Clinical signs and CRP values associated with blood culture results in neonates evaluated for suspected sepsis

Framework for Considering Abnormal Heart Rate Characteristics and Other Signs of Sepsis in Very Low Birth Weight Infants

OBJECTIVE

 A heart rate characteristics index (HeRO score), incorporating low variability and superimposed decelerations, was developed as a sepsis risk indicator for preterm infants in the neonatal intensive care unit (NICU). A rise in the risk score should prompt consideration of other clinical changes that may be signs of sepsis to decide whether a workup and antibiotics are needed. We aimed to develop a framework to systematically consider signs potentially indicating sepsis in very low birth weight (VLBW) infants.

STUDY DESIGN

 We developed easy-recall acronyms for 10 signs of sepsis in VLBW infants. Over 12 months in a level IV NICU, neonatology fellows completed a brief survey after each shift to document changes prompting sepsis workups. We analyzed associations between survey data, hourly heart rate characteristic data, and the diagnosis of the workup, grouped as culture-positive sepsis (CXSEP, positive blood or urine culture), clinical sepsis (CLINSEP, negative cultures treated with antibiotics ≥5 days), or sepsis ruled out (SRO, negative cultures and <3 days antibiotics).

RESULTS

 We analyzed 93 sepsis workups in 48 VLBW infants (35 CXSEP, 20 CLINSEP, and 38 SRO). The most frequently cited changes prompting the workups were heart rate patterns and respiratory deterioration, which were common in all three categories. Low blood pressure and poor perfusion were uncommonly cited but were more likely to be associated with CXSEP than the other signs. A rise in the HeRO score ≥1 from 0 to 12 hours before compared with 12to 72 hours prior the blood culture occurred in 31% of workups diagnosed as CXSEP, 16% CLINSEP, and 31% SRO.

CONCLUSION

 The HeRO score can alert clinicians to VLBW infants at high or increasing risk of a sepsis-like illness, but heart rate characteristic patterns are highly variable in individual babies. The easy-recall NeoSEP-10 framework can assist clinicians in considering other clinical changes when making decisions about sepsis workups and the duration of antibiotics.

KEY POINTS

· Abnormal heart rate characteristics can indicate sepsis or other pathologies in preterm infants.. · We developed a simple bedside tool to consider clinical signs potentially associated with sepsis.. · Considering vital sign trends together with clinical changes is a key to right-timing antibiotics..

Diagnostic Utility of Interleukin-6 in Early-Onset Sepsis among Term Newborns: Impact of Maternal Risk Factors and CRP Evaluation

(1) Background: Interleukin-6 (IL-6) levels act as an early infection marker preceding C-reactive protein (CRP) elevation. This study seeks to analyze IL-6 behavior in suspected early-onset sepsis (EOS) cases among term newborns, comparing it to that of CRP and evaluating IL-6's diagnostic utility. We also aim to assess the impact of maternal risk factors on EOS in term newborns, quantifying their influence for informed decision making. (2) Methods: The retrospective data analysis included 533 term newborns who were admitted to our hospital because of suspected EOS. IL-6, CRP, and the impact of maternal risk factors were analyzed in the context of EOS using binomial test, Chi-squared test, logistic and linear regression. (3) Results: In the cases of EOS, both IL-6 and CRP were elevated. The increase in CRP can be predicted by the initial increase in IL-6 levels. Among the assessed risk factors, intrapartum maternal fever (adjusted odds ratio 18.1; 95% CI (1.7-4.1)) was identified as the only risk factor significantly associated with EOS. (4) Conclusions: Employing IL-6 as an early infection marker enhanced EOS diagnostic precision due to its detectable early rise. However, caution is required, as elevations in IL-6 and CRP levels do not exclusively indicate EOS. Increased CRP levels in healthy newborns with maternal risk factors may be attributed to dynamics of vaginal labor.

Spontaneous behaviors during breast crawling and factors influencing self-locating mothers' breasts in newborns: A cross-sectional study

Breast crawling in newborns to propel themselves to their mothers' breasts normally occurs upon skin-to-skin contact with mothers immediately after birth but is often missed by the neglect of hospital staff and insufficient evidence support. Hence, this study described the behavioral characteristics of 135 newborns from China during breast crawling and further explored the factors influencing newborns' self-locating mothers' breasts (measured by whether fail to experience the familiarization stage, initial time and duration of the familiarization stage) using multivariable analysis. The findings supported and extended previous studies that newborns could emerge in nine instinctive stages and corresponding spontaneous behaviors early in life. Moreover, abnormal fetal heart rate during labor appeared to interfere with newborns experiencing the familiarization stage (aOR = 9.27, 95% CI: 1.41 to 61.07, P = 0.021), while using synthetic oxytocin (β = 5.94, 95% CI: 0.35 to 11.54, P = 0.037), using antibiotics (β = 11.09, 95% CI: 4.11 to 18.07, P = 0.002), and newborns' gender (β = -5.69, 95% CI: 11.26 to -0.12, P = 0.045) would alter the initial time of the familiarization stage. Finally, this study proposes evidence-based strategies to prevent abnormal fetal heart rates and improve medication use.

