Fluid monitoring after a CABG

[Jedi of Zen]

Hey guys, sorry for hogging up the board here, but I have a cardiac test coming up. My instructor went through the material really fast, which leaves me with a lot of unanswered questions...

Regarding fluid status after a CABG: In the lecture note outline that my instructor made up, it says that while in the cardiac surgical unit, the patient's fluids should be restricted to 1500-2000 ml because the pt usually has edema.

Later in the outline, it says that after transfer from the cardiac surgical unit, the patient should be provided adequate fluids and hydration as prescribed to liquefy secretions.

I'm confused about the time span involved here. ie, how long is a patient in the cardiac surgical unit? "1500-2000 ml" suggests a daily measurement, so that makes it sound to me like a matter of several days. Does that mean several days spent in post op recovery? I thought that was only an hour or thereabouts.

I guess another way to phrase my question is: How long does the 1500-2000 ml fluid restriction last after a CABG? Does it just kind of stop whenever the physician decides the edema is gone?

Thanks very much for your time. Would not mind hearing from any experienced nurses out there.

[Daytonite, BSN, RN]

Why don't you try asking on the CCU Nursing Forum (https://allnurses.com/forums/f15/).

[Jedi of Zen]

Why don't you try asking on the CCU Nursing Forum (https://allnurses.com/forums/f15/).

Aww...come on, Dayt! I'd rather hear directly from you :)

[Daytonite, BSN, RN]

I did not work in a hospital where open heart surgery was done so I cannot tell you all the rationale behind fluid restriction done on post-CABG patients. I can only make an educated guess. I can tell you that fluid restriction is done when there is concern about sodium levels. Water and sodium are intimately related and where one goes the other follows. When it is important to keep fluid controlled and blood pressures down, then there is a need to monitor sodium and water intake. The pathophysiology of tissue edema is also intimately related to cardiac output so fluid volumes are watched very carefully since they are one of the components that contributes to cardiac output.

The people going for this surgery have blocked veins and sometimes some degree of atherosclerosis. If their atherosclerotic arteries are not oxygenating the cells of their heart adequately, it can affect the rhythm, or contractility and heart rate, which is the other component of cardiac output.

Here is information about the surgery:

• http://www.surgeryencyclopedia.com/Ce-Fi/Coronary-Artery-Bypass-Graft-Surgery.html
  
• http://www.surgeryencyclopedia.com/Ce-Fi/Coronary-Artery-Bypass-Graft-Surgery.html

Why don't you just ask your instructor to help clarify what you wrote in your notes?

[ghillbert, MSN, NP]

I find the instructor's info confusing. Generally in the CTICU (24-28hrs post op usually, most bypass patients don't go to "recovery unit" but straight to ICU) - you do not restrict fluid.

In fact the opposite is true. Post bypass patients generally are very peripherally dilated and have leaky vasculature due to the reaction to the bypass machine (artificial circuit causing release of inflammatory substances). Because of this, they tend to require tons of fluid postoperatively. They do get edematous due to the leaky vessels, but you still have to give enough fluid to keep adequate perfusion.

Once they hit the stepdown floor (after about 2 days usually with no complications) and are hemodynamically stable, they tend to go back to a fluid restriction to help reduce the peripheral edema.

There is a difference between patients who had CABG for isolated coronary disease and those who have some degree of heart failure/ventricular dysfunction in terms of how much fluid you want them to have.

[Jedi of Zen]

I find the instructor's info confusing. Generally in the CTICU (24-28hrs post op usually, most bypass patients don't go to "recovery unit" but straight to ICU) - you do not restrict fluid.

In fact the opposite is true. Post bypass patients generally are very peripherally dilated and have leaky vasculature due to the reaction to the bypass machine (artificial circuit causing release of inflammatory substances). Because of this, they tend to require tons of fluid postoperatively. They do get edematous due to the leaky vessels, but you still have to give enough fluid to keep adequate perfusion.

Once they hit the stepdown floor (after about 2 days usually with no complications) and are hemodynamically stable, they tend to go back to a fluid restriction to help reduce the peripheral edema.

There is a difference between patients who had CABG for isolated coronary disease and those who have some degree of heart failure/ventricular dysfunction in terms of how much fluid you want them to have.

Thanks for your help; I do appreciate it.

Unfortunately this isn't the first time that I've found confusing information in my instructors' lecture guides. For example, right now I'm reviewing HIV material, and one of our instructors has said in her outline that Nucleoside Reverse Transcriptase Inhibitors kill the HIV virus. Yet I have found no literature to support this, and in fact a lot of the literature that I've found seems to say the opposite. (ie, doesn't kill HIV, only inhibits replication).

Thanks again.

[ghillbert, MSN, NP]

HIV isn't my area of expertise, but it's always been my understanding that NRTIs, just as the name suggests, inhibit reverse transcription and production of viral DNA to stop replication. If they killed the virus, you wouldn't have to keep taking them for life... I don't know of any drug that kills the virus.

Most instructors don't mind if you clarify information with them, or ask for sources of further info. If you find something in lecture notes that conflicts with your textbook or other sources, it's not unreasonable to ask for clarification.