Gastric Dilatation and Volvulus Flashcards
What usually happens to the pylorus during a gastric dilation and volvulus?
- In the vast majority, the pylorus, which is normally on the right, moves ventrally and over to the left side, creating the torsion
What are the three main body systems affected by a GDV?
- Respiratory system
- Cardiovascular
- GI
How is the respiratory system affected by GDV?
- Increased respiratory rate
- Shallow breaths
How is the cardiovascular system affected by GDV?
- Tachycardia
- Pale mucous membranes
- Weak pulses
How is the GI system affected by GDV?
- Non-productive retching
- Abdominal distension
- Abdominal pain
How can GDV lead to stomach necrosis, and what is the consequence of that?
- Compresses gastric wall vessels and wall, obstructing outflow
- This leads to stomach necrosis
- Stomach necrosis can lead to endotoxic septic shock
How does GDV cause hypovolemia, and what are the consequences of that?
- Primarily compressing CVC and portal vein directly (decreased return to the heart)
- In addition, compression of the gastric vessels and wall obstructs outflow, and there is sequestration of fluid
- Ultimately this leads to decreased cardiac output
- Then you get hypotension and decreased perfusion
- Then hypoxia
- Then organ damage and dysfunction
How do you get decreased PaO2, and what is the consequence of that with GDV?
- GDV leads to pressure on the diaphragm
- Decrease tidal volume
- Ventilation/perfusion mismatch
- Decreased PaO2
- Hypoxia
- Organ damage and dysfunction
How do you get DIC and SIRS from GDV?
- It’s a combination of the hypoxia secondary to compression of the CVC and portal vein as well as decreased PaO2 from pressure on the diaphragm
- Additionally endotoxic septic shock from stomach necrosis
- This leads to organ damage and dysfunction, which leads to SIRS and DIC, which further contribute to more organ damage and dysfunction
How do you pancreas necrosis with GDV, and what is a consequence of that?
- It’s a combination of the hypoxia secondary to compression of the CVC and portal vein as well as decreased PaO2 from pressure on the diaphragm
- Additionally endotoxic septic shock from stomach necrosis
- This leads to organ damage and dysfunction, which leads to pancreatic necrosis
- This then leads to release of myocardial depressant factor, which can cause arrhythmias and decreased function of the heart
How do you get kidney failure from GDV, and what are the consequences of that?
- It’s a combination of the hypoxia secondary to compression of the CVC and portal vein as well as decreased PaO2 from pressure on the diaphragm
- Additionally endotoxic septic shock from stomach necrosis
- This leads to organ damage and dysfunction, which leads to kidney failure
- Ultimately the consequence is electrolyte and acid-base imbalances, that can lead to decreased cardiac function and arrhythmias
How do you get decreased heart function and arrhythmias from GDV, and what are the consequences of that?
- It’s a combination of the hypoxia secondary to compression of the CVC and portal vein as well as decreased PaO2 from pressure on the diaphragm
- Additionally endotoxic septic shock from stomach necrosis
- This leads to organ damage and dysfunction, which leads to decreased heart function and arrhythmias
- In addition, myocardial depressant factor released from the heart contributes
- Furthermore, kidney failure from the organ damage leads to electrolyte and acid-base imbalances, which will depress the heart function and cause arrythmias
Look at the chart on page 95
Just do it
Classic presentation of GDV
- Large, deep chested dog with short history (usually hours) of restlessness, depression, non-productive retching, and abdominal distension, progressing to signs of shock
What are the two differentials for the following presentation:
Large, deep chested dog with short history (usually hours) of restlessness, depression, non-productive retching, and abdominal distension, progressing to signs of shock
- Gastric dilatation or gastric dilatation and volvulus
What position should you keep a dog with GDV in and why?
- Keep sternal as much as possible to decrease compression of CVC and portal vein by a distended stomach
What are your top two priorities for a GDV?
1. IVF at shock rate
TREATMENT BEFORE DIAGNOSTIC TESTS
What else should be high on the list with a GDV?
- Oxygen, but it won’t get to the tissues well until you relieve the CVC compression and hypovolemia
- As much as possible, administer flow-by O2 as you work on the dog
Fluid type/rate/route for GDV
- 90 mL/kg/hr IV
Where will you place the catheter for GDV? Why?
- Give via catheters in BOTH FRONT LIMBS
- It needs to get to the heart vs back legs which won’t perfuse well
Describe the steps for decompression of a GDV
- +/- sedation (opioid +/- diazepam)
- Mark tube (measure from nose to last rib)
- Lubricate tube
- Roll tape in mouth
- Gentle, DO not force
- If not passing, gently rotate tube, change dog’s position
Where do you measure for decompression via orogastric tube?
