Elevations in procalcitonin but not C-reactive protein are associated with pneumonia after cardiopulmonary resuscitation

225

149

Used appropriately, biomarkers improve the assessment of respiratory tract infections and sepsis. Most prominently, circulating procalcitonin levels increase by a factor of several tens of thousands during sepsis. Using a sensitive assay, procalcitonin safely and markedly reduces antibiotic usage in respiratory tract infections and nonbacterial meningitis. Procalcitonin is the protopye of hormokine mediators. The term ''hormokine'' encompasses the cytokine-like behaviour of hormones during inflammation and infections. The concept is based on a ubiquitous expression of calcitonin peptides during sepsis. Adrenomedullin, another member of the calcitonin peptide superfamily, was shown to complement and improve the current prognostic assessment in lower respiratory tract infections. Other peptides share some features of hormokines, e.g. natriuretic peptide and copeptin. Hormokines are not only biomarkers of infection but are also pivotal inflammatory mediators. Like all mediators, their role during systemic infections is basically beneficial, possibly to combat invading microbes. However, at increased levels they can become harmful for their host. Multiple mechanisms of action were proposed. In several animal models the modulation and neutralisation of hormokines during infection was shown to improve survival, and thus might open new treatment options for severe infections, especially of the respiratory tract.

Section: Pct In Ventilator-associated Pneumoniamentioning

confidence: 99%

Biomarkers in respiratory tract infections: diagnostic guides to antibiotic prescription, prognostic markers and mediators

Christ‐Crain¹,

Müller²

2007

225

149

“…Its level increases rapidly in bacterial infections but remains low in viral diseases. High plasma concentrations of PCT are typically seen in sepsis, meningitis and pneumonia [12][13][14][15][16][17]. PCT also seems to be a prognostic factor in sepsis and pneumonia [18,19].…”

mentioning

confidence: 99%

Procalcitonin predicts patients at low risk of death from community-acquired pneumonia across all CRB-65 classes

Krüger¹,

Ewig²,

Marre³

et al. 2007

261

179

on behalf of the CAPNETZ Study Group ABSTRACT: The aim of the present study was to investigate the prognostic value, in patients with community-acquired pneumonia (CAP), of procalcitonin (PCT) compared with the established inflammatory markers C-reactive protein (CRP) and leukocyte (WBC) count alone or in combination with the CRB-65 (confusion, respiratory rate o30 breaths?min -1 , low blood pressure (systolic value ,90 mmHg or diastolic value f60 mmHg) and age o65 yrs) score. In total, 1,671 patients with proven CAP were enrolled in the study. PCT, CRP, WBC and CRB-65 score were all determined on admission and patients were followed-up for 28 days for survival.In contrast to CRP and WBC, PCT levels markedly increased with the severity of CAP, as measured by the CRB-65 score. In 70 patients who died during follow-up, PCT levels on admission were significantly higher compared with levels in survivors. In receiver operating characteristic analysis for survival, the area under the curve (95% confidence interval) for PCT and CRB-65 was comparable (0.80 (0.75-0.84) versus 0.79 (0.74-0.84)), but each significantly higher compared with CRP (0.62 (0.54-0.68)) and WBC (0.61 (0.54-0.68)). PCT identified low-risk patients across CRB classes 0-4.In conclusion, procalcitonin levels on admission predict the severity and outcome of community-acquired pneumonia with a similar prognostic accuracy as the CRB-65 score and a higher prognostic accuracy compared with C-reactive protein and leukocyte count. Procalcitonin levels can provide independent identification of patients at low risk of death within CRB-65 (confusion, respiratory rate o30 breaths?min -1 , low blood pressure (systolic value ,90 mmHg or diastolic value f60 mmHg) and age o65 yrs) risk classes.

“…Nonetheless, few studies have analysed the behaviour of procalcitonin levels when the infection is in the lung [6][7][8][9]. Furthermore, there are even fewer studies aiming to establish a diagnostic cut-off value of procalcitonin levels in VAP and their results are discordant [10][11][12].…”

mentioning

confidence: 99%

Sequential measurements of procalcitonin levels in diagnosing ventilator-associated pneumonia

Ramírez

Garcia²,

Ferrer³

et al. 2007

113

The utility of procalcitonin levels to improve the accuracy of clinical and microbiological parameters in diagnosing ventilator-associated pneumonia (VAP) was evaluated.Sequential measurement of procalcitonin and C-reactive protein levels and the calculation of the simplified Clinical Pulmonary Infection Scores (CPIS) were performed in 44 patients mechanically-ventilated for .48 h with neither active infection for the duration or suspicion of VAP. Patients who developed extrapulmonary infection were excluded.In total, 20 cases were suspected of having VAP and diagnosis was microbiologically confirmed in nine. In patients with confirmed VAP, procalcitonin levels were higher than in those without VAP. C-reactive protein levels and CPIS were lower in patients without suspected VAP, but could not discriminate confirmed and nonconfirmed 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%). A CPIS o6 combined with serum levels of procalcitonin o2.99 ng?mL -1 did not improve the sensitivity (67%), but resulted in 100% specificity.Procalcitonin might be useful in the diagnosis of ventilator-associated pneumonia. Combined values of Clinical Pulmonary Infection Scores and procalcitonin below the cut-off points excluded false-positive diagnoses of ventilator-associated pneumonia.