Surgical Lung Biopsy in Adult Respiratory Distress Syndrome: A Meta-Analysis

Diagnostic approach in acute hypoxemic respiratory failure

Acute hypoxemic respiratory failure (AHRF) is the leading cause of intensive care unit (ICU) admissions. Of patients with AHRF, 40 %-50 % will require invasive mechanical ventilation during their stay in the ICU, and 30 %-80 % will meet the Berlin Criteria for Acute Respiratory Distress Syndrome (ARDS). Rapid identification of the underlying cause of AHRF is necessary before initiating targeted treatment. Almost 10 % of patients with ARDS have no identified classic risk factors however, and the precise cause of AHRF may not be identified in up to 15 % of patients, particularly in cases of immunosuppression. In these patients, a multidisciplinary, comprehensive, and hierarchical diagnostic work-up is mandatory, including a detailed history and physical examination, chest computed tomography, extensive microbiological investigations, bronchoalveolar lavage fluid cytological analysis, immunological tests, and investigation of the possible involvement of pneumotoxic drugs.

A structured diagnostic algorithm for patients with ARDS

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2023. Other selected articles can be found online at  https://www.biomedcentral.com/collections/annualupdate2023 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from  https://link.springer.com/bookseries/8901 .

Transbronchial cryobiopsy in unexplained, severe ARDS: a single center retrospective case series

BACKGROUND

Acute respiratory distress syndrome (ARDS) deptics an acute form of lung infjury with often severe respiratory impairment that requires invasive mechanical ventilation. Since ARDS can be caused by several distinct etiologies, correct characterization is desired and frequently challenging. Surgical lung biopsy was previously reported to be of additive value. We describe our institutional experience using transbronchial cryobiopsy (TBCB) for further characterization of severe and unexplained ARDS cases.

CASE PRESENTATION

We retrospectively collected data of TBCB in patients with unexplained ARDS, whether with or without ECMO-support. Between 2019 and 2020 TBCB was performed in eight patients. Decision for the intervention was decided in multidisciplinary discussion. Five patients were treated with ECMO. The median duration of invasive ventilation before TBCB was 24 days. TBCB was performed in one segment, that was prophylactically occluded by Watanabe spigot or swab after the procedure. Histology results and their contribution to further therapeutic decisions were analyzed. Histology revealed five diffuses alveolar damage, one acute fibrinoid organizing pneumonia, one cryptogenic organizing pneumonia and one lung cancer. All results contributed to the decision of further management. While no pneumothorax or severe endobronchial bleeding occurred, two delayed hematothoraces needed surgical treatment. No patients died due to TBCB.

CONCLUSION

TBCB is feasible in ARDS even during ECMO treatment. Histologic results can play a significant role in therapeutic and ethic discussion to guide the patients' care. Side effects should be considered and monitored.

Complications of a lung biopsy for severe respiratory failure: A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to evaluate the complications of lung biopsy in patients with acute respiratory failure (ARF), including acute respiratory distress syndrome (ARDS).

METHODS

We searched the MEDLINE and Cochrane Central Register of Controlled Trials. The primary outcomes were biopsy-related death, respiratory failure, cardiac complications, bleeding, and other major complications. We used the McMaster Quality Assessment Scale of Harms (McHarm) to evaluate the risk of bias. A random-effects model was used to calculate the pooled frequencies.

RESULTS

Thirteen studies (consisting of 574 patients) were included in the meta-analysis. Furthermore, most of the included studies had a high or unclear risk of bias in half of the items in McHarm. All included studies evaluated surgical lung biopsies. The median overall hospital mortality was 53% (range: 17%-90%). The pooled frequencies of biopsy-related death, respiratory failure, cardiac complication, bleeding, and other major complications were 0.00% (95% confidence interval [CI]: 0.00%-0.21%), 1.30% (95% CI: 0.00%-5.69%), 1.03% (95% CI: 0.00%-3.73%), 1.46% (95% CI: 0.16%-3.56%), and 4.26% (95% CI: 0.00%-13.0%), respectively.

CONCLUSIONS

The results of this study will be valuable information in considering the indications of lung biopsy in patients with ARF, including ARDS.

TRIAL REGISTRATION

The protocol was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN 000040650).

Outcome and Post-Surgical Lung Biopsy Change in Management of ARDS: A Proportional Prevalence Meta-Analysis

BACKGROUND

Limited epidemiological data are available on changes in management, benefits, complications, and outcomes after open lung biopsy in patients with ARDS.

METHODS

We performed a literature search of PubMed, Ovid, and Cochrane databases for articles from the inception of each database till November 2020 that provided outcomes of lung biopsy in ARDS patients. The primary outcome was the proportion of patients that had a change in management with alteration of treatment plan, after lung biopsy. Secondary outcomes included pathological diagnoses and complications related to the lung biopsy. Pooled proportions with a 95% confidence interval (CI) were calculated for the prevalence of outcomes.

RESULTS

After analysis of 22 articles from 1994 to 2018, a total of 851 ARDS patients (mean age 59.28 ± 7.41, males 56.4%) that were admitted to the ICU who underwent surgical lung biopsy for ARDS were included. Biopsy changed the management in 539 patients (pooled proportion 75%: 95% CI 64-84%). There were 394 deaths (pooled proportion 49%: 95% CI 41-58%). The most common pathologic diagnosis was diffuse alveolar damage that occurred in 30% (95% CI 19-41%), followed by interstitial lung disease in 10% (95% CI 3-19%), and viral infection in 9% (95% CI 4-16%). Complications occurred among 201 patients (pooled proportion 24%, 95% CI 17-31%). The most common type of complication was persistent air-leak among 115 patients (pooled estimate 13%, 95% CI 9-17%).

CONCLUSION

Despite the high mortality risk associated with ARDS, lung biopsy changed management in about 3/4 of the patients. However, 1/4 of the patients had a complication due to lung biopsy. The risks from the procedure should be carefully weighed before proceeding with lung biopsy.