- Nose to last rib
If you successfully pass a stomach tube and decompress, what does this tell you about whether or not the stomach is torsed?
- You can still pass a stomach tube if the stomach is torsed
Options if you can’t pass a stomach tube (from most to least preferred)
- Percutaneous gastrocentesis
- Get into surgery ASAP and decompress
- Temporary cutaneous gastrotomy
Describe percutaneous gastrocentesis
- What might you risk hitting?
- Insert 14g needle at most tympanic point
- Risk of hitting the spleen, so pull out if you get blood
Temporary cutaneous gastrotomy - describe
- Rarely done
- Buys time until you can get to a surgeon
- Make a paracostal incision –> suture stomach to the skin –> make incision in stomach and leave open until you go to surgery
Again, what treatments take precedent over everything else (including radiographs) for a GDV?
- Fluids and decompression
What things could you do while setting up fluids and decompressing that are also important?
A. Administer O2 via mask/flow-by right from the start
B. Take blood from the catheter just before hooking up fluids
C. Hook up an EKG (VPCs are common in GDV patients)
D. Monitor blood pressure
E. Medications: Prophylactic antibiotics as there is a high risk of devitalized or contaminated tissue; Analgesia
Labwork for GDV
- Run quick assessment tests
- PCV/TP
- Glucose
- Azo
- Lactate
- CBC (may show low platelets and non-degenerative left shift; lymphopenia)
- Blood gas (may show respiratory acidosis)
- I-Stat (may show hypokalemia)
- PT/PTT (may be prolonged)
- Biochemical profile (want to look at albumin)
Radiographs of GDV (NOT A PRIORITY) - which view?
- Right lateral abdominal view is all you need
- Restraining the dog for rads risks further compromise due to even more compression of the caudal vena cava and portal vein
If you do decompression first, doesn’t that risk not being able to see the GDV on radiographs?
- Nope, you can still see the GDV on radiographs after decompression
Opening incision for GDV
- Make a large ventral midline celiotomy from xiphoid to at least mid-way between the umbilicus and pubis
What structure is typically covering the stomach in a GDV, and where does it normally attach?
- Greater omentum
- It is attached to the greater curvature of the stomach and normally extends caudally to the stomach
How should your fingers be placed when handling the stomach?
- Keep your fingers together and flat in order to distribute the pressure you are putting on the stomach over a greater surface area (focal pressure from the tips of fingers can lead to perforation through a compromised wall!)
In the vast majority of cases, GDV occurs when the pylorus moves what two directions?
- Ventrally and to the left
What should you do before derotating the stomach? Why?
- Decompress
- The distended stomach wall can be friable
- If you attempt to rotate it in the distended condition, it may perforate
What is the 1st choice for decompressing a GDV before derotating?
- Pass an orogastric tube
- Even if you couldn’t do this pre-op, you can often get it in at surgery because the surgeon can help manipulate the tube through the cardia
What is the 2nd choice for decompressing a GDV before derotating?
- Gastrocentesis (hook needle up to suction unit)
3rd choice for decompressing a GDV before derotating?
- Gastrotomy
What direction do you derotate most GDVs?
- Derotate from dorsal on left, ventral, and right
- One hand gently pulls the pylorus ventrally and to the right while the other hand gently pushes the body and fundus dorsally and to the left
After derotation, what should you check to make sure you fully derotated?
Check the cardia and pylorus to make sure the stomach is back in normal position
- Depending on how far the stomach is rotated, the derotation move may need to be done more than once
What should you assess after derotating GDV? What do you do if you find areas of necrosis or ischemia in the gastric wall?
- If the gastric wall does not look healthy, give it 5-10 minutes after derotating to see if it pinks up
- Check the cardia too; you can make a window in the superficial leaf or bring the stomach and greater omentum cranioventrally
- If there are areas of ischemia or necrosis, partial gastrectomy can be done via TA stapler (thoracoabdominal), invagination (inverting pattern and auto-digestion) or resection + 2 layer suture closure (slow)
- If you don’t have the resources andcapability to deal with a necrotic stomach, you should pre-operatively refer GDV cases to a practice that does
What other organ can be involved with a GDV, and what should you do if it is?
- Splenic torsion can occur as the stomach twists
- Do NOT untwist the spleen, as this can release vasoactive factors and cause reperfusion injury that further compromises the dog
- Perform splenectomy without untwisting the splenic pedicle
What is a gastropexy?
- Create a permanent adhesion between the stomach and body wall to prevent GDV
Recurrence rate of GDV with and without gastropexy
- Should gastropexy be standard part of GDV surgery?
