Procalcitonin and C-reactive protein during systemic inflammatory response syndrome, sepsis and organ dysfunction

A single procalcitonin level does not predict adverse outcomes of women with pyelonephritis

OBJECTIVES

Predicting medical outcomes for pyelonephritis in women is difficult, leading to unnecessary hospitalization. Unlike other serious infectious diseases, high procalcitonin (PCT) level has never been associated with 28-d adverse medical outcomes in women with pyelonephritis. Therefore, we sought to determine the accuracy of PCT in discriminating between pyelonephritis with adverse medical outcome (PAMO) and pyelonephritis without adverse medical outcome (PWAMO).

PATIENTS AND METHODS

Adult women with pyelonephritis presenting to the emergency department of a French tertiary care hospital were consecutively included. Those patients who developed adverse medical outcomes during a 28-d follow-up period were identified as having PAMO. Baseline characteristics and PCT level were compared between patients with PAMO and PWAMO.

RESULTS

Eleven women (19.0%) had PAMO and 47 (81%) had PWAMO. The median PCT level was higher in PAMO compared with PWAMO 0.51 ng/ml (IQR: 0.04-3.8) and 0.08 ng/ml (IQR: 0.01-1.0), but this difference was not statistically significant (p=0.07). We failed to find a threshold value for PCT that discriminated between PAMO and PWAMO (ROC, AUC=0.67 [95%CI, 0.51-0.86]). All but one subject with PAMO had either a PCT level >0.1 ng/ml or an underlying genitourinary abnormality by radiographic testing.

CONCLUSIONS

A single PCT level was a poor predictor of 28-d adverse medical outcomes in women with pyelonephritis treated in the emergency department. Prediction based on underlying genitourinary abnormality by radiographic testing in addition to the PCT level should be investigated in future studies.

N-terminal brain natriuretic propeptide levels correlate with procalcitonin and C-reactive protein levels in septic patients

The aim of this study was to find the relationship between N-terminal brain natriuretic propeptide (NT-proBNP), procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations in septic patients. This was a prospective study, performed at Medical University Hospital No. 5 in łódź. Twenty patients with sepsis and severe sepsis were included in the study. N-terminal brain natriuretic propeptide, procalcitonin and C-reactive protein concentrations, and survival were evaluated. In the whole studied group (128 measurements), the mean NT-proBNP, procalcitonin and C-reactive protein concentrations were, respectively: 140.80+/-84.65 pg/ml, 22.32+/-97.41 ng/ml, 128.51+/-79.05 mg/l. The correlations for the NT-proBNP level and procalcitonin and C-reactive protein levels were 0.3273 (p<0.001) and 0.4134 (p<0.001), respectively. NT-proBNP levels correlate with PCT and CRP levels in septic patients. In the survivor subgroup, the mean NT-proBNP plasma concentrations were significantly lower than in the non-survivor subgroup.

Procalcitonin in the diagnosis of inflammation in intensive care units

OBJECTIVES

To assess the effectiveness of different procalcitonin cutoff values to distinguish non-infected (negative+SIRS) from infected (sepsis+severe sepsis+septic shock) medical and surgical patients.

DESIGN AND METHODS

PCT plasma concentration was measured using an automated chemiluminescence analyzer in 1013 samples collected in 103 patients within 24 h of admission in ICU and daily during the ICU stay. We compared PCT levels in medical and surgical patients. We also compared PCT plasma levels in non-infected versus infected patients and in SIRS versus infected patients both in medical and in surgical groups.

RESULTS

Median values of PCT plasma concentrations were significantly higher in infected than in non-infected groups, both in medical (3.18 vs. 0.45 microg/L) (p<0.0001) and in surgical (10.45 vs. 3.89 microg/L; p<0.0001) patients. At the cutoff of 1 microg/L, the LR+ was 4.78, at the cutoff of 6 microg/L was 12.53, and at the cutoff of 10 microg/L was 18.4.

CONCLUSIONS

This study highlights the need of different PCT cutoff values in medical and surgical critically ill patients, not only at the ICU admission but also in the entire ICU stay.

C-reactive protein concentration as a predictor of intensive care unit readmission: a nested case-control study

PURPOSE

The purpose of this study is to assess the ability of potential clinical predictors and inflammatory markers to predict intensive care unit (ICU) readmission during the same hospitalization.

MATERIALS AND METHODS

A nested case-control study utilized prospectively collected de-identified data of a 22-bed multidisciplinary ICU in a university hospital.

