Abstract:
Objective：To investigate the relationship between the platelet count and the severity of pneumonia in infants.
Methods：From Nov. 2011 to Feb. 2013,166 cases of infants with pneumonia were divided into three groups（non critical group，critical group and extremely critical group）according to the score of critical illness in children in 24 h after admission. Peripheral blood platelets were collected in 24 h after admission. The number of peripheral blood platelets in three groups was compared.ResultsThe peripheral blood platelets［（427.1±73.6）×109/L］ was higher in critical group than in noncritical group［（343.3±61.2）×109/L］（P＜0.05），and was significantly higher than extremely critical group［（102.1±29.5）×109/L］（P＜0.01）;both differences had statistical significance.
Conclusion：The number of peripheral blood platelets in the critical group is significantly increased, and the number of peripheral blood platelets in the extremely critical group was significantly decreased. Close monitoring of the changes of peripheral blood platelet is helpful in judging the severity of illness and the prognosis of disease.

Key words: Pneumonia, Criticle illness, Platelet, Infant