Dr. Phil Zeltzman’s Blog

This is part 2 of our anesthesia complications blog series. You can read part 1 here.

The bad news: Every anesthesia carries some risk.
The good news: most complications are minor, and quickly and easily fixable.
Let’s go over some cardio-vascular anesthesia complications.

1. Bradycardia
Bradycardia is a fancy word that means that the heart rate is too low.
Common causes include:

• The anesthesia is too deep. The simple solution is lower the amount of anesthesia gas.
• The body temperature is too low. This is something we fight from start to finish.
• Electrolyte abnormalities. Most commonly, it is related to potassium being too high in the blood. This can happen in pets with a blockage that prevents them from urinating. We try to correct that before anesthesia even starts.
• Morphine-like drugs. That’s a common side-effect. If the heart rate is too low, we can use drugs to increase it.

2. Tachycardia
Tachycardia is the opposite of bradycardia, so it means that the heart rate is too fast.
The most common causes include:

• The anesthesia is too low. The simple solution is to give a bit more.
• Pain. We would then give even more pain medications than we typically provide.
• Some diseases, such as a tumor in the adrenal gland. This would be temporary, until the tumor is removed, and we can use drugs to lower the heart rate if needed.

3. Hypotension
Hypotension means that the blood pressure is too low, just like in some people.
The most common causes include:

• Severe bleeding. The solution would be to give more IV fluids or possibly a blood transfusion.
• Cardio-vascular diseases. Hopefully, this is something we know ahead of time, and can treat with meds before anesthesia starts. We sometimes use different drugs for anesthesia. We are also less generous with IV fluids so we don’t overload the heart.
• The anesthesia is too deep. We would then provide less anesthesia gas.
• Some drugs. We can give IV fluids or drugs that can correct that.
• Some conditions. For example, mast cell tumors in the skin can release a substance that causes the blood pressure to drop. We routinely use drugs before anesthesia to prevent this from happening.

4. Hypertension
Hypertension is the opposite of hypotension, so it means that the blood pressure is too high, just like in some people. The most common causes include:

• The anesthesia is too light. So we would simply give more anesthesia drugs.
• Some diseases. For example, a type of tumor of the adrenal gland (pheochromocytoma) can release a substance that causes the blood pressure to spike. There are drugs we can use to lower the blood pressure.

5. Arrhythmias
Arrhythmia is a fancy word that means that there are abnormal or extra heartbeats.
The most common example is extra heartbeats during “bloat” (twisted stomach) or spleen surgery.
This usually resolves eventually with drugs and time.

Fortunately, the risks of severe complications are small, and most complications can be solved quickly.
The key is to have good monitoring equipment, and above all, experienced anesthesia nurses.
Every patient we anesthetize has a dedicated anesthesia nurse whose only job is to keep her patient safe.

If you would like to learn how we can help your pet with safe surgery and anesthesia, please contact us through www.DrPhilZeltzman.com

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Phil Zeltzman, DVM, DACVS, CVJ, Fear Free Certified