Managing High Blood Pressure Before, During, and After Surgery

Surgery
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Anticipating a surgery is an anxiety-provoking time. On top of that, if you have high blood pressure, you may have additional concerns about how your blood pressure will react under general anesthesia. 

Let's take a closer look at the specific effects of surgery on blood pressure, as well as how having this medical condition (called hypertension) may influence the timing of your surgery. 

Managing High Blood Pressure: Prior to Surgery

Having hypertension very well may increase your risk of surgery, and how severe your risk is, depends on how severe your hypertension is.

With that, some of the specific conditions that high blood pressure puts you at risk for when undergoing surgery include:

That said, high blood pressure is usually not a reason to postpone surgery unless a person is undergoing an elective major surgery and the blood pressure is poorly controlled, which means the systolic blood pressure is 180mmHg or higher or the diastolic blood pressure is 110mmHg or higher. In this case, deferring surgery may be considered.   

In addition to following their advice on the timing of your surgery, 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 your high blood pressure medications (called antihypertensives) is generally safe. In fact, stopping some of them can cause a rebound effect, where your blood pressure rises.

On the contrary, some high blood pressure medications (for example, ACE inhibitors or angiotensin receptor blockers) are held for a certain period of time, like 24 hours, prior to surgery.

In the end, be sure to clarify with your doctor precisely which medications you should and should not take before surgery.

Managing High Blood Pressure: 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 his own review of your chart. This way he is 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.

In terms of blood pressure changes during surgery, there are a couple potential causes.

One reason why your blood pressure may rise during surgery is from activation of your sympathetic nervous system during the start of anesthesia—a normal phenomenon. In addition to your blood pressure rising during the start of anesthesia, your heart rate will also likely rise.

To treat high blood pressure during surgery, your anesthesiologist will administer intravenous (through your vein) antihypertensives.

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

Managing High Blood Pressure: After Surgery

As a person recovers from anesthesia, their blood pressure and heart rate may slowly and naturally increase. If a person experiences markedly high blood pressures after surgery (when the systolic pressure is  180mmHg or higher), he will likely be given intravenous medications, instead of oral medications, to lower the blood pressure.

Of course, if the blood pressure is high due to other causes like pain or too much fluid given during surgery, reversal of those issues should bring the blood pressure down. 

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 (for example, a pain medicine) or simply a side effect of the procedure.

In addition, there can be dangerous and life-threatening dips in blood pressure after surgery due to an infection. In order to prevent or treat a potential infection, your doctor may have you take antibiotics before or after your surgery.

Lastly, it's important to note that if you are on chronic blood pressure medications, you should resume them after surgery. In fact, sometimes, high blood pressure after surgery is simply the result of a person not continuing their usual medication regimen.

Of course, be sure to clarify which medications to take with your surgical team. 

A Word From Verywell

The bottom line is that whether or not to postpone your surgery, based on your blood pressure, is not a black and white topic. This is why it's important to follow the guidance of your health team, which includes your surgeon, your primary care physician, and your anesthesiologist.

In the end, knowing that your anesthesiologist will be well prepared to keep your blood pressure under control during surgery and that your doctor will take every precaution before and after your surgery, should hopefully put your mind at ease. 

View Article Sources
  • Whelton PK et al. American College of Cardiology: 2017 Guideline for High Blood Pressure in Adults
  • Bisognano JD. Perioperative management of hypertension. Aronson MD, ed. UpToDate. Waltham, MA: UpToDate Inc. 
  • Kheterpal S et al. Preoperative and intraoperative predictors of cardiac adverse events after general, vascular, and urological surgery. Anesthesiology. 2009 Jan;110(1):58-66.