Interobserver variability in the interpretation of chest roentgenograms of patients with possible pneumonia

Retrospective computed tomography assessment of chemotherapy-related pneumonia with severity screening in pediatric acute lymphoblastic leukemia by radiological imaging

Objectives

To evaluate the radiological imaging-guided severity along the pneumonia course and evaluate the chest computed tomography (CT) findings of chemotherapy-related pneumonia in children with acute lymphoblastic leukemia (ALL).

Materials and methods

A retrospective database review of children with ALL was conducted from March 2016 to August 2021 to identify cases with CT images who developed pneumonia during the chemotherapy course. A total of 51 children with ALL developed pneumonia were ultimately included (31 boys and 20 girls, mean age: 6 ± 4 years [standard deviation]). Each child's demographics, medical records, and laboratory results were collected. The CT images were then reviewed and the radiologic severity index (RSI) was calculated based on the regional opacity and implicated volume. A t-test, U test, Pearson's Chi-square test, and Fisher's exact test were performed to compare the clinical or radiologic features between the severe and moderate cases. The linear regression models were employed to analyze the correlation of RSIs with other clinical features.

Results

Eleven children (22 %, 11/51) displayed severe phenotypes associated with respiratory failure. The ground glass opacity (GGO) frequently appeared (65 % of CT images). The baseline RSI was positively associated with the lowest lymphocyte (p = .003), neutrophil (p = .01) counts, and the highest C-reactive protein level (p = .04). The peak RSI may predict severe phenotypes at a cutoff of 4.5 (AUC 0.76 [0.61, 0.91]) with 73 % sensitivity and 63 % specificity.

Conclusion

The chest CT images of children with chemotherapy-related pneumonia displayed clinically related baseline RSI and a peak RSI of >4.5 of 36 predicted severe phenotypes.

Commonly Missed Findings on Chest Radiographs: Causes and Consequences

Chest radiography (CXR) continues to be the most frequently performed imaging examination worldwide, yet it remains prone to frequent errors in interpretation. These pose potential adverse consequences to patients and are a leading motivation for medical malpractice lawsuits. Commonly missed CXR findings and the principal causes of these errors are reviewed and illustrated. Perceptual errors are the predominant source of these missed findings. The medicolegal implications of such errors are explained. Awareness of commonly missed CXR findings, their causes, and their consequences are important in developing approaches to reduce and mitigate these errors.

Early chest CT-scan in emergency patients affected by community-acquired pneumonia is associated with improved diagnosis consistency

Chest CT-scan (CT) exceeds chest X-ray (CXR) to diagnose community-acquired pneumonia (CAP) but actual use and results remain unclear. We examine whether CT performed at ED visit improved ED diagnosis of CAP as compared to a final diagnosis of CAP at hospital discharge (gold standard diagnosis for the study), and how it impacts relevant clinical outcomes. This retrospective monocenter observational study was based on the analysis of the hospital database. Patients with a diagnosis of CAP in the ED (ICD-10 codes: J110, J111, from J12- to J18-, J440, J690, U0710, and U0711) were included. We compared ED patients who were diagnosed with CAP using CXR and CT. We measured diagnostic consistency, duration of ED visit, percentage of CXR and CT during hospital stay, hospital length-of-stay, ICU admission, and in-hospital mortality. Multivariate analysis was adjusted for CRB65 score by multiple logistic regression analysis for binary outcomes and by multivariate analysis of variance for continuous outcomes. We included 994 ED patients with an initial diagnosis of CAP (751 receiving CXR, 243 receiving CT). CT prescription in the ED increased over time ( P < 0.001). In patients admitted after ED, CT improved diagnosis consistency for CAP [88.2% vs. 80.9%; difference 7.3% (95% confidence interval 1.2-13.3%)] with a trend for lower hospital length-of-stay [10.2 vs. 12.2 days; difference -2.0 (95% confidence interval -3.9 to -0.1)], but not ICU admission ( P = 0.09) and in-hospital mortality ( P = 0.056). Diagnosis of patients admitted with CAP improved when CT was obtained at ED visit. These results should be reproduced at a larger scale to test whether early CT conserves healthcare resources.

[Chest X-ray: implementation and indication : Recommendations of the thoracic imaging working group of the German Radiological Society]

BACKGROUND

Even after more than 100 years, the chest X‑ray is still an important technique to detect important pathological changes of lungs, heart and vessels in a fast and low-dose manner. For the German-speaking regions, there are only recommendations available published by the "Ständigen Strahlenschutzkommission (SSK)" regarding the indication. These recommendations are not updated on a regular basis and more recent developments are only integrated with delayed.

METHODS

The chest division of the German Radiological Society has summarized their expertise for the usage and indication of the chest X‑ray. Especially within the field of oncology the usage of chest X‑ray is evaluated differently to the aforementioned recommendations; here chest computed tomography (CT) is much more sensitive for evaluation of metastasis and local invasion of tumors. Also, within the area of infectious diseases in non-immunocompetent patients, CT is the method of choice. Based on the structure of the current recommendations, many current guidelines and indications are summarized and presented within the context of the usage of chest X‑ray.

Weakly supervised pneumonia localization in chest X-rays using generative adversarial networks

PURPOSE

Automatic localization of pneumonia on chest X-rays (CXRs) is highly desirable both as an interpretive aid to the radiologist and for timely diagnosis of the disease. However, pneumonia's amorphous appearance on CXRs and complexity of normal anatomy in the chest present key challenges that hinder accurate localization. Existing studies in this area are either not optimized to preserve spatial information of abnormality or depend on expensive expert-annotated bounding boxes. We present a novel generative adversarial network (GAN)-based machine learning approach for this problem, which is weakly supervised (does not require any location annotations), was trained to retain spatial information, and can produce pixel-wise abnormality maps highlighting regions of abnormality (as opposed to bounding boxes around abnormality).

METHODS

Our method is based on the Wasserstein GAN framework and, to the best of our knowledge, the first application of GANs to this problem. Specifically, from an abnormal CXR as input, we generated the corresponding pseudo normal CXR image as output. The pseudo normal CXR is the "hypothetical" normal, if the same abnormal CXR were not to have any abnormalities. We surmise that the difference between the pseudo normal and the abnormal CXR highlights the pixels suspected to have pneumonia and hence is our output abnormality map. We trained our algorithm on an "unpaired" data set of abnormal and normal CXRs and did not require any location annotations such as bounding boxes/segmentations of abnormal regions. Furthermore, we incorporated additional prior knowledge/constraints into the model and showed that they help improve localization performance. We validated the model on a data set consisting of 14 184 CXRs from the Radiological Society of North America pneumonia detection challenge.

RESULTS

We evaluated our methods by comparing the generated abnormality maps with radiologist annotated bounding boxes using receiver operating characteristic (ROC) analysis, image similarity metrics such as normalized cross-correlation/mutual information, and abnormality detection rate.We also present visual examples of the abnormality maps, covering various scenarios of abnormality occurrence. Results demonstrate the ability to highlight regions of abnormality with the best method achieving an ROC area under the curve (AUC) of 0.77 and a detection rate of 85%.The GAN tended to perform better as prior knowledge/constraints were incorporated into the model.

CONCLUSIONS

We presented a novel GAN based approach for localizing pneumonia on CXRs that (1) does not require expensive hand annotated location ground truth; and (2) was trained to produce abnormality maps at the pixel level as opposed to bounding boxes. We demonstrated the efficacy of our methods via quantitative and qualitative results.

