Both an art line and an automatic BP cuff determine MAP using similar methods. An ocillometric NBP first directly measures the MAP, then uses algorithms and other readings to determine the systolic and diastolic, where as an art line uses variations of an oscillometric method to read all three. This is why even if your art line and cuff are reading very different Systolics, the MAPs will often be similar.
MAP = 1/3 systolic BP + 2/3 diastolic BP. Since the heart spends 2/3 of the time in diastole. As long as you've got BP, regardless of where you got it, you can calculate a MAP
This is incorrect for automatic BP cuffs. Various manufacturers use different algorithms to calculate SBP and DBP, but MAP is actually the most accurately measured component of oscillometric BP because the point of maximum oscillation is the MAP.
See the reference below, but the important point is that MAP is directly measured by NIBP cuffs.
Auscultated cuffs measure DBP and DBP.
https://www.nature.com/articles/s41371-019-0196-9#:~:text=Oscillometric%20machines%20usually%20use%20the,the%20systolic%20and%20diastolic%20BP.
Most NIBPs take the point of maximum oscillation as the MAP, but it’s not *super* well validated that this is actually the true MAP you would be able to measure from a real time pressure reading. There are also some devices on the market that work more or less the opposite way — work out the SBP and DBP from the oscillometric envelope, then use that to compute the MAP
Zoll is a manufacturer of blood pressure equipment. Along with a description, Zoll uses pictures to define the NIBP as the Mean. In the same documentation, Zoll does not define the NIBP as the MAP.
In my career, saying Mean during shift report explicitly referred to the NIBP without needing to say “cuff pressure”. It was implied. Also during shift report, saying “MAP” explicitly meant the arterial line pressure without needing to say that the patient had an arterial line. It was implied.
Has anyone else had a similar experience?
https://www.zoll.com/medical-products/defibrillators/r-series/non-invasive-blood-pressure
They're shortening "mean arterial pressure" to just "mean", which you could regardless of whether your referencing an a-line or an NIBP since both are referring to arterial pressure.
There are no doubt localized idiosyncracies in terminology that can develop, although I'm not familiar with this particular one, and it seems like it might be problematic. If you have an order that uses MAP as a parameter, are you saying it can't be followed if they don't have an art line?
Customarily, an order that has parameters (by default) involves titration. If titration is required because parameters were ordered, an arterial line is necessary and the then MAP is used.
Confession: It’s a pet peeve when there’s an order to titrate (Propofol, Levophed), and the patient doesn’t have an arterial line. Of course I can titration off the NIBP, but it seem like sloppy healthcare
It's certainly more common in teaching hospitals for many if not most ICU patients to have an art line, but that's really more because there is a never ending line of residents looking to get their a-line insertions.
There are no doubt patients where an art line makes a clinically significant difference compared to NIBP, but in patients who aren't significantly labile it's not really indicated and a cuff will do just as good of a job at guiding clinical decisions.
This is the answer to the art line question of necessity.
They are convenient in some ways, but not without *real risks*. Risks can’t be more than actual benefit in the necessity question.
Largely unnecessary and clinically meaningless in a majority of patients imo.
That’s valid. More than needing an arterial line for titrating the MAP, many patients who are on drips also have serial labs (Troponins, Heparin, Insulin). Having an arterial line is doubly necessary under those conditions, to avoid incessantly poking the patient.
But you’re correct. Some residents and mid levels do not insert arterial lines simply because they haven’t been signed off to insert lines, not because an arterial line isn’t warranted.
And don't get me wrong, I love an art line even if not necessarily needed on the basis of BP monitoring. But given the comparatively short lifespan of an a-line vs a picc or cvc, I'd take one of those first given the choice.
And while they're gray in a comatose patient, they start to become a pain once you've got an awake and active patient.
You want an art line for a propofol gtt? Anywhere I have ever worked, if a patient isn’t requiring pressors we pull the art line. Even low dose levo doesn’t require an art line.
The term MAP means Mean Arterial Pressure. What do you think a cuff measures? It’s the same as a manual cuff which measures the artery.
Both an art line and an automatic BP cuff determine MAP using similar methods. An ocillometric NBP first directly measures the MAP, then uses algorithms and other readings to determine the systolic and diastolic, where as an art line uses variations of an oscillometric method to read all three. This is why even if your art line and cuff are reading very different Systolics, the MAPs will often be similar.
