Thrombocytopenia (low platelet count) is common in the neonatal intensive care unit. Commonly, the decision of when to transfuse platelets is based on platelet number. Recently, Christensen et al (2006) proposed using transfusion guidelines based on platelet mass rather than platelet number. By using platelet size as a guide of when to give platelets, we may be able to decrease the amount platelet transfusions needed.

This study is investigating using platelet size rather than platelet number as a guideline for transfusing platelets in infants who are hospitalized in a NICU (neonatal intensive care unit). After obtaining parental informed consent, thrombocytopenic infants will be randomized to one of two groups. 1: Transfusion based on platelet number; 2: transfusion based on a combination of platelet number and platelet mass. In each group the decision to transfuse platelets will be made using a slightly different, yet strict set of transfusion rules.

The objective is to determine the feasibility, rate of bleeding complications and compliance of transfusing neonates based on platelet mass rather than platelet number.

The investigators hypothesize that transfusing platelets based on platelet mass will not increase bleeding complications and will reduce the number of transfusions in thrombocytopenic neonates.

Inclusion Criteria:

• Thrombocytopenic infants

Exclusion Criteria:

• Major congenital anomalies

Infants who are thrombocytopenic and hospitalized in the NICU