Gastric dilation and volvulus (GDV) describes dilation and torsion or malpositioning of the stomach and can have acute life threatening effects. Gastric dilation alone can also have acute, life threatening effects and the treatment is very similar to treatment of a GDV although emergency surgery may not be necessary for the simple gastric dilation patient. Gastric dilation and volvulus occurs most commonly in large and giant breed dogs although it can occur in small and medium sized dogs, puppies and has even been reported to occur in cats.

1. Initial Phone Call

Patients with a GDV can exhibit a range of signs from mild discomfort and restlessness to acute collapse. Owners often describe restlessness, salivation and unproductive vomiting. Although some owners will have noted abdominal distension it may not be obvious in all cases.

If an owner calls with any of these concerns, especially in a high risk breed, they should be advised to seek veterinary care immediately. Gastric dilation +/- volvulus can be acutely progressive in nature and rapidly create life threatening problems even if the animal currently appears stable.

2. Triage

Triage means 'to sort' and describes the process in which patients are prioritized in order of their disease severity so that the sickest animals are treated first. Any patient arriving at the veterinary hospital for an acute complaint should be immediately evaluated by the triage nurse. This evaluation is based on the 'ABCs' and includes assessment of the animal's breathing rate and effort and the 6 perfusion parameters listed in Table 1. Patients with any abnormality of concern on this examination, active bleeding or seizures should be transported to the treatment area immediately for further assessment and treatment. Animals with GDV may present collapsed in severe shock and clearly require immediate care; if not collapsed they will commonly have evidence of cardiovascular compromise with abnormal perfusion parameters. They may also exhibit increased respiratory rate and effort.

3. Initial Stabilization

All patients should receive oxygen therapy by face mask or flow-by during the initial stabilization period. As previously mentioned, the initial evaluation of all emergency patients should follow the ABC approach. Is there a patent airway (A), is the animal breathing (B) and what is the circulatory state (C)? Any interventions required to secure an airway and maintain adequate ventilation should be instigated immediately. The GDV patient maybe in respiratory distress as a result of the large stomach preventing normal movement of the diaphragm. Rapid evaluation of the circulatory status involves assessment of 6 clinical parameters; level of mentation, mucous membrane colour, capillary refill time, heart rate, pulse quality and extremity temperature (Table 1). From this brief evaluation it is determined if the patient is in shock.

Table 1. Changes in perfusion parameters consistent with hypovolemic shock.

GDV causes hypovolemic shock as a result of third space loss of fluids into the distended stomach. The spleen is commonly engorged as a result of venous obstruction which further compromises circulating blood volume. The large, distended stomach can also compromise venous return from the caudal half of the body which will also reduce the available circulatory volume.

Intravenous Access

During the initial evaluation intravenous (IV) access should be gained. A large size, cephalic catheter is ideal for the shock patient. An 18 gauge catheter is the smallest catheter for medium to large dogs and a 16 gauge catheter is ideal for large to giant breed dogs. Large and giant breed dogs often need such large fluid volumes for resuscitation that two or more peripheral IV catheters are required. If a peripheral IV catheter cannot be placed a jugular venous catheter should be considered (with or without a surgical cut down procedure) or alternatively an intraosseous catheter can be placed for fluid administration.

Blood can be collected at the time of IV catheter placement for evaluation of parameters such as the packed cell volume, total protein, blood glucose and coagulation tests.

Fluid Therapy

The treatment of hypovolemic shock is rapid fluid administration. There are three main fluid types available for resuscitation; isotonic crystalloids (0.9% saline, lactated Ringer's solution), hypertonic saline or synthetic colloids.

The 'shock dose' of fluids for animals is based on one blood volume (Table 2).

Table 2. Guidelines for shock fluid therapy.

* Shock fluid therapy should be given to effect and the total dose determined by the individual response.

These shock doses are guidelines only. Some animals will not require the full shock dose for resuscitation and some patients may require greater than the calculated shock dose. The same 6 clinical parameters of cardiovascular function can be monitored for improvement as an indication of effective resuscitation. Signs such as improved mentation, normal heart rate, improved pulse quality and warming of the extremities are all suggestive of effective resuscitation. Fluid resuscitation must be rapid and the aim should be for it to be completed in the first 10-15 minutes. There is no evidence that one fluid type is superior for resuscitation of hypovolemic shock. Because of the smaller volumes required, hypertonic saline and synthetic colloids (commonly together) are often favoured for GDV patients.

