Diagnosis of ventilator-associated pneumonia: a pilot, exploratory analysis of a new score based on procalcitonin and chest echography

Lung Ultrasonography Accuracy for Diagnosis of Adult Pneumonia: Systematic Review and Meta-Analysis

BACKGROUND

Pneumonia is a ubiquitous health condition with severe outcomes. The advancement of ultrasonography techniques allows its application in evaluating pulmonary diseases, providing safer and accessible bedside therapeutic decisions compared to chest X-ray and chest computed tomography (CT) scan. Because of its aforementioned benefits, we aimed to confirm the diagnostic accuracy of lung ultrasound (LUS) for pneumonia in adults.

METHODS

A systematic literature search was performed of Medline, Cochrane and Crossref, independently by two authors. The selection of studies proceeded based on specific inclusion and exclusion criteria without restrictions to particular study designs, language or publication dates and was followed by data extraction. The gold standard reference in the included studies was chest X-ray/CT scan or both.

RESULTS

Twenty-nine (29) studies containing 6702 participants were included in our meta-analysis. Pooled sensitivity, specificity and PPV were 92% (95% CI: 91-93%), 94% (95% CI: 94 to 95%) and 93% (95% CI: 89 to 96%), respectively. Pooled positive and negative likelihood ratios were 16 (95% CI: 14 to 19) and 0.08 (95% CI: 0.07 to 0.09). The area under the ROC curve of LUS was 0. 9712.

CONCLUSIONS

LUS has high diagnostic accuracy in adult pneumonia. Its contribution could form an optimistic clue in future updates considering this condition.

The Clinical Pulmonary Infection Score Combined with Procalcitonin and Lung Ultrasound (CPIS-PLUS), a Good Tool for Ventilator Associated Pneumonia Early Diagnosis in Pediatrics

Ventilator-associated pneumonia (VAP) is common in Pediatric Intensive Care Units. Although early detection is crucial, current diagnostic methods are not definitive. This study aimed to identify lung ultrasound (LUS) findings and procalcitonin (PCT) values in pediatric patients with VAP to create a new early diagnosis score combined with the Clinical Pulmonary Infection Score (CPIS), the CPIS-PLUS score. Prospective longitudinal and interventional study. Pediatric patients with suspected VAP were included and classified into VAP or non-VAP groups, based on Centers of Disease Control (CDC) criteria for the final diagnosis. A chest-X-ray (CXR), LUS, and blood test were performed within the first 12 h of admission. CPIS score was calculated. A total of 108 patients with VAP suspicion were included, and VAP was finally diagnosed in 51 (47%) patients. CPIS-PLUS showed high accuracy in VAP diagnosis with a sensitivity (Sn) of 80% (95% CI 65-89%) and specificity (Sp) of 73% (95% CI 54-86%). The area under the curve (AUC) resulted in 0.86 for CPIS-PLUS vs. 0.61 for CPIS. In conclusion, this pilot study showed that CPIS-PLUS could be a potential and reliable tool for VAP early diagnosis in pediatric patients. Internal and external validations are needed to confirm the potential value of this score to facilitate VAP diagnosis in pediatric patients.

The potential clinical value of pairing procalcitonin and lung ultrasonography to guide antibiotic therapy in patients with community-acquired pneumonia: a narrative review

INTRODUCTION

Lower respiratory tract infections (LRTIs) are among the most frequent infections and are prone to inappropriate antibiotic treatments. This results from a limited accuracy of diagnostic tools in identifying bacterial pneumonia. Lung ultrasound (LUS) has excellent sensitivity and specificity in diagnosing pneumonia. Additionally, elevated procalcitonin (PCT) levels correlate with an increased likelihood of bacterial infection. LUS and PCT appear to be complementary in identifying patients with bacterial pneumonia who are likely to benefit from antibiotics.

AREAS COVERED

This narrative review aims to summarize the current evidence for LUS to diagnose pneumonia, for PCT to guide antibiotic therapy and the clinical value of pairing both tools.

EXPERT OPINION

LUS has excellent diagnostic accuracy for pneumonia in different settings, regardless of the examiner's experience. PCT guidance safely reduces antibiotic prescription in LRTIs. The combination of both tools has demonstrated an enhanced accuracy in the diagnosis of pneumonia, including CAP in the ED and VAP in the ICU, but randomized controlled studies need to validate the clinical impact of a combined approach.

Lung ultrasound monitoring: impact on economics and outcomes

PURPOSE OF REVIEW

This review aims to summarize the impact of lung ultrasonography (LUS) on economics and possible impact on patients' outcomes, proven its diagnostic accuracy in patients with acute respiratory failure.

RECENT FINDINGS

Despite some previous ethical concerns on LUS examination, today this technique has showed several advantages. First, it is now clear that the daily use of LUS can provide a relevant cost reduction in healthcare of patients with acute respiratory failure, while reducing the risk of transport of patients to radiological departments for chest CT scan. In addition, LUS reduces the exposition to x-rays since can replace the bedside chest X-ray examination in many cases. Indeed, LUS is characterized by a diagnostic accuracy that is even superior to portable chest X-ray when performed by well trained personnel. Finally, LUS examination is a useful tool to predict the course of patients with pneumonia, including the need for hospitalization and ICU admission, noninvasive ventilation failure and orotracheal intubation, weaning success, and mortality.

