### Description

The Maximum Platelet Count Increment (MPI) and Percentage Platelet Recovery (PPR) are two measures of the effectiveness of platelet transfusion.

MPI in platelets per µL =

= (total number of platelets transfused) * (fractional recovery of the transfused platelets) / (1000 * (blood volume in mL))

total number of platelets transfused =

= (number of platelet products transfused) * (average number of platelets per product)

 Patient Condition Fractional Recovery normally sized spleen 0.62 to 0.67 asplenic 0.91 splenomegaly 0.23

where:

• The 1,000 in the denominator is for converting mL blood volume to µL.

• Fractional recovery ranges from 0 (no survival) to 1 (perfect survival).

• Petz (1996) used the following equations (page 383) to estimate blood volume from body weight = 70.5 * (weight in kilograms).

• Petz used the following equations to estimate blood volume from body surface area: for men = 2725 * (BSA in square meters); for women = 2507 * (BSA in square meters)

percentage platelet recovery =

= (platelet increment observed per µL) / (MPI) * 100% =

= 1000 * (blood volume in mL) * (platelet increment observed per µL) * 100% / ((number of platelets transfused) * (fractional recovery of transfused platelets))

If the body weight in kilograms is known:

percentage platelet recovery =

= 7 * 10^4 * (platelet increment observed per µL) * (body weight in kilograms) * 100% / ((number of platelets transfused) * (fractional recovery of transfused platelets))

If the body surface area in square meters is known:

percentage platelet recovery for men =

= 2.725 * 10^6 * (platelet increment observed per µL) * (body surface area in square meters) * 100% /( (number of platelets transfused) * (fractional recovery of transfused platelets))

percentage platelet recovery for women =

= 2.507 * 10^6 * (platelet increment observed per µL) * (body surface area in square meters) * 100% / ((number of platelets transfused) * (fractional recovery of transfused platelets))