Managing High Blood Pressure Before, During, and After Surgery

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Anticipating a surgery can be an anxiety-provoking time. And if you have high blood pressure (also known as hypertension), you may have additional concerns about how you will respond to general anesthesia.

Ideally, your blood pressure will be normalized several months before your surgery. While research has found that "mild to moderate diastolic or systolic hypertension do not place the patient at increased operative risk," high blood pressure may pose "an increased operative risk and must be carefully controlled before surgery."

This article outlines what to expect before, during, and after a surgery if you have high blood pressure.

Quick Facts: Surgery When You Have High Blood Pressure - Illustration by Theresa Chiechi

Verywell / Theresa Chiechi

Prior to Surgery

If you have high blood pressure, surgery might put you at risk for:

In general, the risk increases as a blood pressure reading increases. This said, high blood pressure is usually not a reason to postpone surgery unless a person is undergoing an elective major surgery and blood pressure is poorly controlled. This means the systolic blood pressure is 180 mmHg or higher or the diastolic blood pressure is 110 mmHg or higher. In this case, deferring surgery may be a good idea since a normal pressure is 120/80 mm Hg..

It's essential to follow your healthcare team's instructions on which medications to continue and which to stop prior to your surgery.

For people with chronic high blood pressure, in most instances, continuing high blood pressure medications (called antihypertensives) is generally safe. In fact, stopping some of them can cause a rebound effect, where blood pressure rises.

However, some high blood pressure medications (like ACE inhibitors or angiotensin receptor blockers) are held for a certain period of time, such as 24 hours, prior to surgery. In the end, be sure to clarify with your healthcare provider precisely which medications you should and should not take before surgery. Every patient is different, and so is their medical history. Your provider should know you and your history like the back of their own hand.

During Surgery

Just before you enter the operating room, your anesthesiologist will ask you a few questions about your medical history, in addition to doing a review of your medical chart. This way, they will be aware of your baseline blood pressure, medication allergies, and/or prior reactions to anesthesia.

During surgery, the anesthesiologist will keep a close and constant eye on your blood pressure, as well as other vital signs, like your heart rate and rate of breathing. Blood pressure changes during surgery are normal and could be caused by several factors. For example, your blood pressure may rise during surgery from the activation of your sympathetic nervous system during the start of anesthesia—a normal phenomenon. At the same time, your heart rate may also rise.

To treat high blood pressure during surgery, your anesthesiologist may administer intravenous (through your vein) antihypertensives (or hypertension medicine).

On the other hand, if you lose blood during surgery, your blood pressure may drop. Fluids and/or a blood transfusion may be all you need to increase your blood pressure. But if there is a severe loss of blood during surgery (meaning, more than 20% of your body's blood supply), a life-threatening condition called hypovolemic shock (meaning, a drop in blood volume) may develop.

Hypovolemic shock occurs when the loss of blood makes it hard for the heart to beat properly, which in turn reduces the amount of blood that gets to major organs. This type of shock requires emergent replacement of blood to ensure your organs get the oxygen they need to function.

Recap

An anesthesiologist does much more than administer anesthesia before surgery. It's their job to monitor your blood pressure closely and respond accordingly if it climbs too high or drops too low.

After Surgery

As you recover from anesthesia, your blood pressure and heart rate may slowly and naturally increase. If you experience markedly high blood pressure after surgery (when the systolic pressure is 180 mmHg or higher), you likely will be given intravenous medications (instead of oral medications) to lower your blood pressure.

On the flip side, some people experience a drop in blood pressure after surgery. This may be due to medication that was given by the anesthesiologist (like a pain medicine) or simply a side effect of the procedure.

You should also know that there can be dangerous and life-threatening dips in your blood pressure after surgery due to an infection. In order to prevent or treat a potential infection, your healthcare provider may have you take antibiotics before or after your surgery.

Summary

in general, surgical risks increase the higher your blood pressure happens to be. This said, high blood pressure is usually not a reason to postpone surgery unless you're undergoing an elective major surgery or your blood pressure is poorly controlled. For people with chronic high blood pressure, in most instances, continuing high blood pressure medications is generally safe. In fact, stopping some of them can cause a rebound effect, where blood pressure rises. However, some high blood pressure medications (like ACE inhibitors or angiotensin receptor blockers) are held for a certain period of time, such as 24 hours, prior to surgery.

During surgery, the anesthesiologist will keep a close and constant eye on your blood pressure, as well as other vital signs. As you recover from anesthesia after surgery, your blood pressure and heart rate may slowly and naturally increase. You should know that there can be dangerous and life-threatening dips in your blood pressure after surgery due to an infection. In order to prevent or treat a potential infection, your healthcare provider may have you take antibiotics before or after your surgery.

In the end, be sure to clarify with your healthcare provider precisely which medications you should and should not take before surgery. Every patient is different, and so is their medical history. It follows that their pre- and post-surgical instructions will differ, too.

A Word From Verywell

Knowing all this, you can see why people say that following a physician's advice before surgery can be more important than following post-operative instructions. (In fact, they're both crucial, but pre-op directions can have a direct effect on how things go during your procedure.) It might also put your mind at ease to meet the anesthesiologist before surgery and ask any questions you may have. No one can predict exactly what will happen as your surgery proceeds, but understanding the stps involved—and knowing that your medical team is skilled and proactive—ought to take the edge off your pre-surgery anxiety.

Frequently Asked Questions

  • Does hypertension increase the risk of surgical complications?

    Yes. If you have been diagnosed with hypertension, you are at increased risk of complications from surgery. Possible complications include congestive heart failure, heart attack, kidney problems, and stroke. Treating hypertension before surgery may help lower your risk.

  • How is blood pressure monitored during surgery?

    Your blood pressure is monitored continuously during surgery with a sphygmomanometer (blood pressure cuff). Your anesthesiologist will monitor your blood pressure and administer IV medication as needed to regulate your blood pressure.

  • What happens to blood pressure after surgery?

    Your blood pressure will continue to be closely monitored in the immediate aftermath of surgery. If your blood pressure becomes elevated, you will likely be given medicine through an IV to bring it down.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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