Usefulness of procalcitonin for the diagnosis of ventilator-associated pneumonia.
OBJECTIVE
To assess the predictive capacity for the diagnosis of ventilator-associated pneumonia (VAP) of serum procalcitonin levels before and on the day it is suspected.


METHODS
Single-center observational study in the intensive care unit of a teaching hospital.


METHODS
Consecutive patients whose serum procalcitonin levels were available on the day that VAP was clinically suspected (day 1) and at some time within the preceding 5 days ("before").


RESULTS
Serum procalcitonin levels were determined on day 1 and "before". Among the 73 suspected episodes VAP was confirmed by quantitative bronchoalveolar lavage cultures in 32 and refuted in 41. Respective median "before" procalcitonin levels were 1.89 ng/ml (interquartile range 0.18-6.01) and 2.14 (0.76-5.75) in patients with and without VAP, but their respective median day-1 procalcitonin levels did not differ: 1.07 ng/ml (0.39-6.57) vs. 1.40 (0.67-3.39). On day 1 a 0.5 ng/ml procalcitonin threshold had 72% sensitivity but only 24% specificity for diagnosing VAP. Between "before" and day 1, procalcitonin increased in 41% and 15% of patients with and without VAP, respectively. Thus a procalcitonin rise on day 1, compared to its "before" level, had 41% sensitivity and 85% specificity for diagnosing VAP, with respective positive and negative predictive values of 68% and 65%.


CONCLUSIONS
Crude values and procalcitonin rise had poor diagnostic value for VAP in this particular setting and thus should not be used to initiate antibiotics when VAP is clinically suspected.
Luyt
Charles-Edouard
CE
Service de Réanimation Médicale, Groupe Hospitalier Pitié Salpêtrière, Université Paris 6, 75651, Paris Cedex 13, France. charles-edouard.luyt@psl.aphp.fr
Combes
Alain
A
Reynaud
Catherine
C
Hekimian
Guillaume
G
Nieszkowska
Ania
A
Tonnellier
Marc
M
Aubry
Alexandra
A
Trouillet
Jean-Louis
JL
Bernard
Maguy
M
Chastre
Jean
J
D000368:Aged; D019540:Area Under Curve; D002116:Calcitonin / Q000097:blood* / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000097:blood* / Q000175:diagnosis; D011498:Protein Precursors / Q000097:blood* / Q000378:metabolism; D012372:ROC Curve; D012680:Sensitivity and Specificity
C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide