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?
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