Gastric Dilatation-Volvulus Flashcards
What is the difference between dilatation and dilatation-volvulus?
(dilation) - distension of the stomach with fluid, food, and/or gas, making a frothy mucoid substrate
enlargement of the stomach associated with rotation on its mesenteric axis (malposition/twisting)
(underlying motility problem needs to be addressed!)
How is the gastric flora affected by gastric dilatation?
ileus stops peristalsis, resulting in bacteria from gut translocating into the peritoneal cavity
What is the most common rotation seen in GDV?
clockwise rotation of pylorus over the fundus
- between 90-360 degrees
What is gastric torsion?
rotation of the stomach less than 180 degrees clockwise or 90 degrees counterclockwise, resulting in NO complete obstruction
How is exercise thought to affect development of GDV?
pre/post prandial exercise was believed to be a risk factor
- clinical data does not support this, has not been reproduced
What are some possible dietary influences in developing GDV?
- increased volume of food fed once daily
- table food
- canned food
- fats/oils
- raised food bowl
(not all bloats are filled with food)
What breed has an increased predisposition to developing GDV?
Great Danes —> 40% die of bloat if a gastropexy was not performed
What thoracic conformation is thought to predispose to GDV development?
increased thoracic depth to width ratio —> more room for movement
What temperament predisposes to GDV development?
- high anxiety
- working/military dogs
Should all dogs getting splenectomies also get a gastropexy?
NO —> same low risk for developing GDV, already high-risk surgery that commonly results in anemia
Pathophysiology of GDV:
What are the 4 major parts of the pathophysiology of GDV?
- myocardial ischemia and cardiac arrhythmias due to decreased tissue perfusion and gastric atony (sequestration = electrolyte imbalance)
- obstructive shock correction = reperfusion injury at kidneys, heart, pancreas, stomach, and small intestine
- systemic inflammatory response syndrome (SIRS)
- disseminated intravascular coagulation (DIC)
(3 and 4 = spiraling, 10% survival rate)
What clinical signs are associated with GDV?
ACUTE ONSET:
- abdominal distension and pain with “prayer position” to take pressure off the abdomen (tympanic and painful on palpation)
- retching, vomiting
- hypersalivation
- restlessness
- lateral recumbency
- panting, heavy breathing
- coughing
- collapse
What are signs of compensatory and decompensatory shock?
COMPENSATORY = tachypnea, tachycardia, bounding pulses, prolonged CRTs
DECOMPENSATORY = MM injected (bright red), weak, laterally recumbent
What bolus and maintenance fluids are recommended for stabilization?
BOLUS = crystalloid (LRS, plasmalyte), hypertonic saline, hetastarch
MAINTENANCE = crystalloid (LRS, plasmalyte), colloids (hetastarch)
What is recommended for gastric decompression? 2 other options?
OROGRASTRIC TUBE with sedation
- nasogastric tube
- trocharization, then OG/NG tube
What are the major pros and cons to nasogastric tubes for gastric decompression?
PROS: least invasive, provide continuous drainage when there is a delay between stabilization and surgery
CON: slowest, hard to pass through gastroesophageal sphincter
What is a major pro and con to trocharization for gastric decompression?
PRO = fastest
CON = highest complication rate
How are orogastric tubes placed?
- measure from nose to xyphoid process
- apply lube and gently pass the tube
- remove air, then lavage until fluid is clear
- can tape between incisors to avoid movement of the tube
How is a nasogastric tube placed?
- proparacaine (proxymetacaine) in the nostril
- measure from nostril to xyphoid process
- apply lube and gently pass 14 Fr catheter
- suture in place
How is a gastrocentesis performed?
- clip and prep
- apply sterile gloves
- palpate for widest region
- insert 14-16 IVC
- remove stylet
What complications are associated with gastrocentesis?
- peritoneal contamination
- splenic puncture
What is seen on CBC, chemistry, and PT/aPTT in patients with GDV?
CBC - thombocytopenia if DIC
CHEM - hypokalemia
PT/aPTT - prolonged PT, normal/prolonged aPTT if DIC
What is seen on blood gas and lactate in patients with GDV?
BLOOD GAS - metabolic alkalosis due to sequestration of H+ in gastric lumen and respiratory acidosis due to hypoventilation
LACTATE - < 6.0-7.4 may indicate increased survival/decreased gastric necrosis, may not be a valuable value
When should radiographs be taken in cases of GDV? What is diagnostic?
after stabilization, don’t add stress with restraint
RL (all 3 views still important) - compartmentalization (or double bubble) where the pylorus is displaced dorsally
What are the benefits of early surgery for treating GDV?
