Usefulness of procalcitonin for diagnosis of infection in cardiac surgical patients

Kinetics of procalcitonin in cardiogenic shock and in septic shock. Preliminary data

BACKGROUND

In cardiac acute patients, data on procalcitonin (PCT) are controversial and the clinical interpretation of absolute PCT values represents a major challenge since they may be influenced by several factors. No data are so far available on the dynamics of PCT levels in patients with cardiogenic shock.

AIMS

to evaluate the serum evolution of PCT during intensive cardiac care unit (ICCU) staying in a group of 24 patients with cardiogenic shock (CS) following ST-elevation myocardial infarction (STEMI) submitted to primary percutaneous intervention (PCI) with no laboratory or clinical sign of infection. Furthermore we assessed the kinetics of PCT in a series of 24 patients with septic shock.

RESULTS

In septic shock, no significant difference was detectable in PCT kinetics between survivors (R2 = 0.90; P = 0.051) and non-survivors (R2 = 0.63; P = 0.204). In cardiogenic shock, survivors exhibited a significant reduction in PCT values (R2 = 0.94; P = 0.032) while non survivors did not (R2 = 0.68; P = 0.178).

CONCLUSIONS

differently from septic shock, cardiogenic shock following STEMI was associated with heterogeneous patterns of temporal PCT variations since only patients who survived exhibited a significant PCT reduction during ICCU stay. Our findings support the contention that the 'dynamic' approach may be more reliable that the static one especially in cardiogenic shock.

The value of serum procalcitonin level for differentiation of infectious from noninfectious causes of fever after orthopaedic surgery

BACKGROUND

Early diagnosis of postoperative orthopaedic infections is important in order to rapidly initiate adequate antimicrobial therapy. There are currently no reliable diagnostic markers to differentiate infectious from noninfectious causes of postoperative fever. We investigated the value of the serum procalcitonin level in febrile patients after orthopaedic surgery.

METHODS

We prospectively evaluated 103 consecutive patients with new onset of fever within ten days after orthopaedic surgery. Fever episodes were classified by two independent investigators who were blinded to procalcitonin results as infectious or noninfectious origin. White blood-cell count, C-reactive protein level, and procalcitonin level were assessed on days 0, 1, and 3 of the postoperative fever.

RESULTS

Infection was diagnosed in forty-five (44%) of 103 patients and involved the respiratory tract (eighteen patients), urinary tract (eighteen), joints (four), surgical site (two), bloodstream (two), and soft tissues (one). Unlike C-reactive protein levels and white blood-cell counts, procalcitonin values were significantly higher in patients with infection compared with patients without infection on the day of fever onset (p = 0.04), day 1 (p = 0.07), and day 3 (p = 0.003). Receiver-operating characteristics demonstrated that procalcitonin had the highest diagnostic accuracy, with a value of 0.62, 0.62, and 0.71 on days 0, 1, and 3, respectively. In a multivariate logistic regression analysis, procalcitonin was a significant predictor for postoperative infection on days 0, 1, and 3 of fever with an odds ratio of 2.3 (95% confidence interval, 1.1 to 4.4), 2.3 (95% confidence interval, 1.1 to 5.2), and 3.3 (95% confidence interval, 1.2 to 9.0), respectively.

CONCLUSIONS

Serum procalcitonin is a helpful diagnostic marker supporting clinical and microbiological findings for more reliable differentiation of infectious from noninfectious causes of fever after orthopaedic surgery.

Procalcitonin Levels as an Early Marker in Patients with Multiple Trauma under Intensive Care

This prospective study investigated the levels of procalcitonin (PCT) and C-reactive protein (CRP) in patients with various types and severity of multiple trauma, and their relationship to trauma-related complications. Adult multiple-trauma patients ( n = 113) admitted to the intensive care unit (ICU) in the first 24 h after trauma were included. The Injury Severity Scores (ISS), and PCT and CRP levels were measured in the first 24 h (day 1), on day 7 and on the final day of their ICU stay. Survival at 30 days was recorded. Mean PCT and CRP levels were both significantly higher on day 7 compared with day 1 and the final assessment day in patients with an ISS > 20. Levels of PCT were significantly higher in cases with sepsis, severe sepsis or septic shock compared with cases who developed systemic inflammatory response syndrome (SIRS), however levels of CRP were significantly higher only in cases with severe sepsis or septic shock, but not in cases with sepsis alone. These data support the view that PCT levels may be a better indicator than CRP levels in the early diagnosis of septic complications in patients with multiple trauma.

Procalcitonin in patients with acute coronary syndromes and cardiogenic shock submitted to percutaneous coronary intervention

Procalcitonin (PCT) is known to be a biological diagnostic marker for severe sepsis, or septic shock in critically ill patients. There are still contrasting data about a role of procalcitonin in patients with acute myocardial infarction or cardiogenic shock, and in those with acute coronary syndromes, that is, non-ST-elevation myocardial infarction or unstable angina. We evaluated plasma levels of procalcitonin and C-reactive protein (CRP) in 52 patients admitted to our intensive cardiac care unit (ICCU): 14 patients with cardiogenic shock (CS) following ST-elevation myocardial infarction (STEMI), 15 patients with uncomplicated ST-elevation myocardial infarction (STEMI), and 24 with non-ST-elevation myocardial infarction or unstable angina (NSTEMI/UA). In all patients, infective processes were excluded. Procalcitonin values were significantly higher in CS patients with respect to the other two subgroups (P < 0.001, P < 0.001) while CRP levels were higher than NSTEMI/UA patients (P < 0.001) but not with respect to STEMI patients (P = 0.063). No correlations were found in cardiogenic shock patients between CRP and PCT values (R = 0.02; P = 0.762, ns). Procalcitonin levels measured on ICCU admission are significantly higher in patients with cardiogenic shock following the acute myocardial infarction, and they are not correlated with those of CRP. The degree of myocardial ischemia (clinically indicated by the whole spectrum of ACS, from unstable angina to cardiogenic shock ST-elevation following myocardial infarction) and the related inflammatory-induced response are better reflected by CRP (which was positive in most acute cardiac care patients of all our subgroups), than by PCT which seems more reflective of a higher degree of inflammatory activation, being positive only in all CS patients.

Procalcitonin as a marker of postoperative complications

OBJECTIVE

Procalcitonin (PCT) is a 116 amino acid peptide that functions as a pro-hormone for calcitonin in the C cells of the thyroid gland. Large quantities of intact PCT are present in the blood of patients with sepsis, particularly when organ dysfunction occurs. PCT has been proposed as an early marker of postoperative complications. The aim of this study was to examine the diagnostic accuracy of PCT as a marker of postoperative complications by systematically reviewing the existing literature.

