Checking procalcitonin suitability for prognosis and antimicrobial therapy monitoring in burn patients

Surviving Sepsis After Burn Campaign

INTRODUCTION

The Surviving Sepsis Campaign was developed to improve outcomes for all patients with sepsis. Despite sepsis being the primary cause of death after thermal injury, burns have always been excluded from the Surviving Sepsis efforts. To improve sepsis outcomes in burn patients, an international group of burn experts developed the Surviving Sepsis After Burn Campaign (SSABC) as a testable guideline to improve burn sepsis outcomes.

METHODS

The International Society for Burn Injuries (ISBI) reached out to regional or national burn organizations to recommend members to participate in the program. Two members of the ISBI developed specific "patient/population, intervention, comparison and outcome" (PICO) questions that paralleled the 2021 Surviving Sepsis Campaign [1]. SSABC participants were asked to search the current literature and rate its quality for each topic. At the Congress of the ISBI, in Guadalajara, Mexico, August 28, 2022, a majority of the participants met to create "statements" based on the literature. The "summary statements" were then sent to all members for comment with the hope of developing an 80% consensus. After four reviews, a consensus statement for each topic was created or "no consensus" was reported.

RESULTS

The committee developed sixty statements within fourteen topics that provide guidance for the early treatment of sepsis in burn patients. These statements should be used to improve the care of sepsis in burn patients. The statements should not be considered as "static" comments but should rather be used as guidelines for future testing of the best treatments for sepsis in burn patients. They should be updated on a regular basis.

CONCLUSION

Members of the burn community from the around the world have developed the Surviving Sepsis After Burn Campaign guidelines with the goal of improving the outcome of sepsis in burn patients.

AACC Guidance Document on the Clinical Use of Procalcitonin

BACKGROUND

Procalcitonin (PCT), a peptide precursor of the hormone calcitonin, is a biomarker whose serum concentrations are elevated in response to systemic inflammation caused by bacterial infection and sepsis. Clinical adoption of PCT in the United States has only recently gained traction with an increasing number of Food and Drug Administration-approved assays and expanded indications for use. There is interest in the use of PCT as an outcomes predictor as well as an antibiotic stewardship tool. However, PCT has limitations in specificity, and conclusions surrounding its utility have been mixed. Further, there is a lack of consensus regarding appropriate timing of measurements and interpretation of results. There is also a lack of method harmonization for PCT assays, and questions remain regarding whether the same clinical decision points may be used across different methods.

CONTENT

This guidance document aims to address key questions related to the use of PCT to manage adult, pediatric, and neonatal patients with suspected sepsis and/or bacterial infections, particularly respiratory infections. The document explores the evidence for PCT utility for antimicrobial therapy decisions and outcomes prediction. Additionally, the document discusses analytical and preanalytical considerations for PCT analysis and confounding factors that may affect the interpretation of PCT results.

SUMMARY

While PCT has been studied widely in various clinical settings, there is considerable variability in study designs and study populations. Evidence to support the use of PCT to guide antibiotic cessation is compelling in the critically ill and in some lower respiratory tract infections but is lacking in other clinical scenarios, and evidence is also limited in the pediatric and neonatal populations. Interpretation of PCT results requires guidance from multidisciplinary care teams of clinicians, pharmacists, and clinical laboratorians.

Factors Influencing the Prognosis of Patients with Intra-Abdominal Infection and Its Value in Assessing Prognosis

Purpose

To explore the distribution of pathogenic bacteria in patients with intra-abdominal infection, to clarify the independent factors that affect the prognosis of patients with intra-abdominal infection and its evaluation value for prognosis.

Patients and Methods

The pathogens, underlying diseases, and related clinical data of patients with intra-abdominal infection from January 2012 to December 2019 in our hospital were retrospectively collected and the APACHE II score was calculated. The patients were divided into survival group and death group according to the prognosis, and the index between the two groups was compared. Spearman correlation analysis was used to evaluate the correlation between each index and prognosis, multivariate logistic regression analysis was used to screen the independent prognostic factors.