- Recurrence is 55-98% if no gastropexy
- 4-7% with gastropexy
- It should be a part of GDV surgery standard
What are the layers of the stomach?
- Serosa
- Muscularis
- Submucosa
- Mucosa
Which muscle is the most interior on the abdominal wall?
Transversus abdominus?
What part of the stomach is pexied to the body wall in a gastropexy? Which body wall (Left/right) is it sutured too?
- Pyloric antrum region of the stomach should be pexied to the right body wall
Why shouldn’t you pexy the stomach to your abdominal incision?
- Next time someone has to do a celiotomy in this patient, they will likely end up in the lumen of the stomach
Why shouldn’t you pexy the pylorus to the body wall?
- narrowest point of the stomach and may kink off the outflow
Put the following steps in the order you will proceed to do them
A. Gastrotomy
B. Finish the abdominal explore
C. Gastropexy
B. Finish the abdominal explore
A. Gastrotomy
C. Gastropexy
- If they weren’t doing well, she might prioritize the gastropexy
What does a permanent gastropexy require contact between?
- Muscularis layer of the stomach and the transversus abdominus of the abdominal wall
When you are incising the stomach in preparation for a gastropexy, which layers do you need to cut?
- Through serosa and muscularis
- Submucos aand mucos are intact
Suture for a gastropexy?
- I think absorbable
- 2-0
GDV Post-operative concerns
Monitoring
- TPR
- MM
- CRT
- Pulse quality
- Pain
- Urination
- Defecation
- Vomiting
- Arrhythmias
What are the most common arrhythmias in GDV patients?
- VPCs and ventricular tachycardia
What is the most common time of onset of arrhythmias in GDV patients?
- 12-36 hours post-op
What is it important to counsel owners pre-op about monitoring post-op after GDV?
- Important to tell owners pre-op about the need to monitor for problems such as arrhythmias post-op, and the likelihood of several days of hospitalization after surgery
What are potential causes of arrythmias with GDV?
- Release of myocardial depressant factor from compromised tissues (e.g. pancreas
- Myocardial ischemia due to generalized hypoxia
Pain management for GDVs
- Opioids (Not NSAIDs)
Hydration and electrolytes - what’s a good starting fluid rate for GDV?
- 1.5-2x maintenance
Antibiotics for GDV
- Definitely given during surgery
- Continue post-op if you have indications like perforation or necrosis
Nutrition for GDV
- If the dog is really compromised, place a feeding tube intra-op
- Since stomach may be compromised, a jejunostomy tube makes sense
- Bland food 12-24 hours by mouth, small frequent meals
What can you use to treat for gastritis for post-op GDV?
- Antacids
- Ranitidine
How can you treat for ileus?
- I’m not sure
- Maybe metoclopramide
- I also think decreasing opioids is reasonable once you’re more certain their pain is controlled
Survival for GDV patients treated surgically
- 85-90%
- Thus there is a 10-15% mortality rate
What are poorer prognostic indicators for GDV?
A. Time of onset between signs and presentation
B. Body temperature
C. Patient attitude
D. Lactate pre-op
E. Lactate post-op
F. Heart rhythm
E. Things you find during surgery (2)
A. >5-6 hours between onset of signs and presentation
B. Low body temp
C. Depressed or comatose patient
D. Lactate is high like greater than 6 or 9 mmol/L (measure of the degree of anaerobic metabolism going on)
E. Lactate does not decrease at least 50% in the first 12 hours (more important than pre-op lactate)
F. Arrhythmias especially if they present pre-op
G.Gastric necrosis or splenectomy needed intra-op
When do most dogs who die from GDV die?
- Within 96 hours of treatment, which is during reperfusion
Reperfusion injury reminder
- GDV –> hypoxia and poor perfusion –> anaerobic metabolism –> accumulate hypoxanthein and xanthine oxidase which combine with O2 after reperfusion –> reactive oxygen species (like H2O2 and O-) –> cell death
Predisposing factors for GDV
- Large breed, middle age, deep chested, thin, fed one meal per day, rapid eater, postprandial exercise, hospitalization, fearful temperament, maybe IBD
What % chance do Great Danes have of getting GDV?
- 25%
Does elevated feeding help with GDV prevention?
- No apparently :(
How can you prevent GDV (4 main methods)
- Divide food into >1 meal/day
- Avoid close timing of food and exercise
- Food dish on the ground
- Prophylactic gastropexy (can be done via open surgery or laparoscopically)
Which breeds is it most imperative to be pexied?
- Great Danes are a must
- Labradors, Rottweilers, Standard Poodles
