Insulin amount

The rule someone taught me was always wait till the patient starts eating to administer short acting because what if they decide not to eat? For every unit of SA insulin it can drop BS by 30pts. So 30x6 is 180. However, when pt is eating their BS can rise very quickly so at 120 they should be fine as long as they are eating. With Levemir you will need to ensure pt gets a snack if you are administering it. 

Does this patient have a sliding scale order written for their insulin? The sliding scale would determine at what BG # the short acting insulin would be held regardless of appetite (IE: BG=60, probably would hold insulin and treat per protocol). I agree with Grande_latte that short acting insulin is typically given right when the patient eats or right after if appetite is poor/unknown because of the rapid onset. The long acting HS insulin is generally always given, it works differently than the short acting and should not cause a significant drop in BG at any given point. When in doubt or if you're noticing s/s of hypoglycemia, call the provider to discuss adjustments to the HS long acting insulin but you can't hold long acting insulin based on one BG value unless there is an order for that. Long acting basal insulin is meant to keep up with the body's normal metabolic processes, not to treat hyperglycemia caused by oral intake at any single point in time. Each person responds to insulin differently, 6 units of Lispro at BG 120 might be fine for one person but too much for another, that's why we have sliding scales.