We were initially pleased to see the technical review and position statement on management of hyperglycemic crises in the January issue of Diabetes Care (1,2), believing that this could serve as an excellent educational resource for house staff, until we read the algorithm for treatment of adult diabetic ketoacidosis (DKA), which was presented in both articles. The final recommendation reads, “After resolution of DKA, follow blood glucose (BG) every 4 h and give sliding scale regular insulin SC [subcutaneous] in 5 unit increments for every 50 mg/dl increase in BG above 150 mg/dl for up to 20 units for BG of ≥300 mg/dl.” Although the text of both papers comments on the need to overlap SC insulin with intravenous insulin, the algorithm does not address this. In fact, a physician following this algorithm could very well stop the insulin infusion when the blood glucose is 140 mg/dl, withhold insulin therapy (as the “sliding scale” implies) from a patient known to be prone to ketosis, and not check another blood glucose until 4 h later. Even if the blood glucose at discontinuation of the insulin infusion is >150 mg/dl (which the algorithm suggests it should be, for reasons unclear to us), there is no reason to think that 5 units of SC regular insulin for a 4-h period will be sufficient in every patient. Interestingly, the algorithm for treatment of DKA in children is more appropriate, suggesting the institution of mixed short- and intermediate-acting insulin therapy based on the patient’s body weight. In our experience, we have also found it easier to continue the insulin infusion overnight and transition to SC insulin at breakfast. Although this approach may not be suitable for every patient, in most cases it seems to work well.
We are also very concerned with the term “sliding scale.” We work very hard to explain to house staff that the term is misleading, and we prefer to use “supplemental insulin” instead to drive home the physiological relationship between basal and mealtime insulin requirements. The term “sliding scale” invariably leads to patients being given only short-acting insulin intermittently in response to an already elevated BG and having their insulin withheld at lower BG levels, which clearly is not suitable for most situations.
Because there is no scientific rationale for the recommendation to treat adult ketosis-prone patients with sliding scale insulin only and, in fact, logic would suggest that this could be harmful, we feel that this algorithm should be amended to be more in keeping with what is recommended in the text of these articles.
References
Address correspondence to M. Sue Kirkman, Indiana University, School of Medicine, Division of Endocrinology and Metabolism, Emerson Hall, EH 421, Indianapolis, IN 46202. E-mail: [email protected] or [email protected].
