the left ventrolateral abdominal wall approximately 2.5 cm lateral to the linea alba. A single row of five to six simple interrupted sutures is placed through the peritoneum and then through the anti‐mesenteric surface of the colon. Attempts should be made to engage the submucosa of the colon without entering the lumen with the suture as this may lead to contamination of the colopexy site. For the incisional technique, the seromuscular layer of the colon is incised along the anti‐mesenteric surface and a corresponding incision is made at the proposed colopexy site in the parietal peritoneum. The edges of the two tissues are sutured in a simple interrupted pattern in two rows. Use of both monofilament absorbable and non‐absorbable suture have been described and suture should be sized appropriately for the patient. No difference if efficacy or complications has been reported with either suture type or colopexy technique [10, 11].
Laparoscopic and laparoscopic‐assisted colopexy has been described in dogs and a cat, respectively [12, 13]. For the laparoscopic procedure, a standard three‐cannula technique was used. The peritoneum and serosa were gently abraded using a gauze sponge introduced through a portal and the colopexy was completed by intracorporeal placement of interrupted sutures. Laparoscopic‐assisted colopexy allowed creation of a pexy through a small incision into the left inguinal region of the patient. This procedure is similar to colopexy performed through a limited paramedian approach but allows for intra‐abdominal visualization of the colon prior to incision into the peritoneum. Complications were not reported for either of these procedures.
8 Gastric Dilatation and Volvulus
Michael S. Tivers and Sophie Adamantos
Paragon Veterinary Referrals, Wakefield, UK
Introduction
Gastric dilatation and volvulus (GDV) is a relatively common acute abdominal condition in deep‐chested, large‐breed dogs [1]. A study of first‐opinion emergency clinics in the UK found a prevalence of 0.64% [2]. Small and medium‐sized breeds of dog are uncommonly affected by the condition. It is extremely rare in cats but has been reported as a spontaneous condition and is also associated with diaphragmatic rupture [3–5].
There are several syndromes associated with gastric dilatation in dogs, including a chronic form of GDV [6], and acute gastric dilatation without volvulus. This chapter focuses on the management of dogs presenting with acute GDV.
Dogs with GDV are commonly presented with severe cardiovascular compromise and require rapid stabilization and appropriate management for successful outcomes. Since the condition was first described, mortality has reduced from 33–68% to approximately 15% [7]. Reported survival rates for GDV in referral centers in the past 15 years are between 73.2% and 90.2% [8–15].
The management of GDV can be divided into the following steps:
1 Restoration of perfusion.
2 Gastric decompression.
3 Anesthesia for exploratory laparotomy.
4 Gastric derotation and decompression.
5 Resection of non‐viable tissue.
6 Gastropexy.
7 Postoperative care and monitoring.
Pathogenesis
The pathogenesis of GDV is poorly understood. It is thought that gas accumulates in the stomach as a result of aerophagia and rotation of the stomach occurs.
Risk Factors
A number of studies have examined the many risk factors associated with GDV in dogs. The information from these studies is often contradictory, making firm conclusions difficult. It is likely that GDV is a multifactorial process and therefore the role of single risk factors is unclear. There are certain repeatable findings in many studies, however, that are associated with an increased risk of GDV. Only one finding has been associated with a decreased risk of GDV and this is being of a “happy” temperament [15]. Risk factors that have been proposed as increasing the risk of GDV include breed, with German Shepherds, Great Danes, Standard Poodles and Irish Setters being over‐represented; increasing age; thin body condition; being of anxious temperament and having a first‐degree relative with GDV [2,15–19]. The role of diet has been extensively investigated, although the precise role remains unclear [15, 16, 19, 20]. Being fed large quantities of food, being fed from a raised bowl, dry kibble, being fed one meal a day, and eating quickly are all reported to be associated with an increased risk of GDV [16,19–22].
Pathophysiology
Dogs with GDV have rotation of the stomach, typically clockwise and between 180 and 360 degrees. Once rotation has occurred, a number of local and systemic effects result.
Local Effects
Gastric distension will decrease intramural blood flow and result in stasis, thrombosis, and hypoperfusion to the stomach wall. Gastric rotation will decrease this further; the greater the degree of rotation, the more severe the reduction in gastric blood flow. At its most severe, there will be cessation in blood flow to areas of the stomach that may result in necrosis and possible gastric perforation. Rotation of the stomach can cause stretching and possible rupture of the short gastric arteries, resulting in hemorrhage. In up to 38% of dogs, there will be compromise to the spleen, including torsion and damage to arterial supply, requiring splenectomy [23].
Systemic Effects
Many dogs with GDV are hypoperfused, resulting in generalized tissue ischemia. The hypoperfusion is multifactorial in origin, with the most important cause being obstruction to venous return as a result of occlusion of the caudal vena cava secondary to gastric tympany. Decreased right atrial filling results in decreased cardiac output. Some dogs will also have some degree of hypovolaemia as a result of hemorrhage or third spacing of fluid in the stomach. Cardiogenic shock may also occur as a result of arrhythmias and/or myocardial depression.
It is thought that the majority of postoperative systemic effects occur as a result of ischemia–reperfusion injury [24]. These include systemic inflammatory response syndrome (SIRS), hypotension, cardiac arrhythmias, disseminated intravascular coagulation (DIC), and acute kidney injury [25]. The presence of severe systemic effects is associated with a poorer prognosis [25].
Cardiac arrhythmias can occur in dogs with GDV. Most often these are ventricular in origin and are seen postoperatively (50–77% of dogs) but are also observed preoperatively in a lower proportion of dogs [7, 9]. The exact pathogenesis of these arrhythmias is unclear although alterations in coronary blood flow, circulating epinephrine and myocardial depressant factor have all been implicated [26].
Clinical Presentation
Dogs are often presented acutely. Many have a history of trying to vomit unproductively and some will be presented collapsed. Owners may have noted abdominal distension. Concerned owners should be asked to present their pets as soon as possible. Common findings on physical examination include hypoperfusion (including pale mucous membranes, prolonged capillary refill time, weak pulses, and tachycardia), arrhythmias, obtundation, abdominal pain and distension, gastric tympany, distress, and weakness (Figure 8.1). If the abdominal distension is profound, there may be a
