Hello Carla, 

Thank you for the questions. 

1. Determine if the patient had CKD prior to their acute hear failure episode (did the CKD come first, or was it the heart failure or a combination). If the patient has acute worsening of heart failure symptoms (like edema, congestion-- then the patient will likely have venocongestion and/or hypo renal perfusion). So, after figuring out if they had chronic CKD, and their previous stage and albuminuria status, then figure out if the new changes in Cr are related to acute episode or not. 24 hr urea creatinine clearance is good to figure out a pt's gfr.  

use the calculator: http://ckdepi.org/equations/creatinine-and-urea-clearance-calculator/

2.Once you have determined the new gfr, you will need to dose all the medications to this new gfr becasue overdosing can cause toxicity and underdosing can cause insufficiency of treatment. 

3.Rule of thumb for diuresis: if patient is volume overloaded (chest xray shows significant volume, pleural effusion; +JVD, + dilated IVC and heart strain noted on TTE or TEE; ascities; lymphedema with  open blisters, etc), then give them a dose of diuretics (or trial of 1-3 days) (ref: Koyner, Jay L., et al. "Furosemide Stress Test and Biomarkers for the Prediction of Aki Severity." Journal of the American Society of Nephrology 26 8 (2015): 2023.). IV works faster than oral. You can always try a loop or thiazide diuretic first. (good reference: https://www.kidney-international.org/article/S0085-2538(19)30276-5/fulltext). The goal is to balance diuresis so that the stain on the heart diminishes and the kidney's do not get overdosed with diuretics. This goal is to help decrease the risk of becoming ventilator dependent or having significant irreversible heart failure. Unfortunately, sometimes the kidney's will get severely injured when you are managing the heart failure and giving diuretics, inwhich case you then have to turn to renal replacement therapy (dialysis) that may be acute or long term (>3 months). 

4. It is always a good idea to get a nephrologist involved in the care of a patient with heart failure/heart disease and CKD or AKI on CKD, if the patient can have access to the specialist. It is understandable if some patients may not have access to nephrologist, in which case their heart specialist or primary care doctor will be quite helpful in managing the right balance of fluid (with longterm diuretics). It is an art to balance the dose of diuretics. Normally, I advise my patients to continue their diuretics (for example lasix 20mg BID) and if they weigh themselves at home and find increased 2lbs with or without shortness of breath/leg edema, then they take an additional lasix 80mg daily until the weight and or symptoms improve (you can also add hydrochlorothiazide 25mg if you do not want to increase the lasix). Spironolactone and ACEI/ARBs are very good medications to control heart failure and CKD. However, please make sure that they do not cause side effects of hyperkalemia, dizziness/low BP, or worsening CKD. If any of these side effects happen, it could be that the dosages of ACEI/ARB/spironolactone are high and need to be stopped temporarily or decreased to the lowest dosage. 

5. Many patients who are really sick can have chronic lymphedema. So, please do check if this is the case becasue giving diuretics or extra diuretics in these patients will worsen kidney function. Lymphedema can be checked using US of LE, a negative TTE or TEE (meaning no heart failure on tests), and hx of LE blisters/poor wound healing.   

Hope this helps!