GI emergency patients (Proceedings)

Gastric dilation volvulus

History and clinical signs

Commonly affecting the large breed deep-chested breeds gastric dilatation and volvulus syndrome has the potential to be a life threatening problem. Progressive gastric distension leads to pressure on the vascular system especially the venous system compromising venous return to the heart thus leading to inadequate preload and shock secondary to inadequate stroke volume. Pressure on the diaphragm caused by a progressively dilating stomach may compromise lung expansion and lead to ventilatory compromise. Vascular compromise of the circulation to the stomach itself may lead to tissue ischemia, release of endotoxins into the circulation and ultimately to the release of cytokines and SIRS.

Causes

There are many inciting events that can "cause" GDV. GDV is often associated with a disease processes that involves ilius, anxiety, anatomy of a large deep chest, and age enough to see the suspensory apparatus of the stomach be "stretched " out. Most animals that have a GDV are middle aged (6year or greater). The disease of GDV was first described in humans.

Diagnosis

Diagnosis is commonly made by observing a dog that is restless, attempting to retch nonproductively and perhaps has rapid abdominal distension. Due to the fact that the GDV mainly occurs in the deep chested dog the abdominal distension may not be evident until late in the disease. In early cases the gas distended stomach may be detectable on percussion of the cranial abdomen. On examination the dog may be in hyperdynamic shock or may be in a stage of decompensatory shock. As such findings are variable from tachycardia, tachypnea, bounding pulses and injected mucous membranes to collapse, respiratory distress, weak thready pulses.

Treatment

Immediate treatment should consist of oxygen if the dog is showing any signs of shock, and volume replacement with crystalloids and synthetic colloids started. Recent studies point to the value of hypertonic saline mixed with a colloid and given at 5 –7 ml/kg as a bolus and then reassessing. Hetastarch or Oxyglobin should be considered to maintain BP and flow. ECG should be monitored, as these dog are prone to ventricular arrhythmias. The stomach should only be decompressed after volume replacement has been started due to the potential for worsening the hypovolemic shock. Rapid onset corticosteroids are usually given at shock doses (dexamethesone sodiuum phosphate at 48 mg/kg iv or methylprednisolone sodium succinate at 1530 mg/kg iv) and broad spectrum antibiotics started. However there is NO good controlled randomized blind study of a significant number of patients that has been done to conclude that steroids of any kind make a significant difference in survival.

A right lateral radiograph should be taken. On occasion the volvulus will not be evident on the right lateral in which case if there is a high index of suspicion a left lateral radiograph should taken. A characteristic shelf sign with compartmentalization supports a diagnosis of a gastric volvulus. Barium placed by an NG tube may have to be administered to define the location of the stomach. Coagulation should be monitored as these patients are at risk for DIC. Blood pressure should be monitored.

The dog ideally is taken to surgery as rapidly as possible for derotation and a gastropexy. Gastric lavage can be performed prior to, or during surgery; however it should be remembered a stomach tube can be passed on a twisted stomach. It is also possible to pass a stomach tube through the wall of an ischemic stomach and excessive force should not be used. Following gastric repositioning an incisional gastropexy is accomplished. A nasogastric tube is inserted to prevent re-dilation postoperatively. In cases that have much food material in the stomach the stomach is massaged and the food removed via a large orogastric stomach tube in which water is added to dilute the food material. In cases that have very thick or very large amounts of food material including "chunks" the stomach is opened and all the food material is dumped out and into a basin. The stomach is closed routinely with two continuous closure patterns. An inverting pattern on the second closure can also be used and is recommended if peritonitis is also present or the stomach had previously ruptured. This is a "serosal patch" and helps prevent leakage of the gastric incision line.

When necrosis is present

When the stomach is returned to its normal anatomic position the color of the stomach is observed carefully. If necrosis with a dark blue purple color persists then the area involved, most commonly the greater curvature section, is removed and closure is accomplished. Closure is done with either simple continuous polypropylene in two layers or an automatic stapling system is used (United States Surgical TA 90) which applies two staggered rows of 4.2 mm stainless or titanium b shaped staples along a 90 mm section. The later method is faster but cannot be used in very edematous stomachs because the staples pull out. If resection is required a gastrostomy tube is usually recommended to be inserted to provide an access of continued decompression postoperatively. It is also used to medicate the mucosa with Sucralfate and gruel food and water. The tube is placed through a mucosal purse-string in the antrum incision that is used for the incisional gastropexy. A straight plain 12-20 Fr. red rubber feeding tube is placed through the muscoal purse-string and the purse-string is tied. A seromuscular stitch is placed next to the tube exit site in the stomach and encircled around the tube and tied to prevent the tube from migrating. The incisional gastropexy is then completed with 0 to 1 polypropylene as a simple continuous pattern that closes first the dorsal gastric to abdominal wall incision lines. The submucosa of the stomach and the fascia of the abdominal wall must be grasped with each bite. The suture is placed loosly and then drawn tight to ensure good placement and a tight water tight closure respectively.

