Blood Pressure Basics

Are you taking the blood pressure and heart rate of EVERY patient you see for a new evaluation? How about for every visit? A recent survey of over 1800 Outpatient PTs showed that although 51% of PTs reported that over half their caseload had risk factors for hypertension and cardiovascular disease, only 14% of them are taking blood pressure and heart rates at evaluation. One of the BIGGEST factors for not taking a blood pressure? It’s not having the equipment or knowledge of how to perform it. It’s “Lack of time” and “Lack of perceived importance.” Stab me in the heart RIGHT NOW. I’m going to bring out my Texas accent and say, “YA’LL gotta be kidding me!”

You should know by now that the “basics” are never basic for me. They are essential! Recently, Dr. Rich Severin (PT) and his team released the recommendations for measuring and monitoring blood pressure by physical therapists in the outpatient setting. These recommendations had me literally dancing up and down in my hallway! It has been a long-standing soapbox of mine and many others that taking a set of vitals (or several sets of vitals) for every patient at every visit is a crucial part of maintaining safe and responsible physical therapist practice in any and every setting and for all populations. Dr. Severin refers to this as the “ethical duty to screen” and I can’t think of a better way to explain it. It’s something I teach my students, it’s something I tell my colleagues, and it is a practice I live by regardless of the setting I work in (and I’ve worked in pretty much all of them…).

I have written in recent posts regarding monitoring for COVID-19 in the outpatient setting that taking temperature should reasonably and easily lead to taking heart rate, oxygen saturation, and blood pressure for all patients at rest. But why stop there? As physical therapists and other rehab clinicians, we have the responsibility of exposing our patients to activity and exercise, likely to an extent to which they have rarely, if ever, experienced. From maximal exercise testing to a simple set of bed mobility activities, we have the skill to expose our patients to these varying levels of activity, even in the throes of illness, even while on a ventilator, even while on ECMO, even after a heart attack, even after organ transplant, even after loss of a limb, even after a brain injury… and the list goes on.

But in order to do those things safely, we HAVE to be monitoring vitals. And, like I’ve mentioned before, not just once: resting, during activity, after activity, and after recovery. It’s these readings that truly tell us how a patient is responding to activity and wherein our skill as a PT lies: not in taking these measurements, but interpreting them and modifying activity based on them. So, with that call to action, let’s talk about blood pressure.

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I gave a presentation back in January (before we could only meet in groups of 10 or less) to over 150 PTs and PTAs about how to prescribe high-intensity interval training for even the most medically fragile patients. Here’s the trick: it’s all about blood pressure (and other vitals, of course)! As part of that presentation, I demonstrated how to properly take a blood pressure. Here are the basics:

Resting Blood Pressure: the basis for all decision making

SETUP

1. Patient position:

• Supine is ideal to minimize muscle contractions that alter measurements but seated is probably more realistic in most settings.
• Resting for 5 minutes prior to measurement. This may be achieved by having staff take blood pressure while in the waiting area.
• Feet, arms, and legs uncrossed, and both feet on the floor.
• Brachium at level of Right Atrium/Fourth intercostal space for measurement.

2. Cuff size and positioning:

• Blood pressure cuffs come in several sizes for a reason! Find the right size for your patient based on arm length and circumference. The length of the air bladder within the cuff should be about 80% of the circumference of the brachium.
  • Undersized cuffs significantly falsely elevate measures
  • Oversized cuffs also give false measurements
• Cuff should be placed on a bare arm (up to 40mmHg error for this violation!)
• Cuff should be at the level of the heart, specifically the right atrium
  • Support the patients arm with a surface or with your own arm to achieve this positioning
  • This does NOT mean that the sleeve should be rolled up. Rolling the sleeve up creates a tourniquet effect.
• Midline marker on the cuff should align with the brachial artery
  • Yes, this means you need to palpate it to find it
• The arm should be straight for measurement
• Place the stethoscope over the brachial artery where strongest palpation of the pulse was felt

The Steps of Proper Performance:

Step 1: Find the Systolic Max. If you pump up the cuff too high, you will cause error in your measurements. So, how do you know how high up to pump it? Well, you have to find the systolic max. To do this, once you have the above positioning figured out, palpate the ipsilateral radial pulse, inflate the cuff slowly until you feel the pulse disappear. The pressure number at which this happens is your systolic max. Deflate the cuff.