RESULTS

There were 1,405 consecutive ICU admissions in 2004, and of these, 18 were regarded as ICU readmissions (1.3%). The destination and timing of ICU discharge, the Sequential Organ Failure Assessment scores, white cell counts, and fibrinogen concentrations at discharge were not associated with ICU readmission. C-reactive protein (CRP) concentration within 24 hours before ICU discharge was associated with ICU readmission (mean CRP concentrations of cases vs controls, 177.8 vs 56.5 mg/L, respectively; P < .0001). The results remained unchanged after adjustment with the propensity scores. The area under the receiver operating characteristic curve for the CRP concentrations to predict ICU readmission was 0.884 (95% confidence interval, 0.765-0.999; P < .0001). Patients readmitted to the ICU had a higher predicted mortality in their second ICU admission (34.9% vs 26.1%; P < .01) and a longer total hospital stay (33.3 vs 20.3 days; P < .003) than patients without ICU readmission.

CONCLUSIONS

A high CRP concentration within 24 hours before ICU discharge is associated with a higher risk of readmission to the ICU.

Serum procalcitonin level and leukocyte antisedimentation rate as early predictors of respiratory dysfunction after oesophageal tumour resection

Introduction

Postoperative care after oesophageal tumour resection holds a high risk of respiratory complications. We therefore aimed to determine the value of systemic inflammatory markers in predicting arterial hypoxaemia as the earliest sign of developing lung injury after oesophageal tumour resection.

Methods

In a prospective observational study, 33 consecutive patients were observed for three days (T1–T3) after admission (T0) to an intensive care unit following oesophageal tumour resection. The daily highest values of the heart rate, axillary temperature, leukocyte count and PaCO₂ were recorded. Serum C-reactive protein and procalcitonin concentrations and the leukocyte antisedimentation rate (LAR) were determined at T1 and T2. Respiratory function was monitored 6-hourly measurement of the PaO₂/FIO₂ ratio, and the lowest value was recorded at T3. Patients were categorised as normoxaemic or hypoxaemic using the cutoff value of 300 mmHg for PaO₂/FIO₂.

Results

Seventeen out of 33 patients were classified as hypoxaemic and 16 patients as normoxaemic at T3. Increases of temperature at T0 and of the procalcitonin and LAR values at T2 were predictive of hypoxaemia at T3 (P < 0.05, P < 0.01 and P < 0.001, respectively). The area under the receiver-operating characteristic curve was 0.65 for the temperature at T0, which was significantly lower than that for the procalcitonin level at T2 (0.83; 95% confidence interval, 0.69–0.97; P < 0.01) and that for LAR at T2 (0.89; 95% confidence interval, 0.77–1.00; P < 0.001).

Conclusion

These results suggest that an elevated LAR (>15%) and an elevated procalcitonin concentration (>2.5 ng/ml) measured on the second postoperative day can predict next-day arterial hypoxaemia (PaO₂/FIO₂ < 300 mmHg) after oesophageal tumour resection.

Correlation of procalcitonin and C-reactive protein to inflammation, complications, and outcome during the intensive care unit course of multiple-trauma patients

Background

A comparison of the amount of and the kinetics of induction of procalcitonin (PCT) with that of C-reactive protein (CRP) during various types of and severities of multiple trauma, and their relation to trauma-related complications, was performed.

Methods

Ninety adult trauma patients admitted to the intensive care unit of our tertiary care hospital were evaluated in a prospective case study. During the initial 24 hours after trauma the Injury Severity Score, the Sepsis-related Organ Failure Assessment score, and the Acute Physiology and Chronic Health Evaluation II score were evaluated. PCT, CRP, the sepsis criteria (American College of Chest Physicians/Society of Critical Care Medicine definitions), and the Sepsis-related Organ Failure Assessment score were measured at days 1–7, as well as at days 14 and 21, concluding the observation period with the 28-day survival.

Results

The induction of PCT and CRP varied in patients suffering from trauma. PCT increased only moderately in most patients and peaked at day 1–2 after trauma, the concentrations rapidly declining thereafter. CRP ubiquitously increased and its kinetics were much slower. Complications such as sepsis, infection, blood transfusion, prolonged intensive care unit treatment, and poor outcome were more frequent in patients with initially high PCT (>1 ng/ml), whereas increases of CRP showed no positive correlation.

Conclusion

In patients with multiple trauma due to an accident, the PCT level provides more information than the CRP level since only moderate amounts of PCT are induced, and higher concentrations correlate with more severe trauma and a higher frequency of various complications, including sepsis and infection. Most importantly, the moderate trauma-related increase of PCT and the rapidly declining concentrations provide a baseline value near to the normal range at an earlier time frame than for CRP, thus allowing a faster and more valid prediction of sepsis during the early period after trauma.

Systemic Inflammatory Response Syndrome and Nosocomial Infection in Trauma

BACKGROUND

Admission systemic inflammatory response syndrome (SIRS) score has been previously reported to be an accurate predictor of infection and outcome in trauma. However, the data were limited to the first 7 days of admission. Our objective in this follow-up study was to prospectively evaluate the utility of daily SIRS scores in the second and third week of admission as compared with the first week in prediction of nosocomial infection and outcome in high-risk trauma patients.

METHODS

Prospective data were collected on 1,277 consecutive trauma patients admitted during a 28-month period to the intensive care unit. SIRS scores were calculated daily for the first week and every other day for the following 2 weeks. Patients were categorized into SIRS occurring "early" (week 1), "middle" (week 2), and "late" (week 3). Centers for Disease Control and Prevention guidelines were used for the diagnosis of infection. Multivariate linear and logistic regression analyses were utilized for statistical analyses, controlling for the covariates of age, Injury Severity Score, and admission Glasgow Coma Scale score.

RESULTS

The trauma cohort included patients with blunt injuries (84%) and penetrating injuries (16%). The mean age was 43 +/- 21 years with an overall mortality of 14.7%. Nosocomial infection developed in 580 (45.4%) of the study patients (respiratory site most common) with a total of 1,001 infections (some patients with multiple infections). SIRS (defined as SIRS score >/=2) was common, with 92.4% of patients manifesting SIRS at admission. SIRS was most prevalent during the first week postinjury (91% of patients manifesting SIRS), decreasing to 69% and 50% during postinjury weeks 2 and 3. SIRS was more common in patients who acquired nosocomial infections compared with noninfected patients. Logistic regression analysis confirmed that patients with "middle" SIRS during week 2 (odds ratio [OR] 17.62, confidence interval [CI] 12.95-23.97, p < 0.0001, receiver operating characteristic [ROC] 0.83) and "late" SIRS during week 3 (OR18.12, CI 12.71-25.84, p < 0.0001, ROC 0.81) had significantly greater risk for nosocomial infection compared with patients with "early" SIRS during week 1 (OR 4.55, CI 2.57-8.06, p < 0.0001, ROC 0.65) postinjury.

CONCLUSION

SIRS is predictive of nosocomial infection in trauma through postinjury day 21. Nosocomial infection should be considered as a treatable cause of SIRS in trauma patients, and early diagnostic interventions should be initiated to evaluate for potential causes.

Procalcitonin for early prediction of survival outcome in postoperative critically ill patients with severe sepsis

BACKGROUND

Identification of postoperative patients at high risk of dying early after intensive care unit (ICU) admission through a fast and readily available parameter may help in determining therapeutic interventions or further diagnostic procedures that could have an impact on patients' outcome. The aim of our study was to assess the utility of procalcitonin (PCT) and other readily available parameters, as useful early (days 1-3) predictors of mortality in postoperative patients diagnosed with severe sepsis within 24 h preceding their operation.

METHODS

More than a period of 2 yr, subsets of 69 postoperative patients admitted with severe sepsis and 890 non-septic ICU patients were investigated. PCT, C-reactive protein (CRP) and sequential organ failure assessment (SOFA) score were recorded over the duration of ICU stay.

RESULTS

PCT area under receiver operating characteristic (ROC) curve was 0.78 on day 3 and was highly predictive of fatal outcome (0.90) at day 6. Area under ROC curve of SOFA score was 0.85 on day 3 and remained in this range until day 6. Area under ROC curves on day 3 of CRP (0.61) was non-predictive and remained non-predictive over the duration of ICU stay.

CONCLUSIONS

PCT exhibited no discriminative power early after ICU admission for prediction of mortality in critically ill patients with severe sepsis, compared with a high predictive power of SOFA score on day 3. However, using PCT could still serve as a useful complementary comparator for prediction of survival outcome using the SOFA score.

Procalcitonin as a diagnostic test for sepsis in critically ill adults and after surgery or trauma: a systematic review and meta-analysis

OBJECTIVE

To quantify the accuracy of serum procalcitonin as a diagnostic test for sepsis, severe sepsis, or septic shock in adults in intensive care units or after surgery or trauma, alone and compared with C-reactive protein. To draw and compare the summary receiver operating characteristics curves for procalcitonin and C-reactive protein from the literature.

DATA SOURCE

MEDLINE (keywords: procalcitonin, intensive care, sepsis, postoperative sepsis, trauma); screening of the literature.

STUDY SELECTION

Meta-analysis of all 49 published studies in medical, surgical, or polyvalent intensive care units or postoperative wards. Children, medical patients, and immunocompromised patients were excluded.

DATA EXTRACTION

Thirty-three studies fulfilled inclusion criteria (3,943 patients, 1,828 males, 922 females; mean age: 56.1 yrs; 1,825 patients with sepsis, severe sepsis, or septic shock; 1,545 with only systemic inflammatory response syndrome); eight studies could not be analyzed statistically. Global mortality rate was 29.3%.

DATA SYNTHESIS

Global odds ratios for diagnosis of infection complicated by systemic inflammation were 15.7 for the 25 studies (2,966 patients) using procalcitonin (95% confidence interval, 9.1-27.1) and 5.4 for the 15 studies (1,322 patients) using C-reactive protein (95% confidence interval, 3.2-9.2). The summary receiver operating characteristics curve for procalcitonin was better than for C-reactive protein. In the 15 studies using both markers, the Q* value (intersection of summary receiver operating characteristics curve with the diagonal line where sensitivity equals specificity) was significantly higher for procalcitonin than for C-reactive protein (0.78 vs. 0.71, p = .02), the former test showing better accuracy.

CONCLUSIONS

Procalcitonin represents a good biological diagnostic marker for sepsis, severe sepsis, or septic shock, difficult diagnoses in critically ill patients. Procalcitonin is superior to C-reactive protein. Procalcitonin should be included in diagnostic guidelines for sepsis and in clinical practice in intensive care units.

Interleukin-18: a novel prognostic cytokine in bacteria-induced sepsis

OBJECTIVE

Severe inflammation and sepsis remain a serious clinical challenge worldwide. Despite modern supportive medicine and an improved understanding of the underlying pathophysiology, mortality rates remain high in patients suffering from this severe inflammatory process. The often excess production of pro- and anti-inflammatory cytokines frequently found in the circulation of septic patients has stimulated the search for reliable inflammatory mediators that can be used for the diagnosis and prediction of clinical outcome. Interleukin (IL)-18, formerly termed interferon-gamma inducing factor, is a pro-inflammatory and Th1 cytokine suggested to play a significant role in the pathogenesis of this disease. This review focuses on our current understanding of the pro-inflammatory cytokine, IL-18, and its potentially unique role in sepsis.

METHODS

Bibliographic search of the most recent literature (1995-2005) relating to IL-18 and its role in inflammatory diseases, with emphasis on its pathophysiological importance in sepsis. In addition, a summary of the author's own experimental data from this particular field of research set in the context of current knowledge regarding IL-18.

RESULTS AND CONCLUSIONS

Several studies have shown elevated plasma IL-18 concentrations to be associated with poor clinical outcome in severe inflammatory and septic conditions. Moreover, a significant increase in IL-18 concentrations has been shown to discriminate between Gram-positive and Gram-negative related sepsis, and, thus, may potentially augment existing diagnostic tools. Biological neutralization of IL-18 via caspase-1 intervention or through the administration of IL-18-binding protein has been promulgated as a promising therapeutic approach, but additional studies are required to evaluate its full potential in acute inflammatory diseases.

Clinical laboratory findings associated with in-hospital mortality

The diagnostic approach and the clinical management of critically ill patients is challenging. The recognition of biomarkers related to in-hospital mortality is of importance for identification of patients at increased risk of death. Many prediction models assessing the severity of illness and likelihood of hospital survival were developed using logistic regression analyses. These models include several laboratory parameters, such as white blood cell counts, serum bilirubin, serum albumin, blood glucose, serum electrolytes and markers which reflect acid-base disturbances. Recently, several other biomarkers, including troponin, B-type natriuretic peptide (BNP), N-terminal proBNP, C-reactive protein, procalcitonin, cholesterol and coagulation related markers have emerged as clinically useful tools for risk stratification and mortality prediction of heterogeneous and more specific subgroups of critically ill patients. More investigations are required to verify whether risk stratification based on mortality-related biomarkers may translate into targeted treatment strategies to improve clinical outcome of the critical illness. Biomarkers which are related to in-hospital mortality are highlighted in the current review.

Clinical significance of serum procalcitonin levels in patients with acute or chronic liver disease

OBJECTIVE

To evaluate the diagnostic value of serum procalcitonin levels in patients with acute or chronic liver disease, with or without bacterial infections and to correlate the results with the clinical outcome and the laboratory findings for these patients.

METHODS

One hundred and six consecutive hospitalized patients with liver disease were evaluated for procalcitonin levels on admission. Fifteen of them (14.2%) had acute alcoholic hepatitis on cirrhotic background (group A), 20 (18.9%) had alcoholic cirrhosis without hepatitis and/or bacterial infection (group B), 16 (15.1%) had decompensated cirrhosis with proved bacterial infection (group C), 42 (39.6%) had uncomplicated viral hepatitis-related cirrhosis (group D) and 13 (12.3%) had acute icteric viral hepatitis (group E). Serum procalcitonin levels were measured using an immunoluminometric assay. Statistical analysis was based on Student's t-test and the non-parametric Kruskall-Wallis test (P<0.05).

RESULTS

Serum procalcitonin levels were significantly higher in cirrhotic patients with bacterial infection (9.80+/-16.80 ng/ml) than in those without bacterial infection (0.21+/-0.13 ng/ml, P=0.001), whereas they were within normal range (<0.5 ng/ml) in all patients with uncomplicated cirrhosis, irrespective of the cause of cirrhosis. Seven of 15 group A patients (46.2%) and 4/13 group E patients (30.8%), all of them cirrhotics, had procalcitonin levels higher than 0.5 ng/ml on admission, without established bacterial infection.

CONCLUSION

Serum procalcitonin levels remain below the threshold of 0.5 ng/ml in all patients with uncomplicated cirrhosis, irrespective of the cause of the disease, while they are significantly elevated when bacterial infection complicates the course of the disease. A significant proportion of patients with acute alcoholic hepatitis on a cirrhotic background as well as of patients with acute on chronic viral hepatitis, without bacterial infection, exhibit serum procalcitonin levels above 0.5 ng/ml, suggesting that this cut-off value is probably not enough to discriminate between patients with or without bacterial infection within these subgroups of patients with liver disease.

Procalcitonin kinetics in pediatric patients with systemic inflammatory response after open heart surgery

OBJECTIVE

To evaluate procalcitonin and C-reactive protein as markers of inflammation severity and their value in predicting development of organ failure after pediatric open heart surgery.

DESIGN

Prospective, observational, clinical study.

SETTING

Single university hospital.

PATIENTS

Thirty-three pediatric patients with systemic inflammatory response syndrome (SIRS; n=19) and SIRS+organ failure (SIRS+OF; n=14) following open heart surgery were included.

MEASUREMENTS AND RESULTS

Plasma procalcitonin and C-reactive protein levels were measured before and after the operation, and 1, 2, 3, and 4 days after surgery. Patients were evaluated daily to assess organ failure. Postoperative procalcitonin levels in the SIRS+OF group were significantly higher than in the SIRS group. C-reactive protein levels were similar between the groups throughout the study period. Peak procalcitonin levels were found to be positively correlated with aortic cross-clamp and cardiopulmonary bypass times, duration of mechanical ventilation, intensive care unit and hospital stay, mortality and organ failure development. Peak procalcitonin was found to be a good predictor of postoperative organ failure development and mortality. However, the predictive value of peak C-reactive protein for organ failure and mortality was found to be weak. Double-peak procalcitonin curves were observed in SIRS+OF patients with infection during the intensive care unit stay.

CONCLUSION

In the SIRS+OF group peak procalcitonin levels were found to be highly predictive for mortality and organ failure development, whereas C-reactive protein levels were not. Daily procalcitonin measurements in SIRS+OF patients may help identify the postoperative infection during the follow-up period.

The systemic inflammatory response syndrome

The systemic inflammatory response syndrome (SIRS) is the body's response to an infectious or noninfectious insult. Although the definition of SIRS refers to it as an "inflammatory" response, it actually has pro- and anti-inflammatory components. This review outlines the pathophysiology of SIRS and highlights potential targets for future therapeutic intervention in patients with this complex entity.

