Clinical characteristics and outcomes of neonates with polymicrobial ventilator-associated pneumonia in the intensive care unit

Deep learning models for early and accurate diagnosis of ventilator-associated pneumonia in mechanically ventilated neonates

BACKGROUND

Early and accurate confirmation of critically ill neonates with a suspected diagnosis of ventilator-associated pneumonia (VAP) can optimize the therapeutic strategy and avoid unnecessary use of empirical antibiotics. We aimed to examine whether deep learning (DL) methods can assist the diagnosis of VAP of intubated neonates in the neonatal intensive care unit (NICU).

METHODS

A total of 670 neonates with mechanical ventilation were prospectively observed in a tertiary-level NICU in Taiwan between October 2017 and March 2022, during which image data were collected. All neonates with clinically suspected VAP were enrolled, and various DL methods were used to test the prediction ability of VAP diagnosis. The accuracy, precision, sensitivity, specificity, F1-score, and area under curves (AUCs) of several DL methods were compared.

RESULTS

A total of 900 chest X-ray images derived from 670 neonates with VAP and/or bronchopulmonary dysplasia (BPD) were enrolled, including 399 images from patients with definite diagnosis of VAP based on the strict criteria and 501 images from neonates without VAP. Compared with conventional DNN models such as ResNet, VGG, DenseNet, the RegNetX80 achieved the best specificity of 0.8378, which facilitates a low false positive rate. For accurate diagnosis of neonatal VAP, a combinatorial model of ResNet50 and RegNetX80, created through ensemble learning, further enhanced the AUC to 0.8023 for neonates with VAP on mechanical ventilation. In addition, the consistent XAI results in the left-lower region of chest X-ray image provided informative feedback and increased confidence to AI-assisted doctors.

CONCLUSIONS

Deep learning methods are applicable with good predictive accuracy using chest X-ray images to help diagnosis of VAP in the NICU, which can help clinicians make decisions regarding the choices of empiric antibiotics for critically ill neonates. Future prospective trials are warranted to document its clinical usefulness and benefits on reducing medical resources.

Incidence, Risk Factors, Short-term Outcomes, and Microbiome of Ventilator-associated Pneumonia in Very-low-birth-weight Infants: Experience at a Single Level III Neonatal Intensive Care Unit

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common hospital-acquired infection in neonates on invasive mechanical ventilation, resulting in high morbidity and mortality. The objective of this study is to determine the incidence, risk factors, short-term outcomes and microbiome associated with VAP in very-low-birth-weight (VLBW) infants born at <32 weeks of gestational age (GA).

METHODS

Retrospective study of intubated VLBW infants born at <32 weeks of GA admitted to the Los Angeles General Medical Center neonatal intensive care unit from July 2015 to July 2021 who had routine tracheal aspirate cultures obtained. Neonates were retrospectively classified into 3 groups, confirmed VAP, suspected VAP and no VAP, for comparison of risk factors, outcomes and airway microbial colonization.

RESULTS

Eighty-seven infants met inclusion criteria with a mean GA of 26.1 ± 1 weeks and mean birth weight of 812 ± 281 g. The incidence of VAP was 7.8 per 1000 ventilator days, and the most common causative organisms were Gram-positive organisms (39%), predominantly coagulase-negative Staphylococcus . Duration of postnatal dexamethasone exposure predicted VAP compared to no VAP (coefficient, 0.31; 95% CI 0.03-0.59; P = 0.03) after adjusting for duration of intubation, surfactant use and antenatal steroid exposure. Infants with VAP had higher rate of grade 2/3 bronchopulmonary dysplasia ( P = 0.03) and longer hospital stay ( P = 0.04).

CONCLUSIONS

VAP occurs at a high rate in VLBW infants who are exposed to prolonged dexamethasone use. It is predominantly caused by Gram-positive organisms.

The spectrum of pneumonia among intubated neonates in the neonatal intensive care unit

We review the pathophysiology, epidemiology, diagnosis, treatment, and prevention of ventilator-associated pneumonia (VAP) in neonates. VAP has been studied primarily in adult ICU patients, although there has been more focus on pediatric and neonatal VAP (neo-VAP) in the last decade. The definition as well as diagnosis of VAP in neonates remains a challenge to date. The neonatal intensivist needs to be familiar with the current diagnostic tools and prevention strategies available to treat and reduce VAP to reduce neonatal morbidity and the emergence of antibiotic resistance. This review also highlights preventive strategies and old and emerging treatments available.

