Tips and Tricks for Anesthetizing Diabetic Dogs and Cats

Take away messages:

  • Anesthesia is not contraindicated in healthy diabetic dogs and cats and can even provide relief from complications or treat concurrent conditions that could be causing insulin resistance.
  • Adjusting insulin administration and dextrose supplementation based on frequent blood glucose monitoring is recommended.
  • Try to keep the patient “sweet, not sour.” A mild hyperglycemia is preferred over hypoglycemia.
  • The goal is to provide minimal disruption to the pet’s diet and insulin routine. Schedule the procedure in the morning, adopt outpatient anesthetic protocols, and encourage eating as soon as possible after recovery. Some experts advocate feeding a small meal prior to anesthesia

Anesthesia is not contraindicated in healthy diabetic dogs and cats1. In fact, anesthesia is necessary to treat several conditions that contribute to insulin resistance (e.g., severe dental disease or diestrus in female dogs) or diabetic complications (e.g., cataracts or nonhealing wounds.) By tailoring the entire anesthetic event to the needs of the individual, before, during, and after anesthesia, veterinary teams can rest assured that they are doing the best they can for their patients.

One size doesn’t fit all: A longstanding, generic recommendation for managing diabetic patients was to give a fasted animal half the typical morning insulin dose before anesthesia. However, some experts now believe in more individualized insulin dosing, aiming for somewhat tighter control of blood glucose (150–250 mg/dl) and avoiding hypoglycemia.2,3,4

Table 1 – Sample protocol for perianesthetic blood glucose regulation
Patient’s blood glucose before, during, and/or after anesthesia:

Less than 100 mg/dl
100-200 mg/dl
Greater than 200 mg/dl
Greater than 300 mg/dl

 

Additional individualization of the anesthetic event extends to each part of the process: before, during, and after anesthesia.

Before anesthesia

Careful planning provides minimal disruption to the pet’s insulin dosing or feeding regimen.

  • Schedule the procedure as early as possible.
  • Select short-acting or reversible outpatient anesthetic drug protocols. Consider the following:
    • Use local anesthetic protocols when possible.
    • Opioids (e.g., hydromorphone, morphine sulfate) have minimal effects on glucose metabolism and can provide significant analgesia and sedation; however, some may cause transient nausea and decrease food consumption, especially if used as a sole agent.
    • Opinions vary on the use of alpha-2 agonists (medetomidine and dexmedetomidine) as these drugs are rapidly reversible, but can cause transient hyperglycemia due to inhibition of insulin release.5
    • Choose an induction agent that has a short duration of action and allows for a smooth recovery (e.g. Propofol, etomidate).
    • Ketamine has a sympathomimetic effect and may increase blood glucose.2
    • Protecting the airway through endotracheal intubation, as well as supplemental oxygen and inhalant anesthesia if needed, is recommended.
    • Because return to feeding is so important for diabetic animals, consider maropitant administration prior to premedication with opioids as it has been shown to decrease perioperative nausea and facilitate postoperative feeding.6
    • Consider NSAID use postoperatively (if appropriate) to provide analgesia without sedation.
  • To fast or not to fast? While there may be benefits to glucose regulation if a diabetic pet receives a small meal three hours prior to anesthesia, there remains contradictory evidence on whether or not this practice reduces regurgitation during anesthesia.7,8
  • Screening tests: In addition to testing blood glucose, perform preanesthetic bloodwork and an in-house urine analysis to assess for other concurrent diseases and ketoacidosis. If present, postpone anesthesia and stabilize the pet, if possible.
  • Fluid check: Since even well-controlled diabetic pets may experience fluid imbalances that could lead to intraoperative hypotension, administer IV fluids 4–12 hours prior to anesthesia if hypovolemia or dehydration is noted.

During anesthesia

  • Monitor often: Test blood glucose every 30–60 minutes during anesthesia or at sufficient enough intervals to detect hyperglycemia or hypoglycemia before it becomes severe. Remember that a mild hyperglycemia is preferred over hypoglycemia.
  • Supplement with dextrose: Administer 2.5% or 5% dextrose infusion or 50% dextrose bolus if hypoglycemia occurs or seems imminent. (See Table 1)
  • Support the whole patient: As in any anesthetic event, vigilant monitoring is critical. Use the AAHA Anesthesia Guidelines for Dogs and Cats as a foundation.9 Administer appropriate intravenous fluid therapy for patient support (3ml/kg/hr in cats, 5ml/kg/hr in dogs).10 Avoid hypothermia by providing heat support through warm IV fluids; a fluid line warmer; insulation on the patient’s feet (e.g., baby socks or bubble wrap); circulating warm-water blankets; a warm-air circulation system; or dispersive electric heating pad or surgical table. Do not use supplemental heat sources that are not specifically designed for anesthetized patients, as they can cause severe several thermal injuries that can be challenging to heal in diabetic pets.9,11

After anesthesia

The primary goal after anesthesia is to return the patient’s insulin and feeding regimen to normal as quickly as possible.

  • Let food be thy medicine: Offer small meals as soon as possible after recovery. Use antiemetics if necessary.
  • Police pain: Commit to aggressive yet minimally sedating analgesic therapy as pain may have effects on glycemic control.
  • Test again: Obtain at least one post-anesthesia blood glucose measurement. If insulin was administered during anesthesia, careful monitoring and dextrose supplementation may be necessary, especially if the animal is unable to eat soon after recovery.

With careful planning and attention to detail, diabetic patients can thrive even when anesthesia is necessary.

References

1 Behrend E, Holford A, Lathan P, et al. 2018 Diabetes Management Guidelines for Dogs and Cats. J Am Anim Hosp Assoc 2018; 54:1-21.

2 Mama, K. “Anesthesia for Pancreatic Disease.” Clinician's Brief, June 2013, 91-94.

3 Levensaler A. Anesthesia for the Diabetic Patient. Proceedings: NAVC Conference 2014. http://www.vetfolio.com/veterinary-technician/anesthesia-for-the-diabetic-patient

4 Gurney, M. “Anaesthesia for diabetic pets.” Northwest Surgeons. October 11, 2016. Accessed December 5, 2017. https://www.nwsurgeons.co.uk/anaesthesia-for-diabetics/.

5 Dexdomitor [package insert].Kalamazoo, MI: Zoetis 2015.

6 Mama, K. “Anesthesia for Pancreatic Disease.” Clinician's Brief, June 2013, 91-94.

7 Ramsey D, Fleck T, Berg, T, et al. Cerenia prevents perioperative nausea and vomiting and improves recovery in dogs undergoing routine surgery. Intern J Appl Res Vet Med 2014; 12:3. 228-237.

8 Savvas I, Raptopoulos D, Rallis T. A “Light Meal&rdqou; Three Hours Preoperatively Decreases the Incidence of Gastro-Esophageal Reflux in Dogs. J Am An Hosp Assoc 2016; 52:6, 357-363.

9 Bednarski R, Grimm K, Harvey R, et al. AAHA Anesthesia Guidelines for Dogs and Cats. J Am An Hosp Assoc 2011; 47:6, 377-385.

10 Davis H, Jensen T, Johnson A, et al. 2013 AAHA/AAFP Fluid Therapy Guidelines for Dogs and Cats. J Am Anim Hosp Assoc 2013; 49:149-159.

11 Bednarski R, Grimm K, Harvey R, et al. AAHA Anesthesia Guidelines for Dogs and Cats. J Am An Hosp Assoc 2011; 47:6, 377-385.

12 Swaim SF, Lee AH, Hughes KS. Heating pads and thermal burns in small animals. J Am An Hosp Assoc 1989;25:156–62