When to start SC insulin and bridge with insulin drip
-After the DKA has resolved and when the patient is able to eat, start SC basal insulin (like insulin glargine). In addition, order a pre-meal insulin Lispro regimen, AC TID.
-Continue IV insulin infusion for 2hrs after starting the SC insulin glargine to create a 2-hour bridge. The onset of action of insulin glargine is 2hrs. Bridging ensures adequate plasma insulin levels from the SC insulin before you turn off the insulin drip.
-For people who were on insulin before, restart their normal long-acting insulin dose. For insulin-naive patients, start insulin at 0.5 U/Kg to 0.8 U/kg body weight per day with half of that being basal (long-acting) insulin and the other half pre-meal, divided into three doses to be given before each meal. You will then adjust the insulin as needed.
When to Feed the patient
Ideally when the DKA is resolved and the patient’s condition is stable (there is no n/v, and wants to eat), the 2hr bridge should be initiated and the patient allowed to eat a meal after the two hours. The meal should be preceded by a subcutaneous (SC) dose of regular insulin or a rapid-acting insulin such as insulin Lispro.
A patient may eat before DKA has cleared.
You may feed a patient before the DKA resolves. You just need to give them a pre-meal bolus of insulin to cover their meal and continue the other drips as you would in a patient who hadn’t eaten. The food will raise their blood sugars. Instead of changing the insulin drip, it’s best to give them the pre-meal insulin to cover this rise in sugar from the food. If you increased the insulin rate to cover the food, you will have to decrease the rate when the sugar has been digested and processed otherwise you would risk infusing too much insulin in them.
When DKA has resolved but the patient cannot eat
“If the patient is still nauseated and cannot eat, dextrose infusion should be continued and regular or ultra-short-acting insulin should be administered SC every 4 hours, according to blood glucose level, while trying to maintain blood glucose values at 100-180 mg/dL.” Medscape.
Note that in a patient in whom DKA has cleared but cannot eat, you may do the bridging from insulin drip to SC insulin glargine and continue running the dextrose infusion. Do glucose checks q4hs and give regular or rapid-acting insulin as needed to keep sugars between 100-180 range. When the patient is able to eat, d/c the dextrose solution and give pre-meal insulin.
Another approach is to keep the patient on the insulin drip and continue the dextrose infusion (even though DKA has resolved) until the patient is able to eat. In this case, also continue regular glucose checks q4hrs.
You can use either method of insulin (bridging to long-acting insulin or continuing the drip). If there is any hypoglycemia, you can correct it by changing the dextrose solution (e.g. from d5 to d10).
What if the patient is intubated? You can continue the dextrose solution. Later on, you can start enteral tube feeds e.g. using NGT. The IV dextrose constitutes some sort of parenteral nutrition.
When you do the two-hour bridge of insulin drip and insulin glargine, and the patient is ready to eat two hours later, do you also give a pre-meal insulin before the patient eats?
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Related Article: Diabetic Ketoacidosis (DKA) Treatment
Further Reading
https://emedicine.medscape.com/article/118361-treatment