How Having Surgery Affects Blood Pressure

Even if you have hypertension, most procedures are safe

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Learning you need to have an operation can be worrisome enough. If you're someone who struggles with high blood pressure, the prospect of having a procedure under general anesthesia have you especially concerned. What if your pressure soars while you're asleep? Does this make the risk of surgery even greater?

High blood pressure, or hypertension, is rarely a reason to not have a major operation. And certainly your doctor would not recommend it if in your case it was and you're having a procedure that's elective (cosmetic surgery, for example, or vision correction), or that could wait until your blood pressure is under control.

In fact, often a person needs surgery to treat a condition that is causing high blood pressure, in which case afterward his or her hypertension will likely heal itself.

Whatever your situation, talk to your doctor about your concerns. Meanwhile, here are some important things to know in general about high blood pressure and surgery.

While You're Asleep

During surgery, an anesthesiologist will keep a close and constant eye on all your vital signs: your heart rate, breathing, and blood pressure. It may be reassuring to know that he will have studied your medical history before coming into the operating room to give you anesthesia. This means he'll know what's normal for you and will be able to use the medication if necessary to keep all of your vital signs, including your blood pressure, at the right levels.

It's also helpful to know that the drugs used to control heart rate and blood pressure during surgery are given intravenously, through a needle that will be inserted into your arm before you go to sleep.

That way, if you do need any sort of medication, it will get into your system as soon as possible. What's more, the drugs used are fast-acting and effective.

What to Expect After Surgery

Some people experience a drop in blood pressure after surgery. This may be due to medication that was given or simply a side effect of the procedure.

Another reason for blood pressure to drop post-op is blood loss. A severe loss of blood during surgery—more than a fifth of the total amount of blood in the body—can lead to hypovolemic shock. The loss of this much fluid will make it hard for the heart to beat properly, which in turn will reduce the amount of blood that gets to major organs.

Hypovolemic shock can be life-threatening and will be treated as an emergency while you're still under anesthesia. You may be given medication as well as a blood transfusion to bring the amount of blood in your body up to a normal level.

Finally, there can be a dangerous and life-threatening dip in blood pressure after surgery due to infection, including sepsis. As with other precautions taken to prevent dangerous dips in blood pressure associated with surgery, your doctor may have you take antibiotics before or after your procedure as a safety measure. Knowing that your anesthesiologist will be well prepared to keep you safe during surgery and that your doctor will take every precaution to before and afterward should put your mind at ease—at least regarding your blood pressure.

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