MATERIAL AND METHODS

The databases PubMed, Embase and the Cochrane Library were searched to find studies on the diagnostic accuracy of PCT in the postoperative phase. Primary studies were retrieved using specific inclusion and exclusion criteria.

RESULTS

A total of nine studies were included. These studies were heterogeneous regarding the spectrum of patients, complications, design and methodological quality according to QUADAS (quality assessment of studies of diagnostic accuracy). This could explain the marked variation in diagnostic accuracy. Considering all types of complications the sensitivity ranged from 37% to 100% and the specificity from 70% to 100%. On examining the infectious complications separately, it was found that the sensitivity ranged from 70% to 86% and the specificity from 45% to 98%.

CONCLUSIONS

Owing to a pronounced heterogeneity among the existing studies, the diagnostic accuracy of PCT as a marker for postoperative complications is not yet sufficiently clarified.

Serum concentrations of procalcitonin after cardiac surgery

BACKGROUND AND AIM

Monitoring of complications in patients undergoing cardiac surgery may be difficult because cardiopulmonary bypass (CPB) can lead to a systemic inflammatory response syndrome because of exposure of blood to nonphysiological surfaces. The purpose of the study was to establish the baseline levels of procalcitonin (PCT) after cardiac surgery in our population in order to analyze a possible induction of the inflammatory response that might interfere with the diagnosis of infection by PCT.

METHODS

Serum samples from patients undergoing coronary artery bypass grafting or valve replacement were collected at the time of admission to intensive care unit, after surgery as well as in the first and second postoperative days. Patients were followed for the development of postoperative complications. PCT levels were measured by immunoluminometric assay.

RESULTS

The mean PCT values were significantly higher in the first postoperative day in all the groups except the control group. No increased PCT levels were found related neither to duration of CPB, nor to time of aortic clamping. Only patients who presented complications had significantly increased PCT values immediately after surgery (p = 0.004), in the first postoperative day (p < 0.0001), and in the second postoperative day (p < 0.0001) with respect to those who recovered uneventfully.

CONCLUSIONS

A slight and transient increase in PCT levels was observed in the first postoperative day after cardiac surgery. Significant elevation of PCT was only observed when complications were present.

Should we abandon corticosteroids during septic shock? No

PURPOSE OF REVIEW

With the publication of the results of the recent CORTICUS trial, stress ('low') doses of corticosteroids for the treatment of vasopressor-dependent septic shock in adults can still be considered controversial. The purpose of this narrative review is to elaborate the pros and cons of this treatment in clinical practice and to formulate clinical and research directions.

RECENT FINDINGS

The recent CORTICUS study only shows a beneficial effect of stress doses of corticosteroids in the time interval to shock reversal and not on mortality, potentially explained by an increased risk for superinfection. The mortality in the placebo arm was relatively low and lower than in earlier randomized studies in which stress doses of corticosteroids had a favorable hemodynamic effect and conferred a survival benefit in septic shock.

SUMMARY

Treatment by stress doses of corticosteroids should not be abandoned during septic shock. Additional studies are needed, however, to better delineate the patient group with the highest likelihood to benefit from this therapy, as a function of severity of illness, response to adrenocorticotrophic hormone testing or both. For now, results of the CORTICUS study should not change current clinical practice of administering 200-300 mg of hydrocortisone daily (in divided doses) in case of fluid and vasopressor-insensitive septic shock and rapid tapering of this treatment on the basis of a hemodynamic response.

Procalcitonin in liver transplantation: are high levels due to donors or recipients?

Introduction

To date, a specific marker to evaluate and predict the clinical course or complication of the liver-transplanted patient is not available in clinical practice. Increased procalcitonin (PCT) levels have been found in infectious inflammation; poor organ perfusion and high PCT levels in the cardiac donor appeared to predict early graft failure. We evaluated PCT as a predictor of early graft dysfunction and postoperative complications.

Methods

PCT serum concentrations were measured in samples collected before organ retrieval from 67 consecutive brain-dead donors and in corresponding recipients from day 0, before liver transplantation, up to day 7 after liver transplantation. The following parameters were recorded in donors: amount of vasopressive drug doses, cardiac arrest history 24 hours before retrieval, number of days in the intensive care unit, age of donor, and infection in donor, and the following parameters were recorded in recipients: cold and warm ischemia time, veno-venous bypass, transfusion amount during orthotopic liver transplantation (OLT), and occurrence of postoperative complication or hepatic dysfunction.

Results

In the donor, the preoperative level of PCT was associated with cardiac arrest and high doses of catecholamines before organ retrieval. In the recipient, elevated PCT levels were observed early after OLT, with a peak at day 1 or 2 after OLT, then a decrease until day 7. A postoperative peak of PCT levels was associated neither with preoperative PCT levels in the donor or the recipients nor with hepatic post-OLT dysfunction or other postoperative complications, but with two donor parameters: infection and cardiac arrest.

Conclusion

PCT level in the donor and early PCT peak in the recipient are not predictive of post-OLT hepatic dysfunction or other complications. Cardiac arrest and infection in the donor, but not PCT level in the donor, are associated with high post-OLT PCT levels in the recipient.

Serum markers in community-acquired pneumonia and ventilator-associated pneumonia

PURPOSE OF REVIEW

This article reviews recent data on the usefulness of serum markers in community-acquired pneumonia and ventilator-associated pneumonia. The focus is on clinical studies, with an emphasis on adult critically ill patients.

RECENT FINDINGS

Serum markers have demonstrated potential value in early prediction and diagnosis of pneumonia, in monitoring the clinical course and in guiding antibiotic therapy. C-reactive protein appears to perform better in diagnosing infection, because several studies have shown that procalcitonin may remain undetectable in some patients, specifically those with pneumonia. Procalcitonin exhibited a better correlation with clinical severity, however. Furthermore, one report demonstrated the efficacy and safety of procalcitonin-guided antibiotic therapy in community-acquired pneumonia.

SUMMARY

Serum markers should only be used as a complementary tool to support the current clinical approach. Use of serum markers, in particular procalcitonin and C-reactive protein, represents a promising strategy in the clinical decision-making process in patients in whom pneumonia is suspected. Specifically, these markers can be used to guide culture sampling and empirical antibiotic prescription, and to monitor the clinical course, adjust the duration of antibiotic therapy and identify nonresponders, in whom an aggressive diagnostic and therapeutic approach may prevent further clinical deterioration.

Combination of biphasic transmittance waveform with blood procalcitonin levels for diagnosis of sepsis in acutely ill patients

OBJECTIVES

To assess the diagnostic utility of combining measurement of blood procalcitonin (PCT) concentrations with the presence of a biphasic transmittance waveform (BPW) from the activated partial thromboplastin time (aPTT) to identify sepsis in critically ill patients.

DESIGN

Prospective observational study.