[Imaging in respiratory infections]

The conventional X‑ray image is the method of choice for suspected pneumonia. Computed tomography (CT) is indicated for treatment refractory or recurrent infiltrates, difficult differential diagnostics, suspected complications and in immunocompromised patients. Thoracic sonography can be used as an alternative method for initial diagnostics and in the intensive care unit to monitor progress. In addition to the detection of infiltrates the radiological classification can help to limit the pathogen spectrum. Radiologically, three forms of pneumonia can principally be differentiated: lobar pneumonia, bronchopneumonia and interstitial pneumonia. Furthermore, there are special forms of pneumonia with certain pathogens, such as aspergilloma, invasive mycosis, postprimary tuberculosis and nontuberculous mycobacteriosis or in a specific clinical context, such as aspiration pneumonia, postinfarction pneumonia, retention pneumonia and septic emboli. The most frequent complications of pneumonia are lung abscesses and pleural empyema. Both can sometimes but not always be seen in the X‑ray image. If clinically suspected the indications for CT should be generously applied. Certain pre-existing diseases, such as immunodeficiency or structural alterations of the lungs can predispose to pulmonary infections, frequently with unusual pathogens or manifestation forms and must be taken into account in the diagnostics.

[Management of Adult Community-Acquired Pneumonia and Prevention - Update 2021 - Guideline of the German Respiratory Society (DGP), the Paul-Ehrlich-Society for Chemotherapy (PEG), the German Society for Infectious Diseases (DGI), the German Society of Medical Intensive Care and Emergency Medicine (DGIIN), the German Viological Society (DGV), the Competence Network CAPNETZ, the German College of General Practitioneers and Family Physicians (DEGAM), the German Society for Geriatric Medicine (DGG), the German Palliative Society (DGP), the Austrian Society of Pneumology Society (ÖGP), the Austrian Society for Infectious and Tropical Diseases (ÖGIT), the Swiss Respiratory Society (SGP) and the Swiss Society for Infectious Diseases Society (SSI)]

The present guideline provides a new and updated concept of the management of adult patients with community-acquired pneumonia. It replaces the previous guideline dating from 2016.The guideline was worked out and agreed on following the standards of methodology of a S3-guideline. This includes a systematic literature search and grading, a structured discussion of recommendations supported by the literature as well as the declaration and assessment of potential conflicts of interests.The guideline has a focus on specific clinical circumstances, an update on severity assessment, and includes recommendations for an individualized selection of antimicrobial treatment.The recommendations aim at the same time at a structured assessment of risk for adverse outcome as well as an early determination of treatment goals in order to reduce mortality in patients with curative treatment goal and to provide palliation for patients with treatment restrictions.

Improving reference standards for validation of AI-based radiography

Objective:

Demonstrate the importance of combining multiple readers' opinions, in a context-aware manner, when establishing the reference standard for validation of artificial intelligence (AI) applications for, e.g. chest radiographs. By comparing individual readers, majority vote of a panel, and panel-based discussion, we identify methods which maximize interobserver agreement and label reproducibility.

Methods:

1100 frontal chest radiographs were evaluated for 6 findings: airspace opacity, cardiomegaly, pulmonary edema, fracture, nodules, and pneumothorax. Each image was reviewed by six radiologists, first individually and then via asynchronous adjudication (web-based discussion) in two panels of three readers to resolve disagreements within each panel. We quantified the reproducibility of each method by measuring interreader agreement.

Results:

Panel-based majority vote improved agreement relative to individual readers for all findings. Most disagreements were resolved with two rounds of adjudication, which further improved reproducibility for some findings, particularly reducing misses. Improvements varied across finding categories, with adjudication improving agreement for cardiomegaly, fractures, and pneumothorax.

Conclusion:

The likelihood of interreader agreement, even within panels of US board-certified radiologists, must be considered before reads can be used as a reference standard for validation of proposed AI tools. Agreement and, by extension, reproducibility can be improved by applying majority vote, maximum sensitivity, or asynchronous adjudication for different findings, which supports the development of higher quality clinical research.

Advances in knowledge:

A panel of three experts is a common technique for establishing reference standards when ground truth is not available for use in AI validation. The manner in which differing opinions are resolved is shown to be important, and has not been previously explored.

Deep learning for chest X-ray analysis: A survey

Recent advances in deep learning have led to a promising performance in many medical image analysis tasks. As the most commonly performed radiological exam, chest radiographs are a particularly important modality for which a variety of applications have been researched. The release of multiple, large, publicly available chest X-ray datasets in recent years has encouraged research interest and boosted the number of publications. In this paper, we review all studies using deep learning on chest radiographs published before March 2021, categorizing works by task: image-level prediction (classification and regression), segmentation, localization, image generation and domain adaptation. Detailed descriptions of all publicly available datasets are included and commercial systems in the field are described. A comprehensive discussion of the current state of the art is provided, including caveats on the use of public datasets, the requirements of clinically useful systems and gaps in the current literature.

Diagnostic performance of artificial intelligence model for pneumonia from chest radiography

Objective

The chest X-ray (CXR) is the most readily available and common imaging modality for the assessment of pneumonia. However, detecting pneumonia from chest radiography is a challenging task, even for experienced radiologists. An artificial intelligence (AI) model might help to diagnose pneumonia from CXR more quickly and accurately. We aim to develop an AI model for pneumonia from CXR images and to evaluate diagnostic performance with external dataset.

Methods

To train the pneumonia model, a total of 157,016 CXR images from the National Institutes of Health (NIH) and the Korean National Tuberculosis Association (KNTA) were used (normal vs. pneumonia = 120,722 vs.36,294). An ensemble model of two neural networks with DenseNet classifies each CXR image into pneumonia or not. To test the accuracy of the models, a separate external dataset of pneumonia CXR images (n = 212) from a tertiary university hospital (Gachon University Gil Medical Center GUGMC, Incheon, South Korea) was used; the diagnosis of pneumonia was based on both the chest CT findings and clinical information, and the performance evaluated using the area under the receiver operating characteristic curve (AUC). Moreover, we tested the change of the AI probability score for pneumonia using the follow-up CXR images (7 days after the diagnosis of pneumonia, n = 100).

Results

When the probability scores of the models that have a threshold of 0.5 for pneumonia, two models (models 1 and 4) having different pre-processing parameters on the histogram equalization distribution showed best AUC performances of 0.973 and 0.960, respectively. As expected, the ensemble model of these two models performed better than each of the classification models with 0.983 AUC. Furthermore, the AI probability score change for pneumonia showed a significant difference between improved cases and aggravated cases (Δ = -0.06 ± 0.14 vs. 0.06 ± 0.09, for 85 improved cases and 15 aggravated cases, respectively, P = 0.001) for CXR taken as a 7-day follow-up.

Conclusions

The ensemble model combined two different classification models for pneumonia that performed at 0.983 AUC for an external test dataset from a completely different data source. Furthermore, AI probability scores showed significant changes between cases of different clinical prognosis, which suggest the possibility of increased efficiency and performance of the CXR reading at the diagnosis and follow-up evaluation for pneumonia.

Prevalence of Clinical Signs Within Reference Ranges Among Hospitalized Patients Prescribed Antibiotics for Pneumonia

IMPORTANCE

Antibiotics are frequently prescribed for suspected pneumonia, but overdiagnosis is common and fixed regimens are often used despite randomized trials suggesting it is safe to stop antibiotics once clinical signs are normalizing.

OBJECTIVE

To quantify potential excess antibiotic prescribing by characterizing antibiotic use relative to patients' initial clinical signs and subsequent trajectories.

DESIGN, SETTING, AND PARTICIPANTS

An observational cohort study was conducted in 2 tertiary and 2 community hospitals in Eastern Massachusetts. All nonventilated adult patients admitted between May 1, 2017, and July 1, 2018 (194 521 hospitalizations), were included.

MAIN OUTCOMES AND MEASURES

Identification of all antibiotic starts for possible community-acquired pneumonia (CAP) or hospital-acquired pneumonia (HAP) per clinicians' stated indications. Potential excess antibiotic prescribing was quantified by characterizing the frequency of patients in whom all clinical signs were within reference ranges on the first day of antibiotic therapy and by how long antibiotic therapy was continued after all clinical signs were normal, including postdischarge antibiotics.

