Low Blood Pressure (Hypotension) Signs and Symptoms

 Signs and symptoms of low blood pressure (hypotension)

Low blood pressure, or hypotension, occurs when the force at which the heart pumps blood through the arteries decreases.

Hypotension can present with various symptoms: from nausea, dizziness to heart palpitations. Controlling blood pressure is an important part of evaluating yourself or your patient.

Unfortunately, a problem is not always announced with a trumpet fanfare. Even the highest blood pressure can be completely asymptomatic. Similarly, your patient may have low blood pressure (also known as hypotension), even though there are no apparent symptoms. This is particularly true if the patient is lying still in an unattended bed.

In general, hypotension can be thought of as a frequency, pumping, or volume problem. Examples of these include:

Of course, the easiest way to know that your patient has a blood pressure problem is simply by measuring it, but in some cases, you may notice other symptoms that invite you to check the pressure and find that it is low.

Evaluation of low blood pressure should include a new pressure check and close monitoring. If a client has recently changed positions, they should return to the supine position and then check again in a few minutes.

The best objective symptom of low blood pressure is taking real pressure and getting low numbers. It sounds obvious, but it may not occur to you to apply pressure when a patient complains of certain symptoms.

However, when a patient complains, it is generally recommended that they obtain a full set of vital signs, and this will signal a low blood pressure problem. How low is too low? What does low really mean? It can mean different things to different patients.

The usual metric for measuring low blood pressure is that anything below 90/60 mmHg (millimeters of mercury) (Healthdirect Australia 2018) is considered low enough to treat. You can also have symptoms of low blood pressure when someone with hypertension lowers very high blood pressure. For example, 120/80 mmHg may be normal for everyone else, but if your patient lives at 190/100 mmHg, you will feel the difference. For this reason, the objective sign of pressure must be combined with the subjective symptoms reported by the patient.

Subjective symptoms are those that the patient can report, although objective signs of these may also be seen.

With low blood pressure, the patient may feel dizzy or lose consciousness. This is due to a lack of blood flow to the brain, and generally placing the patient supine will help to raise blood pressure and reduce symptoms. This could be accompanied by a feeling of dizziness and lightheadedness. Typically, your patient will report trouble concentrating, difficulty standing upright, and poor coordination (American Heart Association 2017).

Your patient may also report nausea and possibly vomiting due to low blood pressure. Also, heart palpitations are sometimes felt, which can be easily seen with the use of telemetry or other monitoring. EKG / ECG may or may not show them, depending on the frequency and timing of the palpitations.

Some patients may also be confused, and this can make it appear that they are suffering from poisoning or some other neurological problem. Blurred vision is usually reported with extreme cases of low blood pressure. There are many other symptoms of low blood pressure to look out for.

Orthostasis literally means standing. Orthostatic hypotension, or postural hypotension, is defined as a decrease in systolic blood pressure of at least 20 mmHg or at least 10 mmHg within 3 minutes of standing. If orthostatic hypotension is present, the client may be at risk for falls and should be closely supervised with ambulation or advised to call for assistance with the activity.

To evaluate orthostatic hypotension, take blood pressure while the patient is supine and at rest. Then position the patient; you should be able to stand for 3 minutes before taking your blood pressure again. If the measurements meet the criteria stated above, orthostatic hypotension is evident. If the result is equivocal, record it and request a formal evaluation. (Note that the accuracy of orthostatic hypotension has been questioned in recent years.)