The Ultimate EMT Guide to Vital Signs

Part 2: The Blood Pressure

I love teaching each new EMT class cycle how to take a blood pressure. It’s fairly simple and strait-forward, but there’s also a real art to it. Folks who are good at it wield their blood pressure cuff like a teppanyaki chef wields his knife. You can tell they’re good by watching the confidence in their movements, the order that they perform the steps, and the attention they give to the details.

There’s a big difference between the guy who chops vegetables down at the local Denny’s and the chef at the Benihana. Same tools, different level of skill. You see what I mean right? If your blood pressure skills are still somewhere in between the short order cook and the teppanyaki chef, here are some tips to getting better.

1) The blood pressure starts with a pulse, not a cuff

Most folks put the cuff on the patients arm without much thought to the location. Sure, you were taught how to place the cuff correctly back in school, but, hey, you’ve been doing this a long time so…

I disagree. Cuff placement is important. Start with the brachial pulse. If you have trouble finding the brachial pulse, you can review the location here. The location of the brachial pulse can vary considerably from patient to patient. Don’t assume you know where it is. Find it and place a finger on it while you grab your cuff with the opposite hand. while you’re here, note if the pulse is strong or weak, regular or irregular, fast or slow.

Now place the cuff with the artery label directly above the brachial pulse with about an inch between the pulse point and the cuff. Oh, and this is a good time to make sure you have the correct size cuff. If you have trouble getting a good seal on the Velcro you may need to move up to the big boy cuff. To much overlap may mean you need the Lilliputian size.

2) The stethoscope comes next

Don’t start inflating that cuff yet! Often, folks get the idea that the next move is to start pumping the cuff up to the 200 mmHg range. Hold off their camper.

Place your stethoscope on the patient’s arm and place a bit of pressure on the bell. Now start inflating. Since you placed the cuff and the stethoscope first, now you can listen on the way up. Pay attention to when you start to hear those whooshing Korotkoff sounds. Are they regular or irregular? do they sound fast or slow? Are they loud or soft?

You’re going to know when to stop inflating the cuff because you’re going to hear when the sounds stop. Now you can tailor your cuff inflation to your patient. No more guess work.

3) Nice even drop

With practice, you’ll figure out which needle drop rate is right for you. Too fast and your systolic reading may come out inaccurately low. Too slow and everyone on scene will start tapping their foot waiting for your results. Nice and even.

You’re listening for the first clearly audible whoosh (Or thump…pick your poison.) and the last whoosh before silence. The first clear whoosh is your systolic pressure and the last one represents the diastolic pressure.

There’s some debate over whether the true diastolic pressure is represented by the transition to the fourth Korotkoff sound (deep whoosh) or the fifth korotkoff sound (silence). Don’t worry about it. The current common practice is to use the transition to silence as the true diastolic pressure.

If you want to get fancy you can also grab a quick six-second pulse by counting the korotkoff sounds. Freeze the needle in between the systolic and diastolic pressures, glance at your watch and count how many whoosh sounds you hear in six seconds. Multiply by ten and then continue dropping the needle. Now you’ve got a fairly accurate pulse and a blood pressure all in one.

4) Listen for a blood pressure; don’t look for a blood pressure

The bumping of the needle often seen on the sphygmomanometer (the gauge) during the needle drop may or may not coincide with the audible blood pressure. You can’t take an accurate blood pressure by simply watching the needle. Let me repeat that last line.

You can’t take an accurate blood pressure by simply watching the needle.

It doesn’t work. Believe me, if it was that simple, I’d tell you. The truth is, you may see needle jumps 20 mmHg above the audible systolic pressure or 20 mmHg below. There’s just no reliable correlation. So don’t get fooled.

5) No sound? What now?

OK, so you didn’t hear anything. Don’t panic. It happens to everyone. Start from your ears and work toward the patient.

  • Are the ear pieces angled forward into your ear canals or backward against the side of your ear canals? Angle them forward.
  • Are there any kinks in the stethoscope tubing?
  • Is the bell on the stethoscope turned toward the correct side? Everyone gets fooled by this one occasionally. Tap the business side of the stethoscope and see if you hear clear crisp tapping.
  • Feel for the brachial pulse again and place the stethoscope bell directly over it.
  • Are you putting too much pressure on the bell of the stethoscope? Don’t let the bell ride to far up under the BP cuff or you’ll invert the bell when you inflate the cuff and muffle the sounds. You want gentle pressure on the bell.

Now inflate the cuff and try again. If you still can’t find it consider trying the other arm or palpating the blood pressure. If the patient is unstable, consider that they may not have a viable pressure. Quit fiddling with the BP and treat for shock.

6) Palpation, how do you do that?

Palpation allows you to quickly get a rough estimate of the systolic pressure without the use of a stethoscope. When monitoring critical patients, when time is of the essence and trending vitals is a frequent task, palpating the pressure is a great tool.