RESULTS

Among 194 521 hospitalizations, 9540 patients were treated for possible CAP (4574 [48.0%] women; mean [SD] age, 67.6 [17.0] years) and 2733 for possible HAP (1211 [44.3%] women; mean [SD] age, 66.7 [16.2] years). Temperature, respiratory rate, oxygen saturation, and white blood cell count were all within reference ranges on the first day of antibiotics in 1779 of 9540 (18.6%) episodes of CAP and 370 of 2733 (13.5%) episodes of HAP. Antibiotics were continued for 3 days or longer after all clinical signs were normal in 3322 of 9540 (34.8%) episodes of CAP and 1050 of 2733 (38.4%) episodes of HAP. Up to 24 978 of 71 706 (34.8%) antibiotic-days prescribed for possible pneumonia may have been unnecessary.

CONCLUSIONS AND RELEVANCE

In this study, almost one-fifth of hospitalized patients treated for pneumonia did not have any of the cardinal signs of pneumonia on the first day of treatment and antibiotics were continued for 3 days or longer after all signs were normal in more than a third of patients. These observations suggest substantial opportunities to improve antibiotic prescribing.

Added Value of Bone Suppression Image in the Detection of Subtle Lung Lesions on Chest Radiographs with Regard to Reader's Expertise

BACKGROUND

Chest radiographs (CXR) are the most commonly used imaging techniques by various clinicians and radiologists. However, detecting lung lesions on CXR depends largely on the reader's experience level, so there have been several trials to overcome this problem using post-processing of CXR. We investigated the added value of bone suppression image (BSI) in detecting various subtle lung lesions on CXR with regard to reader's expertise.

METHODS

We applied a software program to generate BSI in 1,600 patients in the emergency department. Of them, 80 patients with subtle lung lesions and 80 patients with negative finding on CXR were retrospectively selected based on the subtlety scores on CXR and CT findings. Ten readers independently rated their confidence in deciding the presence or absence of a lung lesion at each of 960 lung regions on the two separated imaging sessions: CXR alone vs. CXR with BSI.

RESULTS

The additional use of BSI for all readers significantly increased the mean area under the curve (AUC) in detecting subtle lung lesions (0.663 vs. 0.706; P < 0.001). The less experienced readers were, the more AUC differences increased: 0.067 (P < 0.001) for junior radiology residents; 0.064 (P < 0.001) for non-radiology clinicians; 0.044 (P < 0.001) for senior radiology residents; and 0.019 (P = 0.041) for chest radiologists. The additional use of BSI significantly increased the mean confidence regarding the presence or absence of lung lesions for 213 positive lung regions (2.083 vs. 2.357; P < 0.001) and for 747 negative regions (1.217 vs. 1.195; P = 0.008).

CONCLUSION

The use of BSI increases diagnostic performance and confidence, regardless of reader's expertise, reduces the impact of reader's expertise and can be helpful for less experienced clinicians and residents in the detection of subtle lung lesions.

Development and Assessment of Objective Surveillance Definitions for Nonventilator Hospital-Acquired Pneumonia

IMPORTANCE

Hospital-acquired pneumonia is the most common health care-associated infection in the United States. Most cases occur in nonventilated patients, but many hospitals track hospital-acquired pneumonia only in ventilated patients because of the complexity and subjectivity of conducting surveillance for large numbers of nonventilated patients.

OBJECTIVE

To propose and assess potentially objective, efficient, and reproducible surveillance definitions for nonventilator hospital-acquired pneumonia (NV-HAP) using routine clinical data stored in electronic health record systems.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted in 2 tertiary referral and 2 community hospitals in Massachusetts between May 31, 2015, and July 1, 2018. All nonventilated patients aged 18 years or older who were admitted to these hospitals were included (N = 310 651).

EXPOSURES

Ten candidate definitions for NV-HAP based on clinically meaningful combinations of 6 potential surveillance criteria were proposed: worsening oxygenation, temperature higher than 38 °C (fever), abnormal white blood cell count of less than 4000/μL or more than 12 000/μL, performance of chest imaging, submission of respiratory specimen for culture, and 3 or more days of new antibiotics.

MAIN OUTCOMES AND MEASURES

Incidence rates, lengths of stay, hospital mortality rates, and odds ratios (ORs) for time to discharge and mortality compared with those of matched controls were calculated for each candidate definition. The ORs were adjusted for demographics, clinical service, comorbidities, and severity of illness.

RESULTS

The study analyzed 310 651 patients with 489 519 admissions, including 205 054 patients with 311 484 admissions of 3 or more days. Among the patients with 311 484 admissions, the mean (SD) patient age was 58.3 (19.3) years and 176 936 (56.8%) were of women. Incidence rates for candidate definitions per 100 admissions ranged from 3.4 events for worsening oxygenation alone to 0.9 event for worsening oxygenation and at least 3 days of new antibiotics to 0.6 event for worsening oxygenation, at least 3 days of new antibiotics, fever, abnormal white blood cell count, and performance of chest imaging. Crude mortality rates ranged from 16.1% (n = 2643) for patients with worsening oxygen alone to 27.7% (n = 868) for patients with worsening oxygenation, at least 3 days of antibiotics, fever or abnormal white blood cell count, and chest imaging. Patients who met NV-HAP candidate definitions remained in the hospital for twice as long as their matched controls (adjusted ORs ranged from 1.8 [95% CI, 1.7-1.8] to 2.1 [95% CI, 2.0-2.1]) and were 4 to 6 times as likely to die in the hospital (adjusted ORs ranged from 3.8 [95% CI, 3.5-4.0] to 6.5 [95% CI, 5.2-8.2]). Agreement between candidate definitions and clinical diagnoses was fair (κ = 0.33).

CONCLUSIONS AND RELEVANCE

These findings suggest that objective surveillance for NV-HAP using electronically computable definitions that incorporate common clinical criteria is feasible and generates incidence, mortality, and adjusted ORs for hospital mortality similar to estimates from manual surveillance. These definitions have the potential to facilitate widespread, automated surveillance for NV-HAP and thus inform the development and evaluation of prevention programs.

The role of serum procalcitonin in the differential diagnosis of pneumonia from pulmonary edema among the patients with pulmonary infiltrates on chest radiography

The aim of this study is to evaluate the usefulness of serum procalcitonin (PCT) as a diagnostic biomarker for distinguishing pneumonia from pulmonary edema in patients presenting with pulmonary infiltrates on chest radiography.A comparative study was performed retrospectively in a university-affiliated hospital, from May, 2013 to April, 2015. Adult patients (≥18 years) who showed pulmonary infiltrates on chest radiography and had blood tests with C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), PCT, and N-terminal pro-b-type natriuretic peptide (NT-proBNP) on admission were included in the study. Clinical parameters collected on admission were compared between the case group (n = 143) with pneumonia and the control group (n = 88) with pulmonary edema alone.During the study period, a total of 1217 patients were identified. Of them, a total of 231 patients were included in analyses based on exclusion criteria. In the multivariate logistic regression analysis, PCT ≥0.25 ng/mL, ESR ≥35 mm/h, CRP ≥18 mg/L, NT-proBNP ≤200 pg/mL, underlying neurologic diseases, fever, sputum, absence of cardiomegaly, and a low Charlson comorbidity index were independently associated with pneumonia. For this model, the sensitivity, specificity, positive predictive value, and negative predictive value in distinguishing between the 2 groups were 90.2%, 79.6%, 87.8%, and 83.3%, respectively, with an area under the curve of 0.93.This study suggests that the practical use of PCT in conjunction with clinical data can be valuable in the differential diagnosis of pulmonary infiltrates and guidance for clinicians to prevent antibiotic misuse.

