Taking Blood Pressure

Hopeful2011 · May 16, 2010

The needle is a good indicator, but you should go off of the number where you first heard the sound.

TCASII, ADN · May 16, 2010

There's a bit of technique and art form to it. People often find manipulating the stethoscope, bulb, and valve difficult at first.

Anyhow, the method requires that you locate the radial pulse in the wrist, then inflate the sphygmomanometer about 20 - 30 mmHG above the point where the pulse disappears by palpation (touch). This will minimize the pain from inflating the cuff too high since everyone has a different systolic value. Some may be 120 or lower, others may be 150 or higher. Going too high for a person at 120 or lower will just be painful.

Once you have inflated ~30 mmHG above the palpable radial pulse, quickly place the stethoscope bell (or diaphragm, but bell is preferred) over the brachial artery and slowly open the valve so that the needle drops about 2 mmHG per second. Note the first sound - your systolic, and the point where the sound stops - your diastolic.

Keep in mind that the transition between inflation and opening the valve need to be done as quicly as possible since having an inflated BP cuff on your arm is uncomfortable. You'll need to work on your ability to transition the stethoscope over the brachial artery after inflating over 30 mmHG and opening the valve to start releasing the air as fast as possible. I had my arm put to sleep a couple times by students in the past who were too slow and had trouble multitasking this activity. Practice without a real arm to get used to manipulating the equipment.

ETA: A common error students make is to open the valve too fast or too much, thus letting too much air out. This occurs when the student isn't used to the process or they have it too tight and they panic. Keep the valve closed just enough to hold the needle/air in place, or you will have trouble opening it with one hand. If too much air gets out and you can't quickly adjust for the mistake, then you'll miss the systolic value.

sunkissed75, CNA · May 16, 2010

thanks so much for the posts! they definately helped!!

DolceVita, ADN, BSN, RN · May 17, 2010

There's a bit of technique and art form to it. People often find manipulating the stethoscope, bulb, and valve difficult at first.
Anyhow, the method requires that you locate the radial pulse in the wrist, then inflate the sphygmomanometer about 20 - 30 mmHG above the point where the pulse disappears by palpation (touch). This will minimize the pain from inflating the cuff too high since everyone has a different systolic value. Some may be 120 or lower, others may be 150 or higher. Going too high for a person at 120 or lower will just be painful.
Once you have inflated ~30 mmHG above the palpable radial pulse, quickly place the stethoscope bell (or diaphragm, but bell is preferred) over the brachial artery and slowly open the valve so that the needle drops about 2 mmHG per second. Note the first sound - your systolic, and the point where the sound stops - your diastolic.
Keep in mind that the transition between inflation and opening the valve need to be done as quicly as possible since having an inflated BP cuff on your arm is uncomfortable. You'll need to work on your ability to transition the stethoscope over the brachial artery after inflating over 30 mmHG and opening the valve to start releasing the air as fast as possible. I had my arm put to sleep a couple times by students in the past who were too slow and had trouble multitasking this activity. Practice without a real arm to get used to manipulating the equipment.
ETA: A common error students make is to open the valve too fast or too much, thus letting too much air out. This occurs when the student isn't used to the process or they have it too tight and they panic. Keep the valve closed just enough to hold the needle/air in place, or you will have trouble opening it with one hand. If too much air gets out and you can't quickly adjust for the mistake, then you'll miss the systolic value.

Really? We palpate the pulse (brachial) inflate the cuff until the pulse disappears. Deflate the cuff fully and note the reading where the pulse disappeared. Place steth. Reinflate cuff 30 mmHg above the reading we lost the brachial. Allow the cuff to deflate while listening for the K sounds (beg & end). We are permitted to use the radial pulse for the palpation.

Having an inflated cuff on for too long, more than say 10 secs fully inflated, can give you an inaccurate reading (sure it may be uncomfortable too).

TRR8021 · May 17, 2010

I use the radial pulse too only because I can't always palpate brachial pulses as well. Both methods are acceptable in my program.

CoffeemateCNA · May 17, 2010

It really doesn't matter if you use the brachial or the radial pulse initially for the palpation method. It's going to be essentially the same BP reading in the end regardless of the artery palpated.

That first reading is just an estimation so that you know how much to inflate the cuff the second time around.

DolceVita, ADN, BSN, RN · May 17, 2010

I use the radial pulse too only because I can't always palpate brachial pulses as well. Both methods are acceptable in my program.

I do as well because I can always find it versus the brachial. I think it doesn't give a lot of confidence to a pt when you are messing about trying to locate there brachial artery.

What is interesting is no one has ever taken my BP using this method. They slap on the cuff, place the steth and inflate (palpating nothing).

TRR8021 · May 17, 2010

DolceVita, that's true, and I try to look confident to the patients so that they won't say "do you know what you're doing?!" haha

And yes, no one ever takes my blood pressure the right way either. They just pump it up to some arbitrary number and go from there!

Boog'sCRRN246, RN · May 17, 2010

"We palpate the pulse (brachial) inflate the cuff until the pulse disappears. Deflate the cuff fully and note the reading where the pulse disappeared. Place steth. Reinflate cuff 30 mmHg above the reading we lost the brachial."

Just a question...I've been through a CNA program, a LPN program, and I'm almost finished with a RN program and I've never been taught this method of getting a BP. How long are you waiting between initially inflating the cuff to lose the pulse and then inflating the cuff to get an actual BP? I've been taught that inflating the cuff on the same arm more than once within a few minutes can lead to falsely high readings d/t arterial occlusion.

Music in My Heart · May 17, 2010

I have my 'scope in place and go to 140, listen to hear the pulse, if not, a couple more squeezes, listen, squeeze as needed...

CoffeemateCNA · May 17, 2010

"We palpate the pulse (brachial) inflate the cuff until the pulse disappears. Deflate the cuff fully and note the reading where the pulse disappeared. Place steth. Reinflate cuff 30 mmHg above the reading we lost the brachial."
Just a question...I've been through a CNA program, a LPN program, and I'm almost finished with a RN program and I've never been taught this method of getting a BP. How long are you waiting between initially inflating the cuff to lose the pulse and then inflating the cuff to get an actual BP? I've been taught that inflating the cuff on the same arm more than once within a few minutes can lead to falsely high readings d/t arterial occlusion.

My textbook says to wait 10-15 seconds, but I disagree with it. It's too soon to reinflate the cuff and will result in a high systolic reading.

I usually do the estimate first, do the rest of the vitals, then finish the BP last. This gives sufficient time between readings, usually around 2 minutes.