- gastric repositioning improves blood flow
- surgery can be done before onset of arrythmias
What are the 3 objectives in the surgical management of GDV?
- reposition the stomach
- assess the severity of ischemic injury to the stomach and spleen, and resect devitalized tissue
- perform a permanent gastropexy to prevent recurrence
What are the 5 steps to the surgical approach of GDV?
- clip wide
- midline approach from xyphoid to umbilicus/pubis
- decompress the stomach by inserting a 14-16 gauge needle attached to suction into the stomach
- perform gastropexy
- abdominal closure
How can decompression be performed if there is solid material in the stomach? How is the abdomen closed?
pass an orogastric tube and lavage
- linea: 0 or 2-0 PDS
- SQ: 2-0 monocryl/PDS; 3-0 PDS
- intradermal/skin: 3-0 to 4-0 monocryl/PDS
What is seen when first opening the abdomen for GDV surgery?
mesentery covering a black (ischemic) stomach
Why must the stomach be decompressed prior to GDV de-rotation?
air can travel down the GIT and dilate it, making it hard to fit it back into the abdomen and increases abdominal pressure (which decreases venous flow!)
How does a clockwise rotation of the stomach look?
- pylorus moves along the ventral abdominal wall to the left side
- omentum covers the stomach
(position of the spleen is variable)
How does a counterclockwise rotation of the stomach look? How do patients present?
- pylorus moves dorsally to lie adjacent to esophagus, making the greater curvature lie along the midline
- omentum DOESN’T cover stomach
chronic GI signs
How is clockwise rotation of the stomach repositioned? What 2 things must be verified after repositioning?
the pylorus is grasped with RH and greater curvature with LH, then the pylorus is pushed toward the incision
- spleen in proper position and viable
- gastrosplenic ligament is not torsed
What are the 4 standard criteria for assessing gastric viability? What are 2 other options?
- color (black = devitalized)
- pulsation of blood vessels
- bleeding from cut surface
- peristalsis
- palpation of wall thickness (thin = devitalized)
- surface oximetry
How is the spleen evaluated following GDV stomach repositioning?
venous congestion should be self-limiting and revert following repositioning, but if vessel thrombosis or torsion is present a splenectomy is recommended
Where is gastric necrosis commonly found in cases of GDV?
greater curvature near short gastric arteries
How are staples used when treating gastric necrosis? How does it compare to hand ligation?
double rows of staples around the area of necrosis with nice closure
- less association with mortality
- will have a slight inversion, which may catch adhesions
- speeds up procedure
What is a gastrorrhaphy?
invagination of diseased portion of the stomach where devitalized tissue is pushed inward which allows for a strong seal and will slough off with time —> must avoid obstructions and damage to vasculature of greater curvature
(FOCAL necrosis)
How can a gastropexy be done laparoscopically? When is this done?
grid approach where the seramuscularis of the stomach is sutured to the transverse abdominus muscle and close by suturing the internal and external obliques up to the skin
prophylactically
What is a gastropexy? What are 2 indications?
technique where the stomach is permanently adhered to the body wall
- GDV —> antrum to right body wall
- hiatal hernia —> fundus to left body wall
What is the preferred gastropexy technique?
incisional gastropexy
What is a circumcostal gastropexy? What are 2 pros and cons?
seromuscular flap of the pylorus is placed around the 13th rib and tacked down to the stomach
- PROS: strongest technique, gastric lumen is not opened
- CONS: technically demanding, risks rib fracture and pneumothorax
What are 5 steps to a circumcostal gastropexy?
- make a one or two layer hinged flap approx 5-6 cm through the seromuscular layer of the pyloric antrum
- elevate the flap by dissecting under the muscularis
- make a 5-6 cm incision over the 11th or 12th rib at the level of the costochondral junction and form a tunnel
- insert the flap under the tunnel and supply a stay suture
- suture with 2-0 PDS
What is a belt loop gastropexy? What is a pro and con?
seromuscular flap is passed through a tunnel in the abdominal wall (NO RIB)
- PRO: gastric lumen not opened
- CON: not as strong as a circumcostal
What are the 4 steps to a belt loop gastropexy?
- make two 3-5 cm incisions on the abdominal musculature
- create a tunnel under the musculature with forceps
- make a hinged flap through the seromuscular layer of the pyloric antrum and pass it through the tunnel using stay sutures
- suture to original position with 2-0 PDS
What is a tube gastropexy? What are 2 pros and a con?
stomach is sutured to the body wall via a gastrostomy tube
- PROS: quick and simple, can insert medications
- CON: peritonitis from improper placement
What are the 5 steps to a tube gastropexy?