Lung ultrasound compared to chest X-ray for diagnosis of pediatric pneumonia: A meta-analysis

OBJECTIVE

Although a clinical diagnosis, the standard initial imaging modality for patients with concern for pediatric community acquired pneumonia (pCAP) is a chest x-ray (CXR), which has a relatively high false negative rate, exposes patients to ionizing radiation, and may not be available in resource limited settings. The primary objective of this meta-analysis is to evaluate the accuracy of lung ultrasound (LUS) compared to CXR for the diagnosis of pCAP.

METHODS

Data were collected via a systematic review of PubMed, EMBASE, and Web of Science with dates up to August 2017. Keywords and search terms were generated for pneumonia, lung ultrasound, and pediatric population. Two independent investigators screened abstracts for inclusion. PRISMA was used for selecting appropriate studies. QUADAS was applied to these studies to assess quality for inclusion into the meta-analysis. We collected data from included studies and calculated sensitivity, specificity, positive predictive value, and negative predictive values of CXR and LUS for the diagnosis of pCAP.

RESULTS

Twelve studies including 1510 patients were selected for data extraction. LUS had a sensitivity of 95.5% (93.6-97.1) and specificity of 95.3% (91.1-98.3). CXR had a sensitivity of 86.8% (83.3-90.0) and specificity of 98.2% (95.7-99.6). Variations between the studies included ultrasound findings diagnostic of pneumonia, study setting (inpatient vs emergency department) and inclusion of CXR in the reference standard for pneumonia.

CONCLUSIONS

In our meta-analysis, lung ultrasound had significantly better sensitivity with similar specificity when compared to chest x-ray for the diagnosis of pediatric community acquired pneumonia.

Non-invasive biomarkers of fetal brain development reflecting prenatal stress: An integrative multi-scale multi-species perspective on data collection and analysis

Prenatal stress (PS) impacts early postnatal behavioural and cognitive development. This process of 'fetal programming' is mediated by the effects of the prenatal experience on the developing hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). We derive a multi-scale multi-species approach to devising preclinical and clinical studies to identify early non-invasively available pre- and postnatal biomarkers of PS. The multiple scales include brain epigenome, metabolome, microbiome and the ANS activity gauged via an array of advanced non-invasively obtainable properties of fetal heart rate fluctuations. The proposed framework has the potential to reveal mechanistic links between maternal stress during pregnancy and changes across these physiological scales. Such biomarkers may hence be useful as early and non-invasive predictors of neurodevelopmental trajectories influenced by the PS as well as follow-up indicators of success of therapeutic interventions to correct such altered neurodevelopmental trajectories. PS studies must be conducted on multiple scales derived from concerted observations in multiple animal models and human cohorts performed in an interactive and iterative manner and deploying machine learning for data synthesis, identification and validation of the best non-invasive detection and follow-up biomarkers, a prerequisite for designing effective therapeutic interventions.

[Community-acquired pneumonia]

CLINICAL ISSUE

The diagnosis of community-acquired pneumonia (CAP) is often not possible based only on the clinical symptoms and biochemical parameters.

STANDARD RADIOLOGICAL METHODS

For every patient with the suspicion of CAP, a chest radiograph in two planes should be carried out. Additionally, a risk stratification for the decision between outpatient therapy or hospitalization is recommended.

METHODICAL INNOVATIONS

Based on the evaluation of the different radiological patterns as well as their extent and distribution, a rough allocation to so-called pathogen groups as well as a differentiation between viral and bacterial infections are possible; however, because different pathogens cause different patterns an accurate correlation is not feasible by relying purely on imaging.

ACHIEVEMENTS/PRACTICAL RECOMMENDATIONS

The radiological findings serve as proof or exclusion of pneumonia and can also be used to evaluate the extent of the disease (e.g. monolobular, multilobular, unilateral or bilateral). In cases of prolonged disease, suspicion of complications (e.g. pleural effusion or empyema, necrotizing pneumonia or abscess) or comorbid conditions (e.g. underlying pulmonary or mediastinal diseases) computed tomography is an important diagnostic tool in addition to chest radiography. Ultrasound is often used to diagnose pleural processes (e.g. parapneumonic effusion or pleural empyema).

Determining the clinical significance of errors in pediatric radiograph interpretation between emergency physicians and radiologists

OBJECTIVES

Emergency physicians (EPs) interpret plain radiographs for management and disposition of patients. Radiologists subsequently conduct their own interpretations, which may differ. The purposes of this study were to review the rate and nature of discrepancies between radiographs interpreted by EPs and those of radiologists in the pediatric emergency department, and to determine their clinical significance.

METHODS

We conducted a retrospective review of discrepant radiology reports from a single-site pediatric emergency department from October 2012 to December 2014. All radiographs were interpreted first by the staff EP, then by a radiologist. The report was identified as a "discrepancy" if these reports differed. Radiographs were categorized by body part and discrepancies classified as false positive, false negative, or not a discrepancy. Clinically significant errors that required a change in management were tracked.

RESULTS

There were 25,304 plain radiographs completed during the study period, of which 252 (1.00%) were identified as discrepant. The most common were chest radiographs (41.7%) due to missed pneumonia, followed by upper and lower extremities (26.2% and 17.5%, respectively) due to missed fractures. Of the 252 discrepancies, 207 (82.1%) were false negatives and 45 (17.9%) were false positives. In total, 105 (0.41% of all radiographs) were clinically significant.

CONCLUSION

There is a low rate of discrepancy in the interpretation of pediatric emergency radiographs between emergency department physicians and radiologists. The majority of errors occur with radiographs of the chest and upper extremities. The low rate of clinically significant discrepancy allows safe management based on EP interpretation.

Pneumonia and inflammation in acute decompensated heart failure: a registry-based analysis of 1939 patients

Background:

The prognostic impact of pneumonia and signs of systemic inflammation in patients with acute decompensated heart failure (ADHF) has not been fully elucidated yet. The aim of the present study was thus to investigate the association of pneumonia and the inflammation surrogate C-reactive protein with all-cause mortality in patients admitted for ADHF.

Methods:

We analysed data of 1939 patients admitted for ADHF. Patients were dichotomised according to the presence or absence of pneumonia. The primary endpoint of all-cause mortality was determined by death registry linkage.

Results:

In total, 412 (21.2%) patients had concomitant pneumonia. Median C-reactive protein levels were higher in patients with compared to patients without pneumonia (24.9 versus 9.8 mg/l, respectively; P<0.001). All-cause mortality was significantly higher in patients with pneumonia ( P<0.001). In adjusted Cox regression models, pneumonia as well as C-reactive protein were independently associated with in-hospital mortality. Only C-reactive protein remained as independent predictor for long-term mortality.

Conclusion:

Pneumonia is relatively common in ADHF and a predictor for in-hospital mortality. However, inflammation in general seems to be more important than pneumonia itself for long-term prognosis. Compared to community-acquired pneumonia studies, C-reactive protein levels were rather low and therefore pneumonia might be over-diagnosed in ADHF patients.

Diagnostic accuracy of C-reactive protein and procalcitonin in suspected community-acquired pneumonia adults visiting emergency department and having a systematic thoracic CT scan

Introduction

Community-acquired pneumonia (CAP) requires prompt treatment, but its diagnosis is complex. Improvement of bacterial CAP diagnosis by biomarkers has been evaluated using chest X-ray infiltrate as the CAP gold standard, producing conflicting results. We analyzed the diagnostic accuracy of biomarkers in suspected CAP adults visiting emergency departments for whom CAP diagnosis was established by an adjudication committee which founded its judgment on a systematic multidetector thoracic CT scan.

