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45 JULY/AUGUST 2017 ■ TVPJOURNAL.COM PEER REVIEWED metastasis or other comorbidities, particularly if owners are having difficulty deciding whether to pursue surgery. One study found a negative association between survival and the presence of cardiomegaly, despite a low incidence of pulmonary nodules, demonstrating the prognostic utility of preoperative thoracic radiography. 15 PREOPERATIVE TREATMENT AND STABILIZATION For most patients, especially those that are severely affected, stabilization and treatment must be performed before or in conjunction with diagnostic testing. Immediate treatment goals are correction of hypovolemia and gastric decompression. Box 2 summarizes therapeutic measures to consider during stabilization of a patient with GDV. Prompt vascular access is obtained with large- gauge, short IV catheters (16 or 18 gauge). Cephalic veins or jugular veins should be used because of the lack of blood flow from the caudal half of the body. Initial volume resuscitation with a balanced isotonic crystalloid solution is recommended. Initial fluid volumes should be administered in rapid boluses of one-third to one-quarter shock volumes. Monitoring perfusion parameters ( Box 3 ) after fluid boluses is important in assessing response to therapy. Additional fluid boluses and addition of synthetic colloid boluses or hypertonic saline may be required, depending on individual patient needs. Gastric decompression should be performed as soon as possible. This can be achieved by passing a smooth-surfaced orogastric tube or via percutaneous trocharization. When an orogastric tube is passed in an awake patient, sedation (with a pure mu agonist opioid) is typically required, as is holding the patient's mouth open with a roll of tape or gauze between the incisor teeth. Alternatively, the orogastric tube can be passed with the patient under general anesthesia; the presence of an endotracheal tube will help limit the risk for accidental aspiration of gastric contents. Before an attempt to pass a gastric tube, the tube should be lubricated and premeasured to the level of the last rib. Twisting the tube when slight resistance is felt can facilitate passage of the tube into the stomach; however, caution must be used to avoid perforating the esophagus. When passing the gastric tube is difficult, decompression via trocharization may facilitate passage. After successful passage of the tube, observation of hemorrhage or mucosal tissue in the gastric contents can provide an index of suspicion of gastric necrosis and mucosal sloughing. Trocharization can be performed in an awake or anesthetized patient: To perform trocharization, an area of skin on either side of the cranial dorsolateral abdomen should be clipped and aseptically prepared before puncture of the skin, body wall, and stomach with a large-bore needle (ie, 14 gauge) or over-the-needle catheter. The site of greatest distention or greatest tympany can be used. Gas and liquid may escape; pressure can be applied to the body wall to facilitate decompression. BOX 2. Therapeutic Measures for Stabilization of Dogs With GDV • IV fluids: balanced isotonic crystalloids with or without colloids, hypertonic saline • Gastric decompression: orogastric intubation or percutaneous trocharization • Analgesia: pure mu agonist opioid • Antibiotics: broad-spectrum, particularly in patients with suspected gastric necrosis • Antiarrhythmics if needed, lidocaine: can also serve as a free radical scavenger • Consider procainamide or sotalol if lidocaine is ineffective • Oxygen supplementation: particularly in patients with poor perfusion measures • Fresh frozen plasma: for patients with prolonged coagulation times • Drugs that reduce reperfusion injury: unknown efficacy BOX 3. Parameters to Monitor for Effectiveness of Fluid Resuscitation • Mentation • Heart rate • Peripheral pulse quality • Mucous membrane color • Capillary refill time • Blood pressure • Lactate