SETTING

Thirty-one-bed university hospital department of medico-surgical intensive care.

PATIENTS

Two hundred consecutive adult patients admitted to the department during a 3-month period.

MEASUREMENTS AND MAIN RESULTS

aPTT waveform analysis was performed on admission and daily throughout the intensive care unit (ICU) stay. Receiver operating characteristic curves were created to determine the best threshold values of BPW and PCT for prediction of sepsis. Of the 200 patients, 63 (32%) had sepsis during the ICU stay; 29 (15%) patients were diagnosed with sepsis at admission. Using a threshold value of BPW slope_1 = -0.075%T/sec, 37 patients (19%) had a BPW at ICU admission and 84 (42%) at some time during the ICU stay. At this threshold, 23 of the patients (62%) with a BPW at admission and 51 (61%) with a BPW during the ICU stay were diagnosed with sepsis. Using a cut-off value of 1 ng/ml, 60 patients (30%) had abnormal PCT at admission, and 86 during the ICU stay. At this threshold, 24 of the patients (40%) with abnormal PCT at admission and 52 (60%) with abnormal PCT during the ICU stay were diagnosed with sepsis. Thirty patients had a BPW and an abnormal PCT, and 23 (77%) of these had sepsis. Of the other 170 patients, only six patients (4%) had sepsis. Hence, the sensitivity of the combination of BPW and PCT at admission was 79% and specificity 96%; the negative predictive value was 96%.

CONCLUSION

aPTT waveform analysis is an easy and rapid method for identification of sepsis; its combination with PCT increases its specificity.

Guidelines for evaluation of new fever in critically ill adult patients: 2008 update from the American College of Critical Care Medicine and the Infectious Diseases Society of America

OBJECTIVE

To update the practice parameters for the evaluation of adult patients who develop a new fever in the intensive care unit, for the purpose of guiding clinical practice.

PARTICIPANTS

A task force of 11 experts in the disciplines related to critical care medicine and infectious diseases was convened from the membership of the Society of Critical Care Medicine and the Infectious Diseases Society of America. Specialties represented included critical care medicine, surgery, internal medicine, infectious diseases, neurology, and laboratory medicine/microbiology.

EVIDENCE

The task force members provided personal experience and determined the published literature (MEDLINE articles, textbooks, etc.) from which consensus was obtained. Published literature was reviewed and classified into one of four categories, according to study design and scientific value.

CONSENSUS PROCESS

The task force met twice in person, several times by teleconference, and held multiple e-mail discussions during a 2-yr period to identify the pertinent literature and arrive at consensus recommendations. Consideration was given to the relationship between the weight of scientific evidence and the strength of the recommendation. Draft documents were composed and debated by the task force until consensus was reached by nominal group process.

CONCLUSIONS

The panel concluded that, because fever can have many infectious and noninfectious etiologies, a new fever in a patient in the intensive care unit should trigger a careful clinical assessment rather than automatic orders for laboratory and radiologic tests. A cost-conscious approach to obtaining cultures and imaging studies should be undertaken if indicated after a clinical evaluation. The goal of such an approach is to determine, in a directed manner, whether infection is present so that additional testing can be avoided and therapeutic decisions can be made.

Eosinopenia is a reliable marker of sepsis on admission to medical intensive care units

Introduction

Eosinopenia is a cheap and forgotten marker of acute infection that has not been evaluated previously in intensive care units (ICUs). The aim of the present study was to test the value of eosinopenia in the diagnosis of sepsis in patients admitted to ICUs.

Methods

A prospective study of consecutive adult patients admitted to a 12-bed medical ICU was performed. Eosinophils were measured at ICU admission. Two intensivists blinded to the eosinophils classified patients as negative or with systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, or septic shock.

Results

A total of 177 patients were enrolled. In discriminating noninfected (negative + SIRS) and infected (sepsis + severe sepsis + septic shock) groups, the area under the receiver operating characteristic curve was 0.89 (95% confidence interval (CI), 0.83 to 0.94). Eosinophils at <50 cells/mm³ yielded a sensitivity of 80% (95% CI, 71% to 86%), a specificity of 91% (95% CI, 79% to 96%), a positive likelihood ratio of 9.12 (95% CI, 3.9 to 21), and a negative likelihood ratio of 0.21(95% CI, 0.15 to 0.31). In discriminating SIRS and infected groups, the area under the receiver operating characteristic curve was 0.84 (95% CI, 0.74 to 0.94). Eosinophils at <40 cells/mm³ yielded a sensitivity of 80% (95% CI, 71% to 86%), a specificity of 80% (95% CI, 55% to 93%), a positive likelihood ratio of 4 (95% CI, 1.65 to 9.65), and a negative likelihood ratio of 0.25 (95% CI, 0.17 to 0.36).

Conclusion

Eosinopenia is a good diagnostic marker in distinguishing between noninfection and infection, but is a moderate marker in discriminating between SIRS and infection in newly admitted critically ill patients. Eosinopenia may become a helpful clinical tool in ICU practices.

Non-infectious causes of elevated procalcitonin and C-reactive protein serum levels in pediatric patients with hematologic and oncologic disorders

BACKGROUND

Procalcitonin (PCT) is considered a sensitive and specific diagnostic and prognostic marker of systemic bacterial infection, but its value is questionable in certain clinical conditions, particularly in hemato-oncological patients.

MATERIALS AND METHODS

We analyzed PCT and C-reactive protein (CRP) levels in 56 patients of a pediatric hematology-oncology unit during 110 consecutive non-infectious febrile episodes related to administration of T-cell antibodies (group A; n = 22), alemtuzumab (monoclonal CD52 antibody, CAMPATH-1H/group B; n = 8), interleukin-2 (IL-2/group C; n = 41), prophylactic donor granulocyte transfusions (group D; n = 9), or to acute graft-versus-host disease (aGvHD/group E; n = 10) and compared the results with 20 episodes of Gram-negative sepsis (group F).

MAIN RESULTS

In the majority of the non-infectious episodes PCT and CRP increased to serum levels statistically indistinguishable from Gram-negative sepsis. Median peak levels of PCT (normal < 0.5 ng/ml)/CRP (normal < 8 mg/l) for groups A-F were 4.34/59.0 (A), 10.14/93.5 (B), 1.11/175.0 (C), 1.43/164 (D), 0.96/34.0 (E), and 8.14 ng/ml /126.0 mg/l (F). Highest single levels were observed in groups A and F.

CONCLUSIONS

PCT and CRP are of limited value as diagnostic markers of sepsis during T-cell-directed immunomodulatory treatment, granulocyte support, or acute GvHD.

