have a rapid onset of action (e.g., propofol or alfaxalone). Compromised dogs require less induction agent than normal animals. The dog should be maintained in sternal recumbency and the head held elevated until the animal has been intubated. Nitrous oxide should be avoided as this may cause increased gas accumulation in the stomach. Clipping should be performed with the dog in lateral recumbency. Dorsal recumbency is avoided unless the stomach has been decompressed as this may worsen hypoperfusion.
Goals of Surgery
Surgical treatment of GDV consists of several distinct steps that must be performed to ensure the best outcome for the dog:
Decompression and repositioning of the stomach.
Assessment of gastric and splenic viability.
Resection of devitalized tissue.
Gastropexy.
The dog is aseptically prepared for surgery and a standard midline laparotomy is performed. The incision should be as long as necessary to allow adequate inspection and manipulation of the stomach and to perform a gastropexy. Care should be taken on incising the linea alba to prevent inadvertent trauma to the stomach which may be compressed against the ventral body wall. Abdominal retractors (e.g., Balfour) are invaluable in increasing exposure and facilitating surgery.
Repositioning of the Stomach
The initial aim of surgery is to decompress and reposition the stomach. This will help to address continuing hypoperfusion caused by the distended stomach and allow subsequent assessment of tissue viability and a gastropexy to be performed.
Typically, the stomach is twisted between 90 and 360 degrees in a clockwise direction [46]. The direction of torsion is assessed intraoperatively from the caudal aspect of the dog in dorsal recumbency. For a clockwise torsion, the pylorus of the stomach moves ventrally and toward the left side of the abdomen. Owing to the direction of this movement, the stomach enters the omental bursa and is therefore covered by a single layer of omentum (Figure 8.7a).
Repositioning can be facilitated by further gastric decompression. An assistant passes an orogastric tube and the surgeon should be able to manually guide the tube through the cardiac sphincter. If this is not possible, needle gastrocentesis can be performed to reduce the distension. Repeated gastric lavage with warm tap water via the orogastric tube can help to decompress the stomach further. If there is a large amount of food present in the stomach, a gastrotomy may be necessary to allow repositioning.
To derotate a clockwise rotated stomach, the surgeon stands on the right‐hand side of the dog and uses their right hand to grasp the pylorus of the stomach, lying in the cranial aspect of the abdomen on the left‐hand side. The pylorus is then gently retracted ventrally and toward the right‐hand side of the abdomen. At the same time, the surgeon should exert downward pressure with the left hand on the visible portion of the stomach, encouraging it to move dorsally (Figure 8.7b). This movement may need to be performed several times to fully derotate the stomach.
Figure 8.7 Series of intraoperative images showing derotation of the stomach at exploratory laparotomy in a dog with gastric dilatation and volvulus. (a) Initial appearance of the dilated stomach. The stomach is covered by omentum, which is indicative of a clockwise torsion. (b) Appearance of the stomach during derotation. The pylorus (P) is identified. (c) The dilated stomach, which has been restored to a normal position.
Once the stomach has returned to a normal position (Figure 8.7c), further decompression and lavage can be performed using the orogastric tube. If a gastric foreign body is present, a gastrotomy may be necessary.
Assessment of Gastric Viability
Once the stomach is decompressed and repositioned, the gastric wall should be evaluated for evidence of necrosis. The greater curvature, at the junction between the fundus and the body, is the most common site for necrosis. The serosa is often bruised and, following repositioning, it should be monitored for 5–10 minutes prior to full assessment. Subjective assessment of tissue viability is the most practical and useful method. The gross appearance of the stomach wall is a useful indicator. If the wall is discolored (gray, green, purple or black), has areas of seromuscular tearing or is much thinner on palpation, ischemia is present and subsequent necrosis is likely (Figure 8.8). Gastric vessels should be gently palpated for evidence of pulses or thrombi. If a more objective assessment is required, a partial thickness (seromuscular) incision can be made to assess perfusion. Active bleeding implies that the tissue is viable whereas a lack of bleeding suggests that resection is necessary. More objective methods for assessment of gastric wall viability include fluorescein dye, scintigraphy and laser Doppler flowmetry [47–49]. These techniques, however, are not widely available and may be impractical in the clinical setting.
Gastric Necrosis
Gastric necrosis has been reported in 9.3–40.6% of dogs with GDV [9, 10,12–14, 22, 28,50–52]. In dogs with an area of suspected devitalized or necrotic gastric wall, surgical treatment of this, ideally with a partial gastrectomy, is mandatory. Several studies have shown that dogs with gastric necrosis or those that require gastric resection have a significantly increased mortality, with up to 62.5% of dogs not surviving (including those euthanized due to the severity of necrosis) [10, 13, 23, 29, 51, 53]. Failure to perform a partial gastrectomy in dogs with gastric necrosis will result in gastric perforation, peritonitis and SIRS and has been associated with a mortality rate of 100% [11]. Although resection and reconstruction of devitalization and necrosis of the gastric cardia and distal esophagus is possible, it is technically demanding and the prognosis for these animals is grave [9, 13]. Although rare, gastric necrosis can lead to perforation and contamination of the peritoneal cavity prior to surgical exploration. In these dogs, gastric resection and gastropexy as well as treatment for peritonitis (see Chapter 11) are required.
Gastric Resection
Areas of gastric ischemia or necrosis are treated with a partial gastrectomy and primary closure. This can be performed with an open resection by hand or with the use of surgical stapling devices. Prior to resection, the stomach is packed off from the rest of the abdomen with moist laparotomy sponges in case of spillage of gastric contents. Stay sutures using 2‐0 or 3‐0 polypropylene are placed in healthy stomach wall to allow manipulation during resection and closure. Gastric resection has been significantly associated with the development of hypotension, peritonitis, DIC, sepsis and arrhythmias [9].
Figure 8.8 Intraoperative images of gastric necrosis at exploratory laparotomy in two dogs with gastric dilatation and volvulus. (a) Gastric necrosis of the greater curvature, note the purple and black stomach