The Role of Coagulase-Negative Staphylococci Biofilms on Late-Onset Sepsis: Current Challenges and Emerging Diagnostics and Therapies

Infections are one of the most significant complications of neonates, especially those born preterm, with sepsis as one of the principal causes of mortality. Coagulase-negative staphylococci (CoNS), a group of staphylococcal species that naturally inhabit healthy human skin and mucosa, are the most common cause of late-onset sepsis, especially in preterms. One of the risk factors for the development of CoNS infections is the presence of implanted biomedical devices, which are frequently used for medications and/or nutrient delivery, as they serve as a scaffold for biofilm formation. The major concerns related to CoNS infections have to do with the increasing resistance to multiple antibiotics observed among this bacterial group and biofilm cells’ increased tolerance to antibiotics. As such, the treatment of CoNS biofilm-associated infections with antibiotics is increasingly challenging and considering that antibiotics remain the primary form of treatment, this issue will likely persist in upcoming years. For that reason, the development of innovative and efficient therapeutic measures is of utmost importance. This narrative review assesses the current challenges and emerging diagnostic tools and therapies for the treatment of CoNS biofilm-associated infections, with a special focus on late-onset sepsis.

Artificial and human intelligence for early identification of neonatal sepsis

Artificial intelligence may have a role in the early detection of sepsis in neonates. Machine learning can identify patterns that predict high or increasing risk for clinical deterioration from a sepsis-like illness. In developing this potential addition to NICU care, careful consideration should be given to the data and methods used to develop, validate, and evaluate prediction models. When an AI system alerts clinicians to a change in a patient's condition that warrants a bedside evaluation, human intelligence and experience come into play to determine an appropriate course of action: evaluate and treat or wait and watch closely. With intelligently developed, validated, and implemented AI sepsis systems, both clinicians and patients stand to benefit. IMPACT: This narrative review highlights the application of AI in neonatal sepsis prediction. It describes issues in clinical prediction model development specific to this population. This article reviews the methods, considerations, and literature on neonatal sepsis model development and validation. Challenges of AI technology and potential barriers to using sepsis AI systems in the NICU are discussed.

Machine Learning Used to Compare the Diagnostic Accuracy of Risk Factors, Clinical Signs and Biomarkers and to Develop a New Prediction Model for Neonatal Early-onset Sepsis

BACKGROUND

Current strategies for risk stratification and prediction of neonatal early-onset sepsis (EOS) are inefficient and lack diagnostic performance. The aim of this study was to use machine learning to analyze the diagnostic accuracy of risk factors (RFs), clinical signs and biomarkers and to develop a prediction model for culture-proven EOS. We hypothesized that the contribution to diagnostic accuracy of biomarkers is higher than of RFs or clinical signs.

STUDY DESIGN

Secondary analysis of the prospective international multicenter NeoPInS study. Neonates born after completed 34 weeks of gestation with antibiotic therapy due to suspected EOS within the first 72 hours of life participated. Primary outcome was defined as predictive performance for culture-proven EOS with variables known at the start of antibiotic therapy. Machine learning was used in form of a random forest classifier.

RESULTS

One thousand six hundred eighty-five neonates treated for suspected infection were analyzed. Biomarkers were superior to clinical signs and RFs for prediction of culture-proven EOS. C-reactive protein and white blood cells were most important for the prediction of the culture result. Our full model achieved an area-under-the-receiver-operating-characteristic-curve of 83.41% (±8.8%) and an area-under-the-precision-recall-curve of 28.42% (±11.5%). The predictive performance of the model with RFs alone was comparable with random.

CONCLUSIONS

Biomarkers have to be considered in algorithms for the management of neonates suspected of EOS. A 2-step approach with a screening tool for all neonates in combination with our model in the preselected population with an increased risk for EOS may have the potential to reduce the start of unnecessary antibiotics.

Targeting the Toll-like receptor pathway as a therapeutic strategy for neonatal infection

Toll-like receptors (TLRs) are crucial transmembrane receptors that form part of the innate immune response. They play a role in the recognition of various microorganisms and their elimination from the host. TLRs have been proposed as vital immunomodulators in the regulation of multiple neonatal stressors that extend beyond infection such as oxidative stress and pain. The immune system is immature at birth and takes some time to become fully established. As such, babies are especially vulnerable to sepsis at this early stage of life. Findings suggest a gestational age-dependent increase in TLR expression. TLRs engage with accessory and adaptor proteins to facilitate recognition of pathogens and their activation of the receptor. TLRs are generally upregulated during infection and promote the transcription and release of proinflammatory cytokines. Several studies report that TLRs are epigenetically modulated by chromatin changes and promoter methylation upon bacterial infection that have long-term influences on immune responses. TLR activation is reported to modulate cardiorespiratory responses during infection and may play a key role in driving homeostatic instability observed during sepsis. Although complex, TLR signaling and downstream pathways are potential therapeutic targets in the treatment of neonatal diseases. By reviewing the expression and function of key Toll-like receptors, we aim to provide an important framework to understand the functional role of these receptors in response to stress and infection in premature infants.

