Total daily insulin requirement
The starting insulin dose can be calculated based on the patient's body weight with insulin dose of 0.5 - 0.8 unit/kg/day.
________________________________________________________________________
Insulin regimen
Either one of these 2 regimens are usually used for insulin therapy:
Intensive regimen
2 to 5 pre-meals injections of bolus insulin (rapid/short-acting insulin : regular, aspart, lispro) plus 1 (pre-bed) to 2 (pre-bed + pre-breakfast) injections of basal insulin (intermediate or long-acting insulin : NPH, zinc, extended zinc, lispro-protamine, glargine) are given . Example of the regimen is, 3 pre-meals injections (pre-breakfast, pre-lunch, pre-dinner) of actrapid, plus 1 pre-bed injection of NPH. Generally, requirement for basal insulin is 50% to 70% of total daily insulin requirement, and requirement for pre-meals bolus insulin is 30% to 50% of total daily insulin requirement.
Example of calculation:
Body weight : 50 kg
Total daily insulin requirement : 0.5 x 50 = 25 units
Regimen : 3 pre-meals actrapid injections + 1 pre-bed NPH injections
=Intensive regimen of 3 pre-meals injections (pre-breakfast, pre-lunch, pre-dinner) of actrapid, plus 1 pre-bed injection of NPH
Dose of 3 pre-meals actrapid :
50% of total daily insulin requirement (50 to 70%)
=50% x 25 unit
=12.5 unit
Therefore,
Dose for each pre-meal actrapid
= 12.5 unit / number of meals
= 12.5 unit / 3
=4.16unit ~ 4 unit
Dose of 1 pre-bed NPH :
50% of total daily insulin requirement (30 to 50%)
=50% x 25 unit
=12.5 unit ~ 13 unit
or,
or,
Dose of 3 pre-meals actrapid :
70% of total daily insulin requirement (50 to 70%)
=70% x 25 unit
=17.5 unit
Therefore,
Dose for each pre-meal actrapid
= 17.5 unit / number of meals
= 17.5 unit / 3
=5.83unit ~ 6 unit
Dose of 1 pre-bed NPH :
30% of total daily insulin requirement (30 to 50%)
=30% x 25 unit
=7.5 unit ~ 8 unit
Conventional regimen
1-2 injections of a mixture of rapid/short-acting and intermediate-acting insulins is given. Twice daily injections are preferred for better glycemic control. With the 2-injection regimen, generally two-thirds of the total daily insulin requirement is given before breakfast and one-third is given before the evening meal.
________________________________________________________________________
If after around 3 days started insulin with the calculated dose the patient does not achieve the desired level of glycemic control, the insulin dose is titrated accordingly.
 |
| -Example of insulin titration algorithm- Generally, glucose level of 4 - 6 or 7 mmol/l is acceptable, therefore, usually the algorithm is not followed too strictly Refer conversion table below for unit conversion |
________________________________________________________________________
(See also Diabetes mellitus: antenatal management)
No comments:
Post a Comment