Airway Closure and Expiratory Flow Limitation in Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is mostly characterized by the loss of aerated lung volume associated with an increase in lung tissue and intense and complex lung inflammation. ARDS has long been associated with the histological pattern of diffuse alveolar damage (DAD). However, DAD is not the unique pathological figure in ARDS and it can also be observed in settings other than ARDS. In the coronavirus disease 2019 (COVID-19) related ARDS, the impairment of lung microvasculature has been pointed out. The airways, and of notice the small peripheral airways, may contribute to the loss of aeration observed in ARDS. High-resolution lung imaging techniques found that in specific experimental conditions small airway closure was a reality. Furthermore, low-volume ventilator-induced lung injury, also called as atelectrauma, should involve the airways. Atelectrauma is one of the basic tenet subtending the use of positive end-expiratory pressure (PEEP) set at the ventilator in ARDS. Recent data revisited the role of airways in humans with ARDS and provided findings consistent with the expiratory flow limitation and airway closure in a substantial number of patients with ARDS. We discussed the pattern of airway opening pressure disclosed in the inspiratory volume-pressure curves in COVID-19 and in non-COVID-19 related ARDS. In addition, we discussed the functional interplay between airway opening pressure and expiratory flow limitation displayed in the flow-volume curves. We discussed the individualization of the PEEP setting based on these findings.

ERS International Congress 2020 Virtual: highlights from the Respiratory Intensive Care Assembly

During the virtual European Respiratory Society Congress 2020, early career members summarised the sessions organised by the Respiratory Intensive Care Assembly. The topics covered included diagnostic strategies in patients admitted to the intensive care unit with acute respiratory failure, with a focus on patients with interstitial lung disease and for obvious reasons, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. These sessions are summarised in this article, with take-home messages highlighted.

Updates from #ERSCongress 2020 on diagnostic strategies in patients admitted to the ICU with acute respiratory failure and on the management of #SARSCoV2 infectionhttps://bit.ly/38cx0Pi

Transbronchial Forceps Biopsy in the Intensive Care Unit: A Systematic Review and Meta-analysis

BACKGROUND

A transbronchial forceps lung biopsy performed in mechanically ventilated patients with respiratory failure of unknown etiology has significant uncertainty of diagnostic yield and safety along with sparse literature. This study investigated the complication rate of transbronchial biopsies in mechanically ventilated patients in the intensive care unit and its ability to obtain a diagnosis and change current therapy.

METHODS

PubMed, Ovid MEDLINE, and Ovid Cochrane Central Register of Controlled Trials databases were systematically searched for all publications of transbronchial lung biopsies in mechanically ventilated patients. We pooled the results of individual studies using random-effects meta-analysis models to achieve the summary proportions.

RESULTS

Of the identified 9 observational studies with a total of 232 patients undergoing a transbronchial biopsy, complications occurred in 67 patients [25.2%; 95% confidence interval (CI), 11.5%-42.0%; I2=70.0%]. Pneumothorax occurred in 24 patients (9.5%; 95% CI, 4.5%-16.2%; I2=15.9%) and bleeding in 18 patients (8.9%; 95% CI, 4.1%-15.3%; I2=0%). A diagnosis was given in 146 patients (62.9%; 95% CI, 56.0%-69.1%; I2=74.6%), with 103 of 210 patients (49.0%; 95% CI, 44.6%-55.1%; I2=74.9%) having a change in treatment.

CONCLUSION

The results of this meta-analysis suggest that a transbronchial forceps biopsy when performed in mechanically ventilated patients with respiratory failure of unclear etiology had a moderate complication rate. These biopsies resulted in varied diagnoses with a high rate of management change. Randomized controlled trials are necessary to identify the ideal patients to perform a transbronchial forceps biopsy on in the intensive care unit.

Histopathological findings and clinicopathologic correlation in COVID-19: a systematic review

The severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) pandemic has had devastating effects on global health and worldwide economy. Despite an initial reluctance to perform autopsies due to concerns for aerosolization of viral particles, a large number of autopsy studies published since May 2020 have shed light on the pathophysiology of Coronavirus disease 2019 (COVID-19). This review summarizes the histopathologic findings and clinicopathologic correlations from autopsies and biopsies performed in patients with COVID-19. PubMed and Medline (EBSCO and Ovid) were queried from June 4, 2020 to September 30, 2020 and histopathologic data from autopsy and biopsy studies were collected based on 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 58 studies reporting 662 patients were included. Demographic data, comorbidities at presentation, histopathologic findings, and virus detection strategies by organ system were collected. Diffuse alveolar damage, thromboembolism, and nonspecific shock injury in multiple organs were the main findings in this review. The pathologic findings emerging from autopsy and biopsy studies reviewed herein suggest that in addition to a direct viral effect in some organs, a unifying pathogenic mechanism for COVID-19 is ARDS with its known and characteristic inflammatory response, cytokine release, fever, inflammation, and generalized endothelial disturbance. This study supports the notion that autopsy studies are of utmost importance to our understanding of disease features and treatment effect to increase our knowledge of COVID-19 pathophysiology and contribute to more effective treatment strategies.

Acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is an acute respiratory illness characterised by bilateral chest radiographical opacities with severe hypoxaemia due to non-cardiogenic pulmonary oedema. The COVID-19 pandemic has caused an increase in ARDS and highlighted challenges associated with this syndrome, including its unacceptably high mortality and the lack of effective pharmacotherapy. In this Seminar, we summarise current knowledge regarding ARDS epidemiology and risk factors, differential diagnosis, and evidence-based clinical management of both mechanical ventilation and supportive care, and discuss areas of controversy and ongoing research. Although the Seminar focuses on ARDS due to any cause, we also consider commonalities and distinctions of COVID-19-associated ARDS compared with ARDS from other causes.