SUMMARY

LUS should be implemented not only in Intensive Care Units, but also in other setting like emergency departments. Since most data comes from the recent coronavirus disease 2019 pandemic, further investigations are required in Acute Respiratory Failure of different etiologies.

Ultrasound during the COVID-19 Pandemic: A Global Approach

SARS-CoV-2 (severe acute respiratory syndrome Coronavirus-2) rapidly spread worldwide as COVID-19 (Coronavirus disease 2019), causing a costly and deadly pandemic. Different pulmonary manifestations represent this syndrome's most common clinical manifestations, together with the cardiovascular complications frequently observed in these patients. Ultrasound (US) evaluations of the lungs, heart, and lower limbs may be helpful in the diagnosis, follow-up, and prognosis of patients with COVID-19. Moreover, POCUS (point-of-care ultrasound) protocols are particularly useful for patients admitted to intensive care units. The present review aimed to highlight the clinical conditions during the SARS-CoV-2 pandemic in which the US represents a crucial diagnostic tool.

Nosocomial Pneumonia in the Mechanically Ventilated Patient

Ventilator-associated pneumonia (VAP) is a common complication occurring in critically ill patients who are mechanically ventilated and is the leading cause of nosocomial infection-related death. Etiologic agents for VAP widely differ based on the population of intensive care unit patients, duration of hospital stay, and prior antimicrobial therapy. VAP due to multidrug-resistant pathogens is associated with the highest morbidity and mortality, likely due to delays in appropriate antimicrobial treatment. International guidelines are currently available to guide diagnostic and therapeutic strategies. VAP can be prevented through various pharmacological and non-pharmacological interventions, which are more effective when grouped as bundles. When VAP is clinically suspected, diagnostic strategies should include early collection of respiratory samples to guide antimicrobial therapy. Empirical treatment should be based on the most likely etiologic microorganisms and antibiotics likely to be active against these microorganisms. Response to therapy should be reassessed after 3 to 5 days and antimicrobials adjusted or de-escalated to reduce the burden of the disease. Finally, considering that drug resistance is increasing worldwide, several novel antibiotics are being tested to efficiently treat VAP in the coming decades.

The Role of Lung Ultrasound Monitoring in Early Detection of Ventilator-Associated Pneumonia in COVID-19 Patients: A Retrospective Observational Study

Specific lung ultrasound signs combined with clinical parameters allow for early diagnosis of ventilator-associated pneumonia in the general ICU population. This retrospective cohort study aimed to determine the accuracy of lung ultrasound monitoring for ventilator-associated pneumonia diagnosis in COVID-19 patients. Clinical (i.e., clinical pulmonary infection score) and ultrasound (i.e., presence of consolidation and a dynamic linear−arborescent air bronchogram, lung ultrasound score, ventilator-associated lung ultrasound score) data were collected on the day of the microbiological sample (pneumonia-day) and 48 h before (baseline) on 55 bronchoalveolar lavages of 33 mechanically-ventilated COVID-19 patients who were monitored daily with lung ultrasounds. A total of 26 samples in 23 patients were positive for ventilator-associated pneumonia (pneumonia cases). The onset of a dynamic linear−arborescent air bronchogram was 100% specific for ventilator-associated pneumonia. The ventilator-associated lung ultrasound score was higher in pneumonia-cases (2.5 (IQR 1.0 to 4.0) vs. 1.0 (IQR 1.0 to 1.0); p < 0.001); the lung ultrasound score increased from baseline in pneumonia-cases only (3.5 (IQR 2.0 to 6.0) vs. −1.0 (IQR −2.0 to 1.0); p = 0.0001). The area under the curve for clinical parameters, ventilator-associated pneumonia lung ultrasound score, and lung ultrasound score variations were 0.472, 0.716, and 0.800, respectively. A newly appeared dynamic linear−arborescent air bronchogram is highly specific for ventilator-associated pneumonia in COVID-19 patients. A high ventilator-associated pneumonia lung ultrasound score (or an increase in the lung ultrasound score) orients to ventilator-associated pneumonia.

Systematic review of studies investigating ventilator associated pneumonia diagnostics in intensive care

Background

Ventilator-associated pneumonia (VAP) is an important diagnosis in critical care. VAP research is complicated by the lack of agreed diagnostic criteria and reference standard test criteria. Our aim was to review which reference standard tests are used to evaluate novel index tests for suspected VAP.

Methods

We conducted a comprehensive search using electronic databases and hand reference checks. The Cochrane Library, MEDLINE, CINHAL, EMBASE, and web of science were searched from 2008 until November 2018. All terms related to VAP diagnostics in the intensive treatment unit were used to conduct the search. We adopted a checklist from the critical appraisal skills programme checklist for diagnostic studies to assess the quality of the included studies.

Results

We identified 2441 records, of which 178 were selected for full-text review. Following methodological examination and quality assessment, 44 studies were included in narrative data synthesis. Thirty-two (72.7%) studies utilised a sole microbiological reference standard; the remaining 12 studies utilised a composite reference standard, nine of which included a mandatory microbiological criterion. Histopathological criteria were optional in four studies but mandatory in none.

Conclusions

Nearly all reference standards for VAP used in diagnostic test research required some microbiological confirmation of infection, with BAL culture being the most common reference standard used.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01560-0.