Decompression

Decompression of the stomach is essential in the stabilization of the GDV patient but it should not be performed until fluid resuscitation has begun. This is because acute gastric decompression may reduce venous return transiently and allow circulation of inflammatory mediators which can have significant hemodynamic effects. Decompression can be achieved by percutaneous placement of a trochar into the stomach and/or passing a stomach tube orally. Stomach tubes can be placed with sedation and a mouth gag but often requires significant patient restraint and maybe associated with a lot of patient stress. In many cases decompression with a stomach tube is best performed once the patient is anesthetized. A large gauge over-the-needle catheter (12 to 14 gauge) can be used as an effective trochar. The trochar is placed in the dorsolateral aspect of the cranial abdomen (left or right side) where the tympanic stomach can be best appreciated. The area is clipped and prepared aseptically, the catheter is passed into the stomach and maximal gas and fluid is removed.

Electrocardiogram

Ventricular arrhythmias commonly occur in these patients and continuous electrocardiogram (ECG) monitoring is recommended. If ventricular arrhythmias are severe and are believed to be impairing cardiovascular function they may require anti-arrhythmic therapy with drugs such as lidocaine.

Diagnostics

Abdominal radiographs are commonly performed to confirm the diagnosis and to differentiate between simple gastric distension and a GDV. Thoracic radiographs may also be taken in case there is co-existing disease that may change the owners decision regarding management. Thoracic radiographs can also be of benefit to determine if there is any current pulmonary pathology which is relevant prior to anesthesia and provide a baseline with which to compare subsequent radiographs if the patient develops respiratory complications in the post-operative period.

4. Surgery

Emergency surgery to reposition the stomach and fix it in place (gastropexy) is indicated in the GDV patient. Cardiovascular stabilization and decompression is performed a rapidly as possible and as soon as the patient is sufficiently stable general anesthesia and surgery is performed. These patients can be challenging anesthesia patients and they require intensive monitoring. Arterial blood pressure monitoring and pulse oximetry is essential and many patients will require aggressive fluid therapy and vasopressor drugs such as dopamine to maintain adequate blood pressure (systolic blood pressure greater than 90 mm Hg, mean arterial blood pressure greater than 60 mm Hg). Due to the compression of the large stomach many dogs will also need manual/machine ventilation during the surgery to ensure adequate oxygenation. Continuous ECG monitoring during surgery is recommended and anti-arrhythmic therapy given as indicated.

5. Post-operative Care

Post-operative management of the GDV patient is essential to patient survival. Therapy in the post-operative period is focused on maintaining oxygen delivery to the tissues and intensive monitoring to detect abnormalities early. Intravenous fluid therapy is continued, oxygen therapy may be provided if there is any concern regarding lung function or poor perfusion. Monitoring of physical examination parameters (especially those in Table 1), blood pressure, body temperature, pulse oximetry, urine output, ECG and blood work is performed frequently in the initial 12 to 24 hours following surgery, longer if required. Adequate post-operative analgesia is very important and opioid drugs such as morphine are most commonly used. Cardiac arrhythmias most commonly occur in the postoperative period. If a continuous ECG is not used any suggestion of an irregular heart rhythm on physical examination should prompt ECG evaluation.

Specific Nursing Care Issues in the Post-operative Period

 Frequent physical examinations

 Body temperature regulation

 Blood pressure measurement

 Urine output measurement

 Catheter care (avoid infection and inflammation at catheter sites)

 Repositioning patient every 2-4 hours (avoid pressure sores and atelectasis)

 Maintaining clean, dry bedding

 Evaluation of patient comfort

 Perform blood work as requested

 Accurate record keeping

References

1.  Crowe DT. Triage. In: Silverstein DC, Hopper K (eds). Textbook of small animal critical care medicine, Saunders, St Louis, 2009, p5

2.  Volk SW. Gastric dilatation-volvulus. In: Silverstein DC, Hopper K (eds). Textbook of small animal critical care medicine, Saunders, St Louis, 2009, p584

3.  Macintire DK, Drobatz KJ, Haskins SC, Saxon WD. Manual of small animal emergency and critical care medicine. Lippincott, Williams & Wilkins, Philadelphia, 2005