- make a stab incision into the right abdominal wall caudal to the last rib and 4-10 cm lateral to midline
- place an 18-20 Fr foley catheter
- select a hypovascular region of the seromuscular layer of the ventral pyloric antrum where the balloon will not obstruct and place a pursestring in the site with 2-0 PDS, then make a stab incision
- finger trap the catheter to the skin
- bandage until tube can be removed in 5-7 days
What is an incisional gastropexy?
an incision in the seromuscular layer in the gastric antrum and right abdominal wall are sutured together in a simple continuous pattern
pexy of choice because it is simple, fast, and less invasive; usually prophylactic
Where is the gastric incision made in an incisional gastropexy? Why?
between lesser and greater curvature at pyloric antrum no less than 3-5 cm in length ONLY THROUGH SEROSA AND MUSCULARIS
want to create an adhesion for life where scarification will not affect
Incisional gastropexy:
What has been disproven to facilitate effective adhesion?
scarification of the serosal surfaces of the abdominal wall and stomach
How is a laparoscopic-assisted incisional gastropexy performed?
a camera port is placed for visualization of the antrum of the pylorus and an instrument port is with Babcock forceps grip the pylorus and bring it to where it will be attached to the body wall
What are 4 advantages and 2 limitations to incisional gastropexy?
- equipment more widely available
- pyloric antrum accurately visualized
- gastropexy performed with standard surgical instruments
- minimally invasive = best for prophylaxis
- expertise in gastropexy required
- potential organ trauma
How does the addition of a gastrectomy affect the gastropexy? How is the stomach closed?
increases mortality to 35%
- first layer simple continuous in mucosa and submucosa
- second layer inverting pattern, like Cushing (parallel) and Lembert (perpendicular)
What post-op care is required following gastropexies?
- intensive monitoring
- fasting (NPO 24 hrs), enteral nutrition, or bland diet
- low residue antibiotics
- fluid and electrolyte replacement
- cardiogenic control —> myocardial depressant factor made by pancreas, arryhthmias, BP for hypotension
- pain control
- limited exercise
What 3 GI protectants are recommended post-operatively following gastropexies?
- metoclopramide
- H2-receptor antagonists - rantidine, famotidine
- sucralfate
What are the 3 most common causes of post-op deaths following gastropexies?
- hypovolemic or septic shock
- gastric necrosis causes peritonitis, due to unrecognized areas of necrosis, perforating ulcers, or reperfusion
- cardiac arrythmias
What are the 2 most common electrolyte disturbances monitored for following gastropexies?
- hypokalemia - induce/potentiate arrhythmias, muscular weakness, and lethargy
- hypochloremia due to gastric sequestration
What is the most common cardiac arrhythmia following GDV?
ventricular —> most common 12-36 hr after onset of GDV and abate within 24-74 hours of surgery
In what 5 ways can GDV cause cardiac arrhythmias?
- myocardial ischemia
- electrolyte abnormalities
- acid-base alterations
- vasoactive substances
- imbalance of autonomic nervous system
What are the 5 most common signs of ventricular arrhythmia caused by GDV?
- premature ventricular contractions
- paroxysmal ventricular arrhythmias
- idioventricular rhythm (slow V-tach)
- ventricular tachycardia
- multifocal PVCs
When is ventricular arrhythmias treated in patients post-op following gastropexies? What is used?
CLINICAL —> v-tach with high rate causing pulse deficits, poor pulse qualities, or weakness and multifocal PVCs
Lidocaine —> bolus 1-2 mg/kg q 5 mins, CRI 25-80 mcg/kg/min (also corrects electrolyte imbalance)
What should be checked with refractory arrhythmias? What treatment is recommended?
potassium, magnesium, and calcium
pain management
What are the 3 major choices for prophylactic gastropexy?
- open - during elective OVH or castration
- laparoscopic
- endoscopic-assisted
What 4 factors are associated with an increased risk of bloat in large dogs that can, in turn, lead to GDV?
- raising food dish
- fast eaters
- risk increases with age
- family history, especially with first-degree relatives (parent, sibling, offspring)
When is post-op mortality highest following gastropexies? Primary/secondary sources?
first 4 days
- PRIMARY = gastric necrosis, rupture, peritonitis
- SECONDARY = cardiac arrhythmias
How can risk of GDV be reduced?
- feed several small meals
- avoid stress during feeding
- restrict exercise before and after eating
- no elevated food bowls
- careful breeding
- prophylactic gastropexy
