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.
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:
- Congestive heart failure
- Kidney problems
- Heart attack
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 180 mmHg or higher or the diastolic blood pressure is 110 mmHg or higher. In this case, deferring surgery may be considered.
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.
However, 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 healthcare provider precisely which medications you should and should not take before 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 of 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.
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 180 mmHg 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 healthcare provider may have you take antibiotics before or after your surgery.
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 Get Meds Info
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 healthcare provider, 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 healthcare provider will take every precaution before and after your surgery, should hopefully put your mind at ease.