Beyond the classic formula [MAP = DAP + 0.33 PP] ;
PP = systolic-diastolic pressure, DAP = diastolic arterial pressure
Can you suggest other formulas or methods for non-invasive estimation of mean arterial BP?
I don't know myself or should I say I can't recall, but if you contact the baker heart research institute in Melbourne, they did a study where MAP was one variable measured, so they should be able to tell you
Actually, when you have only the non-invasive measures of sys-BP and dia-BP, this is the only formula, that can read many ways (classically MAP = (2.DBP + SBP) / 3).
However, if you have a non-invasive evaluation of a curve (such as by aplanation tonometry), then the MAP can be calculated by the curve.
Even if one has the applanation tonometry waveform, still the raw signal needs to be calibrated based on approaches with inherent assumptions.
I have already found 5 different formulas but, I was not aware of that !! Thank you! Do you have more details about that citation ?
i.e. book or article title? authors?, pages?
if you have DBP and SBP you can use this formula (MAP = 1/3 (SBP – DBP) + DBP)
If you using telemetry system DSI does have option to generate MAP for you as you recording .
Hi Theodore,
This vascular field is often divided and you find several formulas and no agreement.
In the following article from our group we observe that the DBP + 40% of the difference has a much better yield with experimental observations in a large population. Mahieu et al. J Hypertens. 2010 Feb;28(2):300-5. doi: 10.1097/HJH.0b013e3283340a1a.
My personal input would be not to use formulas but to calculate means from actual (carotid) waveforms. This is by far the most reliable approach.
Best regards,
Thierry
Mean arterial blood pressure is the average of all values that arterial blood pressure shows during an entire cardiac cycle, i.e. the integration of a pressure curve. Since diastole last longer than systole, the value of mean pressure is not the average between systolic and diastolic one, but it is a little closer to diastolic presure. This is the reason why the classical formula calculates mean pressure by adding 0.33 PP to diastolic pressure. Obviously a similar measurement requires the availability of a recorder of the pressure curve. Thus it will never be a routine way to measure the pressure......
Occasionally mean pressure can concide with the average between systolic and diastolic, as it occurs in the presence of very high heart rates, when the duration of diastole is reduced.
Best regards.
Gianni
Gianni Losano has already explained it beautifully. There are many ways to calculate mean arterial pressure, but the most commonly used to guide therapy is to add 1/3 of Pulse pressure into diastolic pressure.
I would like to think that the answer given by Gianni Losano is going to be kept in mind by everybody. It could not be formulated any better that what he did.
Beyond the classic formula [MAP = DAP + 0.33 PP]. Can you suggest other formulas or methods for non-invasive estimation of mean arterial BP?
Hi Theodore,
As indicated in my previous message the formula MAP = DAP + 0.40 PP will have a better yield. Our colleagues (from the engineering department of Patrick Segers) derived it from a population of more than 2500 subjects in which they have both office BP's and tonometric signals. As you know mean and diastolic BP's are the same along the arterial tree, so it is crucial to derive values from a proper calibration. The investigation learned us that both carotid artery SBP and central SBP obtained via a transfer function are highly sensitive to the calibration of the respective carotid artery and radial artery pressure waveforms. Our data suggest that the one-third rule to calculate MAP from brachial cuff BP should be avoided, especially when used to calibrate radial artery pressure waveforms for subsequent application of a pressure transfer function. Until more precise estimation methods become available, it is advisable to use 40% of brachial pulse pressure instead of 33% to assess MAP.
Ref. Mahieu et al. J Hypertens. 2010 Feb;28(2):300-5.
Best regards,
Thierry
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