Methods

In an ancillary study of a multi-center prospective study evaluating the impact of systematic thoracic CT scan on CAP diagnosis, sensitivity and specificity of C-reactive protein (CRP) and procalcitonin (PCT) were evaluated. Systematic nasopharyngeal multiplex respiratory virus PCR was performed at inclusion. An adjudication committee classified CAP diagnostic probability on a 4-level Likert scale, based on all available data.

Results

Two hundred patients with suspected CAP were analyzed. The adjudication committee classified 98 patients (49.0 %) as definite CAP, 8 (4.0 %) as probable, 23 (11.5 %) as possible and excluded in 71 (35.5 %, including 29 patients with pulmonary infiltrates on chest X-ray). Among patients with radiological pulmonary infiltrate, 23 % were finally classified as excluded. Viruses were identified by PCR in 29 % of patients classified as definite. Area under the curve was 0.787 [95 % confidence interval (95 % CI), 0.717 to 0.857] for CRP and 0.655 (95 % CI, 0.570 to 0.739) for PCT to detect definite CAP. CRP threshold at 50 mg/L resulted in a positive predictive value of 0.76 and a negative predictive value of 0.75. No PCT cut-off resulted in satisfactory positive or negative predictive values. CRP and PCT accuracy was not improved by exclusion of the 25 (25.5 %) definite viral CAP cases.

Conclusions

For patients with suspected CAP visiting emergency departments, diagnostic accuracy of CRP and PCT are insufficient to confirm the CAP diagnosis established using a gold standard that includes thoracic CT scan. Diagnostic accuracy of these biomarkers is also insufficient to distinguish bacterial CAP from viral CAP.

Trial registration

ClinicalTrials.gov registry NCT01574066 (February 7, 2012)

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1083-6) contains supplementary material, which is available to authorized users.

A national survey of the diagnosis and management of suspected ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) affects up to 20% of patients admitted to intensive care units (ICU). It is associated with increased morbidity, mortality and healthcare costs. Despite published guidelines, variability in diagnosis and management exists, the extent of which remains unclear. We sought to characterise consultant opinions surrounding diagnostic and management practice for VAP in the UK.

METHODS

An online survey was sent to all consultant members of the UK Intensive Care Society (n=∼1500). Data were collected regarding respondents' individual practice in the investigation and management of suspected VAP including use of diagnostic criteria, microbiological sampling, chest X-ray (CXR), bronchoscopy and antibiotic treatments.

RESULTS

339 (23%) responses were received from a broadly representative spectrum of ICU consultants. All respondents indicated that microbiological confirmation should be sought, the majority (57.8%) stating they would take an endotracheal aspirate prior to starting empirical antibiotics. Microbiology reporting services were described as qualitative only by 29.7%. Only 17% of respondents had access to routine reporting of CXRs by a radiologist. Little consensus exists regarding technique for bronchoalveolar lavage (BAL) with the reported volume of saline used ranging from 5 to 500 mL. 24.5% of consultants felt inadequately trained in bronchoscopy.

CONCLUSIONS

There is wide variability in the approach to diagnosis and management of VAP among UK consultants. Such variability challenges the reliability of the diagnosis of VAP and its reported incidence as a performance indicator in healthcare systems. The data presented suggest increased radiological and microbiological support, and standardisation of BAL technique, might improve this situation.

The posterior impingement view: an alternative conventional projection to detect bony posterior ankle impingement

PURPOSE

The purpose of the current study was to clinically evaluate the diagnostic value of the new posterior impingement (PIM) view in the detection of an os trigonum, compared with the standard lateral view, using computed tomography (CT) as a reference standard.

METHODS

Three observers, 2 experienced (orthopaedic surgeon and radiologist) and one inexperienced (resident), independently scored 142 radiographic images for the presence of an os trigonum. The diagnostic performance was assessed using the computed tomographic scan as the reference standard. Accuracy, sensitivity, specificity, positive predicted value (PPV), and negative predicted value (NPV) were calculated.

RESULTS

The PIM view had significantly superior accuracy compared with the lateral view for each observer: orthopaedic surgeon, PIM view = 90 versus lateral view = 75 (P = .013); radiologist, PIM view = 80 versus lateral view = 64 (P = .019); resident, PIM view = 90 versus lateral view = 79 (P = .039). The mean sensitivity and specificity of the lateral view for all observers was 50% and 81%, respectively. For the PIM view, this was 78% and 89%, respectively. The PPV was 50% for the lateral view and 70% for the PIM view. The NPV was 84% for the lateral view and 93% for the PIM view.

CONCLUSIONS

The PIM view has significantly superior diagnostic accuracy compared with the conventional lateral view in the detection of an os trigonum. In cases of symptomatic posterior ankle impingement, we advise that a PIM view be used instead of or in addition to the standard lateral view for detection of posterior talar pathologic conditions. LEVEL OF 

EVIDENCE

Level II, development of diagnostic criteria on basis of consecutive patients with universally applied reference gold standard.

Developing a new, national approach to surveillance for ventilator-associated events*

OBJECTIVE

To develop and implement an objective, reliable approach to surveillance for ventilator-associated events in adult patients.

DESIGN

The Centers for Disease Control and Prevention (CDC) convened a Ventilator-Associated Pneumonia (VAP) Surveillance Definition Working Group in September 2011. Working Group members included representatives of stakeholder societies and organizations and federal partners.

MAIN RESULTS

The Working Group finalized a three-tier, adult surveillance definition algorithm for ventilator-associated events. The algorithm uses objective, readily available data elements and can identify a broad range of conditions and complications occurring in mechanically ventilated adult patients, including but not limited to VAP. The first tier definition, ventilator-associated condition (VAC), identifies patients with a period of sustained respiratory deterioration following a sustained period of stability or improvement on the ventilator, defined by changes in the daily minimum fraction of inspired oxygen or positive end-expiratory pressure. The second tier definition, infection-related ventilator-associated complication (IVAC), requires that patients with VAC also have an abnormal temperature or white blood cell count, and be started on a new antimicrobial agent. The third tier definitions, possible and probable VAP, require that patients with IVAC also have laboratory and/or microbiological evidence of respiratory infection.

CONCLUSIONS

Ventilator-associated events surveillance was implemented in January 2013 in the CDC's National Healthcare Safety Network. Modifications to improve surveillance may be made as additional data become available and users gain experience with the new definitions.

Vitamin C for preventing and treating pneumonia

BACKGROUND

Pneumonia is one of the most common serious infections, causing two million deaths annually among young children in low-income countries. In high-income countries pneumonia is most significantly a problem of the elderly.

OBJECTIVES

To assess the prophylactic and therapeutic effects of vitamin C on pneumonia.

SEARCH METHODS

We searched CENTRAL 2013, Issue 3, MEDLINE (1950 to March week 4, 2013), EMBASE (1974 to April 2013) and Web of Science (1955 to April 2013).

SELECTION CRITERIA

To assess the therapeutic effects of vitamin C, we selected placebo-controlled trials. To assess prophylactic effects, we selected controlled trials with or without a placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently read the trial reports and extracted data.

MAIN RESULTS

We identified three prophylactic trials which recorded 37 cases of community-acquired pneumonia in 2335 people. Only one was satisfactorily randomised, double-blind and placebo-controlled. Two trials examined military recruits and the third studied boys from "lower wage-earning classes" attending a boarding school in the UK during World War II. Each of these three trials found a statistically significant (80% or greater) reduction in pneumonia incidence in the vitamin C group. We identified two therapeutic trials involving 197 community-acquired pneumonia patients. Only one was satisfactorily randomised, double-blind and placebo-controlled. That trial studied elderly patients in the UK and found lower mortality and reduced severity in the vitamin C group; however, the benefit was restricted to the most ill patients. The other therapeutic trial studied adults with a wide age range in the former Soviet Union and found a dose-dependent reduction in the duration of pneumonia with two vitamin C doses. We identified one prophylactic trial recording 13 cases of hospital-acquired pneumonia in 37 severely burned patients; one-day administration of vitamin C had no effect on pneumonia incidence. The identified studies are clinically heterogeneous which limits their comparability. The included studies did not find adverse effects of vitamin C.