Correctly apply the BP cuff and grab a radial pulse. Inflate the cuff until the radial pulse goes away and then slowly deflate the cuff. When the radial pulse returns, that’s a fair estimation of the systolic pressure. it’s worth noting that palpated pressures tend to be about 8-10 mmHg lower than the true systolic. when documenting palpated pressures note the systolic pressure as assessed and replace the diastolic pressure with the letter “P”.

There you have it. The basic blood pressure technique is just like the basic vegetable chop. But there’s a lot more skill to taking a solid accurate blood pressure than initially meets the eye. Just like there’s a lot more to chopping vegetables than just the basic slice. Just ask any teppanyaki chef.

Now it’s your turn: What are your favorite blood pressure tips and tricks?

Read more EMT skills stuff:

The Ultimate Guide to EMT Vital Signs Part 1, The Pulse

The Art of Using Trauma Shears

Remembering The Glasgow Coma Score

Beyond The 1-10 Pain Scale

5 Assessment Findings That Should Concern You

Comments

  1. Yet again, I’ll serve up the first comment on another great article. I love the point about making sure the cuff is aligned correctly; I don’t see that done nearly enough. There’s an artery line on there for a reason, and if the internal bladder isn’t lined up properly, then your BP will be inaccurate.
    I’ll add my own pearl: when sizing your cuff, always err on the side of using one that’s too large if your patient is in-between sizes or you’re unsure which to use. Studies (at least the one or two I’ve seen) have shown that a small cuff can give a reading significantly higher than the true BP, and the reading is higher-still if the bladder is misaligned. Larger cuffs may instead give you a reading that is slightly lower than true BP, but the error is to a lesser extent than a too-small cuff.

    I would also caution about using the method of listening for the loss of the systolic while inflating the cuff to know roughly how far to go, because you could easily miss an auscultatory gap and undershoot the true BP. For those who haven’t heard this term, an auscultatory gap occurs when you are listening to the Korotkoff sounds as the needle drops and note a loss of sound at one point before it picks up again at a lower pressure, finally terminating at the true diastolic pressure. This puts you at risk of either: 1) underestimating the systolic because you started listening in the middle of the gap, unaware of the sounds at a higher pressure (i.e. you record 100/80), or 2) overestimating the diastolic if you quit listening as soon as you hear the pause where the gap begins (record 180/125), when really the pressure is 180/80 with a gap from 100 to 125. I’ve seen prevelances as high as 15 or 20% estimated for this, but I personally doubt many of those are significant ones that would cause you to get a false reading. I’ve also never seen any numbers for the average gap size, but I would guess most you care about are around 15-20 from my own experience, but have seen one as high as 32. The patients most prone to having these gaps seem to be elderly with atherosclerosis or other vessel disease, but it can show up in anyone. Now to combat this problem, most texts suggest you palpate a systolic first, completely deflate the cuff, then take your auscultated bp inflating 15 or 20 past the palpated (since that won’t be affected by the gap), but neither I, nor most people out there probably want to take the trouble to do that on every single patient. I say just keep taking them however you like, but please be aware of the possibility for one of these gaps, especially in your older patients.
    Anyway, sorry for such a lengthy response each time you put out one of these articles, but they’re so close to being fairly comprehensive resources on their topics that I can’t help but add a little bit more. Looking forward to seeing more of these in the future so I can continue to nit-pick. Thanks Steve!

  2. Or there is the other classic ‘newbie’ Trait which i saw and beat down just today.

    “Can you quickly get a BP for me please?”

    I say to my student. I then watch as he puts on the cuff palpates the radial pulse whilst deflating the cuff and announces proudly

    “154 over 82!”

    ehhhh???

    And there began the lesson on how to take a blood pressure!

    Oh, and all students I work with HAVE to comply with my golden rule:

    no one gets a BP from the lifepak until you have taken a manual Reading first.

  3. Awesome article!

    Do I sense a second great online book in the midst?

    “Steve Whitehead’s EMT-Basic skills aren’t Basic” ??

  4. It seems like the more attention I pay to blood pressures, the more trouble I have taking them. For example, lately, I have been hearing a obvious change in quality from the loud pulsing (I guess you’d call it the fourth Korotkoff sound) to a very quiet thumping that will continue for, say, another twenty points. I suppose I ought to report the complete silence as the diastolic, but I feel weird saying my patient has a pressure of 140/40. I ask other people about this and they look at me like I’m crazy.

  5. Great article steve. I’m looking forward to reading your other posts in this section.

    Anyway, I’ve just got my EMT back in February and I’m still a little shaky with vital signs, though I’m much better than I used to be. One thing that I’m noticing now, is to trust yourself more. Sometimes I’m a little unsure when I do actually hear the beats, especially in the back of the rig when we hit bumps in the road and stuff. Anyway, more recently, I’ve decided to just trust myself and whenever I think I hear something, that’s what I record. More often than not, my systolic was right on. My diastolic has been a little higher than the hospital found. So I just need to listen a little longer and I’m there.

  6. Jaymazing says:

    Awesome article, as always.

