In MI, keep K between 3.5 to 4.5 mEq/L

Health Care Comments Off

While serum K levels of 3.5 to 5.0 mEq/L are considered normal, in acute MI the guidelines recommend potassium administration to maintain a range of 4.0 to 5.0 mEq/L so as to lower the risk of ventricular fibrillation (VF) or cardiac arrest.

The current analysis, which is published in the January 11, 2012 Journal of the American Medical Association, is based on >38 000 MI admissions at 67 hospitals in the US from 2000 to 2008, a time when most ST-elevation MI patients received beta blockers and reperfusion therapy.

Serum K levels of 4.5 to 5.0 mEq/L were associated with about twice the in-hospital mortality risk as levels of 3.5 to 4.5 mEq/L after adjustment for many comorbidities and other potential confounders. It’s reasonable for the guidelines to be amended to say that in most patients with acute myocardial infarction, maintaining a potassium [level] of 3.5 to 4.5 mEq/L may be reasonable, unless they’re having a lot of [threatening] ventricular rhythms.

Mortality was lowest for levels of 3.5 to <4.0 mEq/L and went up significantly at both higher and lower concentrations.