A Ventilator-associated Pneumonia Prediction Model in Patients With Acute Respiratory Distress Syndrome

BACKGROUND

Mechanical ventilation is crucial for acute respiratory distress syndrome (ARDS) patients and diagnosis of ventilator-associated pneumonia (VAP) in ARDS patients is challenging. Hence, an effective model to predict VAP in ARDS is urgently needed.

METHODS

We performed a secondary analysis of patient-level data from the Early versus Delayed Enteral Nutrition (EDEN) of ARDSNet randomized controlled trials. Multivariate binary logistic regression analysis established a predictive model, incorporating characteristics selected by systematic review and univariate analyses. The model's discrimination, calibration, and clinical usefulness were assessed using the C-index, calibration plot, and decision curve analysis (DCA).

RESULTS

Of the 1000 unique patients enrolled in the EDEN trials, 70 (7%) had ARDS complicated with VAP. Mechanical ventilation duration and intensive care unit (ICU) stay were significantly longer in the VAP group than non-VAP group (P < .001 for both) but the 60-day mortality was comparable. Use of neuromuscular blocking agents, severe ARDS, admission for unscheduled surgery, and trauma as primary ARDS causes were independent risk factors for VAP. The area under the curve of the model was .744, and model fit was acceptable (Hosmer-Lemeshow P = .185). The calibration curve indicated that the model had proper discrimination and good calibration. DCA showed that the VAP prediction nomogram was clinically useful when an intervention was decided at a VAP probability threshold between 1% and 61%.

CONCLUSIONS

The prediction nomogram for VAP development in ARDS patients can be applied after ICU admission, using available variables. Potential clinical benefits of using this model deserve further assessment.

Nosocomial Pneumonia in the Era of Multidrug-Resistance: Updates in Diagnosis and Management

Nosocomial pneumonia (NP), including hospital-acquired pneumonia in non-intubated patients and ventilator-associated pneumonia, is one of the most frequent hospital-acquired infections, especially in the intensive care unit. NP has a significant impact on morbidity, mortality and health care costs, especially when the implicated pathogens are multidrug-resistant ones. This narrative review aims to critically review what is new in the field of NP, specifically, diagnosis and antibiotic treatment. Regarding novel imaging modalities, the current role of lung ultrasound and low radiation computed tomography are discussed, while regarding etiological diagnosis, recent developments in rapid microbiological confirmation, such as syndromic rapid multiplex Polymerase Chain Reaction panels are presented and compared with conventional cultures. Additionally, the volatile compounds/electronic nose, a promising diagnostic tool for the future is briefly presented. With respect to NP management, antibiotics approved for the indication of NP during the last decade are discussed, namely, ceftobiprole medocaril, telavancin, ceftolozane/tazobactam, ceftazidime/avibactam, and meropenem/vaborbactam.

Point-of-care lung ultrasound for the assessment of pneumonia: a narrative review in the COVID-19 era

In the coronavirus disease-2019 (COVID-19) era, point-of-care lung ultrasound (LUS) has attracted increased attention. Prospective studies on LUS for the assessment of pneumonia in adult patients were extensively carried out for more than 10 years before this era. None of these prospective studies attempted to differentiate bacterial and viral pneumonia in adult patients using LUS. The majority of studies considered the LUS examination to be positive if sonographic consolidations or multiple B-lines were observed. Significant differences existed in the accuracy of these studies. Some studies revealed that LUS showed superior sensitivity to chest X-ray. These results indicate that point-of-care LUS has the potential to be an initial imaging modality for the diagnosis of pneumonia. The LUS diagnosis of ventilator-associated pneumonia in intensive care units is more challenging in comparison with the diagnosis of community-acquired pneumonia in emergency departments due to the limited access to the mechanically ventilated patients and the high prevalence of atelectasis. However, several studies have demonstrated that the combination of LUS findings with other clinical markers improved the diagnostic accuracy. In the COVID-19 era, many case reports and small observational studies on COVID-19 pneumonia have been published in a short period. Multiple B-lines were the most common and consistent finding in COVID-19 pneumonia. Serial LUS showed the deterioration of the disease. The knowledge and ideas on the application of LUS in the management of pneumonia that are expected to accumulate in the COVID-19 era may provide us with clues regarding more appropriate management.

Incorporating Lung Ultrasound in Clinical Pulmonary Infection Score as an Added Tool for Diagnosing Ventilator-associated Pneumonia: A Prospective Observational Study from a Tertiary Care Center