Step 2: Wait! You have to wait at least 1 minute between measures to prevent falsely elevated measures. So after you find the systolic max, you need to wait one minute before re-inflating the cuff.

Step 3: Re-Inflate. After you’ve waited your one minute, re-inflate the cuff to the systolic max pressure that you just found and then another 30mmHg. It used to be 20mmHg, but the newest guidelines, as mentioned above, by Severin et al, recommends 30 mmHg.

Step 4. SLOW DOWN! Deflate the cuff slowly. The rate that gives the most accuracy is between 2-3mmHg per second. Yes, I know, this feels like it takes forever. You’re right, it does. But this is the correct way to get the most accurate measure. The systolic pressure should be the pressure measurement at the sound of the first Korotkoff sound. The diastolic measure should be the pressure measure at the sound of the last Korotkoff sound.

Optional Step 5. When the Korotkoff sounds just keep going… Sometimes this happens. It is not necessarily a good or bad thing depending on the patient. However, it does change how you measure and record your blood pressure measurements. We need to take a closer look at Korotkoff sounds for this discussion. Take a look at the picture here:

If you find that your Korotkoff sounds continue all the way to zero, your diastolic measure will be the last muffled phase sound and then you will also record zero. You will end up with three blood pressure measures in stead of two in this case (136/64/0). I have definitely have this happen several times, typically in the geriatric population in patients who are small or frail as well as dehydrated or orthostatic. When that diastolic number is super low (as in with dehydration or orthostasis), sometimes the heart beats can just still be auscultated all the way to zero. Less tissue impedance to auscultation allows for better transmission of sound.

Are you more of a visual learner? Perfect! You can watch Dr. Severin himself demonstrate this here!

Performing Repeat Measures and Side-to-Side Comparisons

When you need to perform repeat measures, due to a sticky pressure valve, a malfunctioning cuff, a number that just can’t possibly be correct, or not properly identifying the systolic max, it is very important to wait at least 1 minute between measurements to avoid false elevation. Some research indicates that you actually SHOULD take more than one measurement one minute apart and use the average of the measurements to accurately determine a patient’s blood pressure.

Some things that may influence your measurement and may necessitate a repeated measure would include:

• patient has a full bladder
• patient talking during measurement
• realizing half way through the measure that your BP cuff doesn’t fit
• patient hasn’t taken their BP medication or just took it prior to measurement (may need 15-30 minutes prior to remeasuring)
• patient had caffeine, alcohol, or cigarette just prior to measurement
• you are wearing a white coat or are in a medical office (as opposed to the patient’s home) (aka white coat hypertension)
• patient is taking a medication that can elevate BP (decongestant, oral contraceptives, NSAIDs, corticosteroids, some antidepressants, some antipsychotics, cyclosporine, some rheumatologics (end in -mab or -nib))
• PPE items, especially masks, have been linked to transient hypertension

It is also normal for blood pressure to be somewhat different in the left arm from what it is in the right arm. If you think about the anatomical location of the vasculature and heart, blood moving toward the left upper extremity will be at a slightly higher pressure than blood moving toward the right upper extremity. Blood exiting the heart has a much shorter trip to reach the left arm.

Can’t I Just Use An Electronic Cuff?

