Chiefs’ Inquiry Corner – 10/14/19

October 14, 2019

Being an outstanding physician and lifelong learner requires stoking the flames of clinical curiosity.  In Chiefs’ Inquiry Corner (CIC) we attempt to succinctly answer actual clinical questions that have been raised on the wards and in the clinics of NYU’s teaching hospitals.  Our answers are not meant to be all encompassing or practice changing but rather to serve as springboards for further exploration. For those of us with short attention spans, we hope CIC satisfies that craving for a morsel of knowledge in a digestible format.


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The concentration and dose of epinephrine varies by indication. In 2016, the FDA banned the use of ratio expressions of epinephrine dosing, so clinicians should learn concentration-based dosing. An epinephrine auto-injector (aka EpiPen) contains the highest concentration of epinephrine at 1mg/mL. A dose of 0.3mg (0.3mL) should be injected intramuscularly in anaphylaxis. The concentration of epinephrine indicated in a code is lower, at 0.1mg/mL, as it is delivered intravenously. In ACLS, 10mL are delivered for a total dose of 1mg. Continuous epinephrine drips contain the lowest concentration of epinephrine, delivered at a rate of 0.5mcg/kg/min. 

References: Epi Dosing  
A retrospective study at a community hospital reviewed 90 ECGs taken from patients with serum potassium greater than 6 mmol/L. Six ECGs demonstrated new QRS prolongation, 24 had T-wave findings, and the majority were nonspecific. Additionally, the interobserver reliability was moderate. In a separate study of 170 patients with normal potassium levels and 135 patients with potassium >6 mmol/l, 24% of normokalemic patients and 46% of patients with elevated potassium levels had ECG findings suggestive of hyperkalemia. These studies suggest ECG findings should be used with careful consideration in the management of hyperkalemia. 

Patients with type 2 diabetes can develop significant insulin resistance and require doses that outmatch our standard insulin administration. Most insulin preparations contain 100 units per milliliter (ml).  Syringes can deliver at most 100 units and pens at most 60 to 80 units at a single time. Studies have shown that delivering more than 100 units (or 1 ml) at once can lead to patient discomfort and problems with absorption. To that end, concentrated forms of insulin are also available, with up to 500 units per ml. As a rule of thumb, our pharmacy colleagues recommend considering concentrated insulin when you’ve reached a single dose greater than 60 units.

References: SubQ Insulin