Measuring BP wrong?

[Samuel88]

I decided to get a cheap 15 dollar Chinese blood pressure cuff and stethoscope to get some more practice since I'm so-so at it.

I've tried measuring my own BP several times and I keep getting a strange reading around 120/100!
Is this even possible? Isolated eleveated diastolic blood pressure with a pulse pressure of 20?

I'm listening for the start of the sound and get that right, then I try with all my might to listen for the 5th Korotkoff sound but it keeps disappearing at 100 mm Hg.

I've ruled out auscultatory gap since I measured the radial pulse disappearance.

I'm going in to a walk in clinic tomorrow and have them try to check my BP with this equipment.

Anyone have any ideas of why my technique is off? Was that too cheap for the pressure cuff and stethoscope ?

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[Samuel88]

Figured it out.

1) Don't measure with tension in the arm

I read about this being a common source of error but I assumed I was doing it correctly. I measured it while sitting at a LOW table, so my arm was somewhat tensed.
By chance, I remeasured it while slouching in my chair and having the arm fully relaxed. It also helps to hear better since the arm is more stable and no movement sounds are made.


Also, some googling later and I see I'm not the first to notice this:

"Dr. Guss says he first became interested in the issue of arm position and blood pressure levels while measuring his own pressure as a medical student. He noticed the readings went up and down depending on where he put his arm."

h**ps://consumer.healthday.c*m/general-health-information-16/doctor-news-206/arm-position-is-key-to-blood-pressure-reading-516970.

study even published in Annals of Internal Medicine
Interesting stuff that they don't emphasize enough.

 

[bedizen]

Make sure you measure without tension in the arm! a lot of folks will take BP with patients sitting at a low table, so try slouching or relaxing the arm.

 

[RNtoMD87]

You also need to be seated for 15 minutes or so to get an accurate result. If I take it standing/just after sitting its much different than after I've been seated.

 

[Samuel88]

Indeed. I never realized how variable the readings are depending on all sorts of factors.

Remeasured two times at different tables/arm positions again today and it was a big difference.


After a 15 minute rest time: "Overall, systolic BP (SBP) and diastolic BP (DBP) decreased by 11.6 and 4.3 mm Hg, respectively"


Positioniong:

1. Arm/Back/Feet Unsupported (1,3,4) - When having your blood pressure measured, you should always be seated in a comfortable chair, legs uncrossed, with your back and arm supported. If your back is not supported, your diastolic blood pressure measurement may be increased by 6 mmHg. Crossing your legs has shown to raise your systolic blood pressure by 2 to 8 mmHg. The positioning of your upper arm below your heart level will also result in higher measurements, whereas positioning your upper arm above your heart level will give you lower measurements. These differences can increase/decrease your systolic blood pressure 2mmHg for every inch above/below your heart level.

Wow, so a 5 inch difference in positioning can already be 10 mmHg!

Also:

"Studies have shown that your systolic blood pressure measurements could increase 10 to 15mmHg when you have a full bladder"


(Source)
h**ps://www.suntechmed.c*m/blog/entry/4-bp-measurement/49-10-factors-that-can-affect-blood-pressure-readings

(

1. Handler, Joel. The Importance of Accurate Blood Pressure Measurement. The Permanente Journal (2009) 13:3: 51-54
2. Long, JM., J.J. Lynch, N.M Machiran, SA Thomas, KL Manilow. The effect of status on blood pressure during verbal communication. Behavior Science (2004) 5:2: 165-172.
3. O'Brien E, R. Asmar, L Beilin, Y Imai, J. Mallion, G. Mancia, T. Mengden, M. Myers, P. Padfield, P. Palatini, G. Parati, T. Pickering, J. Redon, J. Staessen, G. Stergiou, P. Verdecchia. European Society of Hypertension recommendations for conventional, ambulatory, and home blood pressure measurements. Jounral of Hypertension (2003) 21: 821-848.
4. Pickering, T.G., J.E. Hall, L.J. Appel, B.E. Falkner, J. Graves, M.N. Hill, D.W. Jones, T. Kurtz, S.G Sheps, E. J. Roccella. 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 (2005) 45:142-161.