Is the fall in platelet count associated with intensive care unit acquired pneumonia?

Intensive Care Unit Acquired Pneumonia is the most frequent infection among patients receiving mechanical ventilation and has an important impact on patient mortality. Thrombocytopenia is one of the most common laboratory abnormalities in Intensive Care Unit (ICU). The aim of this study was to evaluate the relationship between platelet count and Intensive Care Unit Acquired Pneumonia (ICUAP).

Medical records of 41 mechanically-ventilated pulmonary ICU patients having at least one ICUAP were reviewed. The date of first ICUAP, etiologic pathogens, platelet count at admission, the nadir value within seven days before and after the date of ICUAP, development of thrombocytopenia (platelet <100 x 10(3)/mm(3)), acute physiology and chronic health evaluation (APACHE) II scores on admission, medications and events that can effect platelet count and other laboratory values were noted.

The meantime for the first ICUAP was 13 +/- 10.3 days after ICU admission. The nadir platelet count associated with ICUAP (ICUAPplatelet count) was seen on 12.1 +/- 11.3th day after ICU admission; with a significant fall (30% fall) when compared to admission platelet count (platelet counts are 157.2 +/- 87.4 x 10(3)/mm(3), 224.1 +/- 106.3 x 10(3)/mm(3) respectively, p <0.001). Fifteen of the 41 patients had an episode of thrombocytopenia during their ICU stay and these patients had a higher mortality rate than nonthrombocytopenics (mortality rates are 80% and 50% respectively, p = 0.05).

Besides the proven role of thrombocytopenia in prognosis in ICU, the significant fall in platelet count can be an early warning parameter and possible diagnostic hint for severe infections in ICU such as ICUAP.