Endocrine markers of severity and prognosis in critical illness

The cellular processes that unfold in critical illness involve a variety of circulating substances, that may provide clinically relevant insight into the severity and outcome. Among hormonal markers, cortisol, several thyroid-related substances, as well as natriuretic peptides are discussed in this review. Glucose and lipids constitute metabolic markers, the identification and treatment of the former has been of particular importance. Among immune markers, both proinflammatory and anti-inflammatory cytokines, such as interleukin-6, contribute essential prognostic information. Finally, the complement and coagulation pathways also provide unique insight into this complex and heterogeneous process.

Serum procalcitonin in uncomplicated falciparum malaria: A preliminary study

BACKGROUND

Procalcitonin (PCT) has been found elevated in complicated forms of Plasmodium falciparum malaria. Its usefulness has almost never been assessed in uncomplicated falciparum malaria.

METHOD

We assessed diagnostic and prognostic value of PCT in a prospective series of 25 adults with uncomplicated P. falciparum malaria. Patients originated mainly from western Africa and were infected during a stay back in their native country (19 semi-immune and 6 non-immune subjects; 11 had not received any chemoprophylaxis).

RESULTS

Parasitaemia ranged from 0.01 to 3%. Eighteen patients had their first PCT determined at admission or within 24h thereafter (mean +/- SD: 3.0 +/- 4.6 ng/ml; range: 0.1-19.7). PCT was higher than 0.5 ng/ml in 14 patients (78%), higher than 2 ng/ml in 7 (39%). PCT correlated with parasitaemia (r = 0.53; p = 0.027), not with C-reactive protein (CRP). Delay between first symptoms and diagnosis was much longer among patients with PCT higher than 2 ng/ml than among those with a lower PCT.

CONCLUSION

PCT was often elevated in uncomplicated malaria, especially when delay between first symptoms and diagnosis was long or parasitaemia was high (prognostic marker).

Biomarkers of sepsis: clinically useful?

PURPOSE OF REVIEW

The purpose of this review is to indicate recent developments in biomarkers of sepsis and to evaluate their impact on clinical use. According to the 'surviving sepsis campaign,' diagnosis of sepsis and infection is urgent; early and specific treatment is most effective to reduce complications and to decrease mortality.

RECENT FINDINGS

A variety of biomarkers of sepsis is presently available. The diagnostic spectrum of the various markers, however, is different. Some primarily indicate severity of inflammation (e.g. interleukin-6), others respond to infection, but do not indicate the host response well (endotoxin, lipoprotein binding protein, triggering receptor on myeloid cells). There are new markers with limited clinical experience, for example triggering receptor on myeloid cells or mid-pro atrial natriuretic peptide (Seristra, Brahms AG, Hennigsdorf, Germany). Procalcitonin is a well-established biomarker of sepsis that fulfills several criteria of clinical needs: it responds both to infection and severity of inflammation and thus has an impact on therapy. Recent studies indicate that antibiotic treatment can also be guided by procalcitonin. Further indications, including diagnosis of invasive bacterial infections and diagnosis of sepsis in neonates and children have been reported recently.

SUMMARY

Recent data and cumulative analyses indicate that biomarkers of sepsis improve diagnosis of sepsis. However, only a few markers have impact on therapy and fulfill the clinical requirements. Procalcitonin is a well-established marker, indicating infection, sepsis, and progression to the more severe stages of the disease. Today, this biomarker should be in the diagnostic portfolio of an intensive care unit or emergency ward.

Diagnostic value and prognostic implications of serum procalcitonin after cardiac surgery: a systematic review of the literature

INTRODUCTION

Systemic inflammatory response syndrome is common after surgery, and it can be difficult to discriminate between infection and inflammation. We performed a review of the literature with the aims of describing the evolution of serum procalcitonin (PCT) levels after uncomplicated cardiac surgery, characterising the role of PCT as a tool in discriminating infection, identifying the relation between PCT, organ failure, and severity of sepsis syndromes, and assessing the possible role of PCT in detection of postoperative complications and mortality.

METHODS

We performed a search on MEDLINE using the keyword 'procalcitonin' crossed with 'cardiac surgery,' 'heart,' 'postoperative,' and 'transplantation.' Our search was limited to human studies published between January 1990 and June 2006.