Accuracy of procalcitonin for sepsis diagnosis in critically ill patients: systematic review and meta-analysis

Procalcitonin is widely reported as a useful biochemical marker to differentiate sepsis from other non-infectious causes of systemic inflammatory response syndrome. In this systematic review, we estimated the diagnostic accuracy of procalcitonin in sepsis diagnosis in critically ill patients. 18 studies were included in the review. Overall, the diagnostic performance of procalcitonin was low, with mean values of both sensitivity and specificity being 71% (95% CI 67-76) and an area under the summary receiver operator characteristic curve of 0.78 (95% CI 0.73-0.83). Studies were grouped into phase 2 studies (n=14) and phase 3 studies (n=4) by use of Sackett and Haynes' classification. Phase 2 studies had a low pooled diagnostic odds ratio of 7.79 (95% CI 5.86-10.35). Phase 3 studies showed significant heterogeneity because of variability in sample size (meta-regression coefficient -0.592, p=0.017), with diagnostic performance upwardly biased in smaller studies, but moving towards a null effect in larger studies. Procalcitonin cannot reliably differentiate sepsis from other non-infectious causes of systemic inflammatory response syndrome in critically ill adult patients. The findings from this study do not lend support to the widespread use of the procalcitonin test in critical care settings.

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.

Early identification of intensive care unit-acquired infections with daily monitoring of C-reactive protein: a prospective observational study

INTRODUCTION

Manifestations of sepsis are sensitive but are poorly specific of infection. Our aim was to assess the value of daily measurements of C-reactive protein (CRP), temperature and white cell count (WCC) in the early identification of intensive care unit (ICU)-acquired infections.

METHODS

We undertook a prospective observational cohort study (14 month). All patients admitted for > or =72 hours (n = 181) were divided into an infected (n = 35) and a noninfected group (n = 28). Infected patients had a documented ICU-acquired infection and were not receiving antibiotics for at least 5 days before diagnosis. Noninfected patients never received antibiotics and were discharged alive. The progression of CRP, temperature and WCC from day -5 to day 0 (day of infection diagnosis or of ICU discharge) was analyzed. Patients were divided into four patterns of CRP course according to a cutoff value for infection diagnosis of 8.7 mg/dl: pattern A, day 0 CRP >8.7 mg/dl and, in the previous days, at least once below the cutoff; pattern B, CRP always >8.7 mg/dl; pattern C, day 0 CRP < or =8.7 mg/dl and, in the previous days, at least once above the cutoff; and pattern D, CRP always < or =8.7 mg/dl.

RESULTS

CRP and the temperature time-course showed a significant increase in infected patients, whereas in noninfected it remained almost unchanged (P < 0.001 and P < 0.001, respectively). The area under the curve for the maximum daily CRP variation in infection prediction was 0.86 (95% confidence interval: 0.752-0.933). A maximum daily CRP variation >4.1 mg/dl was a good marker of infection prediction (sensitivity 92.1%, specificity 71.4%), and in combination with a CRP concentration >8.7 mg/dl the discriminative power increased even further (sensitivity 92.1%, specificity 82.1%). Infection was diagnosed in 92% and 90% of patients with patterns A and B, respectively, and in only two patients with patterns C and D (P < 0.001).

CONCLUSION

Daily CRP monitoring and the recognition of the CRP pattern could be useful in the prediction of ICU-acquired infections. Patients presenting maximum daily CRP variation >4.1 mg/dl plus a CRP level >8.7 mg/dl had an 88% risk of infection.

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.

New diagnostic and prognostic markers of ventilator-associated pneumonia

PURPOSE OF REVIEW

The purpose of this review is to analyze the potential advantages and drawbacks of using biomarkers of bacterial infection for the diagnosis and prognosis of ventilator-associated pneumonia.

RECENT FINDINGS

Whereas procalcitonin and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) have both greater diagnostic accuracies than most commonly used clinical parameters and other biomarkers of infection, such as C-reactive protein, they can be increased in noninfectious conditions or remain low in patients with true infection. Furthermore, these assays cannot determine the causative organisms and associated patterns of antibiotic susceptibility.

SUMMARY

Procalcitonin and sTREM-1 should be used only as a complementary tool, to reinforce the usual diagnostic work-up. However, serial serum procalcitonin and sTREM-1 measurements may provide an opportunity to change the treatment early in the course of patients with ventilator-associated pneumonia, either to intensify treatment when their levels stay high, or to avoid unnecessary prolonged courses of antibiotics when their levels rapidly decrease. Whether procalcitonin and/or sTREM-1 guidance can reduce antibiotic use in such a setting will require additional studies, but such a strategy appears promising.

[Role of plasma procalcitonin determination in the postoperative follow-up of cephalic pancreatoduodenectomy]

BACKGROUND

Procalcitonin (PCT) is widely accepted as an early marker of the severity of sepsis and its prognosis. This study was designed to evaluate the utility of PCT in the early diagnosis of immediate postoperative complications (infectious and non-infectious) following cephalic pancreatoduodenectomy (PD).

PATIENTS AND METHOD

Thirty-one patients who underwent elective PD were prospectively analyzed. The patients were divided into two groups according to the presence or absence of postoperative complications. Plasma PCT concentrations were determined by an immunochromatographic method. The correlation between PCT concentrations and the presence of complications, as well as the existence of statistically significant differences in PCT concentrations between the 2 groups of patients, were analyzed. The value of plasma PCT concentrations in predicting complications compared with that of other biochemical variables (C-reactive protein, lactic acid, base excess) and clinical parameters (systemic inflammatory response syndrome) was analyzed.

RESULTS

Significant differences in PCT concentrations were found between the two groups. An inverse correlation between marker levels and patient outcome was observed. The variables that best predicted the development of complications were PCT concentrations and axillary temperature.

CONCLUSIONS

Plasma PCT should be taken into account as a useful marker for postoperative clinical course in the follow-up of PD and for the early detection of non-infectious complications.

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.

Quantitative analysis of procalcitonin after pediatric cardiothoracic surgery

Procalcitonin appears to be an early and sensitive marker of bacterial infection in a variety of clinical settings. The use of levels of procalcitonin to predict infection in children undergoing cardiac surgery, however, may be complicated by the systemic inflammatory response that normally accompanies cardiopulmonary bypass. The aim of our study was to estimate peri-operative concentrations of procalcitonin in non-infected children undergoing cardiac surgery. Samples of serum for assay of procalcitonin were obtained in 53 patients at baseline, 24, 48, and 72 hours following cardiac surgery. Concentrations were assessed using an immunoluminetric technique. Median concentrations were lowest at baseline at less than 0.5 nanograms per millilitre, increased at 24 hours to 1.8 nanograms per millilitre, maximized at 48 hours at 2.1 nanograms per millilitre, and decreased at 72 hours to 1.3 nanograms per millilitre, but did not return to baseline levels. Ratios of concentrations between 24, 48 and 72 hours after surgery as compared to baseline were 6.15, with 95 percent confidence intervals between 4.60 and 8.23, 6.49, with 95 percent confidence intervals from 4.55 to 9.27, and 4.26, with 95 percent confidence intervals between 2.78 and 6.51, respectively, with a p value less than 0.001. In 8 patients, who had no evidence of infection, concentrations during the period from 24 to 72 hours were well above the median for the group. We conclude that concentrations of procalcitonin in the serum increase significantly in children following cardiac surgery, with a peak at 48 hours, and do not return to baseline within 72 hours of surgery. A proportion of patients, in the absence of infection, had exaggerated elevations post-operatively.

