What is your recommended rule of thumb for converting to an injections strategy in the event of a pump failure and a replacement pump is not available for, say, 48 hours?

There are several ways to do this. I tend to use a relatively easy method. Hopefully, your physician has already talked to you about this very situation and you already have prescriptions for insulin syringes, NPH, and the rapid-acting insulin (which is already in the pump). Rapid-acting insulin dosing would be the same as with the pump. All of our pump patients do carbohydrate counting and would continue to use the same ratio for meals. The most difficult time would be the first one to two days without the pump. NPH insulin is a good substitute as it would reach peak levels more quickly than the other long-acting basal insulins. I usually take the total amount of basal insulin used in units and multiple that by 1.1. Then, the dose should be split two-thirds morning and one-third evening. I would not recommend using rapid-acting insulin only for two days. These insulins last only three hours, which means that you would have to give a shot every three hours at different doses to make up for the lack of a long-acting basal insulin.

JTL