Results

Spearman correlation analysis showed that ALB level was negatively correlated with prognosis, age and APACHE II score were positively correlated with prognosis. Logistic regression analysis showed that age, ALB level, and APACHE II score were independent prognostic factors. The formula of age combined ALB level and APACHE II score was Y = X1-3.6X2 + 6.5X3 (X1 was the age, X2 was the ALB level and X3 was the APACHE II score), Y was positively correlated with poor prognosis, and the optimal cutoff value was Y = 40.96.

Conclusion

Age, ALB level, and APACHE II score are independent factors that influencing the prognosis of patients with intra-abdominal infection, and the combination of age, ALB level, and APACHE II score can better assess the prognosis of patients with intra-abdominal infection.

Contemporary Aspects of Burn Care

The past one hundred years have seen tremendous improvements in burn care, allowing for decreased morbidity and mortality of this pathology. The more prominent advancements occurred in the period spanning 1930-1980; notably burn resuscitation, early tangential excision, and use of topical antibiotic dressings; and are well documented in burn literature. This article explores the advancements of the past 40 years and the areas of burn management that are presently topics of active discussion and research.

The predictive role of Interleukin 6 in burn patients with positive blood cultures

Interleukin 6 (IL-6) is an established biomarker of inflammation with one of the earliest responses in sepsis. Serum levels can easily be measured within a few hours. The clinical significance of IL-6 in the early stage of sepsis in burned patients has not yet been confirmed. The purpose of our research was to investigate the predictive value of IL-6 for positive blood cultures in comparison to Procalcitonin (PCT), white blood cell (WBC) count, body temperature and the Sequential Organ Failure Assessment (SOFA) score in the presence of suspected sepsis in burn patients. In a retrospective study, we included all patients admitted to a regional burn centre in a 7-year period. Patients with a clinical suspicion of sepsis and complete laboratory tests underwent further analysis. Patients were categorized following culture results into either positive or negative bloodstream infection (BSI or non-BSI) groups. 39 of the 101 included patients had positive blood cultures (BSI). The serum IL-6 levels were significantly higher in the BSI group [1047 (339.9; 9000.5) vs. 198.5 (112.4; 702.5) ng/l; P = 0.001]. Receiver operating characteristic (ROC) curve analysis showed an AUC of 0.7 (59; 80.8%). The optimal IL-6 cut-off level was 312.8 ng/l (sensitivity 79.5%, specificity 56.5%). Other biomarkers (PCT, WBC), the maximum body temperature and increase of SOFA score were not different between the groups. IL-6 can be used to predict a positive blood culture even in the early stage of suspected sepsis in burned patients. In this context, other biomarkers (PCT, WBC) and body temperature are of limited clinical utility.

Procalcitonin in special patient populations: Guidance for antimicrobial therapy

PURPOSE

Procalcitonin (PCT) is an endogenous hormone that increases reliably in response to bacterial infection, and measurement of serum PCT levels is recommended to help guide antimicrobial therapy. The utility of PCT assessment in special patient populations (eg, patients with renal dysfunction, cardiac compromise, or immunocompromised states and those undergoing acute care surgery) is less clear. The evidence for PCT-guided antimicrobial therapy in special populations is reviewed.

SUMMARY

In the presence of bacterial infection, nonneuroendocrine PCT is produced in response to bacterial toxins and inflammatory cytokines, resulting in markedly elevated levels of serum PCT. Cytokine induction in nonbacterial inflammatory processes activated by acute care surgery may alter the interpretation of PCT levels. The reliability of PCT assessment has also been questioned in patients with renal dysfunction, cardiac compromise, or immunosuppression. In many special populations, serum PCT may be elevated at baseline and increase further in the presence of infection; thus, higher thresholds for diagnosing infection or de-escalating therapy should be considered, although the optimal threshold to use in a specific population is unclear. Procalcitonin-guided antimicrobial therapy may be recommended in certain clinical situations.

CONCLUSION

Procalcitonin may be a reliable marker of infection even in special populations with baseline elevations in serum PCT. However, due to unclear threshold values and the limited inclusion of special populations in relevant clinical trials, PCT levels should be considered along with clinical criteria, and antibiotics should never be initiated or withheld based on PCT values alone. Procalcitonin measurement may have a role in guiding de-escalation of antibiotic therapy in special populations; however, the clinician should be aware of disease states and concomitant therapies that may affect interpretation of results.

