Inpatient / Cardiology

Diuresis 201: Top Tips to Master Diuresis in the Hospital

Volume overload from acute decompensated heart failure is the most common reason for inpatient admission in the United States. Follow these tips to master the art of diuresing in the hospital!

May 8, 2023

Communicate Early and Often with the ED

You need to communicate clearly with the emergency department staff. Get strict I’s and O’s from the start and determine whetheror not the patient was responding adequately to the first doses the patient receivesin the ED. You might not have the best record of urine output and might need toask the patient directly.

Be Aggressive and Follow Up Within 1 Hour of Dosing

You should be dosing at least two times the patients homedose of loop diuretics. You might need a higher dose if the patient has CKD.You should keep the patient on spironolactone if that's their home medicine,and they've been taking it regularly. This can help prevent hypokalemia whenyou're directing aggressively. You should assess the response within one hour.If it's an adequate dose, the patient will pee immediately and they will feelit. If they're not peeing, make sure you aren't missing a low urine output from a shock state or obstruction. If they're not responding, double the diuretic doseimmediately.

Dose in the Early AM and Again in the Early Afternoon

Bolus in the early AM before rounds and do not leave diuresis decisions to the night team if you can avoid it. If the patient is responding well to your dosing, check the total output 3 to 4 hours after they receive thedose. Ideally this will be in the early afternoon before 3:00 PM and you should redose, if not at least halfway to your goal output. Note that people say Lasix is called that because it lasts 6 hours, but you shouldn't actually wait six hours.

Identify Resistance and Respond Accordingly

If you’ve reached 80-160mg of IV Lasix BID and the patientis not responding, you should be thinking about resistance. You can switch to a Lasix drip, a different loop diuretic like torsemide or bumetanide, or augmentwith a thiazide diuretic such as metolazone or chlorthalidone, which works onthe distal tubule. For drips start at 10 mgs per hour after bolusing to keep above the threshold. 40mg of PO Lasix is equivalent to 10 to 20mg PO of Torsemide and 1mg of PO Bumex. The classic teaching is that Bumex has better oral availability. Classic teaching also says to give Thiazides 30 minutesbefore loops. This is because thiazides are PO and loops in the inpatientsetting are usually still given IV. PO medicines take longer to work. That's why you need to give it 30 minutes before. If both of the medicines are PO, you can give them at the same time. Just make sure you're being explicit with the nursing staff about the ideal timing, since a thiazide may take longer to come up from the pharmacy, you don't want to delay any dialysis decisions just for amedicine to come up.

If the Patient is Alkalotic, Consider Acetazolamide

Other considerations is that if the patient is alkalotic, you can add acetazolamide, especially if the K is over four. Since these medicines can lead to potassium wasting. Recent data from the ADVOR Trial suggests that augmentation with acetazolamide leads to euvolemia quicker, though this is a recent trial and it's not clear how this is going to impact day-to-day practice.

Closely Monitor Potassium, Magnesium, and Creatinine

You should be monitoring the BMP and Mag daily and sometimes twice daily to be looking at the potassium, magnesium, bicarb and creatinine. Hypokalemia is often the limiting factor for aggressive diuresis, so you should be repleting aggressively. You should also be watching out for symptoms of gout, as loop diuretics can lead to hyperuricemia. Many patients with overload willhave an AKI from prerenal physiology or congestion. When diuresing, it takes time to mobilize third space fluid. Effective circulating volume may go down, leading to a lower GFR and increased creatinine. This most commonly reflects hemodynamics and is not actual renal damage. The goal is to go for euvolemic aso trust your physical exam. At the same time, stay humble. If there's asignificant AKI and the exam is challenging, you should be cautious.

Diurese Based on Your Physical Exam

The JVP is a surrogate for right atrial pressures. The best way to do this is to have the patient sit at a 30 to 45 degree angle, lookingat the right side of their neck for the double bounce, you should be reporting the JVP as normal high or low. Normal is 6 to 8 centimeters of water. If you see it at a 90 degree angle, it's high. Note that the JVP can also be high in pulmonary hypertension, tamponade and RV failure. You can also do hepatojugular reflux. A positive finding is if the JVP stays elevated for 10 or more seconds after you compress the liver. Importantly, everybody's JVP should go up if youpush on their liver. It's just a matter of how long it stays elevated. For lower extremity edema, you should push and hold. The grade of the pitting is based onthe depth of the depression and the time to rebound. In general, it's 3 plus.If it takes 60 seconds or more for it to rebound and it's 4 plus if it takes 2 to 3 minutes. You can ask about symptoms including paroxysmal nocturnal dyspnea and shortness of breath, and this should be improving with diuresis.

Switch to PO when Euvolemic and Symptoms Have Improved

For switching to PO and discharging patients, you switch them to PO when their symptoms resolve and their JVP and edema is improved. There's a sweet spot of euvolemia, which is an increase in bicarb, suggesting a contraction alkalosis but no creatinine bump to suggest that the patient is too dry. However, this isn't terribly reliable. Also, dry weight is also unreliable and is not the overall goal. Ideally you would trial a PO dose of diuretic for 24 hours and shoot for net negative of 500 cc’s because we expect the patient to eat more salt and potentially drink more fluid at home. Your chosen PO dose should be based on the etiology of the decompensation. If the patient wasn't taking their home medicine reliably, you can just send them home with the same dose. If you're concerned about possible resistance as the etiology of decompensation, you should go up on the dose.


Make Sure the Patient Understands What to Look Out For At Home

Ask the patient to take their weight daily. Also, to ask them to pay attention to their lower extremity edema. If it's worse or thepatient gains 5 lbs over a three to four day period or 2-3 lbs over a 24 to 48 hour period, ask them to double their diuretic dose and call their PCP or cardiologist for further guidance.

If You Remember Nothing Else

In overloaded states (provided the patient’s heart functionis at baseline and they're not in shock), the mainstay of treatment is aggressive diuresis. You should bolus early in the morning and check response within one hour to see if the patient responded and then redose by the early afternoon if they're not at goal. Diurese based on symptoms and your volume exam not based on weight alone. Continue diuresing through mild elevations and creatinine, as it rarely indicates an intrinsic injury. If they're not responding to higher doses of loop diuretics, switch to a drip, switch to a different loop diuretic, or augment with thiazides. Replenish K and magnesium to not fall behind. Instruct patients to call their PCP or cardiologist if they notice worsening lower extremity edema or gained 3 to 5 lbs over a three to four day period.