Page 114 - WSAVA2018
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 25-28 September, 2018 | Singapore
dogs with early GD or GDV can present with signs of vasodilation (injected or red mucous membranes, fast capillary refill time). Regardless, any compromise to perfusion prompts swift intervention.
The four essential steps for a dog with GD or GDV are opioid analgesia, blood volume expansion, abdominal radiographs and gastric decompression. Pre-treatment electrolyte and blood gas analysis is also useful. Acid base abnormalities usually parallel a lactic acidosis, however, some dogs display high lactate with a standardised base excess that does not reflect the degree of lactic acidosis.(1, 2) This may be due to pyloric outflow obstruction soon before the GDV occurred, causing preceding metabolic alkalosis, and some dogs are known to have either over-eating or a gastric foreign body as a feature of their GDV presentation.
Electrocardiographic monitoring is advised if a pulse irregularity is detected; pre-surgical ventricular arrhythmias have been associated with a higher incidence of gastric necrosis and a higher mortality rate. (3, 4) However, these arrhythmias usually involve isolated ventricular premature complexes and usually do not require treatment. An intravenous catheter should be placed promptly and any signs of shock treated with fluid therapy. Gastric dilation, with or without volvulus, causes obstructive shock by compressing the major veins in
the cranial abdomen, and reducing venous return to
the heart. Expanding blood volume increases perfusion pressure, and therefore venous return. This helps to address hypoperfusion quickly while giving more time
to address the cause of obstruction. Crystalloid fluid therapy, such as Lactated ringer’s solution, is often the most appropriate choice as these dogs can have some degree of dehydration. The use of synthetic colloid fluids in the pre-surgical patient or a patient at risk of Systemic Inflammatory Response Syndrome, without a strong indication, is controversial due to possible adverse effects and should not be routinely administered.
Blood volume expansion and radiography can sometimes be done concurrently if the treatment area
is alongside diagnostic imaging facilities. It is ideal to perform radiographs before decompression in order
to make the diagnosis clear. However, if the dog is in moderate to severe shock, decompression should be performed before taking radiographs. Decompression may result in resolution of the volvulus,(5, 6) or make
it more difficult to appreciate volvulus on radiographs, but should confirm that it was indeed gaseous gastric dilation causing the problem, even if somewhat deflated. Some would debate that if there were no evidence of volvulus on radiographs, then emergency surgery is not indicated. However, if a dog presents with signs of shock on physical examination then chances are that there was some degree of volvulus present. Delaying surgery puts the dog at risk of complications from gastric necrosis or
gastric rupture, ongoing hemorrhage from any ruptured blood vessels or repeat volvulus soon thereafter.(5, 7)
One of the more difficult decisions is surgical planning for large-breed dogs that have simple gastric gaseous dilation on radiographs and no evidence of shock. It
is still advisable to perform a gastropexy in this patient
to prevent future GDV, however, it may not be urgently required. Sometimes these dogs can wait until the
next day to either have a laparotomy or laparoscopy performed. The decision to delay surgery needs to be weighed up carefully in terms of how closely the dog can be monitored until the procedure is performed and whether or not the dog shows any signs of repeat gastric dilation, after the initial decompression, or abdominal pain.
There are two main methods for stomach decompression for gas; gastric trocarisation and orogastric intubation. There are positives and negatives to each procedure and no one method has been shown to be superior
over the other.(8) Orogastric intubation (OGI) should be attempted first as it is less traumatic to the stomach. However, if it is difficult to decompress the stomach
by OGI or the patient requires general anaesthesia
to perform OGI due to non-compliance or the distension is severe accompanied by severe shock, then trocarisation is preferred. Sometimes all it takes is a little decompression via trocarisation to facilitate moving the OGI tube through the fundus. Trocarisation is a procedure that should be done carefully, with appreciation for the location of the spleen and being sure not to leave the stylette in place while the gas is being evacuated. Laceration of the spleen or liver is possible with this procedure.
As emergency laparotomy is usually a large expense, and these dogs typically require a high level of care post-operatively, many owners wish to know the pre- surgical risk of their dog dying before committing to
the investment. Researchers have attempted to aid this process by assessing the ability of many pre-surgical factors to predict outcome. Clinical signs for >5-6 hours, hypothermia at admission and the presence of gastric necrosis combined with the need for splenectomy have been associated with a increased mortality. Pre-surgical factors that have shown some association with gastric necrosis or a higher rate of complications include high lactate on admission,(1, 9) high lactate post-fluids,(10)
and ventricular arrhythmias(3, 4). However, care must be taken in applying results of these studies to individual dogs; the published mortality rates are often from small studies and some are older studies not reflecting today’s standard of care. Also, each individual is unique for it’s own risk, which can’t be well predicted. Overall, for dogs that are taken to surgery, the discharge rate is usually above 90% if appropriate supportive post-operative care is given.

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