Procalcitonin kinetics early after severe burn injury and its value in diagnosis of sepsis

PURPOSE

To investigate the clinical significance of procalcitonin (PCT) kinetics early after burn and the perioperative period, and to assess its diagnostic performance for sepsis in major burn patients.

METHODS

This retrospective study on major burn patents (≥40% total body surface area) admitted from 2014 to 2019 was conducted in Southwest Hospital, Chongqing, China. A total of 321 patients were included. The kinetics of PCT was analyzed during the 1st week after burn, the perioperative period, and at the onset of clinical suspected sepsis.

RESULTS

Serum PCT concentration rose immediately after burn injury. Factors associated with increased PCT level in the 1st week after burn include greater burn area (>70% TBSA) and lower age (≤14 years). Correlations between PCT kinetics after burn and the risk of early development of sepsis and mortality were observed. At the onset of sepsis, serum PCT increased significantly compared to its basal level in the 48 h before diagnosis. The area under the receiver operating characteristics curve of PCT concentration and its kinetic changes was 0.788 and 0.826, respectively. PCT kinetics showed better accuracy than PCT concentration in discrimination of Gram-positive sepsis. The optimal diagnostic thresholds for PCT concentration and its kinetics were 1.41 ng/mL, and a 1.34-fold elevation compared to the baseline level.

CONCLUSIONS

PCT kinetics in the early stage after burn was a prognostic factor for sepsis and mortality among major burn patients. Serum PCT levels could be a diagnostic biomarker for sepsis in major burn patients.

Antibiotic Usage After Procalcitonin-Guided Therapy Algorithm Implementation In A Burn Intensive Care Unit

The study investigated antibiotic utilization after the implementation of a procalcitonin (PCT)-guided antibiotic algorithm in the burn intensive care unit (BICU) to minimize antibiotic exposure appropriately. An algorithm established the ordering of an initial procalcitonin level, an additional level following 48 hours post-admission, and upon suspicion of sepsis. The primary endpoint was the percent of days on antibiotics in the BICU. Secondary endpoints were the percent of patients reinitiated on antibiotics, length of BICU and hospital stay, and 30-day mortality. Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR) methodology aided in antibiotic usage evaluation. The retrospective and prospective phases involved five and seven patients in the final analysis, respectively. The median percent of days on antibiotics in the BICU was 33.3% versus 14.3% in the retrospective and prospective phases, respectively (p=0.222). Secondary outcomes evaluated were percent of patients reinitiated on antibiotics at 80.0% versus 28.6% (p=0.242), the median length of BICU stay at 38 days versus 31 days (p=0.465), the median duration of hospital stay at 39 days versus 37 days (p=0.624) and 30-day mortality of one versus zero cases (p=0.417) in the retrospective and prospective group, respectively. The probability of better DOOR with a PCT-guided antibiotic algorithm versus the control group was 95.7% (95% CI, 81.4-99.5%). The benefit of a PCT-guided antibiotic algorithm implementation cannot be determined based on the small sample size producing a lack of internal validity. Future studies warrant utilizing DOOR/RADAR to evaluate antibiotic stewardship strategies in the burn patient population.

Serum Procalcitonin Level Predicts Acute Kidney Injury After Traumatic Brain Injury

BACKGROUND

A common non-neurologic complication after traumatic brain injury (TBI), acute kidney injury (AKI) is a risk factor of mortality. Some studies confirmed the predictive value of procalcitonin (PCT) on AKI in several clinical settings. We designed this study to explore the predictive value of PCT on AKI after TBI.

METHODS

We retrospectively enrolled patients with TBI admitted to our hospital from February 2015 to June 2019. Multivariate logistic regression analysis was performed to find the risk factors of AKI and construct a predictive model for AKI. Receiver operating characteristics curves were drawn to compare the predictive value of PCT and the constructed model.

