rel="nofollow" href="#ulink_3c120444-565b-52ea-8b3e-4f7bd6251465">Figure 8.3) [41]. If these findings are present, then the impact of previous procedures (e.g., trocharization or orogastric intubation) should be taken into consideration, since these procedures may increase the number of false positive results.
Figure 8.2 Right lateral abdominal radiograph showing gastric dilatation and volvulus. Note the “Popeye arm” appearance caused by dorsal displacement of the pylorus.
Figure 8.3 Right lateral abdominal radiograph showing gastric dilatation and volvulus with gastric pneumatosis. This is indicative of gastric necrosis.
Once GDV has been confirmed radiographically, gastric decompression should be attempted. Two methods commonly used are orogastric intubation and gastric trocharization. Orogastric intubation is the more common technique allowing for the removal of gas and fluid but can be more challenging to perform. Trocharization is a simple and rapid technique but allows relief of gaseous distension only. One study reported good success rates for both orogastric intubation (75.5% of dogs) and trocharization (86% of dogs), with no serious complications associated with either technique [42]. The techniques can be used concurrently and may be complimentary. The authors prefer to use trocharization.
To perform trocharization, an area is clipped and surgically prepared dorsally over the abdominal wall in an area of palpable gaseous distension. An area of tympany is identified and a 14‐ or 16‐gauge over‐the‐needle catheter is placed percutaneously into the stomach (Figure 8.4a). The bung is removed, and the stylet can be left in place or removed, allowing gas to escape (Figure 8.4b). If the stylet is left in place, there is less susceptibility to the catheter obstructing due to occlusion, but there is a slightly higher risk of trauma. Once the flow of gas has stopped, the catheter/trochar is removed. Following trocharization, the dog should be taken promptly to surgery and the corresponding gastric wall examined for signs of continuing leakage or necrosis. If an area of concern exists, it should be resected.
A modified technique of ultrasound‐guided percutaneous gastropexy and placement of a gastrostomy catheter has been described to allow continuing gastric decompression prior to surgery [43]. This has been recommended for managing dogs where a delay in surgical treatment is anticipated, for example prior to referral or transfer to another clinic as it allows repeat decompression. The study showed that it was reasonably safe and effective. However, it was similarly effective to repeat trocharization [43].
Figure 8.4 (a) Once an area of tympany is identified, a 14‐ or 16‐gauge over‐the‐needle catheter is placed percutaneously into the stomach. (b) An extension set has been placed into water to evaluate for bubbles to determine when the flow of gas has stopped.
For orogastric intubation, a large‐bore stomach tube with an end hole is lubricated, measured from nostril to last rib (Figure 8.5) and then the length is marked. The dog is placed in sternal recumbency and a roll of bandage with a large enough hole to pass the tube through is placed in the mouth and the mouth held closed around the bandage (Figure 8.6). In alert dogs, sedation or anesthesia may be necessary. Sedation can be accomplished using oxymorphone (0.1 mg/kg IV) or fentanyl (2–5 μg/kg) in combination with diazepam (0.2–0.25 mg/kg IV). In compromised dogs, this combination may be adequate to induce anesthesia. Endotracheal intubation is recommended in anesthetized dogs to protect the airway from aspiration of gastric contents. The orogastric tube is advanced slowly into the pharynx and the dog is allowed to swallow so that it enters the esophagus. The tube is advanced to the stomach carefully and upon entering, gas should be released. Once the stomach has been decompressed, the tube should be removed. Some authors recommend lavaging the stomach at this point [42]. If the tube cannot be advanced into the stomach, trocharization should be attempted. The tube should not be forced into the stomach as there is a risk of perforation. If perforation does occur, this is probably an indicator of preexisting gastric or esophageal necrosis. In some cases, gastric decompression may not be possible until the dog has been anesthetized for surgery.
Figure 8.5 Measuring stomach tube prior to orogastric intubation. The end of the stomach tube is measured to the last rib and a tape marker is placed to identify how far it should be inserted.
Figure 8.6 Bandage roll placed in dog's mouth as a gag and to facilitate passage of stomach tube, which is inserted through the hole in the center of the bandage.
Some authors have suggested a role for management of ischemia–reperfusion injury to prevent subsequent complications [10, 25, 26]. Suggested interventions have included desferoxamine, dimethyl sulphoxide and allopurinol. All have been evaluated in experimental GDV, although none have been evaluated clinically [24, 26]. Lidocaine, however, has been evaluated retrospectively and prospectively as part of the management of GDV in dogs [10, 25]. Retrospective evaluation failed to show a survival benefit associated with lidocaine, but use was uncontrolled, and it is likely that lidocaine use was biased toward more seriously affected dogs [10]. In a prospective study, GDV dogs were treated with lidocaine and a historical population of dogs with GDV was used as a retrospective control [25]. Dogs received an intravenous bolus of lidocaine (2 mg/kg) immediately on presentation, followed by a lidocaine constant rate infusion (50 μg/kg/min) given over 24 hours. A reduced rate of arrhythmias and acute kidney injury, and shorter hospitalization time were reported with lidocaine therapy. Although it is unclear if other factors played a role in the decreased complication rate, the administration of lidocaine may be warranted in the management of GDV.
While surgical intervention is considered mandatory for management of GDV, medical management of the condition, consisting of orogastric intubation, trocarization if necessary and treatment for shock, has been evaluated [44, 45]. A high mortality (66%) [44] and recurrence rate of 71–76% has been reported [44, 45]. The authors do not recommend medical management alone for the treatment of GDV.
Operative Techniques
Anesthesia using a cardiovascular sparing protocol is recommended. Dogs should be preoxygenated. Premedication with a pure mu‐agonist opioid is useful if not already given. Fentanyl (2–5 ug/kg) is short acting, has a fast onset and can be used immediately prior to induction to reduce the dose of induction agent required. The