Background: Clinical pulmonary infection score (CPIS) is an established diagnostic parameter for ventilator-associated pneumonia (VAP). Lung ultrasound (LUS) is an evolving tool for diagnosing VAP. Various scores have been proposed for the diagnosis of VAP, taking LUS as a parameter. We proposed whether replacing LUS with chest radiograph in CPIS criteria will add to the diagnosis of VAP. The current study was done to evaluate the diagnostic accuracy of LUS alone and in combination with clinical and microbiological criteria for VAP by replacing chest radiograph with LUS in CPIS. Materials and methods: We conducted a prospective single-center observational study including 110 patients with suspected VAP to investigate the diagnostic accuracy of LUS. Quantitative mini-bronchoalveolar lavage (mini-BAL) culture was considered the gold standard for diagnosis of VAP. Here, the authors have explored the combination of LUS, clinical, and microbiology parameters for diagnosing VAP. On replacing chest radiograph with LUS, sono-pulmonary infection score (SPIS) and modified SPIS (SPIS-mic, SPIS-cult) was formulated as a substitute for CPIS. Results: Overall LUS performance for VAP diagnosis was good with sensitivity, specificity, positive or negative predictive value, and positive or negative likelihood ratios of 91.3%, 70%, 89%, 75%, 3, and 0.1, respectively. Adding microbiology culture to LUS increased diagnostic accuracy. The areas under the curve for SPIS and modified SPIS were 0.808, 0.815, and 0.913, respectively. Conclusion: The diagnosis of VAP requires agreement between clinical, microbiological, and radiological criteria. Replacing chest radiograph with LUS in CPIS criteria (SPIS) increases diagnostic accuracy for VAP. Adding clinical and culture data to SPIS provided the highest diagnostic accuracy. Clinical parameters along with lung ultrasound increase diagnostic accuracy for VAP. How to cite this article: Samanta S, Patnaik R, Azim A, Gurjar M, Baronia AK, Poddar B, et al. Incorporating Lung Ultrasound in Clinical Pulmonary Infection Score as an Added Tool for Diagnosing Ventilator-associated Pneumonia: A Prospective Observational Study from a Tertiary Care Center. Indian J Crit Care Med 2021;25(3):284-291.

Multi-organ point-of-care ultrasound for COVID-19 (PoCUS4COVID): international expert consensus

COVID-19 has caused great devastation in the past year. Multi-organ point-of-care ultrasound (PoCUS) including lung ultrasound (LUS) and focused cardiac ultrasound (FoCUS) as a clinical adjunct has played a significant role in triaging, diagnosis and medical management of COVID-19 patients. The expert panel from 27 countries and 6 continents with considerable experience of direct application of PoCUS on COVID-19 patients presents evidence-based consensus using GRADE methodology for the quality of evidence and an expedited, modified-Delphi process for the strength of expert consensus. The use of ultrasound is suggested in many clinical situations related to respiratory, cardiovascular and thromboembolic aspects of COVID-19, comparing well with other imaging modalities. The limitations due to insufficient data are highlighted as opportunities for future research.

Pneumonia Lung Ultrasound Score (PLUS): A New Tool for Detecting Pneumonia in the Oldest Patients

OBJECTIVES

To compare the diagnostic accuracy of lung ultrasound (LUS) and standard chest X-ray (CXR) in older patients admitted to an acute-care geriatric ward for suspected acute pneumonia, and to develop an easy-to-use diagnostic tool, now called Pneumonia Lung Ultrasound Score (PLUS), for early risk stratification.

DESIGN

Prospective, single-center, cohort study.

SETTING

Acute-care geriatric ward of tertiary care center.

PARTICIPANTS

Individuals, aged 65 years and older, with suspected acute pneumonia.

MEASUREMENTS

Participants were stratified according to the Multidimensional Prognostic Index. All the patients underwent CXR and LUS, whereas chest computed tomography was performed in case of mismatch between LUS and CXR. Using logistic multivariate regression, we assessed the influence of age, sex, multimorbidity, cognitive impairment, and clinical biomarkers in the misdiagnosis of acute pneumonia. Finally, an easy-to-perform diagnostic tool based on the combination of biomarkers (brain natriuretic peptide, high-sensitivity C-reactive protein, and partial pressure arterial oxygen/fraction of inspired oxygen ratio) and LUS was realized. A receiver operating characteristic curve was used to verify the predictive accuracy of PLUS, CXR, and LUS in pneumonia diagnosis.

RESULTS

A total of 132 subjects (69% women; mean age = 85.3 ± 6.9 years) were enrolled in the study. Acute pneumonia was diagnosed in 94 of 132 cases. LUS showed higher diagnostic accuracy compared with CXR (0.91 (95% confidence interval (CI) = 0.85-0.93) vs 0.67 (95% CI = 0.58-0.75)) in detecting pneumonic consolidations. A higher degree of cognitive impairment was associated with both LUS and CXR pneumonia misdiagnosis (odds ratio = 1.30 (95% CI = 1.04-1.65)). PLUS showed higher predictive accuracy in the diagnosis of acute pneumonia compared with LUS (AUC = 0.92 (95% CI = 0.87-0.98) vs 0.86 (95% CI = 0.80-0.96); P = .029).

CONCLUSIONS

This study confirms the higher diagnostic accuracy of LUS compared with CXR for acute pneumonia in older adults. Nonetheless, the accuracy of PLUS, an easy-to-use, biomarker-derived diagnostic tool, was superior to LUS regardless of patients' degree of frailty.

A new scoring system for early diagnosis of ventilator-associated pneumonia: LUPPIS

INTRODUCTION

The Clinical Pulmonary Infection Score (CPIS) based on chest X-ray has been developed to facilitate clinical diagnosis of ventilator-associated pneumonia (VAP); however, this scoring system has a low diagnostic performance. We developed the Lung Ultrasound and Pentraxin-3 Pulmonary Infection Score (LUPPIS) for early diagnosis of VAP and evaluated the performance of this new scoring system.

MATERIAL AND METHODS

In a prospective study of 78 patients with suspected VAP, we assessed the detection accuracy of LUPPIS for pneumonia in adult patients. We also evaluated the diagnostic performance of pentraxin-3 (PTX-3) findings of infection. On the day of the study, lung ultrasound was performed, PTX-3 levels were determined, and an endotracheal aspirate was obtained for Gram staining and culture.

