The extended bolus is supported by insulin pumps and it is a bolus amount applied constantly over a specified time period. For MDI treatment, Diabetes:M bolus calculator splits the proposed extended bolus and it can be used even when users are on MDI therapy.
The algorithm which Diabetes:M uses is explained in details in the article
Bolus Calculator with Nutrition Database Software, a New Concept of Prandial Insulin Programming for Pump Users
by Ewa Pańkowska M.D., Ph.D., Marlena Błazik, M.D.
According the rules published in the article Diabetes:M performs the following calculations:
CU = carbohydrates / 10 FPU = (proteins * 4 + fats * 9) / 100 IRFactor = 10 / I:C IF CU + FPU = 0 THEN → CUperc = 0 IF CU + FPU > 0 THEN → CUperc = CU / (CU + FPU) CU_FPU_correction = NBSBCorrection / 100 bolusNormal = 0.0 IF CU_perc >= 0.2 AND CU_perc <= 0.8 THEN → bolusNormal = CU * IRFactor * (1 - CU_FPU_correction) IF CU_perc > 0.8 THEN → bolusNormal = CU * IRFactor bolusExtended = 0.0 IF FPU >= 1 AND CU_perc < 0.2 THEN → bolusExtended = FPU * IRFactor IF FPU >= 1 AND CU_perc >= 0.2 AND CU_perc <= 0.8 THEN → bolusExtended = FPU * IRFactor * (1 + CU_FPU_correction) IF FPU<1 THEN → duration = 0 IF CU_perc > 0.8 THEN → duration = 0 hours IF FPU >= 1 AND FPU < 2 THEN → duration = 3 hours IF FPU >= 2 AND FPU < 3 THEN → duration = 4 hours IF FPU >= 3 AND FPU < 4 THEN → duration = 5 hours IF FPU >= 4 THEN → duration = 8 hours
The final calculation
bolusStandard = bolusNormal + correction + exerciseBolusAdjustment + sicknessBolusAdjustment
bolusStandard must be applied immediately
bolusExtended must be applied over
total bolus = bolusStandard + bolusExtended