The role of early-onset-sepsis in the neurodevelopment of very low birth weight infants

AIMS

The study investigated a putative association between early-onset-sepsis (EOS) and poor neurodevelopmental outcomes at 2 years corrected age in very low birth weight infants.

METHODS

This was a single-center cohort study on infants weighing less than 1500 g with a gestational age below 35 weeks at birth born between 2008 and 2011. Neurodevelopmental outcomes were assessed at follow-up with the Bayley Scales of Infant Development-II. EOS was defined as either culture-proven EOS or clinical EOS using blood culture, CrP levels, and clinical symptoms and treatment. Neurodevelopmental impairment (NDI) was defined as one or more of the following: Mental Developmental Index (MDI) and/or Psychomotor Developmental Index (PDI) scores lower than 70; presence of cerebral palsy.

RESULTS

Of 405 eligible newborns in the study period 166 were included. Two had culture-proven and 29 clinical EOS. Median MDI scores in patients with EOS were 96 (IQR: 86-106) and in the control group 94 (84-106, p = 0.77). PDI scores in patients with EOS were 96 (86-106) and in the control group 99,5 (92-103, p = 0.03). Of infected patients 7/31 (24%) showed NDI as defined, whereas only 11/135 (8%) showed NDI in the control group (OR 3.3, p = 0.03). Multiple regression analyses identified chorioamnionitis and poor CRIB-Scores as individual risk factors for MDI or PDI values < 70.

CONCLUSION

In our study, EOS among VLBW-infants significantly impaired the neurodevelopment at 2 years corrected age. As shown in previous reports infection continues to be a problem and strategies for a reduction need further improvement.

Diagnostic Accuracy of Clinical Tool 'STOPS' and Serum Procalcitonin for Optimizing Antibiotic Therapy in Neonates Born at ≥ 28 Weeks of Gestation with Neonatal Sepsis

Background

Antibiotic therapy is initiated in neonates on suspicion of sepsis. Optimizing therapy is a felt need of clinicians as prolonged injudicious use increases mortality and morbidity risk.

Objective

To evaluate the diagnostic accuracy of clinical tool 'STOPS' and serum procalcitonin (PCT) for identifying neonates with early-onset neonatal sepsis (EONS) or late-onset neonatal sepsis (LONS) and early discontinuation in those with no sepsis.

Methods

The study had a prospective analytical design conducted at a tertiary care hospital. Consecutively admitted neonates with suspected EONS or LONS were enrolled. The 'STOPS' tool comprising sensorium, temperature, oxygenation, perfusion, skin color, and blood sugar was applied at 6 and 12 hours of enrollment. Serum PCT was sent at 12 hr. The sensitivity, specificity, positive and negative predictive value (PPV and NPV), positive and negative likelihood ratio (PLR and NLR) were estimated.

Results

The study enrolled 380 neonates, of which 330 were given antibiotics for EONS and 50 for LONS. Temperature disturbance in the EONS group at 12 hr showed a PPV of 100% and a PLR of 9.1 (7.7 – 18). Perfusion assessment at 12 hr had a PPV of 77% and PLR of 8.25 (2.3 – 29). Skin color assessment at 12 hr had a PPV of 100% and PLR of 13.5 (9.7 – 27). The diagnostic accuracy of PCT in the EONS group was unremarkable. In the LONS group, skin color at 12 hr had a PPV of 100% and PLR of 11.2 (8.6 – 19.5). The diagnostic accuracy of PCT in the LONS group showed a PPV of 82% and PLR of 7 (1.7 – 29).

Conclusion

Identifying abnormal STOPS parameters was superior to PCT alone in EONS and as good as PCT in LONS. The 'STOPS' tool allows early identification of neonates with no sepsis, thereby optimizing antibiotic use.

Non-Contact Heart Rate Monitoring in Neonatal Intensive Care Unit using RGB Camera

Heart rate (HR) measurement is crucial for newborn infant monitoring in the neonatal intensive care unit (NICU). The widely used contact HR measurement methods based on electrocardiography (ECG) and photoplethysmography (PPG) signals can lead to discomfort and possible skin irritation on neonates, which limit its application in NICU scenarios. In this work, we propose a non-contact HR monitoring method simply using a RGB camera. Eulerian video magnification (EVM) is employed to detect the subtle changes of neonatal faces results from blood circulation. The magnified signal is then transformed to the spectral domain to extract HR information. Compared with the widely investigated independent component analysis (ICA)-based HR measurement method using video recordings, the proposed method can achieve the real time HR measurement, which is a significant superiority in NICU neonatal monitoring. To the best of our knowledge, this is the first study to employ EVM algorithm in real time neonatal HR monitoring.

