IABP waveform clarification

Ruby Vee, BSN · Aug 11, 2017

When the patient is hypertensive, your augmented pressures will be the same as (or lower than) your unassisted systolic pressure. If his pressures were already 150-170, you're not going to get much augmentation. Were you getting good unloading? If your diastolic unassisted and assisted were equal, I'd say not. Did you try manually timing your balloon pump? I've found that sometimes helps, but it doesn't seem to be a skill that everyone learns these days. (I learned in 1983, before there was such a thing as automatic timing!)

Catticus11 · Aug 11, 2017

So an equal assisted and unassisted diastolic is an indicator of poor offloading, in the setting of hypertension?

Also, no I haven't tried manually timing. It was briefly reviewed to me by an older nurse (who also probably learned it in 1983 lol) but the waveforms appeared to be augmenting appropriately. I'm just still pretty new with balloon pumps maybe.

PresG33 · Aug 12, 2017

The purpose of a balloon in this case is coronary perfusion, the "offloading" or increased cardiac output is very minimal with balloons, especially in a HTN patient (maybe a 0.5 l/min increase). His DBP is plenty high to perfuse the coronaries, so why did he have the balloon? If it was weaned off would he get chest pain? Sometimes our surgeons would put an IABP in a pre-op based purely on the cath report, which doesn't make sense unless they are hypotensive or have symptoms. It could be that your numbers didn't make sense because he didn't need the balloon. Whenever I couldn't get augmentation higher than the normal BP this was always a potential reason why.

Catticus11 · Aug 12, 2017

Thank you so much for your response!

So a low diastolic pressure would merit the balloon pump sheerly for coronary perfusion? Is there a particular DBP value that they decide for that? Does the type and grade of lesion have anything to do for an IABP indication? I thought it was because he was a 95% left main. Otherwise, I don't believe he was experiencing chest pain when he went into the cath lab (I could be wrong), and he was having issues with hypertension since arrivng from the cath lab for which I was told in report they initiated Nitro for. He also did start experiencing chest pain the day and night after I had him, requiring titration of nitro and IVP morphine with complete relief.

PresG33 · Aug 12, 2017

The DBP needed for adequate coronary perfusion depends on the patients baseline BP, coronary anatomy, O2 demand, and lesions so there is t a set number. Generally a coronary perfusion pressure (MAP minus LVEDP or PAOP or CVP) of > 50 mmHg is targeted. As far as putting a balloon in based solely on lesion size or location, it may make the cardiologists feel better, but they aren't actually treating any specific symptoms and are putting patient at risk of bleeding from the balloon or PE/stroke from DVTs from laying perfectly still in a bed. An IABP is not a benign procedure and shouldn't be initiated on a pt without symptoms. That being said, if the pt had chest pain that was relieved by the balloon, that is a good reason to keep it in no matter what the augmentation is.

allnurses Guide · Aug 13, 2017

It also depends what his LVEF was. Often with a high grade lesion plus a bad EF, preop CABGs will get an IABP. If your actual balloon waveform was abnormal, you check your balloon placement first - was it in the right place on XR? Check the inflation signal waveform to see if it's inflating and deflating appropriately. Put it on pause or 1:2 and see if it changes the blood pressure. Try manually timing if required (or get your engineers or perfusion to, if they run the IABPs in your hospital).

Definitely as a first step, if you are taking care of IABP patients, and before you try manually adjusting - you should know exactly what each waveform point is and what it means (dicrotic notch, augmented diastole, unassisted and assisted systole, patient end diastolic pressure and balloon-assisted end diastolic pressure) and what you are trying to achieve with your timing adjustments.

Manufacturers have plenty of cheat sheets and info available on their websites.

Catticus11 · Aug 13, 2017

It also depends what his LVEF was. Often with a high grade lesion plus a bad EF, preop CABGs will get an IABP. If your actual balloon waveform was abnormal, you check your balloon placement first - was it in the right place on XR? Check the inflation signal waveform to see if it's inflating and deflating appropriately. Put it on pause or 1:2 and see if it changes the blood pressure. Try manually timing if required (or get your engineers or perfusion to, if they run the IABPs in your hospital).
Definitely as a first step, if you are taking care of IABP patients, and before you try manually adjusting - you should know exactly what each waveform point is and what it means (dicrotic notch, augmented diastole, unassisted and assisted systole, patient end diastolic pressure and balloon-assisted end diastolic pressure) and what you are trying to achieve with your timing adjustments.
Manufacturers have plenty of cheat sheets and info available on their websites.

I'm sorry, I forgot to include that his EF per the cath was 50%. Per the CXR the IABP looked like it was in the right place. But waveform could also be affected by inappropriate position?

When I put it in a 1:2 it did change, his unassissted pressures were higher 170s, compared to assissted which was 150s-160s. But I assumed that was a normal response.

Pghfoxfan1 · Aug 16, 2017

Any "seasoned" nurses remember doing Endocardio viability ratios "EVR's" back in the "olden days" to wean IABPs? Oh, the good old days...