AUTHORS' CONCLUSIONS

The prophylactic use of vitamin C to prevent pneumonia should be further investigated in populations who have a high incidence of pneumonia, especially if dietary vitamin C intake is low. Similarly, the therapeutic effects of vitamin C should be studied, especially in patients with low plasma vitamin C levels. The current evidence is too weak to advocate prophylactic use of vitamin C to prevent pneumonia in the general population. Nevertheless, therapeutic vitamin C supplementation may be reasonable for pneumonia patients who have low vitamin C plasma levels because its cost and risks are low.

Improved detection of focal pneumonia by chest radiography with bone suppression imaging

OBJECTIVE

To evaluate radiologists' ability to detect focal pneumonia by use of standard chest radiographs alone compared with standard plus bone-suppressed chest radiographs.

METHODS

Standard chest radiographs in 36 patients with 46 focal airspace opacities due to pneumonia (10 patients had bilateral opacities) and 20 patients without focal opacities were included in an observer study. A bone suppression image processing system was applied to the 56 radiographs to create corresponding bone suppression images. In the observer study, eight observers, including six attending radiologists and two radiology residents, indicated their confidence level regarding the presence of a focal opacity compatible with pneumonia for each lung, first by use of standard images, then with the addition of bone suppression images. Receiver operating characteristic (ROC) analysis was used to evaluate the observers' performance.

RESULTS

The mean value of the area under the ROC curve (AUC) for eight observers was significantly improved from 0.844 with use of standard images alone to 0.880 with standard plus bone suppression images (P < 0.001) based on 46 positive lungs and 66 negative lungs.

CONCLUSION

Use of bone suppression images improved radiologists' performance for detection of focal pneumonia on chest radiographs.

KEY POINTS

Bone suppression image processing can be applied to conventional digital radiography systems. Bone suppression imaging (BSI) produces images that appear similar to dual-energy soft tissue images. BSI improves the conspicuity of focal lung disease by minimizing bone opacity. BSI can improve the accuracy of radiologists in detecting focal pneumonia.

Evaluation of the World Health Organization criteria for chest radiographs for pneumonia diagnosis in children

Our objective was to compare the inter-observer level of agreement in diagnosing pneumonia using the World Health Organization (WHO) guidelines for the interpretation of radiographs. We conducted a prospective study in a pediatric emergency room. Fifteen observers (13 pediatricians, 2 radiologists) interpreted 200 pediatric (<5 years old) chest radiographs using the WHO guidelines. Observers were blinded to the clinical presentation. RESULTS were analyzed for kappa values. Individual readings were compared to two "gold standard" teams: (1) radiologist and pediatrician and (2) two radiologists.

RESULTS

Alveolar pneumonia, non-alveolar pneumonia, and no pneumonia were found (by radiologists) in 12.8%, 2.7%, and 78.6% of readings, respectively. The mean kappa values for alveolar pneumonia, non-alveolar pneumonia, and no pneumonia of observers versus the team consisting of a radiologist and a pediatrician were 0.73, 0.23, and 0.61, respectively. For non-alveolar pneumonia, the mean kappa value was higher for the gold standard consisting of a radiologist and a pediatrician when compared to the two-radiologist team. Pediatricians overdiagnosed "non-alveolar pneumonia" compared with radiologists. In contrast, for the alveolar pneumonia and no-pneumonia diagnoses, no significant differences were found.

CONCLUSIONS

The WHO guidelines for interpretation of chest radiographs result in high level of agreement between readers for the definition of "alveolar pneumonia" and "no pneumonia" but poor agreement for non-alveolar pneumonia. The disagreement with regard to the latter was associated with overdiagnosis by pediatricians, which may lead to overtreatment. We believe that radiographic non-alveolar pneumonia should not be an endpoint for clinical trials and research, nor should it be implemented in clinical setting.

The management of community-acquired pneumonia in infants and children older than 3 months of age: clinical practice guidelines by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America

Evidenced-based guidelines for management of infants and children with community-acquired pneumonia (CAP) were prepared by an expert panel comprising clinicians and investigators representing community pediatrics, public health, and the pediatric specialties of critical care, emergency medicine, hospital medicine, infectious diseases, pulmonology, and surgery. These guidelines are intended for use by primary care and subspecialty providers responsible for the management of otherwise healthy infants and children with CAP in both outpatient and inpatient settings. Site-of-care management, diagnosis, antimicrobial and adjunctive surgical therapy, and prevention are discussed. Areas that warrant future investigations are also highlighted.

Clinical application of transthoracic ultrasonography in inpatients with pneumonia

PURPOSE

The aim of this study was to investigate the clinical applicability of transthoracic ultrasound (TUS) in the diagnosis and follow-up of community acquired pneumonia (CAP).

METHODS

We designed a pilot study in 15 patients and subsequently investigated 342 patients (206 men and 136 women) consecutively admitted to our Department from September 2005 to November 2009 because of radiographically diagnosed CAP. All patients underwent standard chest radiography, and consequently TUS. Follow-up TUS were performed at 4th and 8-10th day, in most patients.

RESULTS

Concerning the reproducibility of TUS method, no reader's bias was present (P=0·18), overall variability and between-subject variability (inter-reader agreement) did not show any difference between readers (P = 0·62 and P = 0·32 respectively), and estimated within-subject variabilities (intra-reader agreement) suggested a very high repeatability of the method (P ∼ 1). Of 342 patients with Rx diagnosis of CAP, in 314 patients (92% of cases) a pulmonary consolidation was also detected using TUS, whose ultrasonographic patterns were studied. Pleural effusion was detected in 120/342 (35%) patients using ultrasound and in 111/342 (32%) patients using chest radiography. Overall dimensional changes of the lung consolidated areas assessed with TUS method showed highly significant results. (1st day mean ± SD: 66·34 ± 19·25; 4th day: 39·92 ± 14·61; 8-10th day: 7·41 ± 1·50; P < 0·0001).

CONCLUSIONS

TUS is easily reproducible and we proved it to be a useful complementary diagnostic tool for the diagnosis and the follow-up of CAP.

[Competence of senior medical students in diagnosing tuberculosis based on chest X-rays]

OBJECTIVE

To evaluate the competence of senior medical students in diagnosing tuberculosis (TB) based on their reading of chest X-rays, as well as to identify the factors associated with high scores for the overall interpretation of chest X-rays.

METHODS

In October 2008, a convenience sample of senior medical students who had undergone formal training in radiology at the Federal University of Rio de Janeiro School of Medicine, in the city of Rio de Janeiro, Brazil, were invited to participate in the study. Six chest X-rays (three of TB patients and three of patients without TB) were selected. Participants were asked to choose one of the three probable radiological interpretations, and one of the four subsequent suitable clinical approaches. They also completed a questionnaire designed to collect data related to demographics, career of interest, time spent in emergency rooms and year of study. The sensitivity and specificity related to competence in the radiological diagnosis of TB, as well as a score for the overall interpretation of chest X-rays, were calculated.

RESULTS

The sensitivity of the probable radiological diagnosis of pulmonary TB, based on the three chest X-rays of patients with TB (minimal, moderate and extensive) was 86.5%, 90.4% and 94.2%, respectively, and the specificity was 90%, 82% and 42%. The only factor associated with a high score for the overall radiological interpretation was the year of study.

CONCLUSIONS

In this sample of medical students, who had received formal training in radiology early in their medical school course, the competence in interpreting the chest X-rays of TB patients was good. The year of study seems to influence overall chest X-ray reading skill.