RESULTS

No significant differences were found between groups with respect to age, mechanical ventilation time, APACHE II score, or SOFA score (p > 0.05). Procalcitonin and PTX-3 levels were significantly higher in the VAP (+) group (p < 0.001 and p < 0.001, respectively). The threshold for LUPPIS in differentiating VAP (+) patients from VAP (-) patients was > 7. In predicting VAP, LUPPIS > 7 (sensitivity of 84%, specificity of 87.7%) was superior to CPIS > 6 (sensitivity of 40.1%, specificity of 84.5%).

CONCLUSIONS

LUPPIS appears to provide better results in the prediction of VAP compared to CPIS, and the importance of lung ultrasound and PTX-3 is emphasized, which is a distinctive property of LUPPIS.

Emergence of Alveolar Consolidations in Serial Lung Ultrasound and Diagnosis of Ventilator-Associated Pneumonia

BACKGROUND

Lung ultrasound (LUS) has been reported as a promising diagnostic tool for ventilator-associated pneumonia (VAP), but patients with previous lung parenchyma commitment have been not studied.

PURPOSE

To evaluate whether the emergence of sonographic consolidations, rather than their presence, can improve the VAP diagnosis in a sample including patients with previous lung parenchyma diseases.

METHODS

Patients who completed 48 hours of mechanical ventilation were prospectively studied with daily LUS examinations. We checked the emergence of different consolidation types on the eve and on the day of a clinical suspicion of VAP. We elaborated an algorithm considering, sequentially, the emergence of (1) subpleural consolidations in anterior lung regions on the eve of suspicion; (2) lobar/sublobar consolidation in anterior lung regions on the day of suspicion; (3) lobar/sublobar consolidation with dynamic air bronchograms on the day of suspicion; and (4) any other lobar/sublobar consolidation on the day of suspicion in association with a positive Gram smear of endotracheal aspirate.

RESULTS

Of the 188 included patients, 60 were suspected and 33 confirmed VAP. The presence of sonographic consolidations at the clinical suspicion had no diagnostic value for VAP. The emergence of subpleural consolidations in anterior lung regions on the eve of suspicion had specificity of 95% (95% confidence interval [CI], 79%-99%). The emergence of lobar/sublobar consolidations in anterior lung regions on the day of suspicion had specificity of 100% (95% CI, 87%-100%). The emergence of lobar/sublobar consolidations with dynamic air bronchograms on the day of suspicion had specificity of 96% (95% CI, 81%-99%). Finally, the proposed algorithm had sensitivity of 63% (95% CI, 46%-77%) and specificity of 85% (95% CI, 67%-94%) for VAP.

CONCLUSIONS

The presence of sonographic consolidations was not accurate for VAP when patients with previous lung parenchyma commitment were included. However, serial LUS examinations detected the emergence of specific signs of VAP.

Poor lung ultrasound score in shock patients admitted to the ICU is associated with worse outcome

Background

The lung ultrasound score has been regarded as a decent semiquantitative score to measure the lung aeration loss. The score has been proven to be valuable in diagnosing and monitoring lung pathology, but no studies have demonstrated its relationship to the outcome. We aimed to investigate the relationship between the lung ultrasound score and outcome in shock patients in the Intensive Care Unit.

Methods

The data were extracted from the SHOCK-ICU study, a 14-month prospective study of shock patients in the Medical Intensive Care Unit in West China Hospital. A bivariate logistic regression model was established to identify the correlation between the lung ultrasound score on admission and the 28-day mortality. For subsequent analyses, we divided patients into lung ultrasound score quartiles, and survival analysis was performed using Cox stratified survival analysis and regression analysis with the Breslow method of ties.

Results

A total of 175 cases with a completed lung ultrasound exam were included. The mean APACHE II score was 23.7 ± 8.8, and the 28-day mortality was 46.3% (81/175). The multivariate analysis demonstrated that the lung ultrasound score was an independent risk factor for 28-day mortality, as well as the APACHE II score and lactate level. When divided into lung ultrasound score quartiles, after correcting for the APACHE II score, vasoactive use, PaO₂/FiO₂, and lactate level, the COX analysis reveals that a higher lung ultrasound score was related to a lower survival rate. Quartile 1 and quartile 2 had a significantly lower hazard ratio versus quartile 4 (OR 0.442[0.215–0.911]; 0.484[0.251–0.934], respectively).

Conclusions

The lung ultrasound score is independently related to the 28-day mortality, as well as the APACHE II score and lactate level, in Intensive Care Unit shock patients. A higher elevated lung ultrasound score on admission is associated with a worse outcome.

Trial registration

The study is registered on Clinical Trials. Trial registration: NCT03082326; retrospectively registered on 3 March 2017.

Diagnostic accuracy of chest ultrasound in patients with pneumonia in the intensive care unit: A single-hospital study

BACKGROUND AND AIMS

Chest radiography (CXR) and computerized tomography (CT) scan are the preferred methods for lung imaging in diagnosing pneumonia in the intensive care unit, in spite of their limitations. The aim of this study was to assess the performance of bedside lung ultrasound examination by a critical care physician, compared with CXR and chest CT, in the diagnosis of acute pneumonia in the ICU.

MATERIALS AND METHODS

This was an observational, prospective, single-center study conducted in the intensive care unit of Ahmadi General Hospital. Lung ultrasound examinations (LUSs) were performed by trained critical care physicians, and a chest radiograph was interpreted by another critical care physician blinded to the LUS results. CT scans were obtained when clinically indicated by the senior physician.

