Help with a question, please...

Nursing Students General Students

Published

Is the specific gravity of urine increased or decreased with congestive heart failure? (this is before treatment)

Well...

It doesn't really matter with congestive heart failure, because the SG of urine depends on renal function. Generally speaking, the SG would be higher if the patient is in CHF because he stopped diuretics. However, if the patient has normal renal function, is urinating, and is in CHF, the SG will be normal.

Remember, CHF is caused by poor cardiac function.

The SG will be lower once diuresis is started (urine becomes more dilute).

Good question. Matt, I am wondering about the ejection fraction and alterations in blood pressure related to hypertrophy of the hearts wall. If the kidneys and other hormone responses are working correctly and the blood pressure is low the SG will be increased due to retention of salt and water to maintain blood pressure thus making the problem worse! If laxis is taken to pull water off the lungs, then SG will be low due to diuresis. What do you think? Stef

Thanks Matt! I thought it would be increased, but just wasn't sure. I also found the correct answer on Family Practice Notebook website.

Originally posted by jobear

Matt, I am wondering about the ejection fraction and alterations in blood pressure related to hypertrophy of the hearts wall. If the kidneys and other hormone responses are working correctly and the blood pressure is low the SG will be increased due to retention of salt and water to maintain blood pressure thus making the problem worse! If laxis is taken to pull water off the lungs, then SG will be low due to diuresis. What do you think?

Yes, Steph, you are correct that once the renin-angiotensin-aldosterone system has kicked in, it will make matters worse and the SG will be higher. Remember, though, that the body has several compensatory mechanisms to deal with decreased blood flow. The first is increase of heart rate, the second is increasing the peripheral vasoconstriction. While these mechanisms are working, the SG will be normal.

Personally, I have never measured the SG of a patient in CHF. I don't see how it would be relevant -- what information would it give you that you need for treatment? If this is a question on a test, then it is for academic purposes only, not clinical.

Matt, it was just a test on fluids and electrolytes that questioned us on what the sg would most likely be in pts with various problems, chf being one of them.

+ Add a Comment