Are You Doing it Right? Taking Accurate BPs

BP is one of the very first hands-on tasks learned in nursing school. Easy enough, right? While taking a quick BP may be one of the less complex tasks nurses execute throughout their day, it is still imperative to take the time to do it right. Nursing Students General Students HowTo


Are You Doing it Right? Taking Accurate BPs

In my personal healthcare experiences, I've noticed several healthcare providers (HCPs) taking blood pressures quickly and often inaccurately. I'm sure you have too. This simple task can sometimes be rushed due to the lack of time providers have available to spend with their patients. However, a documented blood pressure reading can determine many aspects of future care for the patient, including potential medication dosing adjustments or changes.

Blood pressure readings are a measurement of the circulatory system. It is composed of two numbers, the systolic (top number) and the diastolic (bottom number) blood pressure. A simple explanation (useful for explaining blood pressure readings to patients and caregivers) can be found at, "When your heart beats, it squeezes and pushes blood through your arteries to the rest of your body. This force creates pressure on those blood vessels, and that's your systolic blood pressure. The diastolic reading, or the bottom number, is the pressure in the arteries when the heart rests between beats. This is the time when the heart fills with blood and gets oxygen."

Proper blood pressure measurements can be indicative of many medical issues. For example, hypertension (elevated BP) can lead to many life-threatening medical conditions, such as heart attack, stroke or kidney disease. Hypertension can also be due to white coat syndrome or high levels of pain and is greatly influenced by a variety of lifestyle factors including, age, weight, medication, alcohol use, tobacco use, and diet.

Equally as important, hypotension (decreased BP) can be a warning sign for many health-related issues. Examples of such include septicemia, anaphylactic reactions, dehydration, blood loss, and body temperature dysregulation. Many medications have the potential to cause an unexpected drop in blood pressure, so be sure to educate patients on getting up slowly and reinforce proper oral hydration guidelines. Symptoms of hypotension include nausea, blurred vision, dizziness and even fainting,

Many inaccuracies in assessment of this vital sign are avoidable by following some basic guidelines.

How To Ensuring Accurate Blood Pressure Readings

STEP 1: Correct Cuff Size

Using an incorrectly sized blood pressure cuff is one of the most common reasons for skewed results. Many cuffs now have a range marker that indicates if the cuff is a proper fit. A cuff that is too small can result in a false high reading, so ensure that the bladder length encircles 80-100% of the upper arm and the width is about 40%. (Here's a helpful photo to further explain.)

STEP 2: Remove Barriers

Bare skin is best, despite many patients wishes to not roll up their (sometimes thick!) sleeves. This technique also allows for assessment of anatomical landmarks, ensuring correct placement of artery marker on cuff over the brachial artery.

STEP 3: Uncross Legs

This bad habit of many (myself included) can produce false high BP readings. Remind your patient to uncross their legs in order to get an accurate recording.

STEP 4: Give Rest Time

Taking vital signs is typically one of the first tasks many HCPs aim to complete. In a non-emergent scenario, giving the patient adequate time to sit quietly can bring their blood pressure down to a resting rate after that walk from the lobby. Taking other vital signs first is a useful practice.

STEP 5: Don't Talk

This can be difficult. Patients want to tell you their reason for the visit and you want to discuss symptoms. However, explaining the rationale behind this quiet method can go a long way. In order to avoid a false increase in BP, try not to chat with the patient and encourage them to try and rest quietly for a few minutes.

STEP 6: Proper Positioning

To obtain the most accurate reading, have your patient sit up straight with their back supported. Let the patient's forearm rest on yours or use a supportive surface to have the upper arm in the ideal position for a blood pressure reading. (See this quick reference by Welch Allyn for helpful photo.)

STEP 7: Check Manually

Could the monitor be defective? When in doubt, checking manually is best practice. To begin, follow all same steps above. Place bell of stethoscope lightly over the brachial artery. Quickly Inflate the blood pressure cuff to 180 mmHg. Release the air at a steady and moderate pace. The first "bump" sound you hear is your top number (systolic) and the last sound you hear is your bottom number (diastolic). For more detail, visit this page on clinical skills related to BP measurements.

What tips or tricks do you use to ensure accurate BP readings?


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Specializes in CCRN, PCCN.

If I have to take a BP with the patient lying down, I will often elevate their arm slightly with a small pillow so that the arm is at the same level as their heart. I also will ask them to stay on their back, of course.