2015 Zoetis Clinical Challenges: GI, Anesthesia, and Pain Management (NAVC/WVC)

2015 Zoetis Clinical Challenges: GI, Anesthesia, and Pain Management (NAVC/WVC)

Monday, January 19, 2015

The opinions expressed in these answers are those of the speakers and do not necessarily reflect the official label recommendations and point of view of the company or companies that manufacture and/or market and of the pharmaceutical agents, products, or services mentioned.

The Chronic Vomiting Cat and Anesthetic Protocols for the GI Patient: The What, Why, and How

David S. Biller, DVM, DACVR, David Twedt, DVM, DACVIM, and Andre Shih, DVM, DACVA

From Drs. Biller and Twedt:

Do you feel Cerenia® (maropitant, Zoetis) works worse or better if given intravenously?  
No, unless the patient is dehydrated and then blood levels are probably reached faster with intravenous (IV) administration.

Can you use Cerenia intravenously in cats?  What dosage?
Yes, using the same dose, 1 mg/kg, given slowly over a minute or 2.

Does Cerenia block substance P and help pancreatitis directly?  
We don’t know—Cerenia blocks vomiting vagal pathways and likely visceral pain pathways in the pancreas as well.

Why did you not run an fPL in this case (see proceedings)?
We did run an fPL (feline pancreas-specific lipase) test but not in the initial blood workup.

What is the long-term protocol for Cerenia? Do you give it daily or stop for a number of days and restart it? 
Published studies have treated with Cerenia for 30 days with no problems. I personally know longer-term therapies have been used with no problems but there are no published studies of longer-term use.   

Do you find bacteria in a normal pancreas?  
The bacteria most commonly found in the pancreas is E coli followed by enteric streptococci and then other Gram-negative aerobes.

Which antibiotic do you choose if bacteria are contributing to triaditis?
I use amoxicillin, amoxicillin-clavulanic acid (Clavamox®, Zoetis), cephalosporins, and lastly marbofloxcin or enrofloxcin (but I don’t like that for long term). 

I recently cultured Campylobacter from a pancreatic biopsy. How often do you use antibiotics in pancreatic cases?
This case responded to erythromycin after treating for 2 months.  If differs between dogs and cats. In cats, most cases of acute or chronic pancreatitis may have bacteria, but bacteria are less common in dogs. I use antibiotics in severe cases at risk of bacteremia or septicemia.

At what blood level of cobalamin do you start supplementation?  
In dogs, when vitamin B12 < 275 ng/L (normal >250 ng/L) I would consider supplementation if there are GI signs; in cats, when B12 < 325 ng/L (normal is >290 ng/L).

From Dr. Shih:

Do you use or recommend any constant rate infusion (CRI) pain control protocols?
Yes. For dogs, I like an opioid CRI for perioperative pain. One can add lidocaine and/or ketamine to increase analgesia and possibly decrease spinal wind-up. A routine protocol for anesthesia at the University of Florida is HLK:  hydromorphone 0.05 mg/kg/hr, lidocaine 50 µg/kg/min, and ketamine 0.5 mg/kg/hr.

What are your thoughts on Hetastarch in cats that may be hypovolemic and hypotensive under general anesthesia?
I particularly do NOT like synthetic colloids in cats. Cats are more likely to get fluid overloaded than dogs. In humans Hetastach has also been linked to increased risk of renal failure and coagulopathy. We tend to use crystalloids (NaCl and Lactate Ringer’s solution, LRS) here in anesthesia.

Do you prefer propofol over alfaxalone for induction of your case?
I just started to use alfaxalone so my clinical experience is limited. So far I am very happy with alfaxalone it is but too early to say I would prefer one over the other. It depends on the case. For example, for cesarean section or in patients with liver failure or brain disease, I love the unique properties of propofol. Alfaxalone tends to be better for hemodynamically unstable patients (hypotension, low cardiac output)

What is your feeling about PropoFlo (propofol, Abbott) versus PropoFlo™ 28 (propofol, Abbott) in cats?
You can use PropoFlo 28 in cats for a single bolus—for anesthesia induction, it is fine. I would NOT use it for infusion rates or for several repeated boluses. (Note: PropoFlo 28 is not approved for use in cats; it contains benzyl alcohol which may be toxic to cats.)

