Page 143 - Clinical Manual of Small Animal Endosurgery

Diagnostic Laparoscopy 131

insufflation gas. With insufflation of the omentum (or mesentery), visu-
alisation of the abdominal cavity is hindered, and the abdomen needs to
be allowed to desufflate before continuing. If the needle is inappropri-
ately inserted into and insufflates the falciform ligament, more lateral
reinsertion usually allows continuation of the procedure.
A serious complication associated with insufflation is pneumothorax.
This, together with pneumomediastinum and pneumopericardium, may
occur consequently to inadvertent perforation of the diaphragm during
laparoscopy, in the presence of diaphragmatic haernia or rupture, or may
be due to overinsufflation (Twedt and Monnet, 2005). The positive pres-
sure of pneumoperitoneum causes tension pneumothorax, which must
be rapidly recognised and resolved. The abdomen should be promptly
desufflated, and a thoracostomy tube inserted. After thoracic air evacu-
ation the procedure can sometimes be continued laparoscopically, but
more often conversion to open surgery is necessary.
Gas embolism is a potentially life-threatening complication occurring
when gas is insufflated into the circulatory system following accidental
placement of the Veress needle into a vessel or the spleen. Carbon dioxide
continues to be absorbed during the recovery period and consequently
embolism can occur even in the early postoperative period. However, the
occurrence of embolism with carbon dioxide is relatively uncommon, as
carbon dioxide is highly soluble in blood, and penetration of small
amounts into the systemic circulation is usually without consequence.
Large amounts of gas travelling to the right ventricle cause cardiocircula-
tory collapse, with sudden and profound decrease in blood pressure,
insurgence of heart murmur and cardiac arrhythmias, and changes in
end-tidal carbon dioxide (Quandt, 1999). Gas embolism must be treated
quickly to avoid cardiac arrest; the animal should be placed in left lateral
recumbency with the head down (Freeman, 1999; McClaran and Buote,
2009), and ventilated with 100% oxygen.
The cardiopulmonary effects of pneumoperitoneum are well tolerated
in healthy animals (Duke et al., 1996); however, hypoxia and/or hyper-
carbia may develop in animals with pre-existing cardiac or pulmonary
compromise. Insufflation of room temperature gas may also cause hypo-
thermia, especially in long procedures.
Port site metastasis is a complication to be expected in cancer patients.
Although different theories are advocated to explain their development,
such as direct implantation during sample retrieval, exfoliation of cells
during tumour manipulation, and dispersion following carbon dioxide
insufflation or by haematogenous spread (McClaran and Buote, 2009),
the use of specimen retrieval bags for removal of tumour samples is
recommended. Commercially available retrieval bags usually come on a
10 mm applicator, and therefore require a large portal site; to obviate
the problem, in case of smaller samples, bags can be made inexpensively
from a sterile surgical glove.
Conversion to laparotomy cannot be considered a complication.
However, patients undergoing conversion of the procedure often have