In the Surgery/Neurology department at SouthPaws Veterinary Referral Center we see a vast array of surgeries and neurological cases. Although some of the cases we treat are young healthy animals, the majority are critically ill and injured or elderly pets. In our department almost all the diagnostic tests or recommended treatments require that the pets go under general anesthesia. The anesthetic protocols we employ then must be safe, varied and flexible since many of our patients are not "the best" candidates for anesthesia.

Pre-operative Medications and Induction Agents
At SouthPaws we select from a large array of controlled and non-controlled drugs, which gives us the flexibility we need. Almost all of our patients will receive some sort of pre-operative medication. The majority of dogs will get subcutaneous injections of hydromorphone and glycopyrolate. Most cats receive a subcutaneous injection of torbugesic. As for induction agents, we use standard drugs such as sodium pentothal, ketamine/diazepam mixture and propofol. As the nature of the cases change and anesthetic risk of the patient demands, we will alter the protocols. Acepromazine, oxymorphone, fentanyl, etomidate, or even just isoflurane can be used in conjunction with the other drugs or instead of similar agents.

Special Cases
Special cases are pretty much all we deal with, so we have different anesthetic protocols set up and ready.

• Elderly cats or cats with cardiac/respiratory concerns are common patients that we handle. These cats might still get the pre-operative subcutaneous injection of torbugesic, but instead of ketamine/diazepam we will switch to an oxymorphone/diazepam mix for induction and adjunctive doses of etomidate as necessary. We have found this to be more "heart friendly."  The etomidate is diluted 1:1 with saline and given to effect for intubation. Occasionally we will use propofol in cats, but it is our experience that propofol severely depresses the cat's blood pressure and respiratory rate. Many times straight Isoflurane with a mask or induction chamber is also employed.
  

• Dogs with Mast Cell Tumors require special precautions prior to and after induction. These dogs receive pre-operative intramuscular injections of glycopyrolate and diphenhydramine. After induction with pentothal, propofol or ketamine/diazepam, these dogs will get intravenous doses of cimetidine and dexamethasone.
  

• Sight Hounds or other lean, athletic dogs have their own protocol. These pets receive pre-operative doses of both hydromorphone and diazepam intravenously. Propofol is

the induction agent of choice.

• Neurological cases also require special handling and different anesthetic protocols. For these animals all the pre-operative medications are given intravenously and followed immediately by the induction agent. The pre-operative drugs are as follows, in order of administration, glycopyrolate, diazepam, oxymorphone and lidocaine. Propofol is always used as the induction agent, and the full dose is normally not required. This protocol provides a smooth and quick induction and recovery, and it can also be reversed with naloxone.
  

Pain Control
Many of our surgical procedures are very invasive and are performed on very painful animals. We try to be mindful of the necessary pain control before, during and after the surgeries. Most of the pre-operative medications mentioned above have some analgesic component. During the surgeries our main choice for analgesia is intravenous doses of fentanyl, it is fast acting and does not affect the patient's blood pressure. Post-operatively all our surgical patients receive a Duragesic (fentanyl) patch, since these patches take up to 18 hours to reach their full effectiveness, we will use intravenous and/or intramuscular injections of oxymorphone during the recovery period. The duragesic patches should provide pain relief for the patient up to 72 hours post-operatively. Torbugesic is occasionally used, but it is a partial-antagonist which can alter the effectiveness of fentanyl, oxymorphone and/or hydromorphone. Some of our more painful orthopedic procedures require that we send the pets home with prescriptions of percodan, dilaudid, or torbutrol.

Additional Information
Recently we began to us a new induction mixture of propofol/pentothal. An anesthesiologist from the University of Pennsylvania told us we could combine the two drugs in the same syringe, thus giving us the best benefits from both agents and at the same time using less of each. This combination has provided us with smooth and quick inductions that last longer than straight propofol but without the respiratory and blood pressure depression associated with it. The formula for using this "combo" is simple, take your induction doses for both pentothal and propofol and add them together, then divide that amount by two. This amount is the necessary mixture of the two drugs:  just draw up half propofol and half pentothal.

***For more detailed information or specific dosages, please contact John Balthis, LVT, at SouthPaws Surgery/Neurology Department, (703) 451-0909.