know any formulas to calculate systolic and diastolic bp?

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I got pimped today about this and the only thing I could think of was rearranging map = 2/3 Dbp + 1/3 Sbp. Any other suggestions?

You can't calculate systolic and diastolic pressures. Its something you measure (ie with a BP cuff). You can calculated Mean Arterial Pressure.

Originally Posted by cliquesh

I got pimped today about this and the only thing I could think of was rearranging map = 2/3 Dbp + 1/3 Sbp. Any other suggestions?

Yea that would give you one equation with 2 unknown variables. You can't do that.

It was a cardiologist that asked me this question. He said he is going to ask me again tomorrow and he wants specific equations, but i cannot find anything. he wants two equations, one for DBP and one for SBP

bp cuff plus arm = SBP/DBP

Are you sure you understood him correctly? Does he have an accent?

Yea. Press Start BP cuff on the f*cking monitor.



Seriously, you should have said that.

SBP = 110 + 2sqrt(age) + 20x, where x is number of antihypertensives pt. should take but doesn't

No but seriously, your cardio attending should publish his miraculous method of calculating BP. We could save tons of money on BP cuffs.

Actually wait, troll attending can be counter-trolled, observe:

SBP = DBP + PP

DBP = SBP - PP

Originally Posted by jcu

Are you sure you understood him correctly? Does he have an accent?

Fun-ny.

But in all seriousness it could be a trick question..

Originally Posted by AngleWold

You can't calculate systolic and diastolic pressures

Thanks, I bet he hadn't deduced that yet from the 15 prior responses.

Originally Posted by DrSnips

SBP = 110 + 2sqrt(age) + 20x, where x is number of antihypertensives pt. should take but doesn't

Find 2 theoretical calculus proofs on fluid dynamics. $20 says he can't tell you you're wrong

Originally Posted by SpecterGT260

Find 2 theoretical calculus proofs on fluid dynamics. $20 says he can't tell you you're wrong

$20 says he asks you to explain those proofs

DBP = Force of Blood in Brachial Artery / Area of Brachial Artery during Diastolis

There you go.

Originally Posted by cliquesh

I got pimped today about this and the only thing I could think of was rearranging map = 2/3 Dbp + 1/3 Sbp. Any other suggestions?

You can calculate systolic pressure with the modified Bernoulli equation: P = 4 * v^2. This is usually used with echo to estimate RVSP (right ventricular systolic pressure), but I suppose it could be used to estimate systemic pressure. You would have to add the result to the LAP (left atrial pressure), which you would have to measure or estimate.

Hope your attending's not an SDNer.

Originally Posted by PMPMD

You can calculate systolic pressure with the modified Bernoulli equation: P = 4 * v^2. This is usually used with echo to estimate RVSP (right ventricular systolic pressure), but I suppose it could be used to estimate systemic pressure. You would have to add the result to the LAP (left atrial pressure), which you would have to measure or estimate.

Hmmm. I see OP getting a paper out of this. Let me start it for you:

Title: A new method for determining systolic blood pressure by combined use of Doppler ultrasound and cardiac catheterization.

Abstract: Blah Blah insert statistics. The study showed that the new method of BP determination is non-inferior to use of conventional BP cuff when compared with arterial line measurements.

Methodology: We took 300 people who presented to a health fair for BP screening...

There you go OP, all I ask is that you not make me an author.

Originally Posted by PMPMD

You can calculate systolic pressure with the modified Bernoulli equation: P = 4 * v^2. This is usually used with echo to estimate RVSP (right ventricular systolic pressure), but I suppose it could be used to estimate systemic pressure. You would have to add the result to the LAP (left atrial pressure), which you would have to measure or estimate.

I should add that you would need to assume there is no significant AS (aortic stenosis) in this case.

The original concept is used in echo to estimate pulmonary arterial pressure:

PA ~ RVSP + RAP (or CVP) assuming no significant pulmonic stenosis

Also, the Dinamap (the typical automated BP cuffs you will see) or other automated BP cuffs use arterial pressure oscillation to get a mean arterial pressure, then calculate the measurements during the cycle to estimate a systolic and diastolic blood pressure. I'm sure if you read the technical specs of the Dinamap, they would show you how they derive a systolic and diastolic BP from a mean arterial pressure, though I doubt it is very straightforward.

How did it go OP?

Originally Posted by SurfingDoctor

Also, the Dinamap (the typical automated BP cuffs you will see) or other automated BP cuffs use arterial pressure oscillation to get a mean arterial pressure, then calculate the measurements during the cycle to estimate a systolic and diastolic blood pressure. I'm sure if you read the technical specs of the Dinamap, they would show you how they derive a systolic and diastolic BP from a mean arterial pressure, though I doubt it is very straightforward.

Typically, the pressure resulting in the maximal oscillations is the MAP. Algorithms are used to calculate SBP and DBP from the MAP but these are generally proprietary.

I did find one published algorithm:

The Algorithm used by DINAMAP:

1. It first determines the amplitude at MAP, which is the lowest cuff pressure at which maximum amplitude is sensed

2. It then reviews the data above MAP and find the pressure that generates amplitude by 0.5 of the amplitude of MAP --> that is systolic blood pressure

3. Finally it reviews the data below MAP and find the pressures that generates amplitude by 0.625 of the amplitude of MAP --> that is diastolic blood pressure

Originally Posted by PMPMD

The Algorithm used by DINAMAP:

1. It first determines the amplitude at MAP, which is the lowest cuff pressure at which maximum amplitude is sensed

2. It then reviews the data above MAP and find the pressure that generates amplitude by 0.5 of the amplitude of MAP --> that is systolic blood pressure

3. Finally it reviews the data below MAP and find the pressures that generates amplitude by 0.625 of the amplitude of MAP --> that is diastolic blood pressure

I was wrong, that is totally straightforward.