Measuring the incidence of adult community-acquired pneumonia in a Native American community

Few population-based studies have investigated the epidemiology of adult community-acquired pneumonia (CAP). We aimed to determine the incidence of CAP in a population at high-risk for pneumococcal disease and to evaluate a standardized method for interpreting chest radiographs adapted from the World Health Organization paediatric chest radiograph interpretation guidelines. We reviewed radiology records at the two healthcare facilities serving the White Mountain Apache tribe to identify possible pneumonia cases > or =40 years of age. We categorized patients with clinical criteria and a physician diagnosis of pneumonia as clinical CAP and those with clinical criteria and an acute infiltrate as radiographic CAP. We identified 100 (27/1000 person-years) and 60 (16/1000 person-years) episodes of clinical and radiographic CAP, respectively. The incidence of CAP increased with age. Both radiographic and clinical CAP were serious illnesses with more than half of patients hospitalized. Our case definitions and methods may be useful for comparing data across studies and conducting vaccine trials.

Haemophilusinfluenzae type b conjugate vaccine for preventing pneumonia in infants hospitalized for bronchiolitis: a case-control study

BACKGROUND

Haemophilus influenzae type b (Hib) conjugate vaccine reduces the risk of pneumonia in infants.

OBJECTIVE

To determine the effect of Hib conjugate vaccine (HibCV) on the prevention of pneumonia as a complication among infants hospitalized for bronchiolitis.

METHODS

This record-based case-control study was conducted at The Children's Hospital "Dr. Ovidio Aliaga U" in La Paz, Bolivia during 2003 and 2004. Cases were infants hospitalized for bronchiolitis under 1 year of age who developed radiological pneumonia during hospitalization. Controls were patients who had good clinical progress without the use of antibiotics. Pneumonia was defined by alveolar consolidation on chest X-ray that justified the use of antibiotics.

RESULTS

Eighty patients were studied (16 cases and 64 controls). Their median age was 4.5 months. Demographic and clinical features were similar in both groups, except for a higher proportion of vomiting (56.3% vs. 28.1%; p<0.05) in the case group. The percentage of unvaccinated infants was significantly higher in cases (68.8% vs. 26.6%; p<0.05) and the length of hospital stay longer (8.5+/-5.4 vs. 3.1+/-2.2 days; p<0.05). There was a strong association between unvaccinated infants and the occurrence of pneumonia as a complication (odds ratio 6.1, 95% confidence interval 1.8-20.1; p<0.01).

CONCLUSIONS

Unvaccinated infants admitted for bronchiolitis have a higher risk of radiologically confirmed pneumonia. Larger studies are needed to validate these results and reconsider the burden of Hib infection among infants in less developed countries.

Factors associated with length of stay in hospital for suspected community-acquired pneumonia

OBJECTIVE

To determine factors associated with the length of stay (LOS) for patients with suspected community-acquired pneumonia (CAP) who required hospitalization for treatment.

STUDY DESIGN

The authors studied a population-based prospective cohort of 2,757 adults with suspected CAP who were admitted over a two-year period. Logistic regression, multiple linear regression, and classification and regression trees were used to determine the factors associated with LOS.

SETTING

The study was conducted in two community and tertiary care hospitals, two community and secondary care hospitals, and two community hospitals in the Capital Health Region of Edmonton, Alberta.

RESULTS

Symptoms such as sweats, shaking chills and wheezing were associated with an LOS of seven days or shorter, whereas weight loss, functional impairment, heart, renal or neoplastic diseases and time to first dose of antibiotic were predictive of an LOS greater than seven days. Regression tree analysis indicated that rapid achievement of physiological stability was associated with a shorter LOS. The use of an indwelling urinary catheter was found to be an important determinant of LOS.

CONCLUSIONS

The present study found several new associations with increased LOS in patients with CAP, including functional status, time to receipt of first dose of antibiotic therapy, use of certain antibiotics, presence of a urinary catheter and the importance of time to physiological stability. An intervention targeting avoidance of urinary catheters may be associated with a shorter LOS.

Vitamin C for preventing and treating pneumonia

BACKGROUND

Pneumonia is one of the most common serious infections, causing two million deaths annually among young children in developing countries. In developed countries pneumonia is most significantly a problem of the elderly.

OBJECTIVES

To assess the prophylactic and therapeutic effects of vitamin C on pneumonia.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 1), OLD MEDLINE (1950 TO 1965), MEDLINE (1966 to February Week 2, 2006), EMBASE (1974 to March 2006), Web of Science (1945 to February 2006) and reference lists of reviews and articles.

SELECTION CRITERIA

To assess the therapeutic effects of vitamin C, we selected placebo-controlled trials. To assess prophylactic effects, we selected controlled trials with or without a placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently read the trial reports and extracted data.

MAIN RESULTS

We identified three prophylactic trials which recorded 37 cases of pneumonia in 2,335 people. Only one was satisfactorily randomised, double-blind and placebo-controlled. Two trials examined military recruits and the third studied boys from "lower wage-earning classes" attending a boarding school in the UK during World War II. Each of these trials found a statistically significant (80% or greater) reduction in pneumonia incidence in the vitamin C group. We identified two therapeutic trials involving 197 pneumonia patients. Only one was satisfactorily randomised, double-blind and placebo-controlled. One studied elderly patients in the UK which found lower mortality and reduced respiratory symptom scores in the vitamin C group; however, the benefit was restricted to the most ill patients. The other studied adults (with a wide age range) in the former Soviet Union and found a dose-dependent reduction in the time to recovery with two vitamin C doses.

AUTHORS' CONCLUSIONS

The prophylactic use of vitamin C to prevent pneumonia should be further investigated in populations who have high incidence of pneumonia, especially if dietary vitamin C intake is low. Similarly, the therapeutic effects of vitamin C should be studied especially in patients with low plasma vitamin C levels. The current evidence is too weak to advocate widespread prophylactic use of vitamin C to prevent pneumonia in the general population. However, therapeutic vitamin C supplementation may be reasonable for pneumonia patients who have low vitamin C plasma levels because its cost and risks are low.

[Critical evaluation and predictive value of clinical presentation in out-patients with acute community-acquired pneumonia]

Diagnostic probability of community-acquired pneumonia (CAP) depends on data related to age and clinical and radiological findings. The critical evaluation of data in the literature leads to the following conclusions: 1) the prevalence of CAP in a given population with acute respiratory disease is 5% in outpatients and 10% in an emergency care unit. This could be as low as 2% in young people and even higher than 40% in hospitalized elderly patients; 2) the collection of clinical data is linked to the way the patient is examined and to the expertise of the clinician. The absolute lack of "vital signs" has a good negative predictive value in CAP; presence of unilateral crackles has a good positive predictive value; 3) there is a wide range of X-ray abnormalities: localized alveolar opacities; interstitial opacities, limited of diffused. The greatest radiological difficulties are encountered in old people with disorders including chronic respiratory or cardiac opacities and as a consequence of the high prevalence of bronchopneumonia episodes at this age; 4) among patients with lower respiratory tract (LRT) infections, the blood levels of leukocytes, CRP and procalcitonine are higher in CAP patients, mainly when their disease has a bacterial origin. Since you have not a threshold value reliably demonstrated in large populations with LRT infections or acute respiratory disease, presence or absence of these parameters could only be taken as a slight hint for a CAP diagnosis.

Interobserver reliability of radiologists' interpretations of mobile chest radiographs for nursing home-acquired pneumonia

OBJECTIVES

To determine the interobserver reliability of radiologists' interpretations of mobile chest radiographs for nursing home-acquired pneumonia.

DESIGN

A cross-sectional reliability study.

SETTING

Nursing homes and an acute care hospital.

PARTICIPANTS

Four radiologists reviewed 40 mobile chest radiographs obtained from residents of nursing homes who met a clinical definition of lower respiratory tract infections.

