Safety of bronchoalveolar lavage in patients with adult respiratory distress syndrome

Pulmonary Surfactant in Adult ARDS: Current Perspectives and Future Directions

Acute respiratory distress syndrome (ARDS) is a major cause of hypoxemic respiratory failure in adults, leading to the requirement for mechanical ventilation and poorer outcomes. Dysregulated surfactant metabolism and function are characteristic of ARDS. A combination of alveolar epithelial damage leading to altered surfactant synthesis, secretion, and breakdown with increased functional inhibition from overt alveolar inflammation contributes to the clinical features of poor alveolar compliance and alveolar collapse. Quantitative and qualitative alterations in the bronchoalveolar lavage and tracheal aspirate surfactant composition contribute to ARDS pathogenesis. Compared to neonatal respiratory distress syndrome (nRDS), replacement studies of exogenous surfactants in adult ARDS suggest no survival benefit. However, these studies are limited by disease heterogeneity, variations in surfactant preparations, doses, and delivery methods. More importantly, the lack of mechanistic understanding of the exact reasons for dysregulated surfactant remains a significant issue. Moreover, studies suggest an extremely short half-life of replaced surfactant, implying increased catabolism. Refining surfactant preparations and delivery methods with additional co-interventions to counteract surfactant inhibition and degradation has the potential to enhance the biophysical characteristics of surfactant in vivo.

Differential Gene Expression of SARS-CoV-2 Positive Bronchoalveolar Lavages: A Case Series

BACKGROUND

Transcriptomic data on bronchoalveolar lavage (BAL) from COVID-19 patients are currently scarce.

OBJECTIVES

This case series seeks to characterize the intra-alveolar immunopathology of COVID-19.

METHOD

BALs were performed on 14 patients (5 COVID-19, of which 3 mild and 2 largely asymptomatic, 9 controls). Controls included asthma (n = 1), unremarkable BALs (n = 3), infections with respiratory syncytial virus (n = 1), influenza B (n = 1), and infections with other coronaviruses (n = 3). SARS-CoV-2 RNA load was measured by quantitative nucleic acid testing, while the detection of other pathogens was performed by immunofluorescence or multiplex NAT.

RESULTS

Gene expression profiling showed 71 significantly downregulated and 5 upregulated transcripts in SARS-CoV-2-positive lavages versus controls. Downregulated transcripts included genes involved in macrophage development, polarization, and crosstalk (LGALS3, MARCO, ERG2, BTK, RAC1, CD83), and genes involved in chemokine signaling and immunometabolism (NUPR1, CEBPB, CEBPA, PECAM1, CCL18, PPARG, ALOX5, ALOX5AP). Upregulated transcripts featured genes involved in NK-T cell signaling (GZMA, GZMH, GNLY, PRF1, CD3G). Patients with mild COVID-19 showed a significant upregulation of genes involved in blood mononuclear cell/leukocyte function (G0S2, ANXA6, FCGR2B, ADORA3), coagulation (von Willebrand factor [VWF]), interferon response (IFRD1, IL12RB2), and a zinc metalloprotease elevated in asthma (CPA3) compared to asymptomatic cases. In-silico comparison of the 5 COVID-19 BAL cases to a published cohort of lethal COVID-19 showed a significant upregulation of "antigen processing and presentation" and "lysosome" pathways in lethal cases.

CONCLUSIONS

These data underscore the heterogeneity of immune response in COVID-19. Further studies with a larger dataset are required to gain a better understanding of the hallmarks of SARS-CoV-2 immunological response.

Research Bronchoscopies in Critically Ill Research Participants: An Official American Thoracic Society Workshop Report

Bronchoscopy for research purposes is a valuable tool to understand lung-specific biology in human participants. Despite published reports and active research protocols using this procedure in critically ill patients, no recent document encapsulates the important safety considerations and downstream applications of this procedure in this setting. The objectives were to identify safe practices for patient selection and protection of hospital staff, provide recommendations for sample procurement to standardize studies, and give guidance on sample preparation for novel research technologies. Seventeen international experts in the management of critically ill patients, bronchoscopy in clinical and research settings, and experience in patient-oriented clinical or translational research convened for a workshop. Review of relevant literature, expert presentations, and discussion generated the findings presented herein. The committee concludes that research bronchoscopy with bronchoalveolar lavage in critically ill patients on mechanical ventilation is valuable and safe in appropriately selected patients. This report includes recommendations on standardization of this procedure and prioritizes the reporting of sample management to produce more reproducible results between laboratories. This document serves as a resource to the community of researchers who endeavor to include bronchoscopy as part of their research protocols and highlights key considerations for the inclusion and safety of research participants.