Can Cerenia be given IV in both dogs and cats?
You can; however, I tend to give it subcutaneously (SQ) or intramuscularly (IM). The time I administered Cerenia IV it caused hypotension. I administered the IV fast but I have heard that if you give it IV slowly you would not see a drop in blood pressure.

Is lidocaine CRI safe in cats? 
Yes at lower doses. Lidocaine infusion can lead to a drop in cardiac output and an increase in blood pressure. The effect is dose dependent. I prefer NOT to give lidocaine infusion to cats but if I had to give it I would choose a low dose— 25 µg/kg/min for a couple of hours sound safe. 

Can you discuss the use of ondansetron versus maropitant (Cerenia)?
Both are very effective antiemetics. The mechanism of action is a little different as they act on different receptors in the vomiting center. I like Cerenia’s fast onset of action.

Do you do a TAP block bilaterally?
The transversus abdominis plane (TAP) block has to be done bilaterally for abdominal pain.

What dose of lidocaine do you use for a TAP in cats?
I use 2‒4 mg/kg (dilute it to 1% concentration).

What about a ketamine induction?
I like ketamine. It is a great induction agent for hypovolemic or septic patients. It is the only induction drug with significant analgesic properties and it is one of the few that can be used intramuscularly (IM) on very aggressive animals.

The Acute Abdomen: To Cut or Not to Cut

David S. Biller, DVM, DACVR, and David Twedt, DVM, DACVIM

Please comment on the rate of false positives on the SNAP® cPL™ test (IDEXX). I have heard it can be up to 40%.
In a study we did the false-positive rate was 24% in CLINICAL pancreatitis that we would normally treat. Positive dogs with other disease identified may have had secondary pancreatic changes from primary disease or a low grade subclinical pancreatitis.

Can you cut a patient that has just had an upper GI with barium or is it contraindicated?
We try to avoid this. We don’t want to leak barium into the abdomen, so use careful technique. If you suspect a perforation use iodinated contrast.

What is the differential for an abnormal Spec cPL® (IDEXX) test other than pancreatitis?  
An abnormal Spec cPL represents pancreatic acinar damage. It could be clinical pancreatitis, low grade subclinical acute or chronic pancreatitis, or some other disease with secondary pancreatitis—for example, GI foreign body, GI perforation, and peritonitis with the pancreas likely secondary involved.

What is the correlation between a mucocele and hypothyroidism?  
The correlation is probably high triglycerides and cholesterol.

What do steroids do to bile composition?
Steroids increase bile salt independent of bile flow

When you recommend surgery to a patient like this, what do you say to the owner about prognosis and percent recovery?  
In a non-sick dog, prognosis is very good. In a sick dog, factors including high enzymes, biliary obstruction, bile peritonitis, or other comorbidity influence prognosis.

What is your feeling on using ursodiol if you are uncertain about bile duct blockage?  
There is no problem based on studies in rats and humans; it does not blow out the biliary system, however, if obstruction surgery is indicated.

In cases like Lover Boy (see proceedings), do you ever try to clean out and leave the gallbladder?  
No, in cases like this the gallbladder wall is very diseased.

Is there any contraindication to using ursodiol based on liver enzymes, especially alkaline phosphatase, when ultrasound is not available?  
No; ursodiol is very safe to use no matter what the liver enzymes are.

If you are treating a mucocele medically do you empirically treat with antibiotics in addition to ursodiol?  
Although most mucoceles are not infected, since I don’t know I would do 2 to 3 weeks of antibiotics. My choice often is Clavamox® (amoxicillin-clavulanic acid, Zoetis)

Is there any benefit to ventrodorsal compression versus lateral?  
Lateral compression is probably better because there could be spine overlap with ventrodorsal (VD) compression.

How could cutting the string (on a foreign body under the tongue resulting in a linear foreign body) not result in a board complaint?
I would never do that but there was a publication showing success in some cases. I would only consider it if surgery was not an option (i.e., euthanasia or cut and see).

