As an internal medicine doctor who writes hundreds of these a week: SIX SEVENNN year old man with a past medical history of heart failure with preserved ejection fraction, coronary artery disease status post (after) percutaneous coronary intervention (stents) x3, atrial fibrillation on anticoagulation, type 2 diabetes complicated by chronic kidney disease stage 3b (estimated glomerular filtration rate 30-44), hypertension, hyperlipidemia, obstructive sleep apnea using a continuous positive airway pressure device, chronic obstructive pulmonary disease using a baseline 2 liters of oxygen by nasal cannula, presents with shortness of breath, dyspnea on exertion, and paroxysmal nocturnal dyspnea for the past 3 days. Tests show elevated brain natriuretic peptide (released by the atria of the heart when they stretch in the setting of volume overload), nonelevating troponins (less likely to be a heart attack with the markers of cardiac injury), chest x-ray consistent with edema (pulmonary congestion). Assessment is acute hypoxic respiratory failure secondary to acute decompensated heart failure versus acute exacerbation of chronic obstructive pulmonary disease. Status post intravenous lasix (furosemide, a loop diuretic) with good urine output. Plan is to continue to monitor intake & output. Basic metabolic panel (chem-7) twice a day. Replete potassium and magnesium as needed (pro re nata).