Sequential measurements of procalcitonin in diagnosing ventilator-associated pneumonia

¹ Unidad de Cuidados Intensivos
² Unidad de Cuidados Intensivos, Hospital de Sagunto, Sagunto, Valencia
³ Unidad de Cuidados Intensivos e Intermedios Respiratorios, Servei de Pneumologia, Institut Clinic del Torax, Hospital Clinic, Institut d'Investigacions Biomediques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
⁴ Departamentos de Biopatologia
⁵ Microbiologia
⁶ Neumologia, Hospital Universitario La Fe, Valencia
⁷ Unitat d'Avaluacio, Suport i Prevencio and

^* To whom correspondence should be addressed. E-mail: atorres{at}ub.edu.

	Abstract

We evaluated the utility of procalcitonin to improve the accuracy of clinical and microbiological parameters in diagnosing ventilation-associated pneumonia (VAP).

Sequential measurement of procalcitonin and C-reactive protein, and the calculation of the simplified Clinical Pulmonary Infection Score (CPIS) were done in 44 mechanically-ventilated patients >48 hours without active infection at admission until the end of mechanical ventilation or suspicion of VAP. Patients who developed extrapulmonary infection were excluded.

Twenty cases were suspected of having VAP and diagnosis was microbiologically-confirmed in 9. In patients with confirmed VAP, procalcitonin levels were higher that those without VAP (p<0.001). C-reactive protein and CPIS were lower in patients without suspected VAP (p=0.004 and <0.001, respectively) but could not discriminate confirmed and non-confirmed suspicion of VAP. The best sensitivity and specificity (78% and 97%, respectively) corresponded to procalcitonin. The CPIS resulted in the same sensitivity, but had a lower specificity (80%). C-reactive protein had the worst sensitivity (56%), but a good specificity (91%). CPIS 6 combined with serum levels of procalcitonin 2.99 ng·mL^-1 did not improve the sensitivity (67%) but resulted in 100% specificity.

Procalcitonin might be useful in the diagnosis of VAP. Combined values of CPIS and procalcitonin below the cutoff points excluded false positive diagnoses of VAP.