New Insights into Clinical and Mechanistic Heterogeneity of the Acute Respiratory Distress Syndrome: Summary of the Aspen Lung Conference 2021

Clinical and molecular heterogeneity are common features of human disease. Understanding the basis for heterogeneity has led to major advances in therapy for many cancers and pulmonary diseases such as cystic fibrosis and asthma. Although heterogeneity of risk factors, disease severity, and outcomes in survivors are common features of the acute respiratory distress syndrome (ARDS), many challenges exist in understanding the clinical and molecular basis for disease heterogeneity and using heterogeneity to tailor therapy for individual patients. This report summarizes the proceedings of the 2021 Aspen Lung Conference, which was organized to review key issues related to understanding clinical and molecular heterogeneity in ARDS. The goals were to review new information about ARDS phenotypes, to explore multicellular and multisystem mechanisms responsible for heterogeneity, and to review how best to account for clinical and molecular heterogeneity in clinical trial design and assessment of outcomes. The report concludes with recommendations for future research to understand the clinical and basic mechanisms underlying heterogeneity in ARDS to advance the development of new treatments for this life-threatening critical illness.

Bronchoscopy in intubated and non-intubated intensive care unit patients with respiratory failure

Bronchoscopy is one of the important tool for the pulmonary and critical care physicians to diagnose and treat various pulmonary conditions. It is increasingly being used by the intensivist due to its safety and portability. The utilization of bronchoscopy in the intensive care unit (ICU) has made the diagnosis and treatment of many conditions more feasible to intensivists. Sedation, topical or intravenous, usually helps better tolerate the procedure. However, the risks and benefits of bronchoscopy should be carefully considered in critically ill patients. The hypoxic patients in ICU pose a challenge as hypoxemia is one of the known complications of bronchoscopy, and this risk is exacerbated in patients with hypoxic respiratory failure. Bronchoscopy is relatively contraindicated in patients with severe hypoxemia and coagulopathy. However, bronchoscopy in hypoxic patients can have diagnostic as well as therapeutic implications. In patients with hypoxic respiratory failure, the use of non-invasive ventilation (NIV) during bronchoscopy has been shown to reduce the risk of intubation. On the other hand, bronchoscopy in mechanically ventilated patients is not contraindicated and has been widely used. Staying focused, monitoring vital signs closely, limiting the scope time in the airway, and understanding patient’s physiology may help decrease risk of complications. In this review, we discuss indications, techniques, complications, and yield associated with bronchoscopy in critically ill hypoxic patients.

Safety and harms of bronchoalveolar lavage for acute respiratory failure: A systematic review and meta-analysis

BACKGROUND

This review aimed to investigate whether bronchoalveolar lavage (BAL) is safe in patients with severe acute respiratory failure (ARF).

METHODS

We searched the MEDLINE, CENTRAL, and other databases up to June 2, 2021 for studies that examined BAL for severe ARF. We included all cohort studies and randomized or non-randomized trials, while we excluded case-control studies, case reports, and case series. We evaluated the quality of the evidence using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

RESULTS

We included 17 studies (1085 patients) in the meta-analysis. The integrated frequency of death was 0.000% (95% confidence interval [CI]: 0.000-0.045%, I² = 0.0%). The pooled risk of severe complications of respiratory system, cardiovascular system, and major bleeding was 1.32% (95% CI: 0.000-4.41%, I² = 84.8%), 0.040% (95% CI: 0.000-0.71%, I² = 9.3%), and 0.000% (95% CI: 0.000-0.27%, I² = 0.0%), respectively. In the subgroup analysis with mechanical ventilation during BAL, there were few severe complications of the respiratory system (3/717 patients in 13 studies) and almost no heterogeneity (I² = 0.0%).

CONCLUSIONS

Our study suggests that severe complications of BAL for severe ARF are probably rare, particularly in patients receiving mechanical ventilation. After considering the risks and benefits, it would be worthwhile to consider performing BAL in patients with severe ARF of unknown etiology to pursue its cause.

TRIAL REGISTRATION

The protocol was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000040600).

Bronchoalveolar Tregs are associated with duration of mechanical ventilation in acute respiratory distress syndrome

Background

Foxp3⁺ regulatory T cells (Tregs) play essential roles in immune homeostasis and repair of damaged lung tissue. We hypothesized that patients whose lung injury resolves quickly, as measured by time to liberation from mechanical ventilation, have a higher percentage of Tregs amongst CD4⁺ T cells in either airway, bronchoalveolar lavage (BAL) or peripheral blood samples.

Methods

We prospectively enrolled patients with ARDS requiring mechanical ventilation and collected serial samples, the first within 72 h of ARDS diagnosis (day 0) and the second 48–96 h later (day 3). We analyzed immune cell populations and cytokines in BAL, tracheal aspirates and peripheral blood, as well as cytokines in plasma, obtained at the time of bronchoscopy. The study cohort was divided into fast resolvers (FR; n = 8) and slow resolvers (SR; n = 5), based on the median number of days until first extubation for all participants (n = 13). The primary measure was the percentage of CD4⁺ T cells that were Tregs.

