Archive for the ‘glucose’ Category

  I recently assisted in the management of a patient who presented in DKA with critical acidosis and hypokalemia. This presents a variety of therapeutic challenges: what to do about insulin, which treats the acidemia but worsens the hypokalemia? How can I safely supplement potassium as aggressively as possible? In contrast to the previously-posted recommendations from Micromedex, a protocol from the Bon Secours system in Richmond, VA presents the most clinically useful summary we have come across. ___ *If potassium < 3 meq/liter and the patient is symptomatic 40 meq/hour may be administered to intensive care patients. Hourly serum potassium determinations should be drawn to avoid severe hyperkalemia and/or cardiac arrest. Symptoms of hypokalemia include: fatigue, malaise, generalized muscle weakness, respiratory failure, paralysis; EKG changes include T wave flattening or inversion, U waves, or ST segment depression, and arrhythmia’s. Recommended maximum dose should not usually exceed 10 meq/hour or 200 meq for a 24 hour period if the serum potassium level is greater than 2.5 meq/liter per product package insert ___ Additionally, there is literature‚Ć to support providing a baseline rate of 40 mEq/hr (through a central line) with hourly supplementation using “runs” of up to 40 mEq (through a central line). Patients having their potassium replaced this aggressively should be on a monitor and have hourly electrolyte checks. Regarding the benefit/drawback of using insulin in DKA patients, the ADA strongly recommends withholding insulin when K < 3.3. If you want to disregard this recommendation, which I do (seems overly cautious), remember you can slow…

TO THE EDITOR: A frequently encountered problem in clinical practice is a patient who presents with acidosis and hyperglycemia. It has been my experience that the correct calculation of the anion gap in the face of hyperglycemia is often confusing. An example would best serve to illustrate the point. Assume a patient who is admitted with new-onset diabetes mellitus and has the following blood test results: glucose level, 700 mg/dL; sodium level, 128 mEq/L; chloride level, 97 mEq/L; and bicarbonate level, 21 mEq/L. The anion gap in this patient is [Na] ?([Bicarbonate] + [Cl]) = 128 ?(97 + 21) = 10, a value within normal limits; the patient has a mild non-anion gap acidosis. However, physicians often correct the sodium level in the face of hyperglycemia by adding 1.6 mEq/L to the sodium concentration for each 100-mg/dL increment in glucose levels above 100 mg/dL. This correction does not apply to the calculation of the anion gap in patients with acidosis and hyperglycemia because the water moving from the intracellular compartment to the extracellular compartment as a result of the hyperglycemia equally dilutes all electrolytes, including the chloride and bicarbonate. If in this case the sodium level is "corrected" for the hyperglycemia, it will be calculated as 138 mEq/L and lead to a falsely elevated calculated anion gap of 20. Thus, the patient’s condition would be erroneously diagnosed as severe anion gap acidosis, most probably diabetic ketoacidosis. Tomer, Y. Annals of Internal Medicine 129:9 p753

But do not use the hyperglycemia/hyponatremia correction when calculating the anion gap. See this document.