Invasive pulmonary aspergillosis is associated with cytomegalovirus viremia in critically ill patients - A retrospective cohort study

BACKGROUND/PURPOSE

Cytomegalovirus (CMV) viremia is associated with a higher mortality rate and prolonged intensive care unit (ICU) stay for critically ill patients. CMV infection causes transient but substantial immunosuppression for transplant recipients, increasing risk of fungal infection. The association between CMV viremia and invasive pulmonary aspergillosis (IPA) for critically ill patients is still unknown.

METHODS

We retrospectively analyzed patients received bronchoalveolar lavage (BAL), galactomannan test, influenza survey and blood CMV viral load test in ICUs of a university hospital between April 2017 and May 2020. Independent risks for IPA were analyzed by multivariable logistic regression.

RESULTS

A total of 136 patients were included. Twenty-one patients had IPA, 48 patients had CMV viremia and 22 patients had influenza. In a multivariable logistic regression model, patients with CMV viremia or influenza had higher IPA risk (adjusted odds ratio, 3.98 and 8.72; 95% CI, 1.26-12.60 and 2.64-28.82; p value = 0.019 and <0.001, respectively.). Patients with detectable CMV in BAL fluid did not have higher IPA risk (crude odds ratio, 0.95; 95% CI, 0.33-2.79; p value = 0.933). After stratifying patients by CMV viral load, the IPA risk is higher for patients with higher viral loads. There is an additive synergistic effect on IPA risk between CMV viremia and influenza infection.

CONCLUSION

For critically ill patients, CMV viremia is an independent risk factor of IPA. Patients with higher blood CMV viral loads have a higher risk of IPA. CMV viremia and influenza have an additive synergistic effect for IPA risk in critically ill patients.

A novel cell-based assay for dynamically detecting neutrophil extracellular traps-induced lung epithelial injuries

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) are common lung disorders characterized by alveolar-capillary barrier disruption and dyspnea, which can cause substantial morbidity and mortality. Currently, a cluster of acute respiratory illnesses, known as novel coronavirus (2019-nCoV)-infected pneumonia (NCIP), which allegedly originally occurred in Wuhan, China, has increased rapidly worldwide. The critically ill patients with ARDS have high mortality in subjects with comorbidities. Previously, the excessive recruitment and activation of neutrophils (polymorphonuclear leukocytes [PMNs]), accompanied by neutrophil extracellular traps (NETs) formation were reported being implicated in the pathogenesis of ALI/ARDS. However, the direct visualization of lung epithelial injuries caused by NETs, and the qualitative and quantitative evaluations of this damage are still lacking. Additionally, those already reported methods are limited for their neglect of the pathological role exerted by NETs and focusing only on the morphological features of NETosis. Therefore, we established a cell-based assay for detecting NETs during lung epithelial cells-neutrophils co-culture using the xCELLigence system, a recognized real-time, dynamic, label-free, sensitive, and high-throughput apparatus. Our results demonstrated that lung epithelial injuries, reflected by declines in cell index (CI) values, could be induced by lipopolysaccharide (LPS)-activated PMNs, or NETs in a time and dose-dependent manner. NETs generation was verified to be the major contributor to the cytotoxicity of activated PMNs; protein components of NETs were the prevailing cytotoxic mediators. Moreover, this cell-based assay identified that PMNs from severe pneumonia patients had a high NETs formative potential. Additionally, acetylsalicylic acid (ASA) and acetaminophen (APAP) were discovered alleviating NETs formation. Thus, this study not only presents a new methodology for detecting the pathophysiologic role of NETs but also lays down a foundation for exploring therapeutic interventions in an effort to cure ALI/ARDS in the clinical setting of severe pneumonia, including the emerging of NCIP.

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A real-time, dynamical and label-free assay for detecting NETs is established using the xCELLigence system.

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This establishment relies on the co-culture of lung epithelia and neutrophils, focusing on evaluating NETs’ effects.

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This cell-based assay has feasibility and practicality in clinical applications.

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This methodology builds a solid foundation for exploring therapies for ALI/ARDS, including the emerging NCIP.

Evolution of severe acute respiratory syndrome coronavirus 2 RNA test results in a patient with fatal coronavirus disease 2019: a case report

A 65-year-old man was hospitalized owing to fever (38.6 °C) and dry cough since 4 days. He visited Wuhan 8 days ago. At admission, nasopharyngeal swab samples were taken, and polymerase chain reaction analysis confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA positivity. On day 9, after admission, the chest computed tomography scan showed diffuse ground-glass shadows in the patient's bilateral lungs. On day 11, his respiratory symptoms worsened. Subsequently, type I respiratory failure was diagnosed, coinciding with kidney injury, and subsequently, type II respiratory failure occurred, coupled with multiorgan failure including the heart and liver. However, the patient's constitution worsened although SARS-CoV-2 tests were negative since day 13. He died on day 21. Lung biopsy showed areas of diffuse alveolar damage, characterized by extensive acute alveolitis with numerous intra-alveolar neutrophil, lymphocyte, and macrophage infiltrations. Microthrombi were seen in the dilated pulmonary capillaries. Immunohistochemistry staining for SARS-CoV-2 N protein was negative. Taken together, the patient died of multiorgan failure although the SARS-CoV-2 infection was cleared already, implicating that for disease worsening, no active SARS-CoV-2 infection is required.

Benefit-to-risk balance of bronchoalveolar lavage in the critically ill. A prospective, multicenter cohort study

Purpose

To assess the benefit-to-risk balance of bronchoalveolar lavage (BAL) in intensive care unit (ICU) patients.

Methods

In 16 ICUs, we prospectively collected adverse events during or within 24 h after BAL and assessed the BAL input for decision making in consecutive adult patients. The occurrence of a clinical adverse event at least of grade 3, i.e., sufficiently severe to need therapeutic action(s), including modification(s) in respiratory support, defined poor BAL tolerance. The BAL input for decision making was declared satisfactory if it allowed to interrupt or initiate one or several treatments.

