Managing Anesthetic Events

Managing Anesthetic Events

Victoria M Lukasik, DVM, DACVAA

Southwest Veterinary Anesthesiology

EMERGENCY DRUGS

Atropine: bradycardia

Dogs: 0.04 mg/kg IM or 0.01 mg/kg IV

Cats: 0.04 mg/kg IM or 0.01 mg/kg IV

Give one-tenth to one-quarter of the calculated dose IV, chase with an IV fluid bolus, and wait 15 to 30 seconds for a response. Profound tachycardia may occur with IV dosing. Wait it out, it will only last a few minutes. Provide IPPV if necessary. If atropine is unsuccessful, glycopyrrolate may administered.

Ketamine 1 mg/kg IV may also raise the heart rate if no response to anticholinergic

Lidocaine: runs of ventricular premature contractions (VPC), ventricular tachycardia, multiple VPC’s that are affecting blood pressure.

Dogs: 4 mg/kg IV slowly

Cats: 2 mg/kg IV slowly

May repeat dosing every 10 to 15 minutes or start an infusion 25 to 80 μg/kg/min in dogs or 10 to 40 μg/kg/min in cats.

Epinephrine: asystole (not ventricular fibrillation)

Administer very slowly (in 0.01 to 0.05 ml increments every 10 to 15 seconds) while bolusing IV fluids

Dogs: low dose 0.05 mg/kg IV

High dose 0.5 mg/kg IV

Cats: low dose 0.05 mg/kg IV

High dose 0.5 mg/kg IV

Therapies for Hypotension

Decrease the depth of anesthesia

Reduce the vaporizer setting

Increase the oxygen flow for one to two minutes.

Bolus IV Isotonic crystalloids (Caution in cardiac patients)

Boluses are 3 to 10 ml/kg IV

Reassess arterial blood pressure

Repeat if necessary once only

If not responsive to crystalloid boluses, or short lived response, go to next steps

6% Hetastarch (Caution in cardiac patients)

Bolus 5 to 10 ml/kg IV for dogs and 1 to 5 ml/kg IV for cats

Reassess arterial blood pressure

Repeat once if necessary for a total dose of 10 to 15 ml/kg IV

If not responsive or not enough, go to vasopressor or inotrope CRI

Vasopressor or Inotrope therapy

Drug / Contractility / Heart Rate / Vascular tone / IV dose
Dobutamine / ↑↑↑ / ↑↑ / ¯ / 5-20 mcg/kg/min
Dopamine / ↑↑↑ / ↑↑ / ↑↑ / 5-20 mcg/kg/min
Epinephrine / ↑↑↑ / ↑↑↑ / ↑↑↑ / 0.1-1 mcg/kg/min
Norepinephrine / 0 / No change / ↑↑↑ / 0.2-2 mcg/kg/min
Phenylephrine / 0 / ¯ / ↑↑↑ / 1-5 mcg/kg/min
Vasopressin / 0 / ¯ / ↑↑ / 0.5 units/kg

Dobutamine 12.5 mg/ml

Dose is 5 to 20 mcg/kg/min, which is 0.3 to 1.2 mg/kg/hr IV

Dilute 1.5 ml of Dobutamine in 60 ml of 0.9% NaCl, giving a dilution of 300 mcg/ml. Start CRI at 1 ml/kg/hr, which is a dose of 5 mcg/kg/min. Increase up to 4 ml/kg/hr IV, or decrease, as necessary to maintain acceptable ABP.

Phenylephrine 10 mg/ml

Dose is 0.001 to 0.004 mg/kg IV then CRI of 1 to 5 mcg/kg/min, which is 0.06 to 0.3 mg/kg/hr IV. Dilute 0.36 ml of Phenylephrine in 60 ml of 0.9% NaCl, giving a dilution of 60 mcg/ml. Start CRI at 1 ml/kg/hr, which is a dose of 1 mcg/kg/min. Increase up to 5 ml/kg/hr IV, or decrease, as necessary to maintain acceptable ABP.

Ephedrine 50 mg/ml

Dose is 0.1 to 0.2 mg/kg IV then CRI of 5 to 10 mcg/kg/min, which is 0.3 to 0.6 mg/kg/hr IV. Dilute 0.36 ml of Ephedrine in 60 ml of 0.9% NaCl, giving a dilution of 300 mcg/ml. Start CRI at 1 ml/kg/hr, which is a dose of 5 mcg/kg/min. Increase up to 2 ml/kg/hr IV, or decrease, as necessary to maintain acceptable ABP.

Noepinephrine 1 mg/ml

Dose is 0.2 to 2 mcg/kg/min, which is 0.012 to 0.12 mg/kg/hr IV

Dilute 1.45 ml of Norepinephrine in 60 ml of 0.9% NaCl, giving a dilution of 24 mcg/ml. Start CRI at 0.5 ml/kg/hr, which is a dose of 0.2 mcg/kg/min. Increase up to 5 ml/kg/hr IV, or decrease, as necessary to maintain acceptable ABP

Vasopressin 20 U/ml

Dose 0.5 U/kg IV then 0.001 to 0.004 U/kg/min, which is 0.06 to 0.24 U/kg/hr. Dilute 0.36 ml of Vasopressin in 60 ml of 0.9% NaCl, giving a dilution of 0.12 U/ml. Start CRI at 0.5 ml/kg/hr which is a dose of 0.001 U/kg/min. Increase up to 2 ml/kg/hr IV, or decrease, as necessary to maintain acceptable ABP

Epinephrine 1 mg/ml

Dose is 0.1 to 1 mcg/kg/min, which is 0.006 to 0.06 mg/kg/hr IV

Dilute 0.72 ml of Epinephrine in 60 ml of 0.9% NaCl, giving a dilution of 12 mcg/ml. Start CRI at 0.5 ml/kg/hr, which is a dose of 0.1 mcg/kg/min. Increase up to 5 ml/kg/hr IV, or decrease, as necessary to maintain acceptable ABP

Dopamine 40 mg/ml

Dose is 2 to 20 mcg/kg/min, which is 0.12 to 1.2 mg/kg/hr IV

Dilute 0.3 ml of Dopamine in 60 ml of 0.9% NaCl, giving a dilution of 200 mcg/ml. Start CRI at 1 to 2 ml/kg/hr if moderate hypotension, which is 3.3 to 6.6 mcg/kg/min. Start the CRI at 3 to 4 ml/kg /hr if severe hypotension, which is 10 to 13.3 mcg/kg/min. Increase up to 6 ml/kg/hr if necessary. Reassess arterial blood pressure frequently. Adjust CRI as needed to maintain acceptable ABP

Dilution Volumes: amount of drug (ml) to add for CRIs starting at 1 ml/kg/hr IV (shake well to mix properly)

Drug / 60 ml syringe / 150 ml bag / 250 ml bag / 500 ml bag
Dobutamine / 1.5 / 3.75 / 6.25 / 12.5
Phenylephrine / 0.36 / 0.9 / 1.5 / 3
Ephedrine / 0.36 / 0.9 / 1.5 / 3
Vasopressin / 0.36 / 0.9 / 1.5 / 3
Epinephrine / 0.72 / 1.8 / 3 / 6
Dopamine / 0.3 / 0.75 / 1.25 / 2.5
Norepinephrine / 1.45 / 3.6 / 6 / 12