Variations and National Perspectives on Evaluation and Management of Ventilator-Associated Pneumonia in Neonatal Intensive Care Units: An In-Depth Survey Analysis

Introduction Infants in the neonatal intensive care unit (NICU) are vulnerable to ventilator-associated pneumonia (VAP), which increases their morbidity and mortality. There is a significant overlap of clinical features of neonatal VAP with other pulmonary pathologies, particularly in preterm infants, which can make the definitive diagnosis and management of VAP challenging. Objective Our study surveyed NICU providers across the United States to understand the perspectives and variations in neonatal VAP diagnostic and management practices. Methods The REDCap survey was distributed to the actively practicing members of the Section on Neonatal-Perinatal Medicine (SoNPM) of the American Academy of Pediatrics (AAP). We used descriptive statistics to analyze the data from the respondents. Results Of 254 respondents, the majority (86.6%, 220) were neonatologists and had a relatively even geographical distribution. Most (75.9%, 193) stated that they would perform a gram stain and respiratory culture as part of a sepsis workup irrespective of the patient's duration on invasive mechanical ventilation (IMV); 224 (88.2%) of providers preferred the endotracheal aspiration (ETA) technique to collect specimens. In cases where a positive respiratory culture was present, VAP (52.4%, 133) was the predominantly assigned diagnosis, followed by pneumonia (27.2%, 69) and ventilator-associated tracheitis (VAT) (9.8%, 25). Respondents reported a prescription of intravenous gentamicin (70%, 178) and vancomycin (41%, 105) as the initial empiric antibiotic drugs, pending final respiratory culture results. Most respondents (55.5%, 141) opted for seven days of antibiotics duration to treat VAP. The reported intra-departmental variation among colleagues in acquiring respiratory cultures and prescribing antibiotics for VAP was 48.8% (124) and 37.4% (95), respectively, with slightly more than half (53.5%, 136) of providers reporting having VAP prevention guidelines in their units. Conclusion The survey study revealed inconsistencies in the investigation, diagnostic nomenclature, choice of antibiotic, and treatment duration for neonatal VAP. Consequently, there is a pressing need for further research to establish a clear definition and evidence-based criteria for VAP.

Adhesion of Klebsiella oxytoca to bladder or lung epithelial cells is promoted by the presence of other opportunistic pathogens

The intestinal and respiratory tracts of healthy individuals serve as habitats for a diverse array of microorganisms, among which Klebsiella oxytoca holds significance as a causative agent in numerous community- and hospital-acquired infections, often manifesting in polymicrobial contexts. In specific circumstances, K. oxytoca, alongside other constituents of the gut microbiota, undergoes translocation to distinct physiological niches. In these new environments, it engages in close interactions with other microbial community members. As this interaction may progress to co-infection where the virulence of involved pathogens may be promoted and enhance disease severity, we investigated how K. oxytoca affects the adhesion of commonly co-isolated bacteria and vice versa during co-incubation of different biotic and abiotic surfaces. Co-incubation was beneficial for the adhesion of at least one of the two co-cultured strains. K. oxytoca enhanced the adhesion of other enterobacteria strains to polystyrene and adhered more efficiently to bladder or lung epithelial cell lines in the presence of most enterobacteria strains and S. aureus. This effect was accompanied by bacterial coaggregation mediated by carbohydrate-protein interactions occurring between bacteria. These interactions occur only in sessile, but not planktonic populations, and depend on the features of the surface. The data are of particular importance for the risk assessment of the urinary and respiratory tract infections caused by K. oxytoca, including those device-associated. In this paper, we present the first report on K. oxytoca ability to acquire increased adhesive capacities on epithelial cells through interactions with common causal agents of urinary and respiratory tract infections.

Lung Microbiota and Ventilator-Associated Pneumonia in the Neonatal Period

The lung microbiota is a complex community of microorganisms that colonize the respiratory tract of individuals from, or even before, birth. Although the lungs were traditionally believed to be sterile, recent research has shown that there is a diversity of bacterial species in the respiratory system. Knowledge about the lung microbiota in newborns and its relationship with bacterial infections is of vital importance to understand the pathogenesis of respiratory diseases in neonatal patients undergoing mechanical ventilation. In this article, the current evidence on the composition of the lung microbiota in newborns will be reviewed, as well as the risks that an altered microbiota can impose on premature newborns. Although advances in neonatal intensive care units have significantly improved the survival rate of preterm infants, the diagnosis and treatment of ventilator-associated pneumonia has not progressed in recent decades. Avoiding dysbiosis caused by inappropriate use of antibiotics around birth, as well as avoiding intubation of patients or promoting early removal of endotracheal tubes, are among the most important preventive measures for ventilator-associated pneumonia. The potential benefit of probiotics and prebiotics in preventing infectious, allergic or metabolic complications in the short or long term is not clearly established and constitutes a very important field of research in perinatal medicine.