Results

We included 483 BAL in 483 patients [age 63 years (interquartile range (IQR) 53–72); female gender: 162 (33.5%); simplified acute physiology score II: 48 (IQR 37-61); immunosuppression 244 (50.5%)]. BAL was begun in non-intubated patients in 105 (21.7%) cases. Sixty-seven (13.9%) patients reached the grade 3 of adverse event or higher. Logistic regression showed that a BAL performed by a non-experienced physician (non-pulmonologist, or intensivist with less than 10 years in the specialty or less than 50 BAL performed) was the main predictor of poor BAL tolerance in non-intubated patients [OR: 3.57 (95% confidence interval 1.04–12.35); P = 0.04]. A satisfactory BAL input for decision making was observed in 227 (47.0%) cases and was not predictable using logistic regression.

Conclusions

Adverse events related to BAL in ICU patients are not infrequent nor necessarily benign. Our findings call for an extreme caution, when envisaging a BAL in ICU patients and for a mandatory accompaniment of the less experienced physicians.

Electronic supplementary material

The online version of this article (10.1007/s00134-019-05896-4) contains supplementary material, which is available to authorized users.

Open Lung Biopsy in Nonresolving Acute Respiratory Distress Syndrome Commonly Identifies Corticosteroid-Sensitive Pathologies, Associated With Better Outcome

OBJECTIVES

Approximately half of the patients undergoing lung biopsy for nonresolving acute respiratory distress syndrome exhibit another histologic pattern than diffuse alveolar damage, with some of the pathologies characterized by a potential response to corticosteroids. This study aimed to assess whether open lung biopsy performed in the ICU for nonresolving acute respiratory distress syndrome was able to identify steroid-sensitive diseases and whether patients with a steroid-sensitive pathology experienced different clinical courses and outcomes.

DESIGN

Retrospective analysis.

SETTING

One 22-bed mixed ICU within a tertiary medical center.

PATIENTS

Patients age greater than or equal to 16 years old who met the Berlin definition for acute respiratory distress syndrome and underwent open lung biopsy from January 2007 to January 2017.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During the study period, 695 patients diagnosed with acute respiratory distress syndrome were identified, 51 (7%) of whom underwent open lung biopsy. An alternative diagnosis to diffuse alveolar damage was found in 29 patients (57%), and a steroid-sensitive pathology was identified in 19 (37%). In-hospital and 180-day mortality rates were 55% and 61%, respectively. There was a significant difference in hospital mortality and 180-day mortality rates between patients with steroid-sensitive pathology and those with steroid-resistant pathology (37% vs 65%; p < 0.045 and 37% vs 75%; p < 0.007, respectively). We did not identify any variable that could reliably predict a steroid-sensitive histologic pattern before open lung biopsy.

CONCLUSIONS

Open lung biopsy was able to identify a steroid-sensitive pathology in a significant proportion of nonresolving acute respiratory distress syndrome patients. These patients had a better outcome, with lower hospital mortality and 180-day mortality.

Treatment with DNases rescues hidden neutrophil elastase from aggregated NETs

The release of neutrophil extracellular traps (NETs) is one of the weapons neutrophils have in their armory. NETs consist of extracellular chromatin fibers decorated with a plethora of cytoplasmic and granular proteins, such as the antimicrobial serine protease neutrophil elastase (NE). Because the first description of NETs as beneficial to the host, reports on their double-faced role in health and disease have considerably increased recently. On one hand, NETs reportedly trap and kill bacteria and also participate in the resolution of the acute inflammation associated with infection and with tissue damage. On the other hand, numerous negative aspects of NETs contribute to the etiopathogenesis of autoimmune disorders. Employing soluble and solid fluorescent substrates, we demonstrate the interaction of NE with aggregated NETs (aggNETs), the limitation of its enzymatic activity and the containment of the enzyme from surrounding tissues. These events prevent the spread of inflammation and tissue damage. The detection of DNase 1-dependent elevation of NE activity attests the continuous presence of patrolling neutrophils forming NETs and aggNETs even under conditions physiologic conditions.

In Vivo Endomicroscopy of Lung Injury and Repair in ARDS: Potential Added Value to Current Imaging

BACKGROUND

Standard clinical imaging of the acute respiratory distress syndrome (ARDS) lung lacks resolution and offers limited possibilities in the exploration of the structure-function relationship, and therefore cannot provide an early and clear discrimination of patients with unexpected diagnosis and unrepair profile. The current gold standard is open lung biopsy (OLB). However, despite being able to reveal precise information about the tissue collected, OLB cannot provide real-time information on treatment response and is accompanied with a complication risk rate up to 25%, making longitudinal monitoring a dangerous endeavor. Intravital probe-based confocal laser endomicroscopy (pCLE) is a developing and innovative high-resolution imaging technology. pCLE offers the possibility to leverage multiple and specific imaging probes to enable multiplex screening of several proteases and pathogenic microorganisms, simultaneously and longitudinally, in the lung. This bedside method will ultimately enable physicians to rapidly, noninvasively, and accurately diagnose degrading lung and/or fibrosis without the need of OLBs.

OBJECTIVES AND METHODS

To extend the information provided by standard imaging of the ARDS lung with a bedside, high-resolution, miniaturized pCLE through the detailed molecular imaging of a carefully selected region-of-interest (ROI). To validate and quantify real-time imaging to validate pCLE against OLB.

RESULTS

Developments in lung pCLE using fluorescent affinity- or activity-based probes at both preclinical and clinical (first-in-man) stages are ongoing-the results are promising, revealing correlations with OLBs in problematic ARDS.

CONCLUSION

It can be envisaged that safe, high-resolution, noninvasive pCLE with activatable fluorescence probes will provide a "virtual optical biopsy" and will provide decisive information in selected ARDS patients at the bedside.

