Changes

==Pathogenesis==   

==Pathogenesis==   

An obstruction to gastric emptying due to fluid or gas leads to gastric distention and a rapid increase in intra-gastric pressure. As the stomach dilates, the pylorus shifts in a clockwise direction through an angle of between 180 and 360^o from its normal position to a dorsal, cranial and leftward location. The most immediate effect is impairment of the gastric blood supply, leading to severe congestion of the gastric wall and infarction and ulceration of the gastric mucosa. Venous return to heart is reduced due to mechanical compression of the caudal vena cava by the distended stomach, leading to decreased cardiac output and hypovolaemic shock. Gastric distension also causes a mechanical impediment to movement of the diaphragm resulting in reduced tidal volume, hypoxia and hypercapnia.

An obstruction to gastric emptying due to fluid or gas leads to gastric distention and a rapid increase in intra-gastric pressure. As the stomach dilates, the pylorus shifts through an angle of between 180 and 360^o from its normal position to a dorsal, cranial and leftward location. More than 90% of all gastric volvuli rotate in a clockwise direction when viewed from the surgeon's perspective with the dog in dorsal recumbency.

 

The most immediate effect is impairment of the gastric blood supply, leading to severe congestion of the gastric wall and infarction and ulceration of the gastric mucosa. Venous return to heart is reduced due to mechanical compression of the caudal vena cava by the distended stomach, leading to decreased cardiac output and hypovolaemic shock. Gastric distension also causes a mechanical impediment to movement of the diaphragm resulting in reduced tidal volume, hypoxia and hypercapnia.

In addition to the above systemic effects, diplacement of the stomach may lead to avulsion of the gastric branches of the splenic artery. Significant haemorrhage may occur as a result and this may lead to the development of ischaemia-induced gastric necrosis.  

In addition to the above systemic effects, diplacement of the stomach may lead to avulsion of the gastric branches of the splenic artery. Significant haemorrhage may occur as a result and this may lead to the development of ischaemia-induced gastric necrosis.  

==Risk factors==

==Risk factors==

Studies have shown that dogs with a reduced thoracic width to depth ratio are at an in increased risk of developing GDV. Other risk factors include obesity, stress, exercise following feeding and feeding of a dry food diet. Female dogs are also more likely to develop GDV than males. Dogs with an aggressive temperament are also more prone to developing GDV.  

The exact aetiology of the condition is unknown but a number of risk factors have been identified. Studies have shown that dogs with a reduced thoracic width to depth ratio are at an in increased risk of developing GDV. Female dogs are also more likely to develop GDV than males. Other risk factors include obesity, feeding a dry food diet and exercise after feeding. Stressed, anxious dogs are more likely to develop GDV than calm, placid dogs.  

==History and Clinical signs==

==History and Clinical signs==

===Gastric decompression===

===Gastric decompression===

Following a period of aggressive fluid therapy, gastric decompression should be performed. A lubricated large-bore stomach tube is premeasured (from nostril to last rib)and marked. A roll of 2'' adhesive tape should be inserted behind the canine teeth and the dog's mouth should be held closed around the banadage. The stomach tube can then be introduced through the bandage into the oesophagus.  and should not be advanced beyond the marked point. It is important to mimimise stress when this procedure is carried out. Sedation is not usually required but suitable drugs for this include Butorphanol, Fentanyl or Diazepam. It the animal is resistant to orogastric intubation or becomes stressed, trocharizing the most tympanic area caudal to the ribs with a 14 to 16 gauge catheter. This may allow susequent completion of orogastric intubation for further decompression.

Following a period of aggressive fluid therapy, gastric decompression should be performed. A lubricated large-bore stomach tube is premeasured (from nostril to last rib)and marked. A roll of 2 inch adhesive tape should be inserted behind the canine teeth and the dog's mouth should be held closed around the banadage. The stomach tube can then be introduced through the bandage into the oesophagus.  and should not be advanced beyond the marked point. It is important to mimimise stress when this procedure is carried out. Sedation is not usually required but suitable drugs for this include Butorphanol, Fentanyl or Diazepam. It the animal is resistant to orogastric intubation or becomes stressed, trocharizing the most tympanic area caudal to the ribs with a 14 to 16 gauge catheter. This may allow susequent completion of orogastric intubation for further decompression.

===Radiography===

===Radiography===