Are they really accurate? I had a pt. on a lower dose of minoxidil for hypertension. Lower dose is d/t renal failure...blood pressures monitored closely and meds held if systolic BP under 130. CNA couldnt get reading from blood pressure machine but did a manual and got 132 something...we were told to use pediatric BP (very tiny elderly lady)...i went in to double check, i tried auto as well, with pediatric BP which did NOT!!!! at all fit, way too small. She was tiny, but not that tiny. I took manual BP and got 133, about the same. i gave the meds. I was just curious as to why auto wasnt working...i tried a regular sized cuff right after, and it worked. the regular size cuff read "122" as systolic.
How accurate are those?? i mean it was a little big for her, but she is in the range of a regular size...but like i said, even though doc says to use pediatric BP cuff, it just does not fit!!!
Also, im a first year nurse...i nearly crapped my pants when i saw that BP was 122, because thas less than 130!...i KNOW i got 133, but i questioned my self because of what auto says.
she has been hypotensive the past several days.....so as a new nurse i am second guessing myself, and just worried!!!!!!!
Comments??? Anyone know really the accuracy of these things?? was i wrong to go against doctors orders and use regular size if it does not fit?? was i wrong to still give the med?? (even though Manual, was 130 but order was to check BP with auto bp pediatric cuff)???
LIke i said, i am a new nurse....i get nervous asking more experienced nurses questions like that.
if i get a very high reading on the electronic BP, i always recheck it manually.
you'd be surprised of the difference in readings sometimes.
alot of times the machine will pick up background noise, esp if like the TV controller is near it or the patient's visitors are talking... and it makes the reading alot higher than it would be.
same thing for low readings, just a little difference in cuff positioning or cuff size can make a big difference!
always get out your ears when in doubt.
^Yes, our autos won't even do a BP if it reads they are in A-Fib. i didnt know that, and i get an admit the other day....was not told that this person was a-fib and it was giving me numbers but it started flashing and beeping. oooh to be a new nurse :)
but to be honest, i dont think my hearing is flawed, i can hear the beats fine. I am only 21 so i don't think im loosing my hearing....its still pretty good! yesm, i'm a youg nurse...told ya so :)
although we do have a nurse in the ER that is only 20 yrs old, with 2 years exeprience before going to the ER! crazy....
but thanks for all the input.
i realize i should be asking other nurses who have been around a while but i get nervous asking them...i dont want them to think i cant handle it, or think i'm asking stupid questions because that IS something i should know. There is a couple nurses i feel i can trust, and i do have a preceptor. She is super super good but kinda intimitating. She is the kind where she is always on the move and has to have a routine, and if anyone interrupts her routine.......there will be hell to pay! haha.
So she will come help me with something or talk to me, but she will let you know how you through her routine off for the day.
i realize i should be asking other nurses who have been around a while but i get nervous asking them...i dont want them to think i cant handle it, or think i'm asking stupid questions because that IS something i should know.
Ask questions. The nurses who don't ask questions and don't double check and run things by each other are the ones that get talked about and watched like a hawk.
Automatic BP machines detect blood pressure by measuring oscillometric waveforms (and not by detecting Korotkoff sound)
After the cuff inflates, sensors (electronic tranducer) measure pressure oscillatory pattern as well as the cuff pressure in a stepwise deflation pattern. Based on these measurements, the computer determines what the mean arterial pressure is by determining the maximum amplitude. It then uses a propriety algorithm to determine systolic, and then diastolic pressure based on the mean arterial pressure. Each company have it's own algorithm to determine systolic and diastolic pressure from the mean arterial pressure. Because the algorithm is proprietary, you can get different systolic and diastolic pressure reading if you were to theoretically take the BP at the same time using different machines made by different companies (even if the MAP readings are exactly the same). So the most accurate portion of automatic BP is the MAP since that is a measured value (via indirect method via oscillotometery reading), followed by SBP, then DBP.
Factors that can influence BP reading (in addition to having different proprietary software/algorithm) include regularity of the pulse (since measurement of MAP and the algorithm to determine SBP and DBP are based on standard models without variation), cuff size, movement of limbs, compliance of the arterial wall (again, this is due to mathematical assumptions based on standard model, and calcified arteries do not behave according to standard model)
I have been a nurse for wayyyyyyy too many years and I still ask questions! When you stop asking questions and think you don't need help from time to time, you become a danger and a liability.
I think its interesting that whenever someone's vital signs are high/low with an automatic we do a manual. However when they are fine with an automatic we just accept them as is. That's always bugged me. Not that I run and check everything manually. I remember when the nursing home I worked at they got rid of the machines and everything went manual the aides about revolted.
Ask questions!! I agree w/ previous post- I always worry about the nurse that never asks questions. It doesn't matter how wicked awesome someone may be- they are still human.
Anyhow- it's still a judgement call. There's no always or never. Machines are more accurate per studies, but only if xyz is met.
Auto BP's are a necessity- there's just not enough time of you have to take frequent VS. Maybe not perfect, but sometimes it's the overall trend that tells the story.
Some pts can influence their BP, to a point, and auto BPs can get around that. After a bit, they just don't focus on it as much.
Manual BP's have human error. However, a nurse can go slower and pump up again is there's an iffy.
Machines are confused by dysrythmias. Afib is a classic one- but others can do it as well. Machines also don't know if the cuff is loose, in the wrong place, etc. Machines/cuffs have a hard time w/ an overweight pt that has 'cone arms'- a larger circumfrence near the shoulder and almost skinny at the elbow. Machines can also be influenced by the previous reading. I know you can clear the previous reading, but for some reason it doesn't always work. (I've just given up and taken my own BP to 'reset' it in these cases if no manual cuff is at hand. Anyone will have a higher reading after they've been through the pain of a cuff inflation past 200!)
Proper cuff size matters either way. There's a difference between changing the cuff size to get a more accurate reading and changing the cuff size in a hope you'll get the reading you want, lol. Same thing w/ right v/s left. Stay with the side you started with, unless you're looking for something where R v/s L makes a difference.
Having someone else check after you is good- even better if they don't know what the previous reading was or what the target number is.
Parameters can be difficult. I had a very sick pt, and we could not get the BP high enough to do what our ER doc wanted v/s consult on the phone. He kept wanting a manual, but it kept saying the same thing or worse! 'But the pulse is too strong'- well, that may be, but the machine and two other nurses still get a low BP. (If you hear a low BP, and it's just one number- it's SHTF time!)
You can tendelenburg, etc and change the reading, but in the end- what is the pt status? After all, the pt won't tolerate their feet in the air for long! Care for the pt/pt status, not the number.
Jay2daq
78 Posts
^Yes, our autos won't even do a BP if it reads they are in A-Fib. i didnt know that, and i get an admit the other day....was not told that this person was a-fib and it was giving me numbers but it started flashing and beeping. oooh to be a new nurse :)
but to be honest, i dont think my hearing is flawed, i can hear the beats fine. I am only 21 so i don't think im loosing my hearing....its still pretty good! yesm, i'm a youg nurse...told ya so :)
although we do have a nurse in the ER that is only 20 yrs old, with 2 years exeprience before going to the ER! crazy....
but thanks for all the input.
i realize i should be asking other nurses who have been around a while but i get nervous asking them...i dont want them to think i cant handle it, or think i'm asking stupid questions because that IS something i should know. There is a couple nurses i feel i can trust, and i do have a preceptor. She is super super good but kinda intimitating. She is the kind where she is always on the move and has to have a routine, and if anyone interrupts her routine.......there will be hell to pay! haha.
So she will come help me with something or talk to me, but she will let you know how you through her routine off for the day.