Predicting the Impact of Diffuse Alveolar Damage through Open Lung Biopsy in Acute Respiratory Distress Syndrome-The PREDATOR Study

The aim of this retrospective and international study is to identify those clinical variables associated with diffuse alveolar damage (DAD), and to explore the impact of DAD on hospital mortality risk. Inclusion criteria were: adult patients with acute respiratory distress syndrome (ARDS) undergoing open lung biopsy (OLB) during their intensive care unit (ICU) management. The main end-points were: DAD and hospital mortality. In the training (n = 193) and validation cohorts (n = 65), the respiratory rate (odd ratio (OR) 0.956; confidence interval (CI) 95% 0.918; 0.995) and coronary ischemia (OR 5.974; CI95% 1.668; 21.399) on the day of ARDS had an average area under the receiver operating characteristic curve (AUROC) of 0.660 (CI95% 0.585; 0.736) and 0.562 (0.417; 0.706), respectively. PEEP (OR 1.131; CI95% 1.051; 1.218) and coronary ischemia (OR 6.820; CI95% 1.856; 25.061) on the day of OLB had an average AUROC of 0.696 (CI95% 0.621; 0.769) and 0.534 (CI95% 0.391; 0.678), respectively, to predict DAD. DAD (OR 2.296; CI95% 1.228; 4.294), diabetes mellitus requiring insulin (OR 0.081; CI95% 0.009; 0.710) and the respiratory rate (OR 1.045; CI95% 1.001; 1.091) on the day of ARDS had an average AUROC of 0.659 (CI95% 0.583; 0.737) and 0.513 (CI95% 0.361; 0.664) to predict hospital mortality and DAD (OR 2.081; CI95% 1.053; 4.114), diabetes mellitus requiring insulin (OR 0.093; CI95% 0.009; 0.956), PaCO₂ (OR 1.051; CI95% 1.019; 1.084), and platelets count (OR 0.999; CI95% 0.999; 0.999) the day of OLB had an average AUROC of 0.778 (CI95% 0.710; 0.843) and 0.634 (CI95%0.481; 0.787) to predict hospital mortalty in the training and validation cohorts, respectively. In conclusion, DAD could not to be predicted clinically and was significantly associated with hospital mortality.

Cryoprobe biopsy for the diagnosis of acute hypoxemic respiratory failure of undetermined origin

Rationale

Acute hypoxemic respiratory failure is a condition that comprises a wide array of entities. Obtaining a histological lung sample might help reach a diagnosis and direct an appropriate treatment in a select group of patients.

Objective

To describe our experience in the use of cryobiopsy for the diagnosis of acute hypoxemic respiratory failure of undetermined origin.

Methods

Retrospective analysis of case series of patients with acute hypoxemic respiratory failure who underwent lung cryobiopsy at the Intensive Care Unit of the Hospital Italiano de Buenos Aires, Argentina.

Results

Cryobiopsy yielded a histological diagnosis in all patients (n = 10, 100%). This led to either a change in therapy or continuation of a specific treatment in eight of these patients. Cryobiopsy was found to be contributive in all the patients who did not meet Berlin criteria for acute respiratory distress syndrome. No major complications were associated with the procedure.

Conclusions

Cryobiopsy is a safe procedure with a high diagnostic yield in a selected group of patients.

Diagnostic yield and therapeutic impact of open lung biopsy in the critically ill patient

Background

Open lung biopsy (OLB) is a rare procedure in intensive care units (ICUs) for therapeutic management of acute respiratory failure (ARF). The purpose of this study was to analyze the diagnostic yield, therapeutic contribution and complications of OLB in ICU patients with ARF of unclear etiology, including acute respiratory distress syndrome (ARDS) and ARDS mimics.

Methods

Retrospective study conducted in a 10-bed ICU over a 13-year period. Patients undergoing OLB for ARF with undiagnosed infiltrates on CT scan were included. ARDS was defined according to Berlin criteria, and ARDS mimics as a condition looking like ARDS except for the presence of a known cause. OLB was contributive when the OLB findings yielded a specific diagnosis resulting in a change in the patients’ treatment or management.

Results

Forty six patients were included (sex ratio = 2.5, median and [interquartile range] age = 69 [59–77] years, and admission SAPS II = 42 [33–50]. ARF corresponded to ARDS in 22 patients and to ARDS mimics in 16. OLB yielded 61 diagnoses in 45 patients including diffuse alveolar damage (N = 21), lung fibrosis (N = 18), and organizing pneumonia (N = 11). OLB was contributive in 37 patients (80%), including 13/16 ARDS mimickers. The main contributions of OLB were the introduction or maintenance of steroids (N = 32) and discontinuation of antibiotics (N = 9). In 4 patients OLB resulted directly in the decision to forgo life-sustaining treatment. OLB complications occurred in 16 patients (35%), in one case associated with fatal outcome.

Conclusion

OLB can play a useful role in the management of ICU patients with ARF of undetermined origin, including ARDS mimickers. Further studies should be done to identify the groups of ICU patients likely to benefit from the procedure with minimum risk.

Acute respiratory distress syndrome mimics: the role of lung biopsy

PURPOSE OF REVIEW

Acute respiratory distress syndrome (ARDS) mimics is a condition looking like ARDS but that does not fulfill every criterion according to the recent Berlin definition. The purpose of this review is to better delineate ARDS mimics, to discuss why the complete diagnosis of ARDS is important, and to make a brief overview on the role of open lung biopsy in this setting.

RECENT FINDINGS

Recent autopsy and lung biopsy data from ARDS patients compared lung histologic findings with the new Berlin definition of ARDS. Among them, there are some limited data about two niches, namely open lung biopsy and ARDS mimics suggesting that lung histology is important for making the diagnosis and offering the accurate management. This includes specific new treatments or stopping some medications toxic to the lung. Finally, ARDS with diffuse alveolar damage could be a specific subphenotype of ARDS with poor prognosis.

SUMMARY

An ARDS mimic enhances the need of making ARDS diagnosis as comprehensive as possible. In some limited cases, open lung biopsy in skilled hands may have implications for management.

Histopathologic heterogeneity of acute respiratory distress syndrome revealed by surgical lung biopsy and its clinical implications

BACKGROUND/AIMS

Diffuse alveolar damage (DAD) is the histopathologic hallmark of acute respiratory distress syndrome (ARDS). However, there are several non-DAD conditions mimicking ARDS. The purpose of this study was to investigate the histopathologic heterogeneity of ARDS revealed by surgical lung biopsy and its clinical relevance.