Procalcitonin does discriminate between sepsis and systemic inflammatory response syndrome

AIMS

To evaluate whether procalcitonin (PCT) and C reactive protein (CRP) are able to discriminate between sepsis and systemic inflammatory response syndrome (SIRS) in critically ill children.

METHODS

Prospective, observational study in a paediatric intensive care unit. Kinetics of PCT and CRP were studied in patients undergoing open heart surgery with cardiopulmonary bypass (CPB) (SIRS model; group I1) and patients with confirmed bacterial sepsis (group II).

RESULTS

In group I, PCT median concentration was 0.24 ng/ml (reference value <2.0 ng/ml). There was an increment of PCT concentrations which peaked immediately after CPB (median 0.58 ng/ml), then decreased to 0.47 ng/ml at 24 h; 0.33 ng/ml at 48 h, and 0.22 ng/ml at 72 h. CRP median concentrations remained high on POD1 (36.6 mg/l) and POD2 (13.0 mg/l). In group II, PCT concentrations were high at admission (median 9.15 ng/ml) and subsequently decreased in 11/14 patients who progressed favourably (median 0.31 ng/ml). CRP levels were high in only 11/14 patients at admission. CRP remained high in 13/14 patients at 24 h; in 12/14 at 48 h; and in 10/14 patients at 72 h. Median values were 95.0, 50.9, 86.0, and 20.3 mg/l, respectively. The area under the ROC curve was 0.99 for PCT and 0.54 for CRP. Cut off concentrations to differentiate SIRS from sepsis were >2 ng/ml for PCT and >79 mg/l for CRP.

CONCLUSION

PCT is able to differentiate between SIRS and sepsis while CRP is not. Moreover, unlike CRP, PCT concentrations varied with the evolution of sepsis.

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.

Monitoring therapeutic interventions in critically ill septic patients

Sepsis is the leading cause of admission to intensive care units in the United States. Although the treatment of sepsis is complex and multimodal, nutrition support plays an important role in the management of these patients. The diagnosis of sepsis, disease category, and severity of illness and the change in sepsis severity and organ function over time affect the delivery of nutrition support. This paper reviews the diagnostic criteria of sepsis, the use of "sepsis biomarkers," and regional and global markers of organ function in sepsis and quantitative measures of illness severity and organ dysfunction.

Dynamics of serum procalcitonin in patients after major neurosurgery

Classical markers of infection cannot differentiate reliably between inflammation and infection after neurosurgery. This study investigated the dynamics of serum procalcitonin (PCT) in patients following major neurosurgery. PCT concentrations remained < 0.2 ng/mL during the post-operative course. In contrast, leukocyte and neutrophil counts, as well as C-reactive protein (CRP) levels, increased significantly post-operatively (leukocytes, range 7.1-23.7 x 10(9)/L, p < 0.001; neutrophils, range 70.8-94.5%, p < 0.001; CRP, median 14 mg/L, range 3-95 mg/L, p < 0.001). Analysis of PCT levels using assays with improved sensitivity may be useful in the diagnosis of neurosurgical patients with post-operative fever of unknown origin.

Serum albumin and clinical outcome in pediatric cardiac surgery

OBJECTIVE

We evaluated the behavior of serum albumin concentrations in response to metabolic stress that is associated with cardiac surgery and the role of this protein as a predictor of clinical outcome in children at high surgical risk who undergo operative correction of congenital heart defects.

METHODS

Serum albumin concentrations were measured in 30 children who had heart disease and were at high surgical risk. Analyses were performed before surgery, on the second postoperative day, and on discharge from the intensive care unit. Preoperative serum concentrations of albumin were compared with those of a control group that consisted of 20 healthy and well-nourished children.

RESULTS

Preoperative albumin concentrations of patients were lower than those of the control group (3.4+/-0.25 g/dL versus 4.0+/-0.18 g/dL, P<0.05). Serum levels decreased on the second postoperative day and at discharge from the intensive care unit (3.1+/-0.65 g/dL and 3.2+/-0.44 g/dL, P<0.05) compared with preoperative concentrations. Preoperative concentrations lower than 3.0 g/dL were associated with increased postsurgical infection (P=0.0026) and with increased mortality (P=0.0138). Patients whose postoperative levels were lower than 3.0 g/dL had longer hospital stays compared with those whose concentrations were higher than 3.0 g/dL (14.5+/-1.3 d versus 10+/-2.2 d, P<0.05).

CONCLUSION

The results suggest that hypoalbuminemia is common among children who have heart disease and are at high surgical risk, and serum albumin concentrations lower than 3 g/dL may be related to outcome in the period after cardiac surgery.

C-reactive protein as a marker of infection in critically ill patients

A prospective, observational study was conducted in a medico-surgical intensive care unit to assess the value of C-reactive protein (CRP), temperature and white cell count (WCC) measurements for the diagnosis of infection in critically ill patients. CRP, temperature and WCC were monitored daily in 76 infected and 36 non-infected patients. Multiple receiver-operating characteristics (ROC) curves were used to compare each parameter for infection diagnosis. The area under the curve (AUC) of CRP was significantly higher than that of temperature (0.93 and 0.75, respectively; p < 0.001). A CRP concentration of >8.7 mg/dL and a temperature of >38.2 degrees C were associated with infection, with a sensitivity of 93.4% and 54.8%, and a specificity of 86.1% and 88.9%, respectively. The ROC curve of WCC showed a poor diagnostic performance. The combination of CRP and temperature increased the specificity for infection diagnosis to 100%. In the subgroup of patients with ventilator-associated pneumonia (n = 48), CRP measurements were more reliable than temperature (AUC 0.92 and 0.78, respectively; p 0.006). The CRP levels in infected patients with sepsis, severe sepsis and septic shock were 15.2 +/- 8.2, 20.3 +/- 10.9 and 23.3 +/- 8.7 mg/dL, respectively (p 0.044). It was concluded that CRP was a better marker of infection than temperature. However, the combination of CRP and temperature measurements further increased the specificity for infection diagnosis, even in the subgroup of patients with VAP.