Potential causes of early death among admitted newborns in a rural Tanzanian hospital

Background

Approximately 40,000 newborns die each year in Tanzania. Regional differences in outcome are common. Reviewing current local data, as well as defining potential causal pathways leading to death are urgently needed, before targeted interventions can be implemented

Objective

To describe the clinical characteristics and potential causal pathways contributing to newborn death and determine the presumed causes of newborn mortality within seven days, in a rural hospital setting.

Methods

Prospective observational study of admitted newborns born October 2014–July 2017. Information about labour/delivery and newborn management/care were recorded on data collection forms. Causes of deaths were predominantly based on clinical diagnosis.

Results

671 were admitted to a neonatal area. Reasons included prematurity n = 213 (32%), respiratory issues n = 209 (31%), meconium stained amniotic fluid with respiratory issues n = 115 (17%) and observation for < 24 hours n = 97 (14%). Death occurred in 124 infants. Presumed causes were birth asphyxia (BA) n = 59 (48%), prematurity n = 19 (15%), presumed sepsis n = 19 (15%), meconium aspiration syndrome (MAS) n = 13 (10%) and congenital abnormalities n = 14 (11%). More newborns who died versus survivors had oxygen saturation <60% on admission (37/113 vs 32/258; p≤0.001) respectively. Moderate hypothermia on admission was common i.e. deaths 35.1 (34.6–36.0) vs survivors 35.5 (35.0–36.0)°C (p≤0.001). Term newborns who died versus survivors were fourfold more likely to have received positive pressure ventilation after birth i.e. 4.57 (1.22–17.03) (p<0.02).

Conclusion

Intrapartum-related complications (BA, MAS), prematurity, and presumed sepsis were the leading causes of death. Intrapartum hypoxia, prematurity and attendant complications and presumed sepsis, are major pathways leading to death. Severe hypoxia and hypothermia upon admission are additional contributing factors. Strategies to identify fetuses at risk during labour e.g. improved fetal heart rate monitoring, coupled with timely interventions, and implementation of WHO interventions for preterm newborns, may reduce mortality in this low resource setting.

Predicting Neonatal Sepsis Using Features of Heart Rate Variability, Respiratory Characteristics, and ECG-Derived Estimates of Infant Motion

This study in preterm infants was designed to characterize the prognostic potential of several features of heart rate variability (HRV), respiration, and (infant) motion for the predictive monitoring of late-onset sepsis (LOS). In a neonatal intensive care setting, the cardiorespiratory waveforms of infants with blood-culture positive LOS were analyzed to characterize the prognostic potential of 22 features for discriminating control from sepsis-state, using the Naïve Bayes algorithm. Historical data of the subjects acquired from a period sufficiently before the clinical suspicion of LOS was used as control state, whereas data from the 24 h preceding the clinical suspicion of LOS were used as sepsis state (test data). The overall prognostic potential of all features was quantified at three-hourly intervals for the period corresponding to test data by calculating the area under the receiver operating characteristics curve. For the 49 infants studied, features of HRV, respiration, and movement showed characteristic changes in the hours leading up to the clinical suspicion of sepsis, namely, an increased propensity toward pathological heart rate decelerations, increased respiratory instability, and a decrease in spontaneous infant activity, i.e., lethargy. While features characterizing HRV and respiration can be used to probe the state of the autonomic nervous system, those characterizing movement probe the state of the motor system-dysregulation of both reflects an increased likelihood of sepsis. By using readily interpretable features derived from cardiorespiratory monitoring, opportunities for pre-emptively identifying and treating LOS can be developed.

Predictors of early-onset neonatal sepsis or death among newborns born at <32 weeks of gestation

OBJECTIVE

To develop a predictive model for early-onset neonatal sepsis or death among infants born at less than 32 weeks of gestation.

STUDY DESIGN

This was a case-control study of all deliveries <32 weeks between 2011 and 2015 in a single tertiary care center. Cases were defined as neonates diagnosed with early-onset sepsis based on a blood or cerebrospinal fluid culture or neonates who expired during the first week of life. Controls consisted of neonates without these outcomes. Variables previously identified to be associated with neonatal sepsis or death were abstracted from the medical record. Bivariable analyses and multivariable logistic regression were used to determine independent risk factors for early-onset neonatal sepsis or death. An ROC curve was created and AUC calculated to estimate the predictive capacity of these associations.

RESULTS

Of 779 eligible neonates, early-onset neonatal sepsis or death occurred in 73 (9.4%). In bivariable analyses, mothers whose neonates were diagnosed with early-onset sepsis or death were more likely to be obese, have an intrapartum fever, and have meconium-stained amniotic fluid, and were less likely to have received betamethasone or antepartum/intrapartum antibiotics. Gestational age at delivery and birth weight was significantly lower among neonates diagnosed with neonatal sepsis or death. In multivariable analyses, factors remaining independently associated with neonatal sepsis or death were earlier gestational age at the time of delivery (specifically <28 weeks), intrapartum fever, presence of meconium-stained amniotic fluid, and lower birth weight. The AUC for this regression was 0.81 (95% confidence interval 0.77-0.83).