METHODS

We retrospectively analyzed 84 patients with ARDS who met the criteria of the Berlin definition and underwent surgical lung biopsy between January 2004 and December 2013 in three academic hospitals in Korea. We evaluated their histopathologic findings and compared the clinical outcomes. Additionally, the impact of surgical lung biopsy on therapeutic alterations was examined.

RESULTS

The histopathologic findings were highly heterogeneous. Of 84 patients undergoing surgical lung biopsy, DAD was observed in 31 patients (36.9%), while 53 patients (63.1%) did not have DAD. Among the non-DAD patients, diffuse interstitial lung diseases and infections were the most frequent histopathologic findings in 19 and 17 patients, respectively. Although the mortality rate was slightly higher in DAD (71.0%) than in non-DAD (62.3%), the difference was not significant. Overall, the biopsy results led to treatment alterations in 40 patients (47.6%). Patients with non-DAD were more likely to change the treatment than those with DAD (58.5% vs. 29.0%), but there were no significant improvements regarding the mortality rate.

CONCLUSIONS

The histopathologic findings of ARDS were highly heterogeneous and classic DAD was observed in one third of the patients who underwent surgical lung biopsy. Although therapeutic alterations were more common in patients with non-DAD-ARDS, there were no significant improvements in the mortality rate.

Plasma Neutrophil Elastase and Elafin as Prognostic Biomarker for Acute Respiratory Distress Syndrome: A Multicenter Survival and Longitudinal Prospective Observation Study

BACKGROUND

Neutrophil elastase (HNE) is a destructive enzyme and plays crucial roles in the pathophysiology of acute respiratory distress syndrome (ARDS). Endogenous proteinase inhibitors elafin (PI3) is important to protect against lung tissue destruction. We proposed to examine whether HNE and PI3 serve as prognostic biomarkers for ARDS.

METHODS

This study is a survival and longitudinal analysis of plasma profiles of HNE and PI3 in ARDS patients from a multicenter prospective observational cohort in Beijing, China. Plasma samples were collected on day-1, day-3, and day-7 of study enrollment.

RESULTS

HNE levels were higher in ARDS non-survivors than survivors, whereas PI3 showed opposite direction for all three measurements (P < 0.01 for all). Patients with HNE level above median and PI3 level below median values had the lowest survival probability and died the fastest. There was a significant longitudinal effect of HNE levels and PI3 level on mortality. Receiver-operating characteristic analysis demonstrated combination of HNE and PI3 had the discrimination ability for 28-day mortality (area under the receiver-operating characteristic curve [AUC]: 0.76), better than the combination of Berlin categories and APACHE II (AUC: 0.63). The addition of HNE and PI3 to Berlin categories and APACHE II has significantly improved the prognostic discrimination ability (AUC: 0.81, P < 0.0001).

CONCLUSIONS

Imbalance between HNE and PI3 levels in ARDS patients was associated with ARDS mortality. By combining these biomarkers with Berlin categories and APACHE II, prognostic power of ARDS was greatly improved. Circulation levels of HNE and PI3 may have the potential to predict ARDS mortality and better inform clinicians about ARDS mortality risk.

Impact and safety of open lung biopsy in patients with acute respiratory distress syndrome (ARDS)

INTRODUCTION

Acute respiratory distress syndrome (ARDS) is an inflammatory lung disorder, and its pathological hallmark is diffuse alveolar damage (DAD). Given that open lung biopsy (OLB) can sometimes result in severe side effects, it is rarely performed in patients with ARDS.

AIM

The aims of this study were to describe: (a) the rate of treatment change associated with the histological result; and (b) the incidence of side effects induced by OLB.

DESIGN AND PATIENTS

A retrospective, single-center, descriptive observational study was carried out in Hospital Santa Clara (Bogotá, Colombia) from February 2007 to January 2014.

INCLUSION CRITERIA

Critically ill patients over 18 years of age, undergoing invasive mechanical ventilation, diagnosed with ARDS of unknown etiology, and with OLB performed at the bedside. ARDS was diagnosed according to the Berlin definition. DAD was defined by the presence of a hyaline membrane plus at least one of the following: intra-alveolar edema, alveolar type I cell necrosis, alveolar type II cell (cuboidal cells) proliferation progressively covering the denuded alveolar-capillary membrane, interstitial proliferation of fibroblasts and myofibroblasts, or organizing interstitial fibrosis. The rate of treatment change (RTC) was established according to whether the OLB pathology report resulted in: a) the prescription or discontinuation of an antimicrobial; b) the indication of new procedures; c) medical interconsultation; or d) limitation of therapeutic effort. Patients were followed-up until death or hospital discharge. This study was approved by the Ethics Committee.

RESULTS

A total of 32 OLBs were performed during the study period; 17 were ruled out as they did not involve ARDS, and 15 were considered for further analysis. A histological diagnosis was reached in 14 of the 15 patients (12 DAD, one case of bronchiolitis obliterans organizing pneumonia and one case of Wegener's granulomatosis with alveolar hemorrhage). The RTC rate was 0.73. The most frequent intervention was discontinuation of antimicrobial or corticosteroid treatment. No deaths but four side effects (3 airway leaks and one hemothorax) were associated with the OLB procedure. All were resolved before ICU discharge.

CONCLUSION

The information provided by OLB performed at the bedside in ARDS patients of unknown etiology could be relevant, as it may optimize treatment. The risk associated with OLB seems to be acceptable.

Utility of surgical lung biopsy in critically ill patients with diffuse pulmonary infiltrates: a retrospective review

BACKGROUND

There are conflicting reports regarding the role of surgical lung biopsies in patients who present to the intensive care unit (ICU) with unexplained respiratory failure and diffuse pulmonary infiltrates on imaging.

