Page 233 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

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

mentioned, in animals with intrathoracic gastric tympany,
the stomach should be deflated with a nasogastric or oro-
VetBooks.ir uncapped nasogastric tube should be left in place until
gastric tube, or by transthoracic gastrocentesis, and an
surgery is performed. Thoracocentesis should be per-
formed in patients with a significant volume of pleural fluid
or a pneumothorax.
The patient should be allowed to assume a comfort-
able position, which may depend on the side of the rupture
and the presence of chest wall pain. However, certain
positions will allow more efficient ventilation. The patient
should be encouraged to lie in sternal recumbency, so that
both lung fields may be used, or in lateral recumbency with
the affected side down, so that the less affected lobes are
uppermost. The animal should be monitored closely and
continuously during this period since rapid decompensa-
tion may occur.
Ruptured diaphragm: visualization of the left caudal lung lobe
Anaesthetic considerations: Oxygen supplementation 17.13 through a radial tear in the dorsal aspect of the left side of the
should be provided in the pre-induction period. Rapid diaphragm.
induction with an intravenous agent followed by prompt
endotracheal intubation is mandatory. Controlled intermit- and peritoneal fluid is removed by suction. Long-handled
tent positive pressure ventilation, coupled with positive instruments may be useful for suturing the dorsal aspect
end-expiratory pressure if required, is started soon after of the diaphragm, particularly in a deep-chested dog. A
induction. If spontaneous breathing is efficient initially, it is thorough examination of the diaphragm and all the abdom-
important to remember to take control of ventilation as soon inal viscera is made.
as the abdomen is open. Assisted ventilation should not The abdominal organs can often be reduced by gentle
exceed an inspired pressure of 15 mmHg to minimize the traction. If the herniated organs become engorged or
likelihood of re-expansion pulmonary oedema. Chronically adherent to the edges of the diaphragm, traction may be
collapsed lungs should not be forcibly re-expanded during unsuccessful. In this situation, the rent in the diaphragm
surgery. (For more information on anaesthetic considera- may be enlarged to allow careful inspection and reduction
tions, see Chapter 1.) of the organs. This is best performed by extending the
incision in a radial direction ventrally, taking care to avoid
Surgical considerations: There are few indications for emer- vital structures such as the phrenic vessels, phrenic
gency surgery, but these include: nerves and caudal vena cava. Adhesions to intrathoracic
structures should be divided under direct observation.
• Massive organ displacement Adhesions tend to be fibrinous for the first 3 days, becom-
• Continuing haemorrhage ing more organized with greater quantities of fibrous tissue
• An enlarging gas-filled viscus, particularly the stomach, subsequently. Nevertheless, adhesions of less than 7–14
in the thoracic cavity days old can often be gently peeled apart. More mature
• Bowel rupture. adhesions may require division of the affected part, for
example, by partial lung lobectomy or complete liver
Repair of a ruptured diaphragm has a higher priority lobectomy. Incarcerated liver lobes and spleen are often
than repair of some other injuries sustained during the same friable and should be handled with care. If these appear
traumatic event (e.g. long bone fracture). In a stable animal, devitalized, a lobectomy or splenectomy should be per-
definitive fracture repair may be performed following surgi- formed, ideally before returning these organs to the abdo-
cal repair of the ruptured diaphragm. However, anaesthetiz- men. Following reduction, the thoracic cavity is lavaged
ing the animal a few days later may be a better option. with warm saline and a thoracostomy tube is placed under
Although this is a clean or clean-contaminated proce- direct visualization.
dure, perioperative antibiotics are indicated if devitalized
tissue (e.g. liver lobes) or significant atelectasis of lung Herniorrhaphy: Once reduced, the abdominal viscera are
lobes is anticipated. retracted using saline-soaked laparotomy swabs and
malleable ribbon retractors. In animals with an acute dia-
Surgical approach: A number of surgical approaches have phragmatic rupture, it is generally easy to determine the
been recommended for gaining access, including ventral correct orientation of the tissues. It is extremely rare to
midline laparotomy, median sternotomy, intercostal thora- find insufficient tissue for closure of the defect in such
cotomy and trans-sternal thoracotomy. However, adequate animals. In chronic tears, the edges of the defect may have
access can be gained in almost all cases via a cranial ven- ‘rolled over’ and mature fibrous tissue may have formed,
tral midline laparotomy, with extension via a caudal median causing contraction of the tissue. It is not recommended to
sternotomy, involving the caudal one to three sternebrae, if debride the edges of the tear, because that will increase
required (Figure 17.13). the size of the defect further and may reduce the holding
power of the sutures. However, any scar tissue that
Surgical technique: An incision is made from the xiphoid to prevents movement of the diaphragm should be incised.
beyond the umbilicus. A large incision makes it consider-
ably easier to expose the diaphragm and abdominal Suture technique: The tear is examined and the correct
organs. The falciform ligament may be excised to increase orientation of the edges is determined. In tears of a
exposure, particularly of the ventral diaphragm. Self- complex shape, stay sutures may be placed to provide
retaining retractors are placed to aid exposure, and pleural temporary closure in the appropriate manner. Suturing of

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