Background information, risk factors, and pathophysiology
Gastric dilatation and volvulus syndrome (GDV) is a life-threatening condition primarily affecting large breed dogs. Distension
and rotation of the stomach leads to compromised gastric perfusion and obstruction of the caudal vena cava. Sequestration
of blood in the splanchic and skeletal muscle beds as well as hemorrhage from torn gastric vessels leads to a state of hypovolemic
shock. Without aggressive medical and surgical intervention, the condition is generally fatal. GDV is a very common condition
affecting approximately 60,000 dogs per year in the US with mortality rates ranging from 10-60% (overall mortality is much
closer to the 10% range).1 Much research interest has focused on identification of risk factors for GDV such that prophylactic measures may be instituted
to try to prevent the occurrence of the problem. Presently, the following factors have been identified:
- Age: Older dogs are more likely to develop GDV than younger dogs.
- Pure-Breed status: Dogs of pure breeding are 4.4 times more likely to develop GDV than mongrel dogs.
- Size / Conformation: An increased thoracic depth to width ratio has been associated with an increased risk of developing GDV.
This parallels clinical observations that GDV occurs with greater frequency in large, deep chested dogs.
- First-degree relative with a history of GDV
- Faster speed of eating
Overall, risk of developing GDV is likely a result of a complex interplay between age, genetic, conformational, environmental,
and behavioral factors.
Initial stabilization of the dog presenting with suspected GDV should focus on the treatment of hypovolemic shock (decreased
oxygen delivery to the tissues due to inadequate circulating volume). Oxygen therapy should be administered initially by mask
or flow-by techniques while venous access (14-18g) is acquired via the cephalic veins. Hind-limb catheters should be avoided
due to the decreased venous return from the caudal vena cava seen in dogs with GDV. From the catheter, a PCV / TS / Blood
Glucose / Venous Blood Gas (Emergency Database) should be collected. If possible, an entire CBC and Serum Biochemical Profile
should be drawn prior to fluid therapy. Baseline physiologic data in addition to those gained through major body systems assessment
should be collected. These include blood pressure, ECG, and pulse oximetry reading (SpO2).
Assuming that there is no contraindication to aggressive fluid support, (such as history of cardiomyopathy) volume resuscitation
should commence with isotonic crystalloid solutions (LRS, Normosol-R, Saline). A shock rate of fluids (90 ml/kg/hr) should
be calculated and then administered to effect. The authors prefer administer shock rates of fluids in increments of approximately
¼ of the calculated dose, reassessing major body systems after each bolus. It is important to remember that the endpoint of
fluid therapy should be the normalization of vital signs, not the administration of some arbitrary volume. Some dogs may not
need the entire 90ml/Kg, while others will need significantly more.
When rapid or small-volume resuscitation is needed, colloids and/or hypertonic saline may be considered. Colloids have the
advantage of being retained in the vascular space for longer than crystalloids, allowing for smaller administered volumes.
Hetastarch, a synthetic colloid, may be administered for this purpose at a dose of 10-20 ml/kg. Alternately, the following
technique may be utilized. In a 60ml syringe, draw up 43ml of synthetic colloid and 17ml of 23% hypertonic saline. Administer
at a dose of 5ml/Kg no faster than 1ml/Kg/min. This resuscitation option has the main advantage of speed. The osmotic effect
of the hypertonic saline and the oncotic effect of the synthetic colloid will restore intravascular volume extremely rapidly.
Additional crystalloid fluids may then be continued as needed.
Gastric decompression should be considered once volume resuscitation is underway. The authors prefer a combination of trocharization
and orogastric intubation. Trocharization is performed using an 18g needle or 16-18g over-the-needle intravenous catheter
placed transabdominally into the stomach. Anatomically in GDV, the fundus will most often be located on the right side. Palpation
for gas distention, will help identify the optimal location for trochar placement. It is important to avoid the often-distended
spleen while placing the trochar catheter. Trocharization has the advantage of being quick and easy to perform with minimal
risks. It is not stressful and does not require sedation. Disadvantages of trocharization are the risk of puncturing another
abdominal structure of importance (spleen), and inability to evacuate liquid and food material from the stomach.
Orogastric intubation is indicated once the patient is more stable. Orogastric intubation has the advantages of being able
to completely decompress the stomach and to lavage out any food material within. The primary disadvantages of this technique
are the high degree of stress associated with orogastric intubation (often requiring sedation) and the risk of esophageal
or gastric injury. During lavage, aspiration pneumonia is a significant risk. Orogastric intubation should be performed using
a tube appropriate for the size of the patient, well-lubricated, and measured from the mouth to the last rib. A piece of tape
as a marker will ensure that the tube is not advanced too far into the patient. A mouth gag is required (2-3inch PVC tubing
works well) to prevent trauma to your orogastric tube. Once the stomach is entered and the gas decompressed, lavage of the
stomach with warm water is indicated. For patient safety, the authors prefer to endotracheally intubate the patient if gastric
lavage is to be performed. This makes sense logistically as well, since the patient will be proceeding directly to surgery
A dose of broad spectrum antibiotics is indicated early in the course of therapy and should be continues through surgical
intervention and beyond if specific indications exist.