Bleeding in the Newborn
Daniel C. Plunket MD1
1 The Department of Pediatrics, University of Oklahoma Tulsa Medical College
The physician caning for newborns should master four objectives in the assessment and management of bleeding problems in that age group. They are: (1) to recall the neonate's hemostatic peculiarities, (2) to perform a meaningful clinical assessment, (3) to order and interpret appropriate diagnostic tests, and (4) to formulate a treatment plan.
NEONATE'S HEMOSTATIC PECULIARITIES
Table 1 lists the components of the hemostatic mechanism comparing older patient normal values and the neonate's similarities and differences. Certain laboratory tests commonly available are also noted. Several important points should be emphasized. Differences between neonates and older children, in general, are accentuated in direct proportion to the degree of immaturity.
Platelet counts vary little with age. Big platelets (diameter more than one third the size of a red cell's diameter) are young platelets and suggest active thrombocytopoiesis. The blood vessel and platelet function contributions to hemostasis may be suboptimal by older patient standards, but are not of clinical significance unless such dysfunction has been aggravated by drugs or disease.
Most coagulation proteins (procoagulants) are derived from liver and thus are somewhat deficient in amount or function in the neonate whose liver is transiently functionally immature. In general, the more immature the infant the more deficient the procoagulant. This is particularly true of the vitamin K-dependent procoagulants (Factors II, VII, IX, X).
