Hemodynamics

[Pechorin13]

can you brothers and sisters recommend a good book to better understand hemodynamics monitoring?

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[bashwell]

can you brothers and sisters recommend a good book to better understand hemodynamics monitoring?

What about the section on hemodynamic monitoring in The ICU Book? Or were you looking for something more advanced or in-depth?

 

[Pechorin13]

What about the section on hemodynamic monitoring in The ICU Book? Or were you looking for something more advanced or in-depth?

More in depth. I really want to understand CVP and pulmonary pressures, etc.

 

[DrDrummer]

More in depth. I really want to understand CVP and pulmonary pressures, etc.

http://www.derangedphysiology.com/main/core-topics-intensive-care/haemodynamic-monitoring

I find this guy's website to be great -- he also cites the chapters and references he has used to generate a lot of these things. And via this website, I found my way to this online textbook of anesthesia and CC, which has some really in-depth discussions of the physics and physiology involved in hemodynamic monitoring:

http://web.squ.edu.om/med-Lib/MED_CD/E_CDs/anesthesia/site/content/v03/030251r00.htm

 

[Pechorin13]

Wow! That's good.

 

[WheezyBaby]

Amazon product

Is reasonably digestible. Has a bent toward the cath lab though

 

[Pechorin13]

I see a new edition is coming out. I'll wait for that. I was told to look at Morton Kern's book too.

 

[deleted171991]

More in depth. I really want to understand CVP and pulmonary pressures, etc.

There is one thing you need to understand about CVP: it's history, and so should be anybody still using it.

 

[kemper6036]

I see a new edition is coming out. I'll wait for that. I was told to look at Morton Kern's book too.

looks like its out already

 

[drmwvr]

There is one thing you need to understand about CVP: it's history, and so should be anybody still using it.

At the risk of your calling me names (and suggesting I retire) I use CVP (RAP) nearly every day. As you're aware, the period of separation from CPB is constitutes a very fluid situation, balancing vasomotor tone, contractility and volume replacement. We typically come off bypass fairly "empty" and add salvaged blood, pump blood and products carefully. It adds up pretty quickly.

Nothing you are not aware of, but I'm not going to look at the TEE every time I want to give volume quickly. I don't use RAP to tell me when to give volume. I use it to tell me when to stop giving it after I've started. A quick glance at the relationship between the MAP and RAP tells me to stop or slow down. Further, if I can get a hands free, continuous view of LV filling, great, but that's not always practical. Then there's the issue of probe overheating....

Stunned myocardium tolerates stretching only bits at a time and RAP tells me that. There is also that period that begins when the TEE probe is removed (or because of esophageal pathology, contraindicated at the outset). I've diagnosed tamponade more than once based solely on the RAP/MAP in the ICU after settling.

I'm not retiring anytime soon, and I'll be transducing RAP for the foreseeable future.

 

[deleted171991]

I am glad it works for you in that specific situation (post-CPB). It is not that unexpected, given the vasoplegia, stunned myocardium, muscle relaxants and controlled ventilation, hence vessel tone, ventricular compliance, intrathoracic pressure or intra-abdominal pressure play a much smaller role when observing a trend. Most science suggests the opposite, in many settings, especially in the ICU. I would love to see the science behind your defending of the CVP.

The problem with many of our scientific tools is that they are based on certain assumptions. If those assumptions are not met (e.g. for pulse pressure variability as a measure of fluid responsiveness, or for using PCWP to diagnose LV failure, or simply for statistical analysis of medical scientific data), the conclusions will be frequently wrong. CVP is one tool that depends on so many variables that most of the time it's about as valuable as a coin toss for volume replacement purposes (to approximately quote Paul Marik). And that's not based on my own experience (possibly much more limited than yours), but on most studies that contain the word CVP nowadays.

Food for thought: https://surgery.med.uky.edu/sites/default/files/11132013_00.pdf. Even a broken clock is right twice a day.

 

[smartparts]

On a somewhat related note to the CVP debacle, did any of y'all catch those great Point/Counterpoint articles on IVC assessment in this month's Chest?

 

[deleted171991]

On a somewhat related note to the CVP debacle, did any of y'all catch those great Point/Counterpoint articles on IVC assessment in this month's Chest?

Thank you for mentioning them: Point, Counterpoint.

I tend to agree with the counterpoint. To me, IVC ultrasound is just a fancy CVP substitute, plagued by the same kind of problems as the CVP. There are way too many variables it depends on.

 

[engineeredout]

Thank you for mentioning them: Point, Counterpoint.

I tend to agree with the counterpoint. To me, IVC ultrasound is just a fancy CVP substitute, plagued by the same kind of problems as the CVP. There are way too many variables it depends on.

I feel like I've been asking everyone I can why they favor IVC us and laugh at CVP monitoring? Seem like the same thing.

And if we are going to look at respiratory variation of the IVC to attempt to figure out fluid status, why can't we not use CVP monitoring, not for the specific numerical values, but for the variation of the CVP wave with the respiratory cycle? Seems like that would work well because it would be continuously available unlike the US, can work well in patients in whom we can't get good IVC imaging (body habitus, post op abd sx etc...), and does not require prior training in ultrasound.

Nobody seems able to answer that question either.

 

[Nephro critical care]

Going off track maybe but I used to work as a nephrologist at a large community hospital in rural Kentucky where physicians used to order radiology to come and do an IVC exam to figure out respiratory variation to figure out volume status. The U/S tech would come and do an ultrasound exam of IVC and radiologist would report it as being e.g 1.7 cm in expiration and 1.5 cm inspiration. The nephrologist / cardiologist etc would then decide if additional fluids were needed and also pretend to look smart.

What an absolute scam / abuse of insurance money . If you have a question about IVC diameter borrow the ICU / ED U/S and do the determination yourself !

 

[jdh71]

Thank you for mentioning them: Point, Counterpoint.

I tend to agree with the counterpoint. To me, IVC ultrasound is just a fancy CVP substitute, plagued by the same kind of problems as the CVP. There are way too many variables it depends on.