MEASUREMENTS

Radiologists were asked to interpret radiographs with respect to the film quality; presence, pattern, and extent of an infiltrate; and the presence of a pleural effusion or adenopathy. Interrater reliability was evaluated using the intraclass correlation coefficient derived from a 2-way random effects model.

RESULTS

On average the radiologists reported that 6 of the 40 films were of very good or excellent quality and 16 of the 40 were of fair or poor quality. When the finding of an infiltrate was dichotomized (0 = no; 1 = possible, probable, or definite) all 4 radiologists agreed on 21 of the 37 chest radiographs. The intraclass correlation coefficient for the presence or absence of infiltrates was 0.54 (95% confidence intervals [CI] 0.38 to 0.69). For the 14 radiographs where infiltrates were observed by all radiologists, intraclass correlation coefficients for the presence of pleural effusions was 0.08 (95% CI -0.10 to 0.41), hilar adenopathy 0.54 (95% CI 0.29 to 0.79), and mediastinal adenopathy 0.49 (95% CI 0.21 to 0.76).

CONCLUSION

In conclusion, the interrater agreement among radiologists for mobile chest radiographs in establishing the presence or absence of an infiltrate can be judged to be "fair." Treatment decisions need to include clinical findings and should not be made based on radiographic findings alone.

Competency in chest radiography. A comparison of medical students, residents, and fellows

BACKGROUND

Accurate interpretation of chest radiographs (CXR) is essential as clinical decisions depend on readings.

OBJECTIVE

We sought to evaluate CXR interpretation ability at different levels of training and to determine factors associated with successful interpretation.

DESIGN

Ten CXR were selected from the teaching file of the internal medicine (IM) department. Participants were asked to record the most important diagnosis, their certainty in that diagnosis, interest in a pulmonary career and adequacy of CXR training. Two investigators independently scored each CXR on a scale of 0 to 2.

PARTICIPANTS

Participants (n=145) from a single teaching hospital were third year medical students (MS) (n=25), IM interns (n=44), IM residents (n=45), fellows from the divisions of cardiology and pulmonary/critical care (n=16), and radiology residents (n=15).

RESULTS

The median overall score was 11 of 20. An increased level of training was associated with overall score (MS 8, intern 10, IM resident 13, fellow 15, radiology resident 18, P<.001). Overall certainty was significantly correlated with overall score (r=.613, P<.001). Internal medicine interns and residents interested in a pulmonary career scored 14 of 20 while those not interested scored 11 (P=.027). Pneumothorax, misplaced central line, and pneumoperitoneum were diagnosed correctly 9%, 26%, and 46% of the time, respectively. Only 20 of 131 (15%) participants felt their CXR training sufficient.

CONCLUSION

We identified factors associated with successful CXR interpretation, including level of training, field of training, interest in a pulmonary career and overall certainty. Although interpretation improved with training, important diagnoses were missed.

Reliability of radiographic findings and the relation to etiologic agents in community-acquired pneumonia

In a clinical setting the chest radiograph is the reference standard in establishing the diagnosis of community-acquired pneumonia (CAP). This study aimed to assess interobserver reliability (IR) of radiographic findings and the relationship to different causative pathogens in CAP. Chest radiographs of 192 patients with pneumonia, obtained from a database, were reviewed by 2 radiologists and 1 respiratory physician without specific clinical information. Main pattern of infiltrate, extent of pneumonia, presence of pleural fluid, thickened bronchial walls, lymphadenopathy and air bronchogram were scored. Also, the involved lobes were identified. Sputum cultures, blood cultures and serological tests were performed to identify the causative pathogen. IR was poor (kappa <0.4) for determining the main pattern of infiltrate and presence of air bronchogram, lymphadenopathy and thickening of bronchial walls. IR was fair to good (kappa 0.4-0.7) or even excellent (kappa>0.7) for determining the presence of pleural effusion, the extent of pneumonia and for identifying the lobes involved. Mycoplasma pneumoniae was associated more often with patchy alveolar opacities than Streptococcus pneumoniae (P=0.05). Chlamydia spp. were associated with unilobar involvement (86%), especially when compared to M. Pneumoniae (P=0.03) and S. pneumoniae (P=0.004). In conclusion, simple features such as presence of pleural fluid, the extent of pneumonia and identifying the involved lobes show fair to excellent IR. Other features such as main pattern of infiltrate are difficult to assess and show poor IR. Hardly any relation between different pathogens and radiological features was found. Therefore, chest radiographs are of limited value in predicting the causative pathogen, but are of good use to determine the extent of pneumonia and to detect complications such as parapneumonic effusion.

Factors influencing in-hospital mortality in community-acquired pneumonia: a prospective study of patients not initially admitted to the ICU

PURPOSES

To determine the factors that predict in-hospital mortality among patients who require hospitalization for the treatment of community-acquired pneumonia (CAP).

STUDY DESIGN

Prospective observational study of all patients who were admitted to six hospitals in Edmonton, AL, Canada, with a diagnosis of CAP from November 15, 2000, to November 14, 2002. Pneumonia was defined as two or more respiratory symptoms and signs and an opacity on a chest radiograph as interpreted by the attending physician.

RESULTS

A total of 3,043 patients were enrolled in the study, 246 of whom died (8.1%). On multivariate analysis, increasing pneumonia severity score, increasing age, site of care, consultation with a respirologist or infectious diseases physician, and functional status at the time of admission were all independently predictive of mortality. Increasing pneumonia severity risk score, increasing age, site of hospitalization, functional status, and consultation with an infectious diseases physician or a respirologist were independently associated with both early (< 5 days) and late (>/= 5 days) mortality. In contrast, partial or complete use of the pneumonia pathway was associated with decreased early mortality, but had no effect on late mortality. A low lymphocyte count and a high serum potassium level were associated with early but not with late mortality. The type of antibiotic therapy had an effect on late but not on early mortality.

CONCLUSIONS

Functional status at the time of hospital admission is a powerful predictor of mortality and should be incorporated into any scores or models that are used to predict mortality. While there are some common predictors of early and late in-hospital mortality, early mortality is not affected by the timing or type of antibiotic therapy, whereas late mortality is influenced by the type of antibiotic therapy. Hyperkalemia and lymphopenia are associated with early mortality.

Factors influencing in-hospital mortality in community-acquired pneumonia: a prospective study of patients not initially admitted to the ICU

Purpose

To determine the factors that predict in-hospital mortality among patients who require hospitalization for the treatment of community-acquired pneumonia (CAP)

Study design

Prospective observational study of all patients who were admitted to six hospitals in Edmonton, AL, Canada, with a diagnosis of CAP from November 15, 2000, to November 14, 2002. Pneumonia was defined as two or more respiratory symptoms and signs and an opacity on a chest radiograph as interpreted by the attending physician

Results

A total of 3,043 patients were enrolled in the study, 246 of whom died (8.1%). On multivariate analysis, increasing pneumonia severity score, increasing age, site of care, consultation with a respirologist or infectious diseases physician, and functional status at the time of admission were all independently predictive of mortality. Increasing pneumonia severity risk score, increasing age, site of hospitalization, functional status, and consultation with an infectious diseases physician or a respirologist were independently associated with both early (< 5 days) and late (≥ 5 days) mortality. In contrast, partial or complete use of the pneumonia pathway was associated with decreased early mortality, but had no effect on late mortality. A low lymphocyte count and a high serum potassium level were associated with early but not with late mortality. The type of antibiotic therapy had an effect on late but not on early mortality

Conclusions

Functional status at the time of hospital admission is a powerful predictor of mortality and should be incorporated into any scores or models that are used to predict mortality. While there are some common predictors of early and late in-hospital mortality, early mortality is not affected by the timing or type of antibiotic therapy, whereas late mortality is influenced by the type of antibiotic therapy. Hyperkalemia and lymphopenia are associated with early mortality