A jejunostomy tube is placed for feeding if a portion of the stomach had to be resected. The patient is then fed by this tube postoperatively as a continuous rate infusion. The abdomen is irrigated and closed IF the contamination is not a concern. With gastric rupture the abdomen is generally left open with only a back and forth suture pattern. These dogs will take three to four days before its generally time for the abdomen to be closed.

Postoperative treatment

his involved around the clock monitoring and supportive care. Frequently arrhythmias are a problem after the first 24 hours post GDV rotation back to normal.

Protocol for assessment and treatment of gastric volvulus

• Blow By Oxygen Administered As ASSESSMENT (Physical Exam) is completed

• Gastric Tympany Present and Gastric Distension suspected, Assess Shock

• IV Catheters (two) Large Bore (14 gauge ) in the cephalic veins

• Plasmalyte Bolused (40 ml/kg mini) or 5 ml/kg Hypertonic Saline and Hetastarch begun

• Radiograph the Abdomen and Chest (Right Laterals) and see Double Bubble

• If Severe Distension perform gastrocentesis with long 14 gauge needles or catheters

• If Unsure pass an NG Tube - administer Barium (2-3 ml/kg) and re radiograph

• Confirmed cases induced with Ketamine/Diazepam & begin positive pressure ventilation

• Clip and Prep for Wide Exploration from Xyphoid to Pubis

• Aspirate Air from NG tube passed and reposition stomach into normal position

• Pull Pylorus ventrally from the right and push the body dorsally with right hand to the left

• Explore; Remove Spleen at the least bit of thrombus formation or hemorrhage

• Assess the Gastric Wall for evidence of necrosis

• Place NG tube (unless much solid material present in the stomach –if so do gastrotomy & dump!

• Perform an incisional gastropexy if the stomach wall appears OK – Incision G tube if not

Intestinal foreign body – Perforation

The general presentation is common to most of us but also know all-to-often that there are cases that do not have the common clinical signs we are used to seeing (vomiting, inappetence, depression, and abdominal pain). Also some other disease conditions mimic the G.I. tract foreign body. These include pancreatitis, perforation with peritonitis, parvovirus, and neoplasia. As a general rule that should be followed is the following in my opinion: If the patient has signs of an acute abdomen or GI foreign then these cases need to be aggressively managed with immediate labs, radiographs, providing of intravenous fluids and broad spectrum antibiotics and then an exploratory celiotomy and the surgery needed to correct the problem found and then extensive irrigation, suction or open drainage is indicted (see this discussion below) and continued supportive care as required (nutritional support, physical therapy, broad spectrum antibiotics, intravenous fluids, and pain control as required. Hyperbaric oxygen as an adjunctive therapy is also indicated if it is available.

Important facts and steps to follow when in the abdomen are the following

1. Explore the entire abdomen regardless if you find a foreign body on first exam;

2. If in doubt cut it out – this in regards to the observation of the bowel or stomach or other structures – if they look necrotic – remove the necrotic section (the only exception is if this involves the angle of the duodenum, entire bowel, stomach, or pancreas...in these cases a phone call to the owner is prudent. In very rare cases miracles have happened and with omental wrapping, supplemental oxygen, decompression if distended, and continued fluid support and antibiotics and, if available, hyperbaric oxygen therapy, some of these cases have survived;

3. In bowel that is distended from the build-up of air and fluid and toxic material it is best to remove this obstructed material before the bowel is reclosed. This can be done with careful packing off and a bowel that the intestinal contents are simply "milked" into;

4. Close bowel or stomach incisions with a monofilament suture on a fine-taper point swaged on needle, and engage the submucosal with each bite of a single layer closure;

5. Wrap new joined tissues with omentum;

6. If an anastomosis of intestine is required make sure that the mesenteric section of the intended anastomosis has fat cleared away from this are. Identify the edges of the bowel and insure these edges are joined;

7. Test the newly closed enterotomy or anastomosis with saline injected into the area until pressure is observed. If a leak is noted close with further suture;

8. Irrigate extensively with warm saline following all procedures and carefully look for any sponges or other materials "left behind" before closure. Inspect the entire abdomen.

9. Close the abdominal wall (external rectus fascia only needed) with a continuous pattern of monofilament suture that is one-two sizes larger than would be used for interrupted closures. Make sure of the two knots at each end of the fascial closure.

10. Irrigate the subcutaneous tissues before these are closed with a continuous pattern of monofilament suture. Consider the use of skin staples to cut down on closure time.

Severe pancreatitis

These are very serious cases that demand much intensive care. In my opinion I have seen them do better if they are operated on early. In these cases I note the severity, gently remove any necrotic tissue, remove abscessed tissue, irrigate the pancreas extensively, place a jejunostomy tube, place 2 suction drains nearby and used one for irrigation daily and the other for drainage, consider keeping the abdomen open for a repeat exam, it allows the air from the outside of the body to come in, increasing the oxygen tension of the area, and closing in one to three re-visits back into the area and repeated debridement and irrigation. In all these cases large amounts of plasma, some blood , and nutrition is key to survival. Hyperbaric oxygen must be used carefully with antioxidants on board in my opinion.