CONCLUSION

Earlier gestational age at the time of delivery, intrapartum fever, meconium, and lower birth weight are independently associated with early-onset neonatal sepsis or death among deliveries occurring at <32 weeks of gestation; these factors can be used to create a model with fair predictive capability.

C-reactive protein for diagnosing late-onset infection in newborn infants

BACKGROUND

Late-onset infection is the most common serious complication associated with hospital care for newborn infants. Because confirming the diagnosis by microbiological culture typically takes 24 to 48 hours, the serum level of the inflammatory marker C-reactive protein (CRP) measured as part of the initial investigation is used as an adjunctive rapid test to guide management in infants with suspected late-onset infection.

OBJECTIVES

To determine the diagnostic accuracy of serum CRP measurement in detecting late-onset infection in newborn infants.

SEARCH METHODS

We searched electronic databases (MEDLINE, Embase, and Science Citation Index to September 2017), conference proceedings, previous reviews, and the reference lists of retrieved articles.

SELECTION CRITERIA

We included cohort and cross-sectional studies evaluating the diagnostic accuracy of serum CRP levels for the detection of late-onset infection (occurring more than 72 hours after birth) in newborn infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility for inclusion, evaluated the methodological quality of included studies, and extracted data to estimate diagnostic accuracy using hierarchical summary receiver operating characteristic (SROC) models. We assessed heterogeneity by examining variability of study estimates and overlap of the 95% confidence interval (CI) in forest plots of sensitivity and specificity.

MAIN RESULTS

The search identified 20 studies (1615 infants). Most were small, single-centre, prospective cohort studies conducted in neonatal units in high- or middle-income countries since the late 1990s. Risk of bias in the included studies was generally low with independent assessment of index and reference tests. Most studies used a prespecified serum CRP threshold level as the definition of a 'positive' index test (typical cut-off level between 5 mg/L and 10 mg/L) and the culture of a pathogenic micro-organism from blood as the reference standard.At median specificity (0.74), sensitivity was 0.62 (95% CI 0.50 to 0.73). Heterogeneity was evident in the forest plots but it was not possible to conduct subgroup or meta-regression analyses by gestational ages, types of infection, or types of infecting micro-organism. Covariates for whether studies used a predefined threshold or not, and whether studies used a standard threshold of between 5 mg/L and 10 mg/L, were not statistically significant.

AUTHORS' CONCLUSIONS

The serum CRP level at initial evaluation of an infant with suspected late-onset infection is unlikely to be considered sufficiently accurate to aid early diagnosis or select infants to undergo further investigation or treatment with antimicrobial therapy or other interventions.

Blood culture indications in critically ill neonates: a multicenter prospective cohort study

Due to potential lethality of healthcare-associated sepsis (HAS), a low threshold for blood culturing and antimicrobial therapy (ABT) initiation is accepted. We assessed variability in the trigger for blood culturing between three neonatal intensive care units. A multicenter prospective cohort study was conducted. In newborns with suspicion of HAS, 10 predefined clinical signs, nosocomial sepsis (NOSEP) score, C-reactive protein, ABT initiation, and risk factors were registered at time of culturing. Outcome was lab-confirmed HAS, defined according to the NeoKISS-criteria. Two hundred ninety-nine suspected HAS episodes were considered in 212 infants, of which 118 had birth-weight ≤ 1500 g; proportion of lab-confirmed HAS per suspected episode was 30/192 (center 1), 28/60 (center 2), and 8/47 (center 3) (p < 0.001). Median C-reactive protein and number of clinical signs at time of culturing differed between centers 1, 2, and 3 (respectively 11 vs. 5 vs. 3 mg/L, p = 0.001; 1 sign [IQR 0-2, center 1] vs. 3 signs [IQR 2-4, centers 2 and 3], p < 0.001). Median NOSEP score at time of culturing was 5 (IQR 3-8, center 1), 5 (IQR 3-9, center 2), and 8 (IQR 5-11, center 3) (p = 0.016). Difference in ABT initiation was noticed (82 vs. 93 vs. 74%, p = 0.05).

CONCLUSION

Center heterogeneity in sampling practice is substantial. Optimizing sampling practice can be recommended. What is Known: • Blood culture test is a common diagnostic procedure in critically-ill newborns. • A low threshold for sampling and antimicrobial therapy initiation is accepted. What is New: • Variability in blood culture practice was assessed between 3 neonatal intensive care units by the registration of sampling frequencies, clinical indications, and antimicrobial therapy initiation.

The cut-off levels of procalcitonin and C-reactive protein and the kinetics of mean platelet volume in preterm neonates with sepsis

Background

Sepsis is a leading cause of morbidity and mortality among newborns. C-reactive protein (CRP) and procalcitonin (PCT) have some limitations in the diagnosis of preterm neonatal sepsis. In this study, the cut-offs of PCT and CRP, and the efficacy of mean platelet volume (MPV) were investigated.

