Dr. Brandon Varr, an advanced heart failure and transplant cardiologist, provides insight into how heart failure is managed by diuretics and whether or not fluid restriction is important.
Heart Failure (HF) Refresher
Heart Failure (HF) simple means that the heart is not pumping enough blood to adequately supply organs.
- Body’s “Short Term Fix”: Kidneys sense that there is not enough blood → salt retention to expand fluid volume in body
- Long Term effect of above “Short Term Fix”: Fluid retention → congestion, breathing discomfort, edema
Diuretics not only provide diuresis but they can increase the efficiency of the heart muscle.
TYPES OF DIURETICS (MAIN 4):
- “Workhorse” or most commonly known diuretic known time and time again for their effectiveness and safety
- Flexible in routes of medication administration: PO and IV
- Furosemide (Lasix) is the most commonly used loop diuretic in the hospital. Bumetanide (Bumex) is also used.
- Adjunct (aka booster) therapy to loop diuretics in HF (ie augments the effects of loop diuretics when a loop diuretic is not producing the desired effects)
- There is a misconception of needing to “prime the pump” and give thiazide 30 minutes prior to loop diuretics. Studies show that it is optimal to administer them simultaneously as peak their effects overlap.
- Potassium Sparing (Aldosterone Antagonists)
- Another adjunct diuretic. Notably, as its name implies, does not lower serum potassium levels.
- Act much later on in the kidneys, exchanging their Na for K, whereas Loop Diuretics dump everything into urine
- Per Dr. Varr, this class of medication is often under-dosed or not given when could be beneficial to stabilize serum potassium levels.
- An example Dr. Varr gave about an inpatient use of aldosterone antagonists, “I got this patient: They’re on 25mg of spironolactone and 40mg of Lasix a day, but their potassium is running in the mid threes. [If you ask me] ‘Should I give them potassium?’, I’ll say ‘No, just double their spironolactone and their potassium will come up into the normal range.'”
- Most common: Spironolactone (Aldactone)
- Not flexible in medication route: Oral Only
- Vasopressin inhibitors
- Reserved for patients who are experiencing significant hyponatremia
- SGLT2 Inhibitors
- (-FLOZIN) Ex: Empagliflozin
- Per Dr. Varr: Upcoming blockbuster agent because it not only provides diuresis but also increases cardiac efficiency
- Angiotensin Receptor Neprilysin Inhibitor (ARNI)
- Ex: Entresto
- Vasopressin inhibitors
How much do diuretics influence BP?
- Concerned more with combo diuretic therapy with thiazide
- Loop and aldosterone antagonists with modest effects
When are we justified in holding on diuretics?
- Hypotension due to hypovolemia
- Hypotension with symptoms
- Severe electrolyte derangements
Think critically as to WHY your patient is here in the hospital. For example, a decompensated HF patient is in the hospital to lose weight, salt, and take aggressive diuretics to help them feel better.
If a patient is hypotensive, look at their meds and think about which medication to hold (usually NOT the diuretic). Consider adjusting BP meds before holding a diuretic.
Nurses should hold other BP meds before holding diuretics if patient is hospitalized for fluid overload
“If you have to replace a patient’s potassium, you’re doing it wrong.”Dr. Brandon Varr
- Think about patient’s quality of life and patient happiness when it comes to fluid restriction.
- Drinking tap water (1800 – 2200 ccs) will not be hugely impactful on HF management, but can be for their quality of life.
- Keeping people on fluid restrictions as they are nearing their dry weight can lead to adverse effects → low BP, dehydration, worsening kidney function
“In general, I stay away from aggressive fluid restrictions of patients in the hospital. When they’re coming into the hospital, they’re generally going to lose a lot of salt and weight. And whether they drink, let’s say 1800 cc’s of water that day, is not going to be hugely impactful for their heart failure management, but it might be hugely impactful for their quality of life.Dr. Brandon Varr
When to implement Fluid Restrictions:
- Severe kidney failure
- Advanced HF
I&Os v. Os & Weight
I think that strict intakes are just complete waste of time, from a general telemetry floor level patient who’s getting Lasix BID and responding. On average, we know that people drink around 2L a day. So, what I’m more concerned with is How much urine came out that day: did we get three liters? four liters? We’re definitely losing weight. Did we get around two liters? We’re probably stable. Okay, what was their weight yesterday and what was their weight today on the same scale standing up in the morning, right? And those are the most useful things to me is their overall urine output for the day and how much weight they’ve gained or lost.Dr. Brandon Varr
- More useful: Overall output for day and daily weights
- Use a partnering approach. For example,“Hey can you teach me about this new class of drugs? Is this a good match for our patient?”
- Discuss literature regarding the need for fluid restrictions, such as Johansson et al’s 2016 article which states, “In both studies, a stringent fluid restriction compared to a liberal fluid intake was not more beneficial with regard to clinical stability or body weight.”
- Guest: Dr. Brandon Varr, MD
- Editor (written materials): Salena Phong, RN, BSN
- Editor (audio): Chris Hayes