RESULTS

Out of 92 patients with suspected pneumonia, 73 (79.3%) were confirmed to have a diagnosis of pneumonia based on radiological reports, clinical progress, inflammatory markers, and microbiology studies. Of the 73 patients, 31 (42.5%) were male, with a mean age of 68.3 years, and a range of 27 to 94 years. Eleven (15%) patients had community-acquired pneumonia, and 62 (85%) had hospital-acquired pneumonia. In the group of patients with confirmed pneumonia, 72 (98.6%) had LUSs positive for consolidation (sensitivity 98.6%, 95% CI 92.60%-99.97%), and in the group without pneumonia, 16 (85%) had LUS negative for consolidation (specificity 84.2%, 95% CI 60.42%-96.62%), compared with 40 (55%) with CXRs positive for consolidation (sensitivity 54.8%, 95% CI 42.70%-66.48%) and 33 (45%) with CXRs negative for consolidation (specificity 63.16%, 95% CI 38.36%-83.71%).A chest CT was performed in 38 of the 92 enrolled patients and was diagnostic for pneumonia in 32 cases. LUSs were positive in 31 of 32 patients with CT-confirmed pneumonia (sensitivity 96%), and CXR was positive in 5 of 32 patients with CT-confirmed pneumonia (sensitivity 15.6%).

CONCLUSION

Bedside lung ultrasound is a reliable and accurate tool that appears to be superior to CXR for diagnosing pneumonia in the ICU setting. LUS allows for a faster, non-invasive, and radiation-free method to diagnose pneumonia in the ICU.

Lung ultrasound for diagnosis and monitoring of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is the most frequent nosocomial infection in intensive care units (ICU) and is associated with increased mortality, use of antimicrobials, longer mechanical ventilation, and higher healthcare costs. Lung ultrasonography (LUS) can be used at the bedside and gained widespread acceptance in ICU. Although the visualization of a single LUS sign cannot be considered specific for a diagnosis, clinically-driven LUS examination in particular setting and clinical conditions allow ruling in or out quickly and accurately several causes of acute respiratory failure. This article reviews LUS signs for VAP diagnosis and summarizes the studies testing LUS for VAP diagnosis and monitoring. Many VAP occurs in already injured regions, thus presence of lobar consolidation is not enough to affirm VAP. However, a linear/arborescent air-bronchogram confirms the diagnosis of VAP with a good specificity, a normal LUS rules out the diagnosis of VAP (in experimented hands). LUS, thanks to its bedside ready availability, has the potential to become a key tool in early VAP diagnosis. LUS could ideally represent the decision-making tool for antimicrobial therapy administration in the timeframe of the technical time required for bronchoalveolar lavage analysis. A systematic approach for diagnosis and monitoring of VAP with LUS is also proposed in this review. But specific data on LUS specificity and sensitivity for the diagnosis of VAP are still lacking and should be investigated.

The current status of biomarkers for the diagnosis of nosocomial pneumonias

PURPOSE OF REVIEW

Nosocomial pneumonia is a frequent and severe nosocomial infection divided in two distinct groups: hospital-acquired pneumonia and ventilator-associated pneumonia (VAP). In this context, the VAP is notoriously difficult to diagnose clinically, resulting from the lack of a 'gold standard' method of diagnosis.

RECENT FINDINGS

The use of biomarkers may potentially improve the early diagnosis of infections allowing earlier and better identification and treatment. An exhausting list of biomarkers has been studied and although far from perfect, procalcitonin (PCT) and C-reactive protein (CRP) are the most studied biomarkers used in clinical practice. Data coming from literature suggests the use of PCT for VAP prognosis and as a based algorithm tool for the reduction of duration of pneumonia therapy, as well as, the use of the CRP dynamics to the early prediction of VAP and the response to the antibiotics.

SUMMARY

The evidence for the use of biomarkers to diagnose nosocomial pneumonia as a stand-alone tool is low to moderate. Improved performance for both PCT and CRP can be obtained by using them in association with clinical features or scoring systems but prospective studies are still needed to validate this hypothesis.

Accuracy and Applications of Lung Ultrasound to Diagnose Ventilator-Associated Pneumonia: A Systematic Review

BACKGROUND

Lung ultrasound (LUS) is an accurate tool to diagnose community-acquired pneumonia. However, it is not yet an established tool to diagnose ventilator-associated pneumonia (VAP).

PURPOSE

To assess the evidence about LUS in the diagnosis of VAP, we conducted a systematic review of the literature.

METHODS

We searched PubMed, Embase, Scopus, Web of Science, and LILACS. Two researchers independently selected the studies that met the inclusion criteria. Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was used to assess the quality of the studies. In a qualitative synthesis, 3 questions guided the review: Q1. What are the sonographic signs of VAP? Q2. How can LUS be combined with others tests or signs of VAP? Q3. What is the role of LUS in VAP screening?