    I was just wondering, what kind of differences can I expect in readings when auscultating through clothing? Or when using the NIBP over clothing?

    Of course, I’m not talking about really thick clothing or anything…I’m mainly referring to tight t-shirt sleeves or long sleeved shirts that can’t be rolled up very far.

  7. What about alternate sites for taking blood pressures? I’ve heard if the cuff is appropriately sized that bp can also be taken with the cuff around the forearm or the calf.

  8. Sean Fontaine says:

    Steve, as usual thanks for putting this out there, I know that I’m guilty of not always lining up the artery line as accurately as I should. I am glad I have a good stethoscope and a good set of ears for hearing BP and lung sounds when others can’t.
    Entirely my personal opinion here: I don’t think that any of the LP12 NIBP cuffs are calibrated well/or often enough to be trusted w/out a manual double check, they don’t allow you to appreciate any change in pulse quality/strength, and as such aren’t worth a damn. One of my preceptors would disconnect it every morning and that became my habit even after moving off of his ambulance.

  9. MysteryMedic says:

    I’m sure I am going to start some controversy with this post, but why, when taken correctly with the appropriate cuff size and level with the heart, is using the LP12 to take the initial blood pressure always wrong? Walk into any emergency department and sit in triage, some (if not all) of our doctors offices, and even my own pediatricians office, see what they use to take the patients blood pressure. Auto right? Why? On average these are mostly used on stable patients because they walked in right (Mostly). The manual blood pressure is most effective, in my experience as a medic, at extreme ends (such as a patient presenting with a decreased LOC or a moderate to severe level of distress). When I suspect a CHF patient (like spitting foam) and I’m dosing my NTG on pressure, I do a quick initial palpation and all pressures are taken manually until the blood pressure starts getting low (not very often). If I suspect severe hypotension then I do a manual pressure. If I happen to walk into a call without my LP12 (again not very often) for let’s say a injured person and I need a blood pressure then I do a manual pressure on scene or maybe the LP12 for an (I need a place to sleep tonight but my left toe hurts) transporting as safely possible to the closest hospital because you’ve picked them up twice today. Let’s be honest, some of you will make that number up but all of you should at least take a pressure to tell said patient that even though their toe hurts that their blood pressure is so high it may kill them if they don’t stop their lifestyle and get medicated soon. HOWEVER, if I walk into a chest pain call and I start my initial assessment and the patient has an appropriate palpable radial pulse, all blood pressures will be taken by the LP12. Why you say? All my NTG will be based on the continuation of that blood pressure from the drop in systolic pressure taken on the same machine. Manual blood pressures will differ from the LP12. If the the first pressure was obtained manually and a medication is delivered then any pressure obtained after that should be obtained by the same method. All pressures obtained later should not correspond to the original pressure because it was obtained in a different matter and it should be documented as such (I know that most of you do not). If you suspect hypotension, we put on a manual cuff and leave it there. Palpate the pressure as you fluid bolus or medicate the patient until an appropriate pressure is achieved. Blood pressure in the body reacts to your intervention, internal mechanisms, or the environment. Medications should be given based on the same site/method. If an EMT-B responds before me (sometimes in an area of my local) if the first BP taken by them is manual (and I trust them or if the number doesn’t match the patient (whole different discussion!!!)) then I continue with my own manual pressure. BP’s are important but they are also relative to equipment and user and treatment…

  10. MysteryMedic says:

    BTW…Love your site and read it often!!!

  11. A really fun web site for learning to take blood pressure is http://practicalclinicalskills.com/blood-pressure.aspx. They have an online blood pressure cuff simulator and several dozen case studies.

  12. christine says:

    i was measuring the blood pressure for a 6o years old patient that had done a colostomy operation after receiving a stab wound in the abdomen, she was confused and audible chest wheezes are heard..the pressure was 150 / 2o …i repeat it and 4th kortokoff sound was heard till the end…my resident cry in my face when i told him this blood pressure . 2 days after this patient died…i think she was in septic shock…does anyone have information about this? thanks

  13. Christopher says:

    I’m concern that the description of the systolic as “the first clearly audible whoosh (Or thump…pick your poison.)” may confuse the students with phase 3 Korotkoff sound. many EMT’s mistakenly believe that the intensified sound in phase 3 is “when the sound becomes clear”.

  14. ‘When browsing for having the best money saving deals on laptop computers,
    check out if you’ll find any nearby outlets mentioned in the website,
    where one can take a look at the notebook computers directly.
    According to HP’s website, the lowest priced desktop computer will be the
    HP Pavilion p6300z, which has a base tariff of $299.
    These laptops are technically identical,
    aside from the processor configuration.

Trackbacks

  1. […] respiratory vital sign rounds out our “big three” vital signs. (Pulse and blood pressure being the other two.) It is, quite possibly, the most misunderstood and overlooked of the big three […]

  2. […] Pulse The Blood Pressure The First Rule of Vital Signs The Art of The Pulse […]