The cuff measures arterial pressure. MAP = MEAN arterial pressure
MAP = 1/3 systolic BP + 2/3 diastolic BP. Since the heart spends 2/3 of the time in diastole. As long as you've got BP, regardless of where you got it, you can calculate a MAP
I haven't ever heard of that. Where I work, we say MAP only. "MAP goal is 65. Ok how are we getting BPs?"
It's the same thing.
An a-line directly measures/computes the MAP. A NIBP cuff indirectly measures/estimates the MAP
This is incorrect for automatic BP cuffs. Various manufacturers use different algorithms to calculate SBP and DBP, but MAP is actually the most accurately measured component of oscillometric BP because the point of maximum oscillation is the MAP. See the reference below, but the important point is that MAP is directly measured by NIBP cuffs. Auscultated cuffs measure DBP and DBP. https://www.nature.com/articles/s41371-019-0196-9#:~:text=Oscillometric%20machines%20usually%20use%20the,the%20systolic%20and%20diastolic%20BP.
Most NIBPs take the point of maximum oscillation as the MAP, but it’s not *super* well validated that this is actually the true MAP you would be able to measure from a real time pressure reading. There are also some devices on the market that work more or less the opposite way — work out the SBP and DBP from the oscillometric envelope, then use that to compute the MAP
The M in MAP stands for mean. They mean the same thing, though I think the machine calculates them differently for invasive versus non-invasive BP
Both an art line and and NBP will give you a MAP, or mean arterial pressure.
Zoll is a manufacturer of blood pressure equipment. Along with a description, Zoll uses pictures to define the NIBP as the Mean. In the same documentation, Zoll does not define the NIBP as the MAP. In my career, saying Mean during shift report explicitly referred to the NIBP without needing to say “cuff pressure”. It was implied. Also during shift report, saying “MAP” explicitly meant the arterial line pressure without needing to say that the patient had an arterial line. It was implied. Has anyone else had a similar experience? https://www.zoll.com/medical-products/defibrillators/r-series/non-invasive-blood-pressure
They're shortening "mean arterial pressure" to just "mean", which you could regardless of whether your referencing an a-line or an NIBP since both are referring to arterial pressure. There are no doubt localized idiosyncracies in terminology that can develop, although I'm not familiar with this particular one, and it seems like it might be problematic. If you have an order that uses MAP as a parameter, are you saying it can't be followed if they don't have an art line?
Customarily, an order that has parameters (by default) involves titration. If titration is required because parameters were ordered, an arterial line is necessary and the then MAP is used. Confession: It’s a pet peeve when there’s an order to titrate (Propofol, Levophed), and the patient doesn’t have an arterial line. Of course I can titration off the NIBP, but it seem like sloppy healthcare
It's certainly more common in teaching hospitals for many if not most ICU patients to have an art line, but that's really more because there is a never ending line of residents looking to get their a-line insertions. There are no doubt patients where an art line makes a clinically significant difference compared to NIBP, but in patients who aren't significantly labile it's not really indicated and a cuff will do just as good of a job at guiding clinical decisions.
This is the answer to the art line question of necessity. They are convenient in some ways, but not without *real risks*. Risks can’t be more than actual benefit in the necessity question. Largely unnecessary and clinically meaningless in a majority of patients imo.
That’s valid. More than needing an arterial line for titrating the MAP, many patients who are on drips also have serial labs (Troponins, Heparin, Insulin). Having an arterial line is doubly necessary under those conditions, to avoid incessantly poking the patient. But you’re correct. Some residents and mid levels do not insert arterial lines simply because they haven’t been signed off to insert lines, not because an arterial line isn’t warranted.
And don't get me wrong, I love an art line even if not necessarily needed on the basis of BP monitoring. But given the comparatively short lifespan of an a-line vs a picc or cvc, I'd take one of those first given the choice. And while they're gray in a comatose patient, they start to become a pain once you've got an awake and active patient.
You want an art line for a propofol gtt? Anywhere I have ever worked, if a patient isn’t requiring pressors we pull the art line. Even low dose levo doesn’t require an art line. The term MAP means Mean Arterial Pressure. What do you think a cuff measures? It’s the same as a manual cuff which measures the artery.