C-reactive Protein Trends and Clinical Outcomes in Patients Treated for Complicated Parapneumonic Effusion and Empyema.

Treatment endpoints of empyema thoracis lack specificity when determining clinical success. While a declining C-reactive protein (CRP) may indicate a response to treatment, the expected rate of decline is not well-established. An observational analysis was performed on patients who were treated for either a parapneumonic effusion or empyema by tube thoracostomy and possessed at least two sequential CRP measurements. CRP trends were retrospectively modeled in a cohort of 104 patients. The rate of CRP decline was affected by the use of intrapleural enzymatic therapy, baseline CRP, and the value of the pleural pH. CRP declined at a daily rate of 12.3% in those who received intrapleural enzymatic therapy (IET) and by 17.8% in those who did not, but frequently remains elevated at discharge, thus lacking specificity as an isolated biomarker in determining treatment success or failure.