Health care-associated infections in neonatology

Health care-associated infections are common in neonatology, but there is no consensus on their definitions. This makes it difficult to compare their incidence or assess the effectiveness of prevention bundles. This is why we think it is very important to achieve a consensus on the definitions and diagnostic criteria for one of the most frequent causes of morbidity in hospitalised neonates. This document aims to standardise the definitions for the most frequent health care-associated infections, such as catheter-associated bloodstream infection, ventilator-associated pneumonia and surgical wound infection, as well as the approach to their diagnosis and treatment.

Risk factors for bronchopulmonary dysplasia infants with respiratory score greater than four: a multi-center, prospective, longitudinal cohort study in China

Bronchopulmonary dysplasia (BPD) is the most common complication of prematurity involving both pre- and post-natal factors. A large, prospective, longitudinal cohort study was conducted to determine whether inflammation-related factors are associated with an increased risk of BPD in preterm infants who were born at a gestational age < 32 weeks, < 72 h after birth and respiratory score > 4. The study included infants from 25 participating hospitals in China between March 1, 2020 and March 31, 2022. The primary outcomes were BPD and severity of BPD at 36 weeks post-menstrual age. A total of 1362 preterm infants were enrolled in the study. After exclusion criteria, the remaining 1088 infants were included in this analysis, of whom, 588 (54.0%) infants were in the BPD group and 500 (46.0%) were in the non-BPD group. In the BPD III model, the following six factors were identified: birth weight (OR 0.175, 95% CI 0.060-0.512; p = 0.001), surfactant treatment (OR 8.052, 95% CI 2.658-24.399; p < 0.001), mean airway pressure (MAP) ≥ 12 cm H2O (OR 3.338, 95% CI 1.656-6.728; p = 0.001), late-onset sepsis (LOS) (OR 2.911, 95% CI 1.514-5.599; p = 0.001), ventilator-associated pneumonia (VAP) (OR 18.236, 95% CI 4.700-70.756; p < 0.001) and necrotizing enterocolitis (NEC) (OR 2.725, 95% CI 1.182-6.281; p = 0.019). Premature infants remained at high risk of BPD and with regional variation. We found that post-natal inflammation-related risk factors were associated with an increased risk of severe BPD, including LOS, VAP, NEC, MAP ≥ 12 cm H2O and use of surfactant.

Antimicrobial materials for endotracheal tubes: A review on the last two decades of technological progress

Ventilator-associated pneumonia (VAP) is an unresolved problem in nosocomial settings, remaining consistently associated with a lack of treatment, high mortality, and prolonged hospital stay. The endotracheal tube (ETT) is the major culprit for VAP development owing to its early surface microbial colonization and biofilm formation by multiple pathogens, both critical events for VAP pathogenesis and relapses. To combat this matter, gradual research on antimicrobial ETT surface coating/modification approaches has been made. This review provides an overview of the relevance and implications of the ETT bioburden for VAP pathogenesis and how technological research on antimicrobial materials for ETTs has evolved. Firstly, certain main VAP attributes (definition/categorization; outcomes; economic impact) were outlined, highlighting the issues in defining/diagnosing VAP that often difficult VAP early- and late-onset differentiation, and that generate misinterpretations in VAP surveillance and discrepant outcomes. The central role of the ETT microbial colonization and subsequent biofilm formation as fundamental contributors to VAP pathogenesis was then underscored, in parallel with the uncovering of the polymicrobial ecosystem of VAP-related infections. Secondly, the latest technological developments (reported since 2002) on materials able to endow the ETT surface with active antimicrobial and/or passive antifouling properties were annotated, being further subject to critical scrutiny concerning their potentialities and/or constraints in reducing ETT bioburden and the risk of VAP while retaining/improving the safety of use. Taking those gaps/challenges into consideration, we discussed potential avenues that may assist upcoming advances in the field to tackle VAP rampant rates and improve patient care. STATEMENT OF SIGNIFICANCE: The use of the endotracheal tube (ETT) in patients requiring mechanical ventilation is associated with the development of ventilator-associated pneumonia (VAP). Its rapid surface colonization and biofilm formation are critical events for VAP pathogenesis and relapses. This review provides a comprehensive overview on the relevance/implications of the ETT biofilm in VAP, and on how research on antimicrobial ETT surface coating/modification technology has evolved over the last two decades. Despite significant technological advances, the limited number of gathered reports (46), highlights difficulty in overcoming certain hurdles associated with VAP (e.g., persistent colonization/biofilm formation; mechanical ventilation duration; hospital length of stay; VAP occurrence), which makes this an evolving, complex, and challenging matter. Challenges and opportunities in the field are discussed.