RESULTS

Uncomplicated cardiac surgery induces a postoperative increase in serum PCT levels. Peak PCT levels are reached within 24 hours postoperatively and return to normal levels within the first week. This increase seems to be dependent on the surgical procedure and on intraoperative events. Although PCT values reported in infected patients are generally higher than in non-infected patients after cardiac surgery, the cutoff point for discriminating infection ranges from 1 to 5 ng/ml, and the dynamics of PCT levels over time may be more important than absolute values. PCT is superior to C-reactive protein in discriminating infections in this setting. PCT levels are higher with increased severity of sepsis and the presence of organ dysfunction/failure and in patients with a poor outcome or in those who develop postoperative complications. PCT levels typically remain unchanged after acute rejection but increase markedly after bacterial and fungal infections. Systemic infections are associated with greater PCT elevation than is local infection. Viral infections are difficult to identify based on PCT measurements.

CONCLUSION

The dynamics of PCT levels, rather than absolute values, could be important in identifying patients with infectious complications after cardiac surgery. PCT is useful in differentiating acute graft rejection after heart and/or lung transplantation from bacterial and fungal infections. Further studies are needed to define cutoff points and to incorporate PCT levels in useful prediction models.

Usefulness of procalcitonin levels in community-acquired pneumonia according to the patients outcome research team pneumonia severity index

STUDY OBJECTIVES

To evaluate the usefulness of procalcitonin serum levels as a predictor of etiology and prognosis in adult patients with community-acquired pneumonia (CAP) when they are stratified according to severity.

DESIGN

One-year, population-based, prospective study.

SETTING

University teaching hospital.

PATIENTS

All adult patients who received a diagnosis of CAP throughout the study period.

INTERVENTIONS AND MEASUREMENTS

An extensive noninvasive microbiological workup was performed. In patients who gave informed consent, a blood sample was collected at the time the diagnosis of CAP was established to measure biological markers. Procalcitonin levels were measured by a commercially available monoclonal immunoluminometric assay (limit of detection, 0.1 microg/L). Patients were classified according to microbial diagnosis, Patients Outcome Research Team pneumonia severity index (PSI), and outcome measures, and procalcitonin levels were compared among groups.

RESULTS

Of 240 patients who received a diagnosis of CAP during the study period, procalcitonin concentrations were measured in 185 patients (77.1%). Levels were higher in patients with high-severity risk classes (PSI classes III-V) [p = 0.01] and in those with complications (p = 0.03) or death (p < 0.0001). Among patients classified into PSI low-severity risk classes (classes I-II), levels tended to be higher in those with bacterial etiology (p = 0.08); in this group, a serum procalcitonin level > or = 0.15 microg/L was more frequently found in patients with bacterial pneumonia than in those with nonbacterial pneumonia (p = 0.03). In patients with higher-severity risk classes, no significant differences were observed in procalcitonin levels among etiologic groups, but higher concentrations were associated with development of complications (p = 0.01) and death (p < 0.0001).

CONCLUSIONS

Procalcitonin contribution to the evaluation of CAP varies according to severity. While procalcitonin may have a role to predict the microbial etiology in patients with a low PSI score, in patients classified within high PSI risk classes, it is a prognostic marker rather than a predictor of etiology.

Modulation and Source of Procalcitonin in Reduced Renal Function and Renal Replacement Therapy

Serum procalcitonin (PCT), an accurate marker of severe infection, is moderately increased in chronic kidney disease (CKD), peritoneal dialysis (PD) and haemodialysis (HD). We studied the extent of PCT elevation and factors accounting for elevated PCT in CKD and dialysis, and whether peripheral blood mononuclear cells (PBMC) contribute to increased PCT. In 37 controls, 281 CKD, 31 PD, and 65 HD patients without infection, PCT was measured and correlated with CKD stage, PD, HD, C-reactive protein (CRP), cardiovascular disease (CVD) and other clinical parameters. PCT release by PBMC from controls, advanced CKD, PD and HD patients (12 subjects each) was measured. PCT increased in parallel to the deterioration of CKD. Oliguria, advanced CKD, PD, HD, CVD and elevated CRP were independently associated with PCT elevation. PCT release from PBMC significantly increased in advanced CKD, PD and HD. PCT release from PBMC correlated closely with the corresponding serum PCT values (r=0.76, P <0.001). In the absence of infection, PCT may increase due to reduced renal elimination and increased synthesis, as due to PBMC. Furthermore, serum PCT could serve as a marker of low-grade inflammation and CVD, which substantially increase mortality in CKD and dialysis.