Hi HOlly
Holly and Pablo said:
I was under the (mistaken?) impression that Sevo was safer than injectables, but I guess that's NOT when it's used as an induction agent, Jess?
Sevo is a great drug for maintaining anesthesia, it's just that administering it by mask or box is uncontrolled and poses a danger to the staff and the cat.
When I asked my vet yesterday about the use of Domitor in cats (since the dental vet plans to use it on Pablo for his recheck), he said he thought it was safe, but he just "doesn't use it in cats." Why? "I just don't."
I think that is his way of saying that he just doesn't feel comfortable with it d/t lack of experience.
These are our standard practices: For canine S/N: Propfol IV, then intubation and maintenance with Sevo. For feline S/N: Telazol IM, then intubation/masking with Sevo (more often masking if the cat isn't sleeping from the Telazol). For canine procedures like suturing a wound, NT for fractious dogs, we use a combo of Xylazine/Butophanol or Domitor/Butophanol IV or IM, the former most commonly. For feline non-invasive procedures like sedated grooms, wounds, etc.: Masking with Sevo, then intubation if warranted.
A few things:
1- It sounds like you and other staff members are getting a lot of exposure to anesthetic gas. I would ask for a monitoring badge. Even if he doesn't want to buy one for all the techs, all the time, he can do a trial and see what the exposure is for one full-time tech/assist.
2- I think the problem here is that the animals aren't getting IV catheters. With an IV catheter you needn't worry about hitting a vein. This means that the animals aren't getting fluids during their anesthesia, and I suppose that also means they aren't getting BP monitoring (or else he'd see that the animals were hypotensive). Is that correct?
3- Oh, xylazine. It is actually related to Dormitor (officially Dexdormitor now, slight change in formula) and pre-dates it, so a lot of older-school vets use it. It is significantly cheaper. There is some evidence that Dexdormitor, a more "specific" drug, keeps patients on a smoother plane both analgesically and anesthetically. You can check out more info on
http://www.vasg.org/alpha_2_agonists.htm which is generally a great site for anesthesia/analgesia in small animals. From a vet journal:
"Comparison of xylazine and medetomidine as premedicants for cats being anaesthetised with propofol-sevoflurane
Vet Rec. July 2005;157(5):139-43.
A L Selmi, G M Mendes, B T Lins, J P Figueiredo, G R Barbudo-Selmi
Universidade Anhembi Morumbi, São Paulo, Brazil.
Abstract
The effects of premedicating cats with saline, xylazine or medetomidine before anaesthetising them with propofol-sevoflurane were compared. Twenty-four cats were randomly assigned to three groups of eight to receive either 0.25 ml of saline, 0.50 mg/kg of xylazine or 0.02 mg/kg of medetomidine intravenously, and anaesthesia was induced with propofol and maintained with sevoflurane. Medetomidine produced a greater reduction in the induction dose of propofol and fewer adverse postoperative effects than saline or xylazine. Hypoxaemia was observed after induction with propofol in the cats premedicated with saline and xylazine, but not in the cats given medetomidine. The cats treated with medetomidine and xylazine developed profound bradycardia. The blood pressure of the cats premedicated with saline and xylazine decreased, but the blood pressure of the cats premedicated with medetomidine was maintained. The cats premedicated with saline took longer to recover from anaesthesia than the other two groups."
Moving on :
what are your options for sedation and what are the effects of the sedative? If you'd prefer to PM your thoughts, that's fine too. I try to do what's best for Pablo and thought I was making a decent choices, given my limited resources. As it stands now, I will probably attempt Propofol on him on Monday, followed by intubation and Sevo. But for future instances and other cats, I'd love thoughts to pass on to my vet. Even if he doesn't do anything about my suggestions, at least they're a thought in his mind. :roll: I get so frustrated with him, but he always listens to my concerns and doesn't think I'm a moron after more than three years of my endless questioning at times. A nuisance at times, but not a moron.
Saying that there are ideal and less-ideal sedation protocols doesn't mean that the less-ideal protocols cause mass perioperative death. It's a matter of a few things, including:
1-- Do you get the animal where you need to in the first round, or is there frequently more struggle and added drugs?
2-- How is the pain management during and after the procedure?
3-- What are the unseen side effects? Hypoxia due to low blood pressure?
4-- How smooth is the induction and wake-up?
To really compare protocols head-to-head, you need to do proper monitoring. You may find that xyalzine does a great job and then get a Doppler and realize everyone is hanging out at 60mmHg. Monitor SpO2, and if possible, use a capnometer (these will hopefully become popular soon), and then compare your protocols. Can a young cat do great on a spay with telazol, sevo mask, and no perioperative meds? Sure. Can she do better (much better) on IV fluids and a more modern protocol? You bet. We will never know if the CKD cats we encounter later in life could have had a few more nephrons working if they hadn't become hypoxic and hypotensive during their spay and then their FB surgery, their two dentals, etc. Also, vet med is rife with stories of elderly cats who seemed to do great during their dental but came back in renal failure a week or two later, or just outright died. You have to think the events are related, but we can't know for sure.
For your cat, if the point is just to take a look at the bump on the chin, I don't know if you need to intubate, but you know your cat better than I do. I would think that with most cats -- even the grumps, though not the wild ones -- you can get them onto their side, and then turn the front end up (ventral/dorsal) to look at the chin. If the weird bumps and scabs are still there and look like they need attention, why not ask the vet if you can use some valium/torb or something? If this does not sound feasible given your cat's typical behavior, I'd put in an IVC and get the torb/val and propofol together, and see what you need. If you're doing a needle aspirate, I don't know why he'd need intubation -- this should take less than two minutes. We do some aspirates (of thoracic masses) with just torb/valium plus a touch of propofol, believe it or not.
Anyway I can't reasonably give you specific advice since there are so many variables and it's really the vet's choice of what he's comfortable with. I'm just trying to offer ideas without being *too* confusing ;-) If you are interested in analgesia/anesthesia, you can check out the vasg site I mentioned earlier, or pubmed.gov for peer-reviewed articles (I speak journal-ese and can help you with any absurdly worded phrases/paragraphs), or consider joining VSPN which has a lot of VIN info on these topics.
Take care
Jess