Ugh… I hate this question. Yes, of course you can. BUT, electronic cuffs underestimate systolic and diastolic measurements. If the batteries are low, they won’t give you accurate measurements. Patients CANNOT position the cuff or themselves properly (see above list of positioning items required!). They need regular calibrating and that just doesn’t happen. They can also error and perform repeat measures too close together, resulting in falsely elevated measures. I need accuracy and precision. I need to know FOR SURE if my patient is safe to start, continue, and repeatedly perform exercise. An electronic cuff DOES NOT provide me with this information. Does your primary care provider use an electronic cuff? If so, you should probably switch providers. In our role as primary providers of healthcare services, we need to ensure proper measurement, screening, interpretation, and application of blood pressure for every patient we see.

“…almost two-thirds of hypertensive individuals would be denied morbidity preventing treatment if the diastolic blood pressure were underestimated by 5 mm Hg; the number of persons diagnosed with hypertension would more than double if systolic pressure were over estimated by 5 mm Hg.”

Freeze, et al. (2011)

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Now that you have your numbers, what do you do with them?

Here is the information for the standard accepted classification of hypertension. Find where your patient falls and then determine your next steps. Is it safe to exercise?

• Normal: systolic less than 120 mm Hg and diastolic less than 80 mm Hg
• Elevated: systolic between 120-129 mm Hg and diastolic less than 80 mm Hg
• Stage 1: systolic between 130-139 mm Hg or diastolic between 80-89 mm Hg
• Stage 2: systolic at least 140 mm Hg or diastolic at least 90 mm Hg

You may find, as I have on many occasions, that your patient is in a hypertensive emergency. Hypertensive emergencies are defined as severe elevations in
BP (>180/120 mm Hg) associated with evidence of new or worsening target organ damage (AHA, 2017). This, of course, would warrant a big loud ride to the hospital for management. But, that is the skill of your intervention: assessing, interpreting, and managing appropriately. If your patient is demonstrating resting blood pressures above 180/120 but is asymptomatic, that is deemed a hypertensive urgency and the primary physician should be notified and consulted for instruction. Odds are, they are going in anyway.

Just because someone isn’t being seen for a cardiovascular diagnosis, doesn’t mean they cannot end up finishing their visit with you in the back of an ambulance. I can list several total joint replacement admission in home care that resulted in this. I can’t do your knee ROM if you’re in a hypertensive crisis, so you’ll need to get that taken care of first, and I’ll see you tomorrow! You shouldn’t be surprised if you find your patients in hypertensive crises from time to time. Compliance with pharmacological treatment for hypertension is about 48% so even if they have been to the doctor for treatment, they may not be taking it the way they are supposed to. But, if you never take that first measure, you’ll never know.

“Every 10% increase in effective HTN treatment could prevent an additional 14,000 deaths per year in the adult population.”

Severin, et al. (2020).

You may also find that your patient is hypotensive! We discuss that in great detail in the posts on orthostasis and beta blockers. This can result from several items other than medications and could indicate general hemodynamic instability which would definitely change your plan for the day.

You also may find that patients have interesting blood pressure responses to exercise, whether high or low. We will talk about how to interpret and address that in another post!

Finally, get going. Physical activity is one of the best evidence-based ways to provide long term treatment for high blood pressure. WE ARE THE EXPERTS OF MOVEMENT! We are the experts of prescribing proper intensities of physical activity. We should be gearing our practice toward this type of treatment provision and education. According to Dr. Severin, only 15% of providers utilize exercise as a primary intervention for hypertension. Maybe that’s because only 15% of therapists are taking blood pressures. Start upping the ante here! Start demonstrating your skill, knowledge, ability, and marketing to these other primary care providers! They have the evidence that what you are saying is true, they just need to know that you can provide it!