Interleukin-6, interleukin-8, and a rapid and sensitive assay for calcitonin precursors for the determination of bacterial sepsis in febrile neutropenic children

OBJECTIVE

Children with cancer often develop febrile illnesses after cytotoxic chemotherapy. Determining which children have serious bacterial infections in this vulnerable period would be valuable. We evaluated the ability of a rapid and sensitive assay for the concentration of calcitonin precursors (CTpr) as a sensitive diagnostic marker for bacterial sepsis in febrile, neutropenic children and determined the utility of measuring cytokines to improve the predictive value of this approach.

DESIGN

Prospective cohort study.

SETTING

Academic children's hospital.

PATIENTS

Fifty-six children (aged 5 months to 17 yrs) with a known malignancy who presented with fever and neutropenia.

INTERVENTIONS

Serial blood samples were obtained (admission, 24 hrs, and 48 hrs), and concentrations of CTpr, interleukin-6, and interleukin-8 were determined. Demographic and laboratory data from the patients were collected from the medical record.

MEASUREMENTS AND MAIN RESULTS

Sixteen (29%) of the children met the criteria for bacterial sepsis. Plasma levels of CTpr and interleukin-8, but not interleukin-6, were increased at all time points in children with sepsis compared with those without sepsis. CTpr at 24 and 48 hrs after admission were reliable markers for sepsis (area under the curve = 0.92 and 0.908, respectively). Logistic regression using CTpr at 24 hrs in addition to interleukin-8 at 48 hrs produced the best-fit models associated with sepsis. Using cutoff values of CTpr >500 pg/mL and interleukin-8 >20 pg/mL produced a screening test for sepsis with 94% sensitivity and 90% specificity.

CONCLUSIONS

Our data show the utility of a rapid and sensitive assay for CTpr combined with interleukin-8 as a highly sensitive and specific diagnostic marker of bacterial sepsis in febrile, neutropenic children. The use of these markers as a clinical tool may allow for better prognostication for clinicians and may eventually lead to more targeted therapies for this heterogeneous population.

Pleural fluid and serum procalcitonin as diagnostic tools in tuberculous pleurisy

BACKGROUND

Diagnosis of tuberculous pleuritis is difficult because of its nonspecific clinical presentation and decreased efficiency of traditional diagnostic methods. We investigated the use of procalcitonin (PCT) concentration in tuberculous pleuritis diagnosis.

METHODS

A prospective clinical study was performed with two different patient groups. A total of 28 patients were included: 18 with tuberculosis and 10 with nontuberculous pleurisy. Serum and pleural fluid PCT concentrations were evaluated before treatment.

RESULTS

Serum and pleural fluid PCT concentrations were statistically different between tuberculous and nontuberculous pleurisy groups (P = 0.012 and P = 0.004, respectively), even though they were not elevated in relation to the cut-off level of 0.5 ng/mL. A positive and significant correlation was detected between serum and pleural fluid PCT levels (r = 0.49, P = 0.008). Diagnostic specificity and sensitivity values for serum and pleural fluid PCT in discriminating tuberculous from nontuberculous pleurisy were 80% and 72.2%, and 90% and 66.7% at the 0.081 and 0.113 ng/mL cut-off values, respectively.

CONCLUSION

Relative to the current cut-off level of 0.5 ng/mL, PCT concentration is not a useful parameter for the diagnosis of tuberculous pleurisy. Because there were PCT levels in patients with tuberculous pleurisy that were below the current cut-off level but were significantly different from those of the nontuberculous group, the use of PCT should be further investigated.

Serum procalcitonin and C-reactive protein levels as markers of bacterial infection: a systematic review and meta-analysis

A meta-analysis was performed to evaluate the accuracy of determination of procalcitonin (PCT) and C-reactive protein (CRP) levels for the diagnosis of bacterial infection. The analysis included published studies that evaluated these markers for the diagnosis of bacterial infections in hospitalized patients. PCT level was more sensitive (88% [95% confidence interval [CI], 80%-93%] vs. 75% [95% CI, 62%-84%]) and more specific (81% [95% CI, 67%-90%] vs. 67% [95% CI, 56%-77%]) than CRP level for differentiating bacterial from noninfective causes of inflammation. The Q value for PCT markers was higher (0.82 vs. 0.73). The sensitivity for differentiating bacterial from viral infections was also higher for PCT markers (92% [95% CI, 86%-95%] vs. 86% [95% CI, 65%-95%]); the specificities were comparable (73% [95% CI, 42%-91%] vs. 70% [95% CI, 19%-96%]). The Q value was higher for PCT markers (0.89 vs. 0.83). PCT markers also had a higher positive likelihood ratio and lower negative likelihood ratio than did CRP markers in both groups. On the basis of this analysis, the diagnostic accuracy of PCT markers was higher than that of CRP markers among patients hospitalized for suspected bacterial infections.

Procalcitonin and C-reactive protein kinetics in postoperative pediatric cardiac surgical patients

OBJECTIVE

To determine the kinetics of procalcitonin (PCT) and C-reactive protein (CRP) concentration after pediatric cardiac surgery with cardiopulmonary bypass.

DESIGN

Prospective, clinical cohort study.

SETTING

A fifteen-bed tertiary-care pediatric intensive care unit.

PATIENTS

Fourteen pediatric patients admitted for cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Serum PCT and CRP were measured before cardiopulmonary bypass (CPB); after CPB; and on the first, second, and third days after surgery by means of immunoluminometry and nephelometry, respectively. Reference values for systemic inflammatory response syndrome are 0.5 to 2.0 ng/mL for PCT and <5 mg/L for CRP. Baseline serum PCT and CRP concentrations were 0.24 +/- 0.13 ng/mL and 4.06 +/- 3.60 mg/L (median 25th percentile-75th percentile), respectively. PCT concentrations increased progressively from the end of CPB (0.62 +/- 0.30 ng/mL), peaked at 24 hours postoperatively (POD1) (0.77 +/- 0.49 ng/mL), and began to decrease at 48 hours or POD2 (0.35 +/- 0.21 ng/mL). CRP increased just after CPB (58.82 +/- 42.23 mg/L) and decreased after 72 hours (7.09 +/- 9.81 mg/L).

CONCLUSION

An increment of both PCT and CRP was observed just after CPB. However, PCT values remained within reference values, whereas CRP concentrations increased significantly after CPB until the third day. These preliminary results suggest that PCT was more effective than CRP to monitor patients with SIRS and a favorable outcome.

Procalcitonin: improved biochemical severity stratification and postoperative monitoring in severe abdominal inflammation and sepsis

BACKGROUND

Infections and sepsis are among the most devastating complications in abdominal surgery and significantly contribute to morbidity and mortality. Early and reliable diagnosis of septic complications is notoriously difficult, and the search for novel approaches to overcome this problem is still a compelling issue for clinicians. Among a large array of inflammatory parameters, procalcitonin (PCT), the 116-amino-acid pro-peptide of calcitonin, has gained considerable importance in identifying patients at risk of developing infection and sepsis in clinical practice.

