Principles of Sliding Scale Insulin in the Hospital Setting

In the Hospital, Everyone goes on Insulin, because we don't like the side effects of the oral meds on top of the stresses on the patient from hospital procedures. But how much of what kind to give?

Step 1: Figuring out the base insulin you will give to Patient:

For Pts on Orals outside the hospital (e.g. metformin), multiply their weight (kg) times 0.3 to get total insulin.
For Pts on Insulin with controlled glucose outside the hospital, mult. weight times 0.5 to get total insulin.
For pts on insulin with uncontrolled glucose outside the hospital, multiply wt times 0.7 to get total insulin.

Step 2: What insulin to give as a baseline

First divide total by 2. Half will be Glargine, long-acting that will cover baseline metabolic activity. Half will be untra-short-acting Lispro, which will further be divided in three for each of the three meals of the day.

Step 3: Sliding Scale

Everybody is different, and some people won't react as well as you want. Ideally you want your patient to be between 120 and 179 Serum Glucose at ALL times. You'll try using the amount of Glucose we derived from Step 2, but if their post-prandial glucose levels are out of range (measure for each of their meals), use the sliding scale.

Start with a low sliding scale, and if they are way  out of range, use a medium scale, which basically amounts to more units to be added the next day to the total insulin.

Typical scales look like this:

100-149: 0 addt'l units
150-199: 1 add'l unit
200-249: 2 add'l units
250-299: 3 add'l units
300+: 4 add'l units.

You will take each of the meals' glucose levels and add together add'l units of insulin from each meal. You will take the total add'l insulin and divide this in the same proportions as baseline insulin we calculated in Step 2, adding it to whatever we used the previous day.

Repeat as necessary, until patient is back in the normal range of 120-179 after meals.

For Example:

Let's say you have a 100 lb patient who takes oral metformin to control their diabetes who you are admitting.

Step 1: They will get a baseline of 30 units of insulin a day.

Step 2: 15 will be insulin glargine, and 15 insulin lispro divided among their 3 meals, making 5 units of lispro before every meal.

Step 3: After the first day, you note their post-prandial glucose levels are as follows:

Breakfast: 200
Lunch: 270
Dinner: 170

Using the scale above, You would then have to add 2 add'l units for breakfast, 3 for lunch and 1 for dinner, making a total of 6 units. So your insulin the next day will be 15 + 3 = 18 units of Glargine for the day, and 5 + 1 = 6 units of Lispro insulin for each meal.