Methods

We identified key demographic details and compared laboratory values between preterm infants with early onset and late onset neonatal sepsis (EONS/LONS) retrospectively. Blood samples were collected within the first few hours of the onset of clinical sepsis (CRP 1, PCT 1, MPV 1) and were repeated after 24 h (CRP 2, PCT 2, MPV 2). The optimal cut-offs for CRP, PCT and MPV were determined using receiver operating characteristic (ROC) analysis. Furthermore, pairwise comparisons of ROC curves were made to evaluate the performances of these tests.

Results

In EONS, the cut-off of CRP 1 was 2.6 mg/L, the sensitivity, specificity, PPV and NPV were 80.6, 83.0, 67.5 and 90.7%, respectively (p < 0.001). At a PCT 1 cut-off of 1.1 ng/mL, the sensitivity, specificity, PPV and NPV were 78.6, 81.2, 64.7 and 89.6%, respectively (p < 0.001). The sensitivity, specificity, PPV, and NPV of the CRP 1 cut-off of 3.6 mg/L for LONS were 78.3, 87.4, 74.8, and 89.4%, respectively. At a PCT 1 cut-off of 5.2 ng/mL, the sensitivity, specificity, PPV and NPV were 58.5, 95.5, 86.1, and 82.9% respectively. For proven sepsis, the cut-off of CRP 1 was 7.0 mg/L with a 76.5% sensitivity, 98.2% specificity, 94.9% PPV and 90.5% NPV (p < 0.001). At a PCT 1 cut-off of 1.36 ng/mL, the sensitivity, specificity, PPV and NPV were 90.8, 83.4, 70.6 and 94.4%, respectively (p < 0.001). In each subgroup, other than EONS, the performances of CRP 1 and PCT 1 measurements were found to be statistically higher than MPV 1. CRP 2 cut-off levels of LONS group and proven sepsis group were found to be lower than the initial values.

Conclusions

Optimal cut-off levels of CRP 1 and PCT 1 may differ in preterm sepsis subgroups. The diagnostic performances of CRP 1 and PCT 1 didn’t differ however, they were more efficacious than MPV.

Diagnostics for neonatal sepsis: current approaches and future directions

Progress has been made in the reduction of morbidity and mortality from neonatal sepsis. However, diagnosis continues to rely primarily on conventional microbiologic techniques, which can be inaccurate. The objective of this review is to provide the clinician with an overview of the current information available on diagnosing this condition. We review currently available diagnostic approaches for documenting neonatal sepsis and also describe novel approaches for diagnosing infection in neonates who are under development and investigation. Substantial progress has been made with molecular approaches and further development of non-culture-based methods offer promise. The potential ability to incorporate antimicrobial resistance gene testing in addition to pathogen identification may provide a venue to incorporate a predominantly molecular platform into a larger program of neonatal care.

The role of elevated central-peripheral temperature difference in early detection of late-onset sepsis in preterm infants

AIMS

The study investigated the association between clinical symptoms and late-onset sepsis (LOS) in preterm infants with the aim of identifying a non-invasive tool for the early detection of LOS.

METHODS

This was a prospective study of 83 episodes of suspected LOS in 67 preterm infants. At the time LOS was suspected, we recorded a standardized set of clinical symptoms. A diagnosis of "clinical LOS" (Clin-LOS), "culture-proven LOS" (Prov-LOS) or "LOS not present" (No-LOS) was made on the basis of C-reactive protein (CrP) and blood culture results where Clin-LOS was defined as CrP>10mg/l, Prov-LOS was defined as CrP>10mg/l AND positive blood cultures, or it was established that there was no sepsis present (No-LOS). We examined univariable associations between clinical signs and LOS using odds ratio (OR) analysis and then adjusted the odds ratio (adOR) through binary regression analysis.

RESULTS

Clin-LOS was diagnosed in 20/83 episodes, 19 cases were found to have Prov-LOS. Clinical signs which had a significant association with Clin-LOS were capillary refill time >2s (OR 2.9) and decreased responsiveness (OR 5.2), whereas there was a negative association between gastric residuals and LOS (OR 0.35). However, the most marked association was found for a greater central-peripheral temperature difference (cpTD) >2°C (OR 9). In Prov-LOS an increased heart rate (OR 3.1), prolonged capillary refill time (OR 3.3) and again an increased cpTD (OR 16) had a significant association with LOS, whereas gastric residuals were negatively associated (OR 0.29). Regression analysis showed that cpTD was the most striking clinical sign associated with both Clin- (adOR 6.3) and Prov-LOS (adOR 10.5).

CONCLUSIONS

Prolonged capillary refill time and - more impressive - elevated cpTD were the most useful clinical symptoms for detection of LOS in preterm infants. We especially suggest using cpTD as a predictor of LOS. It is a cheap, non-invasive and readily available tool for daily routines.

Glucosuria as an early marker of late-onset sepsis in preterms: a prospective cohort study

Background

Early and accurate diagnosis of late-onset sepsis (LONS) in preterm infants is difficult since presenting signs are subtle and non-specific. Because neonatal sepsis may be accompanied by glucose intolerance and glucosuria, we hypothesized that glucosuria may be associated with LONS in preterms, in an early stage. We aim to evaluate the association of glucosuria and late-onset neonatal sepsis (LONS) in preterm infants, in an attempt to improve early and accurate diagnosis of LONS.

