› Measure Blood Pressure

What If You Have To Measure Blood Pressure
The Old Fashioned Way Someday?

One basic skill is taking a manual blood pressure. Yes, lots institutions have the automatic cuffs, but there are still plenty of jobs out there that require a manual method. And if you ever get a really wonky blood pressure measurement it might be good to double check the results using your own ears!

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In home care, it’s required to measure blood pressure manually. When I started to use my auto cuff that I purchased myself, I was told it was unacceptable. Why? Because they couldn’t calibrate the electronic ones. When I mentioned that the manual cuffs were never calibrated either, there was silence on the other end.

Not particularly logical. But you will find many “sacred cows” in the nursing field that should be shot but aren't. 

I choose my battles.

Watching new students learning about blood pressures I realized it is as much about learning to “practice with your props” the same as an actor, as it is to actually measure blood pressure. 


Here's a great one to practice your listening skills:

What Affects The Results
When You Measure Blood Pressure

A few things not mentioned in the videos:

  • Be aware of possible auscultatory gaps in the sounds. That is the period during which sounds indicating true systolic pressure fade away and reappear at a lower pressure point
  • A cuff that is too small will give you an inaccurate higher blood pressure measurement 
  • A BP cuff too large will give you an inaccurate lower blood pressure

It won’t take long before you can eyeball whether a cuff will be the right size for what you need. 

  • Placement of the patient’s arm should be level with the heart when taking a blood pressure measurement. When the patient is lying down, the position is already appropriate. If you have a patient sitting or standing, you must raise the arm to approximately heart level.
  • Wrap the BP cuff around the upper arm.
  • Put the stethoscope in your ears, 
  • Place the stethoscope on the brachial artery. Hold the stethoscope in place with your thumb and wrap your other fingers around the elbow and hold the elbow straight with your other fingers. 
  • Pump up the cuff and take the blood pressure measurement.
Blood pressure cuff and stethoscope

Some patients are nice and hold their arm up for you but this is tiring for the entire procedure.

So, take hold of their forearm and and tuck their wrist under your upper arm and clamp it down there. That way you have control of the extended position and you still have both hands free.

Which Arm To Use

Do not take a blood pressure in an arm: 

  • With an IV 
  • With an A-V (Arterial – Venous) fistula or shunt. These are the large, bulgy looking areas in an arm that are used for people on dialysis.
  • That has had a mastectomy with lymph nodes removed from that side
  • The side affected by a stroke if possible

WNL (Within Normal Limits)

Anything between 90/50 and 140/90 is considered normal. You will get patients that make a big deal over a change from 110/70 and 120/70. Don’t let them suck you into that! Both readings are fine!

What do you do when you measure blood pressure and find it too high or low? I can tell you the first thing the doctor will say when you call…. Wait 15 minutes and try it again. 

Soooooo, take it on the right arm, the left arm, write the results down, then wait 15 minutes and see if they are better. If they are not WNL (within normal limits) at that time, then call the doc.

What Affects Blood Pressure Measurements

  • Diet (high sodium can increase the blood pressure measurement significiantly as it sucks excess water into the circulatory system)
  • Dehydration can lower the BP
  • Medications
  • Stress
  • Body position can cause orthostatic hypotension for some patients
  • Acute pain (chronic pain doesn’t usually change the BP as the system has acclimated to the longstanding condition)

Can you think of other things that may change the readings?


BP: Blood Pressure

Blood pressure: is how much pressure is applied to the arterial walls. Analogous with be how much pressure is in the tires of your car? The higher the pressure and the greater chance for a blow out if there is a weak spot in the tire wall (or artery wall).

Hypertension: high blood pressure (greater than 140/90)

Hypotension: low blood pressure (less than 90/50)

Sphygmomanometer (how to pronounce) this is the blood pressure machine itself 

Systolic: (how to pronounce)  This is the top number of the blood pressure, e.g., 120/80. 120 is the systolic blood pressure. This means that when the heart contracts and pushes blood through the arteries it is 120 mm/Hg pressure exerted against the artery walls.

Diastolic: (how to pronounce): This is the bottom number of the blood pressure, e.g., 80 for that blood pressure of 120/80. It is a measurement of how much pressure is against the artery wall in between beats, when the heart is resting. 

mm /Hg: (millimeters of mercury): millimeters is a length measurement. Hg is the symbol for mercury. Blood pressure is measured by how much pressure it takes to move a column of mercury one millimeter. If you look at the older column sphygmomanometer, you will see the mercury inside the column and the lines on the outside. Each line is two millimeters in length (or height, I guess).  Even though you may have a cuff with the round dial it is still measuring the same amount of pressure. 

Korotkoff sounds: (how to pronounce: kor-ROT-koff) These are the sounds you hear when you measure blood pressure. There are four:

  • Tapping
  • Swishing
  • Knocking
  • Muffling

Remember you are now a nurse. It is your responsibility for being accurate, understanding results and deciding if anything needs to be done about it. It's on your shoulders now.

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