AIM

To describe the utility of surgical lung biopsies in patients presenting to the ICU with unexplained respiratory failure and diffuse pulmonary infiltrates.

METHODS

A retrospective cohort study was performed. All patients admitted to the ICU who underwent a surgical lung biopsy for the investigation of respiratory failure and unexplained pulmonary infiltrates between 1998 and 2012 were included. The primary outcome measures for this descriptive study were the biopsy histopathology, changes in patient management following biopsy and in-hospital mortality.

RESULTS

A total of 30 patients was included in the review. Biopsies in 22 patients (73%) demonstrated diffuse alveolar damage (DAD), with 15 of these biopsies (50%) suggesting a specific underlying aetiology. In 73% of cases (n = 22), the biopsy finding was associated with a change in management, although this generally involved the escalation of an existing therapy rather than initiation of a new treatment. Biopsies were performed at a median 10 days after admission (interquartile range 5-17 days), with the majority of patients being treated empirically prior to the biopsy with systemic steroids and broad-spectrum antimicrobials. Mortality was 53%.

CONCLUSION

In this series, DAD was the most frequent pathology. The biopsy result was associated with a change in management in a majority of the subjects, most frequently an escalation of prior empiric therapy. Mortality was high.

Survival predictor in patients with acute respiratory distress syndrome and diffuse alveolar damage undergoing open lung biopsy

Background

Diffuse alveolar damage (DAD) is a typical pathological finding of open lung biopsies in patients with acute respiratory distress syndrome (ARDS). Patients with ARDS and DAD have been reported to have a poorer prognosis than those without DAD. The aim of this study was to investigate the survival predictors in patients with ARDS and DAD.

Methods

We retrospectively reviewed all ARDS patients who underwent an open lung biopsy which showed evidence of DAD from January 2006 to June 2015 at Chang Gung Memorial Hospital. Clinical data including baseline characteristics, medication, and survival outcomes were analyzed.

Results

A total of 64 ARDS patients with DAD were eligible for analysis and divided into known etiology (n = 17, 26.6%) and unknown etiology groups (n = 47, 73.4%). There was no significant difference in hospital mortality rate between the two groups (71.9% vs. 70.6%, p = 0.890). Univariate logistic regression analysis revealed that sequential organ failure assessment (SOFA) score at the time of a diagnosis of ARDS, and SOFA score, PaO₂/FiO₂ ratio, and positive end expiratory pressure level when the biopsy was performed were associated with hospital mortality. Multivariate analysis showed that the SOFA score on the day of the biopsy was an independent predictor of hospital mortality (odds ratio 1.413, 95% confidence interval 1.127–1.772; p = 0.03). There were no significant differences in the use, dose, duration and timing from ARDS to glucocorticoid therapy between the survivors and nonsurvivors.

Conclusion

For selected ARDS patients who underwent an open lung biopsy with pathological DAD, SOFA score was an independent predictor of hospital mortality.

Etiologies, diagnostic work-up and outcomes of acute respiratory distress syndrome with no common risk factor: a prospective multicenter study

Background

Patients meeting the Berlin definition for the acute respiratory distress syndrome (ARDS) might lack exposure to one or more “common” risk factors and exhibit different clinical phenotype and outcomes. We aimed to compare the clinical presentation and outcome of ARDS patients with or without risk factors, the impact on hospital mortality, and to assess the diagnostic work-up performed. The current study is an ancillary analysis of an international, multicenter, prospective cohort study (the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure, LUNG SAFE). Patients meeting ARDS criteria within 2 days of acute hypoxemic respiratory failure onset were included in the study and categorized as having risk factors or not. Outcomes were compared using propensity score matching.

Results

Among 2813 patients, 234 (8.3% [7.3–9.3]) had no ARDS risk factor identified. These were older, had more frequent chronic diseases and presented with less severe SOFA and non-pulmonary SOFA scores (p < 0.001). Compared to other ARDS, CT scan (32.1 vs 23.9%, p < 0.001) and open lung biopsy (2.6 vs 0.2%, p < 0.001) were slightly more frequent but left heart filling pressures assessment was not (69.4 vs 68.4%, p > 0.99). Among ARDS with no risk factor, 45 patients (19.2%) had a specific diagnosis made. As compared to others, patients having ARDS with no risk factor had a lower ICU but not hospital mortality (34.6 vs 40.0%; p = 0.12). A matched cohort analysis confirmed the lack of significant difference in mortality.

Conclusion

Eight percent of ARDS patients have no identified risk factor, 80% of whom have no etiological diagnosis made. The outcome of ARDS with no risk factor was comparable to other ARDS but few had a comprehensive diagnostic work-up, potentially leading to missed curable diseases.

Trial registration clinicaltrials.gov Identifier: NCT02010073

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-017-0281-6) contains supplementary material, which is available to authorized users.

The diagnostic yield and complications of open lung biopsies in kidney transplant patients with pulmonary disease

BACKGROUND

The purpose of this study was to assess the efficacy of open lung biopsy (OLB) in determining the specific diagnosis and the related complications in patients with undiagnosed diffuse pulmonary infiltrates.

METHODS

This single center, retrospective study included adult kidney transplant patients who underwent OLB. The patients had diffuse pulmonary infiltrates without definitive diagnoses and failed to respond to empiric antibiotic treatment. We analyzed the number of specific diagnoses, changes in treatment and the occurrence of complications in these patients. A logistic regression was used to determine which variables were predictors of hospital mortality.

RESULTS

From April 2010 to April 2014, 87 patients consecutively underwent OLB. A specific diagnosis was reached in 74 (85.1%) patients. In 46 patients (53%), their therapeutic management was changed after the OLB results. Twenty-five (28.7%) patients had complications related to the OLB. The hospital mortality rate was 25.2%. Age, SAPS3 score and complications related to the procedure were independent predictors of all-cause mortality.

CONCLUSIONS

OLB is a high-risk procedure with a high diagnostic yield in kidney transplant patients with diffuse pulmonary infiltrates who did not have a definitive diagnosis and who failed to respond to empiric antibiotic treatment. Complications related to OLB were common and were independently associated with intra-hospital mortality.