METHODS

Along with the latest insights into pathophysiological aspects of this pro-hormone, the literature as well as our own experience on the usefulness of PCT determinations in patients with severe inflammatory abdominal disorders was reviewed.

RESULTS

Although the term "sepsis" does not embrace the integral properties of PCT, a remarkable number of clinical studies have demonstrated the pivotal role of this parameter in the host response to microbial and fungal infections. In acute pancreatitis PCT allows early severity stratification and closely correlates with the development of subsequent pancreatic infections. In patients with peritonitis PCT reflects overall disease severity and is an early and reliable indicator of overall prognosis. Postoperative monitoring of PCT is a helpful tool to identify patients with evolving or persisting septic complications after elective and emergency abdominal surgery.

CONCLUSIONS

Compared with established biochemical routine variables, PCT significantly contributes to earlier and better stratification of patients at risk of developing septic complications and provides excellent prognostic assessment in severe abdominal inflammation. The currently available test systems render PCT an applicable and readily available parameter under clinical routine and emergency conditions.

Calcitonin precursors: early markers of gut barrier dysfunction in patients with acute pancreatitis

BACKGROUND

Severe acute pancreatitis is associated with an early increase in intestinal permeability and endotoxemia. Endotoxin is a potent stimulator for the production and release of procalcitonin and its components (calcitonin precursors; [CTpr]). The aim of this study is to evaluate the role of plasma CTpr as an early marker for gut barrier dysfunction in patients with acute pancreatitis.

METHODS

Intestinal permeability to macromolecules (polyethylene glycol 3350), serum endotoxin and antiendotoxin core antibodies, plasma CTpr, and serum C-reactive protein (CRP) were measured on admission in 60 patients with acute pancreatitis. Attacks were classified as mild (n = 48) or severe (n = 12) according to the Atlanta criteria.

RESULTS

Compared with mild attacks of acute pancreatitis, severe attacks were significantly associated with an increase in intestinal permeability index (median: 0.02 vs. 0.006, P < 0.001), the frequency of endotoxemia (73% vs. 41%, P = 0.04), and the extent of depletion of serum IgM antiendotoxin antibodies (median: 43 MMU vs. 100 MMU, P = 0.004). Plasma CTpr levels were significantly elevated in patients with severe attacks compared with mild attacks on both the day of admission and on day 3 (median: 64 vs. 22 fmol/mL, P = 0.03; and 90 vs. 29 fmol/mL, P = 0.003 respectively). A positive and significant correlation was observed between the admission serum endotoxin and plasma CTpr levels on admission (r = 0.7, P < 0.0001) and on day 3 (r = 0.96, P < 0.0001), and between plasma CTpr on day 7 and the intestinal permeability index (r = 0.85, P = 0.0001). In contrast, only a weak positive correlation was observed between peak serum levels of CRP and plasma CTpr on admission (r = 0.3, P = 0.017) and on day 7 (r = 0.471, P = 0.049), as well as between CRP and each of the admission serum endotoxin (r = 0.3, P = 0.03) and the intestinal permeability index (r = 0.375, P = 0.007).

CONCLUSIONS

In patients with acute pancreatitis, plasma concentrations of CTpr appear to reflect more closely the derangement in gut barrier function rather than the extent of systemic inflammation.

Staphylococcus aureus bacteremia after median sternotomy: clinical utility of blood culture results in the identification of postoperative mediastinitis

BACKGROUND

Mediastinitis is a complication of coronary artery bypass graft surgery (CABG) that can be difficult to diagnose. This study evaluated the utility of blood culture results in identifying patients with mediastinitis.

METHODS AND RESULTS

All unique patients undergoing CABG at our institution over a 60-month study period (n=5500) and all blood cultures performed on these patients <or=90 days after CABG were identified. Mediastinitis was identified by prospective active infection control surveillance. Eight hundred fifty-five (15.5%) patients had >or=1 blood culture drawn within 90 days of CABG. Mediastinitis occurred in 46 of 60 (76.7%) patients with blood cultures positive for Staphylococcus aureus, 15 of 126 (11.9%) patients with blood cultures positive for other pathogens, 37 of 669 (5.5%) patients with blood cultures with no growth, and 44 of 4645 (0.9%) patients with no blood cultures obtained. The isolation of S aureus from even 1 blood culture drawn after <or=90 days of CABG was strongly associated with mediastinitis (likelihood ratio [LR], 25; 95% CI, 14.7 to 44.4). Bacteremia attributable to other organisms did not alter pretest suspicion for mediastinitis (LR, 1.0; 95% CI, 0.6 to 1.7). Patients with negative blood cultures were less likely to have mediastinitis (LR, 0.45; 95% CI, 0.35 to 0.58). The association between S aureus bacteremia and mediastinitis remained highly significant when all unique patients undergoing CABG were analyzed in a logistic regression model and when a case-control analysis was used to evaluate patients with >or=1 blood culture obtained after CABG.

CONCLUSIONS

Among patients with blood cultures drawn after CABG, S aureus bacteremia strongly suggests the presence of mediastinitis.

Comparison of procalcitonin and C-reactive protein as markers of sepsis

OBJECTIVE

To compare the clinical informative value of procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations in the detection of infection and sepsis and in the assessment of severity of sepsis.

DESIGN

Prospective study.

SETTING

Medicosurgical intensive care unit.

PATIENTS

Seventy consecutive adult patients who were admitted to the intensive care unit for an expected stay >24 hrs.

INTERVENTIONS

None.

MEASUREMENTS

PCT and CRP plasma concentrations were measured daily during the intensive care unit stay. Each patient was examined daily for signs and symptoms of infection and was classified daily in one of the following four categories according to the American College of Chest Physicians/Society of Critical Care Medicine criteria: negative, systemic inflammatory response syndrome, localized infection, and sepsis group (sepsis, severe sepsis, or septic shock). The severity of sepsis-related organ failure was assessed by the sepsis-related organ failure assessment score.