RESULTS

A total of 214 patients were included in this study. The incidence of AKI after TBI was 25.70% in this study. Compared with the non-AKI group, the AKI group had higher age (P = 0.031), lower Glasgow Coma Scale (P < 0.001), and higher incidence of coagulopathy (P < 0.001) and shock (P < 0.001). Moreover, patients complicated with AKI had higher in-hospital mortality (P < 0.001) and worse 90-day outcome (P < 0.001). Multivariate logistic regression analysis indicated that age (P = 0.033), PCT (P = 0.002), serum chlorine (P = 0.011), and creatinine (P < 0.001) were independent risk factors of AKI. We constructed a predictive model using these 4 risk factors. The area under receiver operating characteristics curves of the predictive model was 0.928, which was significantly higher than that of a single PCT value (area under receiver operating characteristics curves = 0.833) (Z = 2.395, P < 0.05).

CONCLUSIONS

PCT is valuable in predicting AKI after TBI. To avoid AKI after TBI, physicians can adjust treatment strategies according to the level of PCT.

Prediction of median survival time in sepsis patients by the SOFA score combined with different predictors

Background

Sepsis is the leading cause of intensive care unit (ICU) admission. The purpose of this study was to explore the prognostic value of the Sequential Organ Failure Assessment (SOFA) score, the Acute Physiological and Chronic Health Evaluation II (APACHE II) score, and procalcitonin (PCT), albumin (ALB), and lactate (LAC) levels in patients with sepsis.

Methods

Consecutive adult patients with suspected or documented sepsis at ICU admission were recruited. Their basic vital signs and related auxiliary examinations to determine their PCT and ALB levels and APACHE II score were recorded at ICU admission, and their LAC levels and SOFA scores were recorded for one week after admission. The influence of these variables on hospital mortality was evaluated. Logistic regression was used to derive the Sepsis Hospital Mortality Score (SHMS), a prediction equation describing the relationship between predictors and hospital mortality. The median survival time was calculated by the Kaplan-Meier method. In the validation group, the kappa value was calculated to evaluate the stability of the derived formula.

Results

This study included 894 sepsis patients admitted to 18 ICUs in 16 tertiary hospitals. Patients were randomly assigned to an experimental group (626 cases) and validation group (258 cases). In addition, a nonsurvival group (248 patients) of the experimental group was established according to the outcome at the time of discharge. The hospital mortality rate in the experimental group was 39.6% (248/626). Univariate and multivariate regression analyses revealed that the APACHE II score (odds ratio [OR] = 1.178), △SOFA (OR = 1.186), △LAC (OR = 1.157), and SOFA mean score (OR = 1.086) were independently associated with hospital mortality. The SHMS was calculated as logit(p) = 4.715 - (0.164 × APACHE II) - (0.171 × △SOFA) - (0.145 × △LAC) - (0.082 × SOFA mean). A receiver operating characteristic curve was constructed to further investigate the accuracy of the SHMS, with an area under the curve of 0.851 (95% confidence interval [CI] 0.821-0.882; p < 0.001) for hospital mortality. In the low-risk group and high-risk groups, the corresponding median survival times were 15 days and 11 days, respectively.

Conclusion

The APACHE II score, △SOFA, △LAC and SOFA mean score were independently associated with hospital mortality in sepsis patients and accurately predicted the hospital mortality rate and median survival time. Data on the median survival time in sepsis patients could be provided to clinicians to assist in the rational use of limited medical resources by facilitating prudent resource allocation.

Trial registration

ChiCTR-ECH-13003934, retrospectively registered on August 03, 2013.

Severe Burn Injury Progression and Phasic Changes of Gene Expression in Mouse Model

Patients with severe burns are susceptible to infectious complications including burn-site infections and sepsis. The purpose of this study was to explore the pathologic development of burn injury in a mouse model and to screen genes dysregulated at different time points on the basis of gene expression microarrays. Differential expression analysis identified a total 223 genes that related to only time progression independent of burn injury and 214 genes with aberrant expression due to burn injury. Weighted gene co-expression network analysis (WGCNA) of the 214 genes obtained seven gene modules which named as red, blue, turquoise, green, brown, yellow, and gray module, and the blue module was found to be significantly associated with severe burn injury progression, and in which several genes were previously reported being associated with inflammation and immune response, such as interleukin IL-6, IL-8, and IL-1b. Functional enrichment analysis indicated significant enrichment of biological processes that related to metabolism and catabolism, and pathways of proteasome, notch signaling and cell cycle. This result supports a phase progression of severe burn with gene expression changes and interpretation of biological processes in mouse.

