Vet360, December 2016 - Page 28

CPD ACCREDITED ARTICLE Article sponsored by Petcam® Patients with GDV progress through different degrees of shock that need to be recognised during the patient evaluation. Animals early in the syndrome present with clinical signs similar to those of hypovolaemic shock because most of their blood volume is restricted in the caudal vena cava and the portal vein. Thus, animals will exhibit: • Tachycardia and tachypnoea with normal femoral pulses • Slow capillary refill times • Pale mucous membranes • Cold extremities. With progression of the syndrome, patients will go into endotoxaemic shock and will experience: • Tachycardia and tachypnoea with weak femoral pulses • Injected mucous membranes • Fever • Slow capillary refill times. Finally, patients will decompensate and exhibit: • Severe hypotension • Bradycardia • Hypothermia • White mucous membranes • Cold extremities. Laboratory findings Early on in the disease progression, complete blood count results often reveal a stress leukogram with neutrophilic leukocytosis and lymphopenia. Serum chemistry profile results may show evidence of hepatocellular damage and cholestasis with increased alanine transaminase activity and total bilirubin concentration and azotemia. Hypokalaemia may also be present. Lactate is produced as a byproduct of anaerobic metabolism and has been shown to be elevated in animals with GDV.17,18 In one study, a lactate concentration < 6.4 mmol/L at presentation, a decrease of lactate of 4 mmol/L or more after fluid treatment and decompression, or a decrease in lactate of > 42.5% of the original value after fluid treatment and decompression was associated closely with survival.18 Radiography Radiography can help to differentiate between gastric dilatation and GDV. If radiography is necessary to determine the diagnosis, do not perform it until the patient is stable. Since the pylorus is displaced on the left side of the abdominal cavity in a dorsocranial position to the fundus, right lateral recumbency radiography is required to be vet360 Issue 06 | DECEMBER 2016 | 28 Fig 1. A lateral radiograph of a dog in right lateral recumbency. The double bubble image (boxing glove) of the stomach is characteristic of GDV. able to obtain the diagnostic double bubble image (Figure 1). The two bubbles are caused by the accumulation of air in the pylorus and the fundus. Free gas is present and may be seen in the abdomen when the stomach has ruptured. If gastric dilatation is present without volvulus, radiographs show a dilated stomach with dilated loops of jejunum. Emergency Treatment Emergency medical treatment of hypovolaemic shock and gastric decompression is required before surgically treating GDV. Treating shock Place venous catheters of the largest gauge possible in the cephalic veins or jugular vein to deliver shock doses (90 ml/kg) of intravenous fluid. Deliver isotonic fluids in increments of one-fourth of the shock dose, and evaluate the patient's response after each one-fourth bolus. Adjust the rate and volume of fluids administered according to the assessment of several clinical parameters: heart rate, pulse, mucous membrane color, capillary refill time, and central venous pressure. Colloids at a dose of 4 ml/kg are recommended during hypovolaemic shock treatment.19 Blood gas and electrolyte evaluations are required before acid-base and electrolyte imbalance corrections are attempted. A dog presented with a GDV can be either alkalotic or acidotic, hypokalaemic or normokalaemic.14 Gastric decompression Gastric decompression is attempted first with an orogastric tube after initiating fluid therapy. The amount of gastric distention, the patient's level of compliance, and the degree of volvulus are factors that contribute to the ability to pass the tube. The difficulties or easiness of passing the tube does not have a diagnostic value for the