Pulmonary Manifestations of Acute Lung Injury: More Than Just Diffuse Alveolar Damage

CONTEXT

- Acute pulmonary injury may occur as a result of myriad direct or indirect pulmonary insults, often resulting in hypoxemic respiratory failure and clinical acute respiratory distress syndrome. Histologically, most patients will exhibit diffuse alveolar damage on biopsy, but other histologic patterns may be encountered, such as acute eosinophilic pneumonia, acute fibrinous and organizing pneumonia, and diffuse alveolar hemorrhage with capillaritis.

OBJECTIVE

- To review the diagnostic features of various histologic patterns associated with a clinical picture of acute lung injury, and to discuss key features in the differential diagnosis.

DATA SOURCES

- The review is drawn from pertinent peer-reviewed literature and the personal experience of the authors.

CONCLUSIONS

- Acute pulmonary injury is a significant cause of morbidity and mortality. In addition to diffuse alveolar damage, pathologists should be aware of alternate histologic patterns of lung disease that may present with a similar clinical presentation because this may impact treatment decisions and disease outcome.

Open Lung Biopsy Among Critically Ill, Mechanically Ventilated Patients. A Metaanalysis

RATIONALE

Open lung biopsy may be performed to guide therapy in mechanically ventilated patients with diagnostic uncertainty regarding etiology of pulmonary infiltrates. Current evidence for open lung biopsy in mechanically ventilated patients comes from single-center case series.

OBJECTIVES

We performed a metaanalysis of case series to determine diagnoses, complications, and changes in therapy after lung biopsy in critically ill patients requiring mechanical ventilation.

METHODS

We searched Medline for case series of lung biopsies in critically ill patients requiring mechanical ventilation. We pooled results of individual case series using random effects metaanalysis models to obtain summary proportions.

MEASUREMENTS AND MAIN RESULTS

We identified 14 case series including a total of 512 mechanically ventilated patients with 530 histopathological diagnoses. The most common diagnoses were "fibrosis/pneumonitis" (n = 155, 25%; 95% confidence interval [CI], 14-37%) and infection (n = 113, 20%; 95% CI, 15-27%). Viruses were the most commonly identified infectious etiology identified on open lung biopsy, representing 50% of potential pathogens. Diffuse alveolar damage was present in a minority of specimens (n = 100, 16%; 95% CI, 8-25%). Therapeutic changes after lung biopsy occurred in 399 patients (78%; 95% CI, 64-81%). Procedure-related complications occurred in 29% of patients (95% CI, 25-33%), most commonly persistent air leak. Mortality among mechanically ventilated patients after diagnostic open lung biopsy was 54%.

CONCLUSIONS

Among mechanically ventilated patients with respiratory failure of unclear etiology, lung biopsy yielded a wide range of diagnoses and was associated with a change in therapy in most patients.

Which patients with ARDS benefit from lung biopsy?

A central tenet of caring for patients with ARDS is to treat the underlying cause, be it sepsis, pneumonia, or removal of an offending toxin. Identifying the risk factor for ARDS has even been proposed as essential to diagnosing ARDS. Not infrequently, however, the precipitant for acute hypoxemic respiratory failure is unclear, and this raises the question of whether a histologic lung diagnosis would benefit the patient. In this review, we consider the historic role of pathology in establishing a diagnosis of ARDS and the published experience of surgical and transbronchial lung biopsy in patients with ARDS. We reflect on which pathologic diagnoses influence treatment and suggest a patient-centric approach to weigh the risks and benefits of a lung biopsy for critically ill patients who may have ARDS.

Diffuse alveolar damage associated mortality in selected acute respiratory distress syndrome patients with open lung biopsy

INTRODUCTION

Diffuse alveolar damage (DAD) is the pathological hallmark of acute respiratory distress syndrome (ARDS), however, the presence of DAD in the clinical criteria of ARDS patients by Berlin definition is little known. This study is designed to investigate the role of DAD in ARDS patients who underwent open lung biopsy.

METHODS

We retrospectively reviewed all ARDS patients who met the Berlin definition and underwent open lung biopsy from January 1999 to January 2014 in a referred medical center. DAD is characterized by hyaline membrane formation, lung edema, inflammation, hemorrhage and alveolar epithelial cell injury. Clinical data including baseline characteristics, severity of ARDS, clinical and pathological diagnoses, and survival outcomes were analyzed.

RESULTS

A total of 1838 patients with ARDS were identified and open lung biopsies were performed on 101 patients (5.5 %) during the study period. Of these 101 patients, the severity of ARDS on diagnosis was mild of 16.8 %, moderate of 56.5 % and severe of 26.7 %. The hospital mortality rate was not significant difference between the three groups (64.7 % vs 61.4 % vs 55.6 %, p = 0.81). Of the 101 clinical ARDS patients with open lung biopsies, 56.4 % (57/101) patients had DAD according to biopsy results. The proportion of DAD were 76.5 % (13/17) in mild, 56.1 % (32/57) in moderate and 44.4 % (12/27) in severe ARDS and there is no significant difference between the three groups (p = 0.113). Pathological findings of DAD patients had a higher hospital mortality rate than non-DAD patients (71.9 % vs 45.5 %, p = 0.007). Pathological findings of DAD (odds ratio: 3.554, 95 % CI, 1.385-9.12; p = 0.008) and Sequential Organ Failure Assessment score on the biopsy day (odds ratio: 1.424, 95 % CI, 1.187-1.707; p<0.001) were significantly and independently associated with hospital mortality. The baseline demographics and clinical characteristics were not significantly different between DAD and non-DAD patients.

CONCLUSIONS

The correlation of pathological findings of DAD and ARDS diagnosed by Berlin definition is modest. A pathological finding of DAD in ARDS patients is associated with hospital mortality and there are no clinical characteristics that could identify DAD patients before open lung biopsy.