Methods

We performed a prospective observational cohort study in 316 preterms (<34 weeks). We daily measured glucosuria and followed patients for occurrence of LONS, defined as clinical and blood culture-proven sepsis occurring after 72 h. Attending physicians were blinded to glucosuria results. We assessed the diagnostic value of glucosuria for clinical and blood culture-proven LONS using logistic regression analysis.

Results

Glucosuria was found in 65.8 % of 316 preterm patients, and sepsis was suspected 157 times in 123 patients. LONS was found in 47.1 % of 157 suspected episodes. The presence of glucosuria was associated with LONS (OR 2.59, 95 % CI 1.24–5.43, p = 0.012) with sensitivity 69.0 % and specificity 53.8 % (Likelihoodratio 1.49). After adjustment for gestational age, birth weight, and postnatal age, this association weakened and was no longer significant (adjusted OR 2.16; 95 % CI 0.99–1.85, p = 0.055). An increase in glucosuria 48–24 h before onset of symptoms was not associated with LONS.

Conclusion

In preterms glucosuria is associated with LONS within 24 h, however this association is too weak to be of diagnostic value.

Host response biomarkers in the diagnosis of sepsis: a general overview

Critically ill patients who display a systemic inflammatory response syndrome (SIRS) are prone to develop nosocomial infections. The challenge remains to distinguish as early as possible among SIRS patients those who are developing sepsis. Following a sterile insult, damage-associated molecular patterns (DAMPs) released by damaged tissues and necrotic cells initiate an inflammatory response close to that observed during sepsis. During sepsis, pathogen-associated molecular patterns (PAMPs) trigger the release of host mediators involved in innate immunity and inflammation through identical receptors as DAMPs. In both clinical settings, a compensatory anti-inflammatory response syndrome (CARS) is concomitantly initiated. The exacerbated production of pro- or anti-inflammatory mediators allows their detection in biological fluids and particularly within the bloodstream. Some of these mediators can be used as biomarkers to decipher among the patients those who developed sepsis, and eventually they can be used as prognosis markers. In addition to plasma biomarkers, the analysis of some surface markers on circulating leukocytes or the study of mRNA and miRNA can be helpful. While there is no magic marker, a combination of few biomarkers might offer a high accuracy for diagnosis.

Prediction models for neonatal health care-associated sepsis: a meta-analysis

BACKGROUND AND OBJECTIVES

Blood culture is the gold standard to diagnose bloodstream infection but is usually time-consuming. Prediction models aim to facilitate early preliminary diagnosis and treatment. We systematically reviewed prediction models for health care-associated bloodstream infection (HABSI) in neonates, identified superior models, and pooled clinical predictors.

DATA SOURCES

LibHub, PubMed, and Web of Science.

METHODS

The studies included designed prediction models for laboratory-confirmed HABSI or sepsis. The target population was a consecutive series of neonates with suspicion of sepsis hospitalized for ≥ 48 hours. Clinical predictors had to be recorded at time of or before culturing. Methodologic quality of the studies was assessed. Data extracted included population characteristics, total suspected and laboratory-confirmed episodes and definition, clinical parameter definitions and odds ratios, and diagnostic accuracy parameters.

RESULTS

The systematic search revealed 9 articles with 12 prediction models representing 1295 suspected and 434 laboratory-confirmed sepsis episodes. Models exhibit moderate-good methodologic quality, large pretest probability range, and insufficient diagnostic accuracy. Random effects meta-analysis showed that lethargy, pallor/mottling, total parenteral nutrition, lipid infusion, and postnatal corticosteroids were predictive for HABSI. Post hoc analysis with low-gestational-age neonates demonstrated that apnea/bradycardia, lethargy, pallor/mottling, and poor peripheral perfusion were predictive for HABSI. Limitations include clinical and statistical heterogeneity.

CONCLUSIONS

Prediction models should be considered as guidance rather than an absolute indicator because they all have limited diagnostic accuracy. Lethargy and pallor and/or mottling for all neonates as well as apnea and/or bradycardia and poor peripheral perfusion for very low birth weight neonates are the most powerful clinical signs. However, the clinical context of the neonate should always be considered.

Risk factors associated with laboratory-confirmed bloodstream infections in a tertiary neonatal intensive care unit

BACKGROUND

Bloodstream infections (BSI) remain a leading cause of morbidity and mortality among infants admitted to neonatal intensive care units (NICUs). At the time of evaluation for suspected BSI, presenting signs may be nonspecific. We sought to determine the clinical signs and risk factors associated with laboratory-confirmed BSI among infants evaluated for late-onset sepsis in a tertiary NICU.

METHODS

This prospective cohort study included infants >3 days of age admitted to a level 4 NICU from July 2006 to October 2009 for whom a blood culture was drawn for suspected sepsis. Clinicians documented presenting signs at the time of culture. Laboratory-confirmed BSI was defined as per the National Healthcare Safety Network. Multivariate analyses were performed using a logistic regression random effects model.

