# BP by needle bounce is older than your silly auscultation



## Brandon O (Jan 10, 2014)

Given how much time is spent telling new folks not to take blood pressures using palpation, and certainly not by looking at the bouncing needle, I thought this historical note from the early days of hemodynamic monitoring (at the turn of the 20th century) was amusing...



> At this time the method used for determining whether or not pulsation was present beyond the region of arterial constriction was that of palpation. This was quite alright for systolic pressure measurements, and is the technique still used today, but it was useless for an accurate determination of the diastolic pressure. In order to overcome this deficit so that both systolic and diastolic pressures, and hence pulse pressures, could be recorded clinicians started to use the oscillatory method. This involved observing the oscillations which were transmitted to the mercury in the manometer from the artery, since when the cuff pressure was equal to the arterial pressure the compressed artery would throb, thus causing small regular fluctuations in the cuff pressure. The appearance of definite oscillations defined the systolic pressure, and the transition from large to small oscillations, the diastolic pressure. In England, Hill and Barnard invented a device which had a needle pressure gauge which was sensitive enough to record the diastolic phase. (Booth)


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## usalsfyre (Jan 10, 2014)

Brandon O said:


> Given how much time is spent telling new folks not to take blood pressures using palpation, and certainly not by looking at the bouncing needle, I thought this historical note from the early days of hemodynamic monitoring (at the turn of the 20th century) was amusing...



We also used to use columns of water to measure CVP and generate PEEP by dropping the exhalation tube of a vent in a bucket of water...doesn't mean we haven't found better, more accurate ways to do it by now.


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## mycrofft (Jan 10, 2014)

I got you, OP.

Teaching "second best" technique to students should be done only to tell them those are what to avoid, then tell them how to avoid them by citing WHEN people resort to them, and how to circumvent (ask the students how as well).
They can learn the second best once they know the first best, and that includes documenting what you did and why you did it instead of meeting standard of care.


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## Brandon O (Jan 10, 2014)

Ahh, I just thought it was a fun piece of history. Nothing new under the sun and all that.


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