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The “What Ifs” of Taking Blood Pressure

What if…

• my patient doesn’t have one arm?
  • use the other arm
• my patient has a PICC line?
  • use the other arm
• my patient has a fistular or shunt?
  • use the other arm
• my patient has a history of breast cancer with mastectomy on one side?
  • use the other arm
• breast cancer with mastectomy on both sides?
  • use the lower leg (yes really)
• my patient has lymphedema in an arm? or both arms?
  • use the other arm (or the lower leg)
• my patient is always hypertensive?
  • call their primary care provider, discuss your findings, ask about treatment, discuss treatment compliance with the patient (pill counts, drug diaries, etc), or request altered parameters
• I don’t have the right cuff size for my patient, it’s too small!
  • take the blood pressure at the forearm manually
• I don’t have the right cuff size for my patient, it’s too big!
  • take the blood pressure at the lower leg
• my patient had their radial artery removed for a CABG?
  • use the other arm or a lower leg until 2 weeks after surgery
• my patient is pregnant?
  • take their blood pressure at every visit! You may catch early pre-eclampsia and save a life (or 2)!
  • women tend to experience hypotension due to vasodilation during pregnancy and may require supportive devices or activities
• I can’t hear the Korotkoff sounds?
  • you can use a special amplified stethoscope provided by your employer under the ADA guidelines for those who are hard of hearing
  • you can use a doppler device to better target vasculature and increase volume of output
  • you can make sure your stethoscope is functioning properly
• my patient’s upper arm is too short for my cuff or my cuff overhangs their elbow?
  • use a forearm measurement

Notes: When utilizing a blood pressure measure from a location other than the brachium, always note this in your charting as these measurement standards are not established and are not interchangeable. Distal blood pressures tend to be higher than brachial blood pressures.

Basically, you are going to have a really hard time convincing me that there is ever an incidence where you shouldn’t or can’t find a way to take a blood pressure. I discuss more of the details on taking blood pressure in the lower leg in the post on Ankle Brachial Indexes which you can view HERE!

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This is all really just breaking the surface. This is only how to take a RESTING BLOOD PRESSURE properly. Let’s not forget that our job doesn’t stop there! We need to be assessing blood pressure response to exercise, especially in those who have a known cardiovascular pathology. We will be the ONLY ones who have the patient in a situation where an exercise blood pressure can and should be performed PRIOR to a major health event taking place. This means that we are the only ones who have the ability to detect, defer, and reduce the risk of the occurrence of this major event.

So now that you know the importance, I know you’ll take the time. I don’t have time to NOT take my patient’s vitals prior to treatment every single time and I don’t have time for a malpractice suit. Within our scope, within our ability, within our clinical judgement, therefore, our RESPONSIBILITY. Like Dr. Severin says, it is our “ethical duty to screen” and it is definitely our ethical and professional duty to continue to measure, interpret, and implement these measures and findings to guide our intervention intensity.

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References

American Heart Association. (2017). Guideline for the Prevention,
Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hyppertension. 71(6). Retrieved from https://www.ahajournals.org/doi/pdf/10.1161/HYP.0000000000000065

APTA. (2019). Survey of PTs Reveals ‘Significantly Inadequate’ Rates of BP and HR Measurement. Retrieved from https://www.apta.org/news/2019/07/08/survey-of-pts-reveals-significantly-inadequate-rates-of-bp-and-hr-measurement

APTA Cardiovascular and Pulmonary Section. (n.d.) Vitals Are Vital. Retrieved from http://www.cardiopt.org/vitalsarevital/

Frese, E. M., Fick, A., & Sadowsky, H. S. (2011). Blood pressure measurement guidelines for physical therapists. Cardiopulmonary physical therapy journal, 22(2), 5–12.

Pickering, T. G., Hall, J. E., Appel, L. J., Falkner, B. E., Graves, J., Hill, M. N., Jones, D. W., Kurtz, T., Sheps, S. G., Roccella, E. J., & Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research (2005). Recommendations for blood pressure measurement in humans and experimental animals: Part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research. Hypertension. 45(1), 142–161. https://doi.org/10.1161/01.HYP.0000150859.47929.8e

Severin, R., Sabbahi, R., Albarrati, A., Phillips, S. A., Arena, S. (2020). Blood Pressure Screening by Outpatient Physical Therapists: A Call to Action and Clinical Recommendations. Physical Therapy. 100(6):1008–1019. Retrieved from https://doi.org/10.1093/ptj/pzaa034

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