RESULTS

Six-hundred and eighty eligible episodes of suspected BSI were recorded in 409 infants. Enteral contrast within the preceding 48 hours was the most significant risk factor for laboratory-confirmed BSI [Odds Ratio: 9.58 (95% confidence interval: 2.03-45.19)] followed by presence of a central venous catheter. Apnea and hypotension were the most strongly associated presenting signs.

CONCLUSION

Among infants evaluated in a tertiary NICU, recent exposure to enteral contrast was associated with increased odds of developing BSI. Apnea and hypotension were the most strongly associated clinical signs of infection.

Non-contact heart rate monitoring utilizing camera photoplethysmography in the neonatal intensive care unit - a pilot study

BACKGROUND

Presently the heart rate is monitored in the Neonatal Intensive Care Unit with contact sensors: electrocardiogram or pulse oximetry. These techniques can cause injuries and infections, particularly in very premature infants with fragile skin. Camera based plethysmography was recently demonstrated in adults as a contactless method to determine heart rate.

AIM

To investigate the feasibility of this technique for NICU patients and identify challenging conditions.

STUDY DESIGN AND PARTICIPANTS

Video recordings using only ambient light were made of 19 infants at two NICUs in California and The Netherlands. Heart rate can be derived from these recordings because each cardiovascular pulse wave induces minute pulsatile skin color changes, invisible to the eye but measurable with a camera.

RESULTS

In all infants the heart beat induced photoplethysmographic signal was strong enough to be measured. Low ambient light level and infant motion prevented successful measurement from time to time.

CONCLUSIONS

Contactless heart rate monitoring by means of a camera using ambient light was demonstrated for the first time in the NICU population and appears feasible. Better hardware and improved algorithms are required to increase robustness.

Clinical signs to identify late-onset sepsis in preterm infants

Late-onset neonatal sepsis (LOS) in preterm infants is an important cause of morbidity and mortality in preterm infants. Since presenting symptoms may be non-specific and subtle, early and correct diagnosis is challenging. We aimed to develop a nomogram based on clinical signs, to assess the likelihood of LOS in preterms with suspected infection without the use of laboratory investigations. We performed a prospective cohort study in 142 preterm infants <34 weeks admitted to the neonatal intensive care unit with suspected infection. During 187 episodes, 21 clinical signs were assessed. LOS was defined as blood culture-proven and/or clinical sepsis, occurring after 3 days of age. Logistic regression was used to develop a nomogram to estimate the probability of LOS being present in individual patients. LOS was found in 48 % of 187 suspected episodes. Clinical signs associated with LOS were: increased respiratory support (odds ratio (OR) 3.6; 95 % confidence interval (CI) 1.9-7.1), capillary refill (OR 2.2; 95 %CI 1.1-4.5), grey skin (OR 2.7; 95 %CI 1.4-5.5) and central venous catheter (OR 4.6; 95 %CI 2.2-10.0) (area under the curve of the receiver operating characteristic curve 0.828; 95 %CI 0.764-0.892).

CONCLUSION

Increased respiratory support, capillary refill, grey skin and central venous catheter are the most important clinical signs suggestive of LOS in preterms. Clinical signs that are too non-specific to be useful in excluding or diagnosing LOS were temperature instability, apnoea, tachycardia, dyspnoea, hyper- and hypothermia, feeding difficulties and irritability.

Precursors of adrenomedullin, endothelin and atrial natriuretic peptide as diagnostic markers of neonatal infection

AIM

To evaluate the serum levels of three precursors of vasoactive peptide as diagnostic markers for neonatal infections.

METHODS

Overall, 356 neonates (160 without infection, 114 with mild infections and 82 with severe infections) were enrolled in this study. Their serum levels of mid-regional pro-adrenomedullin (MR-pro-ADM), C-terminal pro-endothelin-1 (CT-pro-ET-1) and mid-regional pro-atrial natriuretic peptide (MR-pro-ANP) were measured by immunoassay, and receiver operating curve analysis was performed for each biomarker to evaluate their diagnostic values for neonatal infection.

RESULTS

The serum levels of MR-pro-ADM (2.079 ± 1.195 nM), CT-pro-ET-1 (109.4 ± 62.9 pM) and MR-pro-ANP (1221.4 ± 725.0 pM) in the severe infection group were significantly higher than those in the mild infection group (1.025 ± 0.421 nM, 86.7 ± 51.8 pM, and 687.6 ± 575.7 pM, respectively) and in the non-infection group (0.853 ± 0.488 nM, 51.3 ± 40.6 pM, and 943.3 ± 847.3 pM, respectively) (p < 0.01-0.001). Their areas under the curve were 0.72, 0.76 and 0.61, respectively. Among them, CT-pro-ET-1 had the highest sensitivity (82.65%), whereas MR-pro-ADM had the highest specificity (86.25%).

CONCLUSIONS

MR-pro-ADM, CT-pro-ET-1 and MR-pro-ANP may serve as useful laboratory markers to indicate bacterial infection in neonates.