Accuracy of the spontaneous breathing trial using a combined CPAP + PSV model to predict extubation outcomes in very preterm infants

Background

Very preterm infants often require mechanical ventilation. However, objective criteria to predict the outcomes of extubation in very premature neonates remain lacking. The aim of this study was to investigate the accuracy of the spontaneous breathing trial (SBT) using a combined model of continuous positive airway pressure (CPAP) and low-level pressure support ventilation (PSV) to predict the extubation outcomes of preterm infants with gestational age < 32 weeks.

Methods

Preterm infants with gestational age < 32 weeks, birth weight < 1500 g and requiring mechanical ventilation were selected for the study. All infants underwent a 10-minute SBT using CPAP combined with low-level PSV prior to the planned extubation. Then, the infants were extubated within 1 h after SBT. The outcomes of extubation were considered successful if the neonates did not require reintubation 72 h after extubation.

Results

A total of 119 eligible preterm infants were enrolled in the study, with a median gestational age of 28.9 (27.1–30.3) weeks and a median birth weight of 1100 (900–1350) g. In total, 101 of all infants had successful extubation, 18 of whom failed and eventually had to be reintubated. Of the 102 infants who achieved SBT, 99 were successfully extubated, and 15 of the 17 infants who did not pass SBT had failed extubation. Finally, the diagnostic value for SBT could be assessed with a sensitivity of 98%, a specificity of 83.3%, a positive predictive value of 97.1% and a negative predictive value of 88.2%.

Conclusion

SBT using a combined CPAP + low-level PSV model can predict the outcomes of extubation in very preterm infants with high sensitivity and specificity.

Neonatal intensive care unit nurse training in identifying ultrasound landmarks in the neonatal mediastinum. Α training program for nurses in North-Eastern Greece

PURPOSE

To demonstrate methods and landmarks for mediastinum ultrasound as part of ultrasound examination of the lung for nurses. This will be the first step in their education to detect finally the tubes and lines malpositioning in order to distinguish emergency conditions of the lungs in neonates hospitalized in neonatal intensive care units.

DESIGN AND METHODS

Theoretical and practical interventions were developed to create a 3-month training program based on similar medical courses. The study was approved by the hospital's ethics committee.The program was performed in the neonatal intensive care unit of a single academic institution. Participating nurse was supervised by a paediatric surgeon and trained in lung ultrasound (a safe method without radiation) by a paediatric radiologist.

RESULTS

During the practical period (2 months), the neonatal intensive care unit nurse examined 50 neonates (25 + 6-40 + 4 weeks gestational age; 21 males) separated into two subgroups of 25 neonates each for each training month. In the first month under supervision, the nurse was trained to recognise the aortic arch, the right pulmonary artery, the esophagus, the tracheal air, and the 'sliding lung sign' in the anterior, lateral, and posterolateral aspects of the thoracic cage. In the second month, the nurse recorded the ultrasound examinations. The identified structures were then assessed and graded by the supervising radiologist. The overall estimated success rate (5 landmarks × 25 neonates = 125) was 90.4%.

CONCLUSIONS

Although this is the first report of the design of a 'hands-on', lung ultrasound training program for neonatal intensive care unit nurses, our findings demonstrate that it is a safe and useful program for all neonatal intensive care unit nurses because theoverall success rate of the 3-month program was determined by accurate identification of basic anatomical structures (90,4%) by the nurse.

PRACTICE IMPLICATIONS

This study describes the first educational training program for NICU nurses designed to recognise basic structures in the neonatal mediastinum. If the program is effective, NICU nurses will be able to identify respiratory emergencies. NICU nurses can inform doctors about emergencies according to tubes and lines malpositioning in a timely manner to avoid negative consequences.

Ventilator-Associated Pneumonia in the Neonatal Intensive Care Unit

See Bonus NeoBriefs videos and downloadable teaching slides Intubated infants in the NICU are at risk of developing ventilator-associated pneumonia (VAP), a common type of health care-associated infection. The Centers for Disease Control and Prevention developed guidelines for diagnosing VAP in patients younger than 1 year, which include worsening gas exchange, radiographic findings, and at least 3 defined clinical signs of pneumonia. VAP in infants is treated with empiric antibiotics selected based on local resistance patterns and individualized patient data. Many NICUs have implemented prevention bundles in an effort to decrease VAP by ensuring the cleanest environment for intubated neonates (hand hygiene, sterile handling of equipment), positioning of infants to prevent gastric reflux, and constantly reevaluating for extubation readiness. Although these prevention bundle elements are intuitive and generally low risk, none are based on strong research support. This article reviews the epidemiology, pathogenesis, diagnosis, treatment, and prevention of VAP in NICU patients, focusing on recent evidence, highlighting areas of emerging research, and identifying persistent knowledge gaps.