MAIN RESULTS

Three studies (n = 377 patients) with different designs were included. In terms of Q1, the 3 studies assessed the accuracy of sonographic consolidations. In patients suspected for VAP, lobar or hemilobar consolidation alone was not sufficient to diagnose VAP but seems useful to exclude it. The most useful signs were small subpleural consolidations (sensitivity: 81%; specificity: 41%) and dynamic air bronchograms (sensitivity: 44%; specificity: 81%). Two studies were assessed for Q2, when the 2 signs above were included in a clinical score (Ventilator-associated Pneumonia Lung Ultrasound Score associated with quantitative culture of endotracheal aspirate-VPLUS-EAquant), the accuracy was amplified (sensitivity: 48% and specificity: 97% for score ≥4; sensitivity: 78% and specificity: 77% for score ≥3 points). Finally, regarding Q3, no studies have assessed the use of LUS in screening of VAP.

CONCLUSION

Small subpleural consolidations and dynamic air bronchograms were the most useful sonographic signs to diagnose VAP in suspected patients. Clinical scores including LUS had better diagnosis accuracy than LUS alone. There are no data on LUS for VAP screening.

Diagnostic accuracy of lung ultrasonography combined with procalcitonin for the diagnosis of pneumonia: a pilot study

BACKGROUND

The diagnostic value of lung ultrasonography (LUS) and procalcitonin (PCT) in the diagnosis of lung infections is known. No studies evaluated the combination of LUS and PCT for the diagnosis of pneumonia in the emergency department (ED). We evaluated the diagnostic accuracy of the combination of LUS and PCT in the diagnosis of pneumonia.

METHODS

Patients with respiratory symptoms of unexplained origin who underwent a chest CT in ED were included in the study if PCT assay was available. LUS was performed before CT and was targeted to the detection of lung consolidations with the morphologic features of pneumonia. A PCT assay was performed at presentation, and cut-off of 0.25 and of 0.5 ng/ml were used to rule-out and rule-in pneumonia. The final diagnosis of pneumonia was established by independent clinicians, on the basis of clinical chart review including CT results.

RESULTS

We enrolled 128 patients and pneumonia was the final diagnosis in 61 (47.7%). In 38 patients (29.7%) LUS and PCT were negative (PCT < 0.25 ng/ml). The overall accuracy, sensitivity and negative predictive value of LUS/PCT were 88.8, 96.7 and 94.7% respectively. Sensitivity of the LUS/PCT test was significantly superior to LUS alone (85.2%) and PCT alone (73.8%) (p < 0.05 for both). Specificity and positive predictive value of the combination of positivity of LUS/PCT (PCT > 0.5 ng/ml) were 94% and 83.3% respectively. Specificity of LUS/PCT was not significantly different to LUS alone (88.1%) (p = 0.125).

CONCLUSIONS

The sensitivity of the combination of LUS with PCT for the diagnosis of pneumonia was significantly superior when compared with the sensitivity of LUS and PCT alone.

New diagnostic methods for pneumonia in the ICU

PURPOSE OF REVIEW

Pneumonia leading to severe sepsis and critical illness including respiratory failure remains a common and therapeutically challenging diagnosis. Current clinical approaches to surveillance, early detection, and conventional culture-based microbiology are inadequate for optimal targeted antibiotic treatment and stewardship. Efforts to enhance diagnosis of community-acquired and health care-acquired pneumonia, including ventilator-associated pneumonia (VAP), are the focus of recent studies reviewed here.

RECENT FINDINGS

Newer surveillance definitions are sensitive for pneumonia in the ICU including VAP but consistently underdetect patients that are clinically shown to have bacterial VAP based on clinical diagnostic criteria and response to antibiotic treatment. Routinely measured plasma biomarkers, including procalcitonin and C-reactive protein, lack sufficient precision and predictive accuracy to inform diagnosis. Novel rapid microbiological diagnostics, including nucleic-acid amplification, mass spectrometry, and fluorescence microscopy-based technologies are promising approaches for the future. Exhaled breath biomarkers, including measurement of volatile organic compounds, represent a future approach.

SUMMARY

The integration of novel diagnostics for rapid microbial identification, resistance phenotyping, and antibiotic sensitivity testing into usual care practice could significantly transform the care of patients and potentially inform significantly improved targeted antimicrobial selection, de-escalation, and stewardship.

Ultrasound in the diagnosis and management of pneumonia

PURPOSE OF REVIEW

Point of care ultrasound continues to become more prevalent in the diagnosis and management of many disease states. In this review, we focus on the use of bedside lung ultrasound (LUS) in the diagnosis of pneumonia. We describe the sonographic findings associated with pneumonia and the recent literature exploring its use in different settings and patient populations.

RECENT FINDINGS

The limited sensitivity of chest radiography in the diagnosis of pneumonia has been well described. Ultrasound is an attractive option because of its low cost, lack of ionizing radiation, portability, and repeatability. An alveolar or focal interstitial pattern has been described as the usual sonographic findings in pneumonia. Multiple studies have compared LUS with chest radiography in pneumonia, and have shown that LUS is at least equivalent, and in many instances superior, to chest radiography.

SUMMARY

Point of care LUS is an invaluable tool in the diagnosis of multiple pulmonary conditions, including pneumonia. Its use in real time with clinical correlation makes it an ideal tool for rapid diagnosis, especially in situations with unstable patients or in low-resource settings.

Accuracy of Lung Ultrasonography in the Diagnosis of Pneumonia in Adults: Systematic Review and Meta-Analysis

BACKGROUND

Some studies suggest that lung ultrasonography could be useful for diagnosing pneumonia; moreover, it has a more favorable safety profile and lower cost than chest radiography and CT. The aim of this study was to assess the accuracy of bedside lung ultrasonography for diagnosing pneumonia in adults through a systematic review and meta-analysis.