MAIN RESULTS

A total of 800 patient days were classified into the four categories. The median plasma PCT concentrations in noninfected (systemic inflammatory response syndrome) and localized-infection patient days were 0.4 and 1.4 ng/mL (p <.0001), respectively; the median CRP plasma concentrations were 79.9 and 85.3 mg/L (p =.08), respectively. The area under the receiver operating characteristic curve was 0.756 for PCT (95% confidence interval [CI], 0.675-0.836), compared with 0.580 for CRP (95% CI, 0.488-0.672) (p <.01). The median plasma PCT concentrations in nonseptic (systemic inflammatory response syndrome) and septic (sepsis, severe sepsis, or septic shock) patient days were 0.4 and 3.65 ng/mL (p <.0001), respectively, whereas those for CRP were 79.9 and 115.6 mg/L (p <.0001), respectively. The area under the receiver operating characteristic curve was 0.925 for PCT (95% CI, 0.899-0.952), compared with 0.677 for CRP (95% CI, 0.622-0.733) (p <.0001). The linear correlation between PCT plasma concentrations and the four categories was much stronger than in the case of CRP (Spearman's rho, 0.73 vs. 0.41; p <.05). A rise in sepsis-related organ failure assessment score was related to a higher median value of PCT but not CRP.

CONCLUSION

PCT is a better marker of sepsis than CRP. The course of PCT shows a closer correlation than that of CRP with the severity of infection and organ dysfunction.

Procalcitonin as a diagnostic test for sepsis: health technology assessment in the ICU

Elevation in the serum concentration of procalcitonin (PCT) is associated with systemic infection. This association has led to the proposed use of PCT as a novel biomarker of bacterial sepsis. The advantages and limitations of the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) definitions of sepsis are an important consideration that affects the impact of any diagnostic test for sepsis and these issues are discussed. Our main objective is to perform a systematic health technology assessment of PCT as a diagnostic test for sepsis. In an adult intensive care unit (ICU) population, we identify a specific and important question-can PCT accurately distinguish sepsis in patients with systemic inflammatory response syndrome (SIRS) who have a suspected infection? Likelihood ratios are calculated from published data to attempt to find the best answer. The published evidence does not support a general claim that PCT is a useful decision support tool for diagnosing sepsis in patients who have SIRS. Procalcitonin has a slightly better ability to exclude the diagnosis of sepsis. The role for using PCT testing in the ICU will continue to evolve along with our understanding and definition of sepsis.

Calcitonin precursors in the prediction of severity of acute pancreatitis on the day of admission

BACKGROUND

Calcitonin precursors are sensitive markers of inflammation and infection. The aim of this study was to evaluate the role of plasma calcitonin precursor levels on the day of admission in the prediction of severity of acute pancreatitis, and to compare this with the Acute Physiology And Chronic Health Evaluation (APACHE) II scoring system.

METHODS

Plasma concentrations of calcitonin precursors were determined on admission in 69 patients with acute pancreatitis. APACHE II scores were calculated on admission. Attacks were classified as mild (n = 55) or severe (n = 14) according to the Atlanta criteria. Plasma calcitonin precursor levels were determined with a sensitive radioimmunoassay.

RESULTS

On the day of hospital admission, plasma levels of calcitonin precursors were significantly greater in patients with a severe attack compared with levels in those with a mild attack of pancreatitis (median 64 versus 25 fmol/ml; P = 0.014), but the APACHE II scores were no different (median 9 versus 8; P = 0.2). The sensitivity, specificity, positive predictive and negative predictive values, and accuracy for the prediction of severe acute pancreatitis were 67, 89, 57, 93 and 85 per cent respectively for plasma calcitonin precursor levels higher than 48 fmol/ml, and 69, 45, 23, 86 and 50 per cent respectively for an APACHE II score greater than 7. Differences in the specificity and accuracy of the two prognostic indicators were significant (P < 0.001 and P = 0.001 respectively). A plasma calcitonin precursor concentration of more than 160 fmol/ml on admission was highly accurate (94 per cent) in predicting the development of septic complications and death.

CONCLUSION

The assay of plasma calcitonin precursors on the day of admission to hospital has the potential to provide a more accurate prediction of the severity of acute pancreatitis than the APACHE II scoring system.

Procalciton: A new marker and mediator of systemic inflammatory response of the host to infection

<zakljucak> Prokalcitonin je medijator generalizovane reakcije domacina na infekciju, koji poseduje znacajan imunomodulatorni efekat. Indukcija PCT i porast njegovog nivoa u plazmi povezani su sa ekstenzivnoscu i tipom sistemske inflamacije, a njegova koncentracija se naglo smanjuje posle saniranja inflamacije. Kod bolesnika sa sepsom PCT je odlican dijagnosticki i prognosticki marker i veoma dobar parametar za procenu uspeha terapijskog tretmana i klinickog toka septickog procesa. Rutinsko odredjivanje njegove koncentracije u krvi moze popraviti laboratorijsko pracenje bolesnika sa sepsom.

[Frequency of postoperative fever in children with congenital heart disease undergoing cardiovascular surgery and associated risk factors]

OBJECTIVES

To determine the frequency of postoperative fever in children with congenital heart disease who undergo cardiovascular surgery, and the risk factors associated.

PATIENTS AND METHODS

In a prospective cohort study, 100 children under the age of less than 9 years were followed-up during hospitalization in order to detect fever after cardiac surgery. Preoperative, perioperative, and postoperative variables were assessed to determine their relationship with postoperative fever. The cases were patients who developed fever. Multivariate analysis was used, and the odds ratio (OR) and 95% confidence intervals (95% CI) were calculated.

RESULTS

The frequency of postoperative fever was 46%. Fever appeared within 24 hours of surgery in 56% cases. In 32/46 (70%) cases, fever remitted within 72 hours. Fever was more common in patients who underwent open-heart surgery than in those treated with a closed technique (28 vs. 18, P = 0.045). Prolonged extracorporeal circulation (OR = 1.024; 95% CI, 1.004-1.045), aortic cross-clamping (OR = 2.83; 95% CI, 1.21-6.61) and postoperative infections (OR = 24.07; 95% CI, 7.2-75.0) were the risk factors associated with the development of postoperative fever.

CONCLUSIONS

Postoperative fever is common in children with congenital heart disease. The identification of risk factors associated to the development of fever should help clinicians to identify the cause of fever in this group of patients.

Pediatric sepsis and multiple organ dysfunction syndrome

Systemic inflammatory response syndrome may be viewed as the systemic expression of cytokine signals that normally function on an autocrine or paracrine level. Sepsis is defined as systemic inflammatory response syndrome caused by an infection. Multiple organ dysfunction syndrome may represent the end stage of severe systemic inflammatory response syndrome or sepsis. Many cells are involved, including endothelial cells and leukocytes and multiple proinflammatory and antiinflammatory mediators (cytokines, oxygen free radicals, coagulation factors, and so forth). Various pathophysiologic mechanisms have been postulated. The most popular theory is that the inflammatory process loses its autoregulatory capacity; however, microcirculatory dysregulation and apoptosis may also be important, and a new paradigm posits a complex nonlinear system. Many new treatments have been studied recently. The usefulness of immune modulating diets remains to be evaluated. Molecular immunomodulation is still of unclear value. The therapy of sepsis and multiple organ dysfunction syndrome remains mainly supportive.