Anesthesia and Analgesia for Geriatric and Neonatal Patients

Andre Shih, DVM, DACVA

What is the current belief about the analgesic effect and duration of butorphanol?
Butorphanol is a great sedative but a weak analgesic. Its analgesic effects are very short lasting. I believe it lasts about ~1 hour for analgesia, and for sedation I would guess 2 hours.

What about glycopyrrolate instead of atropine for pediatric patients?
You can use glycopyrrolate or atropine. Glycopyrrolate tends to have a longer duration of effect and a longer onset of action—that is, it takes longer to see effects but it lasts longer also.

You said to use NSAIDs for pain. How young will you use NSAIDs in puppies and kittens?
I use nonsteroidal anti-inflammatory drugs (NSAIDs) in fairly young patients—as early as 4 weeks of age.

Do you think the reason some dogs are hypersensitive to nail clips is because they were clipped too short as a puppy?
There has been no scientific research looking at this specifically but it makes a lot of sense. If you cause severe pain when animals are neonates there is a chance this patient will become allodynic and hyperalgesic in the future.

Do you do a splash block with lidocaine for a pedicle block? If so, do you worry about infections?
I don't do splash blocks but I like to recommend pedicle blocks, especially for complicated ovariohysterectomy (OHE) cases, such as patients in heat or with pyometra or for cesarean section.

Do you give Cerenia preoperatively and does it affect any anesthetic drug doses?
Cerenia has some analgesic effect and it does decrease MAC (minimum alveolar concentration, the anesthetic requirement) but I do not trust Cerenia as a sole agent for analgesia—meaning I would still give a patient NSAIDs or opioids despite the fact that it received Cerenia. (Note: Cerenia is not approved for use as an analgesic.)

Do you use or recommend any CRI pain control protocols? Do you need to reduce doses in pediatric patients that are 16 weeks and older?
Once they are 16 weeks old, pharmacologically they behave like adults. For a CRI I would use an opioid CRI, such as a fentanyl infusion or an HLK infusion (see earlier question for regimen).

Is there an equivalent dose of methadone to the hydromorphone dose of 0.1 mg/kg?
Methadone can be used at a dose of 0.1 to 0.5 mg/kg. A high dose of hydromorphone, 0.1 mg/kg, is probably equipotent to a 0.3 mg/kg dose of methadone.

Do you use Cerenia as part of your routine premed protocol for spays and neuters?
I like the postoperative "anti-nausea" effect of Cerenia. The only downside is the cost. It has to be factored into the anesthesia fee if you want to incorporate it in your spay and neuter protocol.

How do you feel about acepromazine and dexdetomidine together?
Good question. I don't like Dex and Ace together because one is an alpha receptor blocker (Ace) and the other an alpha receptor agonist (Dex) so the body will have vasodilation and vasoconstriction at the same time. It may cause a hemodynamic imbalance during anesthesia.

Should I not use ketamine in older patients or patients with increased renal values?
I have no problem with ketamine and renal disease. Ketamine will last longer in cats with renal disease but it is still safe

Are you using carprofen (Rimadyl®, Zoetis) in cats/kittens? What dose?
I use NSAIDs and use Rimadyl in pediatric patients. The main disadvantage of Rimadyl injectable is that because of its formulation it is hard to pull a low enough volume for very small cats (1 kg or less).

Is it better to do a local pedicle block in a spay and wait for the lidocaine to take effect or have a shorter surgical time?
I would use a pedicle block if it is a complicated OHE. On the routine cases the surgical time is so short and the incision is so small that NSAIDs probably are enough to provide adequate analgesia.

Are you concerned about the minimum age on the label for Cerenia?
I used Cerenia in patients as young as 4 weeks of age. However, the manufacturer (Zoetis) reported that use of Cerenia in young patients can lead to medullary changes.

Since there are no v-gel® airway management systems specifically for dogs, can you use a cat or rabbit v-gel on a puppy?
No. The rabbit v-gel (JorVet) works great on rabbits but it will probably leak on a puppy. There is a mini v-gel product for cats that will probably work on a dog (1 kg).

Is morphine use okay in geriatric patients?
Yes. Morphine is a great opioid. Intravenous morphine can lead to histamine release (regardless of age of the patient).

 

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