Diastolic BP of zero

Never heard of that. What did you get in the other arm?

If cardiac output is high, K sounds can be heard until zero. In these cases, it is best to read BP when the sounds first muffle. This can be a fairly subjective thing.

I'm surprised that they told you not to worry about it, several pathological states can cause increased cardiac output. Having said that, it's quite normal to hear sounds until zero in children.

What was the person being seen for? I'm curious now. Age group of patient?

I have a resident that this is the case. When determining the diastolic pressure I listen for when the sound changes to a less crisp sound. This change may be very subtle at times.

I work w/ kids ages 11 - 19 and I was taught by the NP to pay attention to the muffle and use that last 'normal' sound if the sounds don't go away as expected.

Awww, man!!!!! I hope I don't get something like that in nursing school. I'm having trouble as it is with the "normal" sounds!!!!!

I have a resident that this is the case. When determining the diastolic pressure I listen for when the sound changes to a less crisp sound. This change may be very subtle at times.

:yeahthat:

Hi,

The guy was about 70 years old, with no cardiac hx. BP in the right arm was 115/40, which was consistent with all other readings. As far as I can remember he was in for poorly controlled diabetes and a Pneumonia.

I agree it does seem strange that they thought it was nothing to worry about, the only other time I seen this kind of thing mentioned (on the internet) was in pregnant women! Didn't say why though!

Don't think it could have been a high Cardiac output, because systolic was fairly low, and it was only in one arm.

Hi,

The guy was about 70 years old, with no cardiac hx. BP in the right arm was 115/40, which was consistent with all other readings. As far as I can remember he was in for poorly controlled diabetes and a Pneumonia.

I agree it does seem strange that they thought it was nothing to worry about, the only other time I seen this kind of thing mentioned (on the internet) was in pregnant women! Didn't say why though!

Don't think it could have been a high Cardiac output, because systolic was fairly low, and it was only in one arm.

A high CO does not neccessarily mean a high systolic pressure.

Remember, CO = HR x stroke volume.

A high CO does not neccessarily mean a high systolic pressure.

HR was about 80 BPM if that makes a difference...?

Heck, that frequently happens to me and has for years. When I was in nursing school and we used to take BPs on each other for practice, I always confused my fellow students because my BP "bumps all the way down." My BP tends to run lower anyway (SBP 100). My doctor just told me "you'll live forever."

Warning: Long and technical - but interesting.

These days, when dr's ask me for B/P, they normally want the systolic.

Ex: 'What's her b/p?", "110".

In 10 yrs, we'll all be using mean arterial pressure (MAP). The Mean is the 'average' pressure of the system as opposed to sys/dia, which are the high and low of the system.

Hint: I'm using the terms MAP and 'Mean' interchangeably.

MAP = Sys +(Dia x2)/3 or also, Dia + (Sys-Dia/3).

Or, to use both formulas:

Ex 120/80 = Sys 120 + (Dia x2) 160 = 280/3 = 93.3

or

120/80 = 80 + (120-80 = 40/3) = 13.3 +80 = 93.3

A mean is a better indicator than the high and low. But that being the case, an accurate diastolic is even MORE important, because it will affect the mean.

You might be interested to know that when you manually ascultate BP, you find the high and the low (sys/dia) and then calculate the mean (MAP) - see above.

When a non-invasive b/p machine (NIBP) takes a b/p, it uses an oscillometric method of finding the MAP (or rather, the 'pulse envelope' surrounding the MAP), and then uses a formula/algorithm to calculate the high and the low (sys/dia) from the mean.

But the take home point is this: the mean better seats the 'pulse envelope' of a blood pressure than its outlier values (sys and dia). What this means in English is that MAP is a better and more predictable and reliable indicator of a B/P's ability to get blood to the the right organs. And so, it is in the process of becoming the standard measurement. What it also means is that, while the sys/dia is a more reliable value w/ ascultation (because they are measured and the mean is calculated), the MAP is a more reliable machine value (because the MAP is measured and the sys/dia are calculated).

And you might also be interested to know that the gold standard for an acceptable MAP that reliably 'perfuses' vital organs is a minimum of 60.

From a manual:

"When the NIBP method is the source for determining BP, the Oscillometric method is used. This method measures the pressure pulse within the cuff in incremental steps and has a maximum value of approximately 1 mmHg, which occurs at the MAP. A sophisticated algorithm is then applied to plot the Oscillometric Envelope of pulse pressure measurements vs. cuff pressure measurements. This oscillometric envelope is used to determine the MAP, SBP and DBP values.

The shape of an actual patient Oscillometric Envelope varies from measurement-to-measurement and from individual-to-individual. Therefore, it is quite possible to have different systolic and diastolic pressures for the same measured MAP, as well as different MAPs for the same systolic and diastolic pressures."

~faith,

Timothy.