A Critical Update of the Assessment and Acute Management of Patients with Severe Burns

Significance: Burns are debilitating, life threatening, and difficult to assess and manage. Recent advances in assessment and management have occurred since a comprehensive review of the care of patients with severe burns was last published, which may influence research and clinical practice. Recent Advances: Recent advances have occurred in the understanding of burn pathophysiology, which has led to the identification of potential biomarkers of burn severity, such as protein C. There is new evidence about the potential superiority of natural colloids over crystalloids during fluid resuscitation, and new evidence about components of initial and perioperative management, including an improved understanding of pain following burns. Critical Issues: The limitations of the clinical examination highlight the need for imaging and biomarkers to assist in estimations of burn severity. Fluid resuscitation reduces mortality, although there is conjecture over the ideal method. The subsequent perioperative period is associated with significant morbidity and the evidence for preventing and treating pain, infection, and fluid overload while maximizing wound healing potential is described. Future Directions: Promising developments are ongoing in imaging technology, histopathology, biomarkers, and wound healing adjuncts such as hyperbaric oxygen therapy, topical negative pressure therapy, stem cell treatments, and skin substitutes. The greatest benefit from further research on management of patients with burns would most likely be derived from the elucidation of optimal fluid resuscitation protocols, pain management protocols, and surgical techniques from randomized controlled trials.

Plasma protein C levels are directly associated with better outcomes in patients with severe burns

Protein C circulates in human plasma to regulate inflammation and coagulation. It has shown a crucial role in wound healing in animals, and low plasma levels predict the presence of a wound in diabetic patients. However, no detailed study has measured protein C levels in patients with severe burns over the course of a hospital admission. A severe burn is associated with dysfunction of inflammation and coagulation as well as a significant risk of morbidity and mortality. The current methods of burn assessment have shortcomings in reliability and have limited prognostic value. The discovery of a biomarker that estimates burn severity and predicts clinical events with greater accuracy than current methods may improve management, resource allocation and patient counseling. This is the first study to assess the potential role of protein C as a biomarker of burn severity. We measured the plasma protein C levels of 86 patients immediately following a severe burn, then every three days over the first three weeks of a hospital admission. We also analysed the relationships between burn characteristics, blood test results including plasma protein C levels and clinical events. We used a primary composite outcome of increased support utilisation defined as: a mean intravenous fluid administration volume of five litres or more per day over the first 72 h of admission, a length of stay in the intensive care unit of more than four days, or greater than four surgical procedures during admission. The hypothesis was that low protein C levels would be negatively associated with increased support utilisation. At presentation to hospital after a severe burn, the mean plasma protein C level was 76 ± 20% with a range of 34-130% compared to the normal range of 70-180%. The initial low can be plausibly explained by impaired synthesis, increased degradation and excessive consumption of protein C following a burn. Levels increased gradually over six days then remained at a steady-state until the end of the inpatient study period, day 21. A multivariable regression model (Nagelkerke's R² = 0.83) showed that the plasma protein C level on admission contributed the most to the ability of the model to predict increased support utilisation (OR = 0.825 (95% CI = 0.698-0.977), P = 0.025), followed by burn size (OR = 1.252 (95% CI = 1.025-1.530), P = 0.027), burn depth (partial thickness was used as the reference, full thickness OR = 80.499 (1.569-4129.248), P = 0.029), and neutrophil count on admission (OR = 1.532 (95% CI = 0.950-2.473), P = 0.08). Together, these four variables predicted increased support utilisation with 93.2% accuracy, 83.3% sensitivity and 97.6% specificity. However if protein C values were disregarded, only 49.5% of the variance was explained, with 82% accuracy, 63% sensitivity and 91.5% specificity. Thus, protein C may be a useful biomarker of burn severity and study replication will enable validation of these novel findings.