Insulin and protamine are two drugs which
require 
Very careful attention. »
I’ve seen insulin concentrations ranging from 1 unit/cc to 500 units/cc (U-500)… a dosing error waiting to happen!
Remember that insulin is also metabolized by the kidneys, so patients with renal insufficiency or anticipated kidney dysfunction (ie, prolonged deep hypothermic circulatory arrest) should have their doses adjusted accordingly. When considering morbidity/ mortality, I fear hypoglycemia MUCH more than hyperglycemia. People walk around with glucoses> 200 mg/dL all the time asymptomatically (NOT talking about DKA, hyperosmolar syndrome, etc.)
It’s the cases of severe HYPO-glycemia that often present as seizures, coma, and even cardiovascular collapse. For this reason,be careful about administering insulin overnight to patients who aren’t receiving glucose (eating, tube feeds, TPN, etc.) because hey, a hypoglycemic coma can be mistaken as “oh, I thought the patient was sleeping”
Be careful! I like to see patient’s insulin requirements over a day or two. Remember inpatient diets are often different from what patients are used to Protamine is routinely used to reverse the effects of heparin. It has well known side effects ranging from transient hypotension and anaphylaxis (remember risk factors like prior vasectomy, NPH insulin, fish alergy, etc.) to catastrophic pulmonary hypertension. The timing of protamine is extremely important too.
If given too early, a patient on cardiopulmonary bypass can go into full blown extracorporeal clotting, and if given in excess, protamine promotes platelet dysfunction.
Closed-loop communication is imperative when administering protamine!