METHODS

We searched MEDLINE, Scopus, The Cochrane Library, Web of Science, DARE, HTA Database, Google Scholar, LILACS, ClinicalTrials.gov, TESEO, and OpenGrey. In addition, we reviewed the bibliographies of relevant studies. Two researchers independently selected studies that met the inclusion criteria. Quality of the studies was assessed in accordance with the Quality Assessment of Diagnostic Accuracy Studies tool. The summary receiver operating characteristic (SROC) curve and a pooled estimation of the diagnostic odds ratio (DOR) was estimated using a bivariate random-effects analysis. The sources of heterogeneity were explored using predefined subgroup analyses and bivariate meta-regression.

RESULTS

Sixteen studies (2,359 participants) were included. There was significant heterogeneity of both sensitivity and specificity according to the Q test, without clear evidence of threshold effect. The area under the SROC curve was 0.93, with a DOR at the optimal cutpoint of 50 (95% CI, 21-120). A tendency toward a higher area under the SROC curve in high-quality studies was detected; however, these differences were not significant after applying the bivariate meta-regression.

CONCLUSIONS

Lung ultrasonography can help accurately diagnose pneumonia, and it may be promising as an adjuvant resource to traditional approaches.

Lung ultrasound: a promising tool to monitor ventilator-associated pneumonia in critically ill patients

Ventilator-associated pneumonia (VAP) is the most frequent intensive care unit (ICU)-acquired infection that is independently associated with mortality. Accurate diagnosis and timely treatment have been shown to improve the prognosis of VAP. Chest X-ray or computed tomography imaging are used for conventional assessment of VAP, but these methods are impractical for real-time measurement in critical patients. Therefore, lung ultrasound (LUS) has been increasingly used for the assessment of VAP in the ICU. Traditionally, LUS has seemed unsuitable for the detection of lung parenchyma owing to the high acoustic impedance of air; however, the fact that the reflection and reverberation in the detection region of the ultrasound reflect the underlying pathology of lung diseases has led to the increased use of ultrasound imaging as a standard of care supported by evidence-based and expert consensus in the ICU. Considering that any type of pneumonia causes air volume changes in the lungs, accumulating evidence has shown that LUS effectively measures the presence of VAP as well as dynamic changes in VAP. This review offers evidence for ultrasound as a noninvasive, easily repeatable, and bedside means to assess VAP; in addition, it establishes a protocol for qualitative and quantitative monitoring of VAP.

Advances in antibiotic therapy in the critically ill

Infections occur frequently in critically ill patients and their management can be challenging for various reasons, including delayed diagnosis, difficulties identifying causative microorganisms, and the high prevalence of antibiotic-resistant strains. In this review, we briefly discuss the importance of early infection diagnosis, before considering in more detail some of the key issues related to antibiotic management in these patients, including controversies surrounding use of combination or monotherapy, duration of therapy, and de-escalation. Antibiotic pharmacodynamics and pharmacokinetics, notably volumes of distribution and clearance, can be altered by critical illness and can influence dosing regimens. Dosing decisions in different subgroups of patients, e.g., the obese, are also covered. We also briefly consider ventilator-associated pneumonia and the role of inhaled antibiotics. Finally, we mention antibiotics that are currently being developed and show promise for the future.

Lung Ultrasound for Early Diagnosis of Ventilator-Associated Pneumonia

BACKGROUND

Lung ultrasound (LUS) has been successfully applied for monitoring aeration in ventilator-associated pneumonia (VAP) and to diagnose and monitor community-acquired pneumonia. However, no scientific evidence is yet available on whether LUS reliably improves the diagnosis of VAP.

METHODS

In a multicenter prospective study of 99 patients with suspected VAP, we investigated the diagnostic performance of LUS findings of infection, subpleural consolidation, lobar consolidation, and dynamic arborescent/linear air bronchogram. We also evaluated the combination of LUS with direct microbiologic examination of endotracheal aspirates (EA). Scores for LUS findings and EA were analyzed in two ways. First, the clinical-LUS score (ventilator-associated pneumonia lung ultrasound score [VPLUS]) was calculated as follows: ≥ 2 areas with subpleural consolidations, 1 point; ≥ 1 area with dynamic arborescent/linear air bronchogram, 2 points; and purulent EA, 1 point. Second, the VPLUS-direct gram stain examination (EAgram) was scored as follows: ≥ 2 areas with subpleural consolidations, 1 point; ≥ 1 area with dynamic arborescent/linear air bronchogram, 2 points; purulent EA, 1 point; and positive direct gram stain EA examination, 2 points.

RESULTS

For the diagnosis of VAP, subpleural consolidation and dynamic arborescent/linear air bronchogram had a positive predictive value of 86% with a positive likelihood ratio of 2.8. Two dynamic linear/arborescent air bronchograms produced a positive predictive value of 94% with a positive likelihood ratio of 7.1. The area under the curve for VPLUS-EAgram and VPLUS were 0.832 and 0.743, respectively. VPLUS-EAgram ≥ 3 had 77% (58-90) specificity and 78% (65-88) sensitivity; VPLUS ≥ 2 had 69% (50-84) specificity and 71% (58-81) sensitivity.

CONCLUSIONS

By detecting ultrasound features of infection, LUS was a reliable tool for early VAP diagnosis at the bedside.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02244723; URL: www.clinicaltrials.gov.