What factors about this case made this error more likely to occur?

You are a RN in a busy urban medical/surgical ICU. It is 3 a.m. on your 12-hour night shift (your fourth in a row). Your patient, Mr. H, is a 78-year-old man recently admitted to the cardiac ICU with an active MI (myocardial infarction) and GI bleed. You have just begun an ordered transfusion a unit of packed red cells for a HCT of 22. At the same time, the lab calls the unit and notifies you of a critical lab result. Mr. H’s potassium is dangerously high at 6.8. You call the on-call provider, Dr. Z, who writes an order to administer 10 units of insulin IV push (in addition to the other concurrently utilized potassium-lowering treatments). Knowing you must act quickly; you reach for the insulin vial and draw 10 mls. Your charge nurse (who is also helping to admit a recent code blue from the surgical floor), states: “I have never given insulin IV push before”, but trust your judgement and signs off on the dose. You then attach your 10-ml syringe to the IV line and inject all of the insulin.
1. What error occurred? How much insulin did the patient actually receive?2. What factors about this case made this error more likely to occur?3. How could this error been prevented?4. How could you improve communication on the unit to prevent a similar error from occurring next time?5. Now, let us assume that the nurse caught the mistake before injecting the insulin. What do we call this type of event? If this was you, would you report your “almost error”? Why or why not?