placed, an assistant Thoracic radiographs are taken to evaluate tube position
standing at the head of the animal draws the skin of the and the effectiveness of drainage. Two views must be evalu-
thorax cranially to pull the skin opening forward from the ated. Ideally, the tube should extend along the ventral aspect
tenth to the seventh ICS (Fig. 23.6). With the skin held in of the pleural space to the thoracic inlet. The most important
this position, hemostats are used to bluntly dissect through sign of adequate tube placement is the absence of areas of
the thoracic and intercostal musculature to the pleura. persistent fluid or air accumulation. If areas of fluid or air
At this point, the chest tube with the stylet or hemostats persist, it may be necessary to replace the tube or place a
is easily popped through the pleura into the chest with second tube in the opposite side.
minimal force. The tube is then advanced and the skin Once a chest tube is in place and determined to be in
released. a satisfactory position, its effectiveness is monitored every
Air will be sucked into the pleural cavity during tube 24 to 48 hours by thoracic radiography and by the gross
placement regardless of the method used. This air is imme- and cytologic assessment of recovered fluid. The animal
diately removed through the tube using a 35-mL syringe. The must also be monitored for the development of second-
purse-string suture is then tied around the tube. Immediately ary complications. These include infection and leakage
external to the skin entrance, the tube is attached to the body of air. The bandage should be removed at least daily. The
wall by suturing the tape that is formed as a butterfly around site where the tube enters the skin should be evaluated
the tube to the skin on either side of it (see Fig. 23.5, F) or for signs of inflammation or subcutaneous emphysema.
by using a Chinese finger trap suture around the tube and The tube and skin sutures should be examined for signs
attached to the skin. This prevents the chest tube from being of motion. The skin around the tube is kept clean, and a
withdrawn if tension is accidentally applied to the tubing. sterile sponge is replaced over the entry site of the tube
The opening in the skin is covered with a sterile sponge with before re-bandaging. Stopcock ports should be protected
antiseptic ointment. with sterile caps when not in use. Gloves should be worn
A light wrap is placed around the tube to hold it against and the stopcock ports wiped with hydrogen peroxide
the chest wall. The wrap must not be too tight. A wrap that before use.