Once Versus Twice Daily Electrolyte Monitoring in CHF

Background: Over 5 million Americans are currently suffering from heart failure, resulting in over 1 million hospital admissions each year. Heart failure hospitalizations are one of the most expensive medical problems facing Americans today]. Admissions for acute decompensate heart failure exacerbations are managed medically through oral and intravenous (IV) diuretics. Side effects of diuretics are well established, the most common of which is metabolic derangements, more specifically alterations in levels of potassium . Clinical manifestations of hypokalemia and hyperkalemia are most commonly muscle cramps and clinically insignificant arrhythmia. The most concerning manifestations of hypo and hyperkalemia include symptomatic arrhythmia, myalgia, and more rarely rhabdomyolysis. Active use of diuretics requires monitoring of serum electrolytes to prevent clinically significant derangements in potassium. The frequency of monitoring required to prevent these events has not been established. Monitoring is thus provider dependent. At our single large academic medical center monitoring frequency ranges from 1-2 times daily on average. In this trial we will determine whether twice-daily electrolyte labs result in less frequent clinically hypo or hyperkalemia. We will also investigate a multitude of other outcomes including potential cost savings by reduced laboratory test ordering.

Intervention: Randomization of study population to ONCE daily scheduled BMP or TWICE daily scheduled BMP.

Risk: Risks to both arms of the study are in clinical equipoise and include: Hypokalemia, hyperkalemia, arrhythmia (secondary to hypokalemia or hyperkalemia), delayed identification of rising creatinine (acute kidney injury).

Project goals: Twice daily basic metabolic panel's or labs are common practice at Vanderbilt University Medical Center. However, it is unclear how often the second BMP each day is acted on. Our project aims to answer a few fundamental questions about the need for twice daily labs in patients hospitalized with acute/subacute-decompensated congestive heart failure who are being actively diuresed.

Descriptive:

Age Race Sex JVP on admission JVP on discharge Congestion on CXR Left ventricular ejection fraction Diabetes (Type I, or Type II [defined as HgA1C >6.5%]) Type of cardiomyopathy- ICM vs NON Ace-I or ARB Beta blocker Aldosterone antagonist HF hospitalization within past 12 months Na K (all recorded during stay) Cl BUN Cr (all recorded during stay and most recent prior to hospitalization) Total dose of loop diuretics received during admission Total dose of thiazide diuretics received Total dose of mineralocorticoid antagonist received

Outcomes:

Primary: Proportion of labs spent in ideal potassium range (defined at 3.5-5.0 mmol).

Secondary: Clinically relevant hypokalemia or hyperkalemia; defined as new muscle weakness, rhabdomyolysis, paralysis, ECG changes or conduction. Amount of potassium given, number of times per day potassium was given and average potassium value during stay. Time free from readmission, length of stay, change in weight (as surrogate for amount of diuresis), Input and output, mortality at 1mo and 3mo, cost savings during admission.