Results

The BAL of FR contained more Tregs than SR. This finding did not extend to Tregs in tracheal aspirates or blood. BAL Tregs expressed more of the full-length FOXP3 than a splice variant missing exon 2 compared to Tregs in simultaneously obtained peripheral blood.

Conclusion

Tregs are present in the bronchoalveolar space during ARDS. A greater percentage of CD4⁺ cells were Tregs in the BAL of FR than SR. Tregs may play a role in the resolution of ARDS, and enhancing their numbers or functions may be a therapeutic target.

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.

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.

The use of bronchoscopy in critically ill patients: considerations and complications

INTRODUCTION

Flexible bronchoscopy has been well established for diagnostic and therapeutic purposes in critically ill patients. Areas covered: This review outlines the clinical evidence of the utility and safety of flexible bronchoscopy in the intensive care unit, as well as specific considerations, including practical points and potential complications, in critically ill patients. Expert commentary: Its ease to learn and perform and its capacity for bedside application with relatively few complications make flexible bronchoscopy an indispensable tool in the intensive care unit setting. The main indications for flexible bronchoscopy in the intensive care unit are the visualization of the airways, sampling for diagnostic purposes and management of the artificial airways. The decision to perform flexible bronchoscopy can only be made by trade-offs between potential risks and benefits because of the fragile nature of the critically ill. Flexible bronchoscopy-associated serious adverse events are inevitable in cases of a lack of expertise or appropriate precautions.

Safety profile of blind bronchial sampling-A prospective study in pediatric intensive care unit

OBJECTIVE

To study the safety profile of blind bronchial sampling in mechanically ventilated children.

DESIGN

Prospective interventional study.

SETTING

Tertiary level pediatric intensive care unit of a multispecialty hospital.

PATIENTS

Children aged 1 month to 16 years on mechanical ventilator for ≥48 h, were assessed by clinical pulmonary infection score for ventilator-associated pneumonia (VAP).

INTERVENTIONS

Blind bronchial sampling was performed following standard procedural guidelines. The hemodynamic, ventilation parameters, and arterial blood gases done before, and in next 24 h post procedure were recorded and compared.

MEASUREMENTS AND MAIN RESULTS

Among the 40 enrolled children, VAP was suspected at 5.8 ± 3.7 days post intubation with insignificant increase in median (IQR) PELOD score to 15 (11-23) from 13.5 (11-23) (P value 0.29). A statistically significant increase in mean blood pressure (75.5 ± 14.7 to 79.1 ± 14.2, P 0.04) and transient drop in SpO₂ (98.2 ± 2.3 to 92.2 ± 9.2, P < 0.001) were noted with insignificant change in heart rate (128.7 ± 25.6 vs 132.0 ± 30.8, P 0.52), though these variations were clinically not significant. There were no major complications like significant airway bleed, arrhythmia, air leaks, edema, and change in pulmonary infiltrates during the procedure. There were no significant (either clinical or statistical) effects of BBS procedure, whether transient or prolonged, on ventilatory requirements or gas exchange parameters.

CONCLUSIONS

Blind bronchial sampling is a safe procedure in children with no major adverse events related to hemodynamics, oxygenation, and ventilation parameters.

Therapeutic bronchoscopy vs. standard of care in acute respiratory failure: a systematic review

BACKGROUND

We aimed to assess patient-important benefits and harms of therapeutic bronchoscopy vs. standard of care (no bronchoscopy) in critically ill patients with acute respiratory failure (ARF).

METHODS

We conducted a systematic review with meta-analysis and trial sequential analysis (TSA) according to the Cochrane Handbook and GRADE methodology, including a predefined protocol (PROSPERO no. CRD42016046235). We included randomized clinical trials (RCTs) comparing therapeutic bronchoscopy to standard of care in critically ill patients with ARF. Two reviewers independently assessed trials for inclusion, extracted data and assessed risk of bias. Risk ratios (RR) with 95% confidence intervals (CI) were estimated by conventional meta-analysis. The risk of random errors was assessed by TSA. Exclusively patient-important outcomes were evaluated.

RESULTS

We included five trials (n = 212); all were judged as having high risk of bias. There was no difference in all-cause mortality between therapeutic bronchoscopy and standard of care (TSA adjusted RR 0.39; 95% CI 0.14 to 1.07; I² 0%), and only 3% of the required information size had been accrued. There was no difference in ICU length of stay. A shorter duration of mechanical ventilation was suggested by conventional meta-analysis, however TSA highlighted that only 42% of the required information size had been accrued, indicating high risk of random errors. No trials reported data on adverse events, hospital length of stay, quality of life or performance status.

CONCLUSIONS

The quantity and quality of evidence supporting therapeutic bronchoscopy in critically ill patients with ARF is very low with no firm evidence for benefit or harm.

Clinical course and complications following diagnostic bronchoalveolar lavage in critically ill mechanically ventilated patients

Background

Flexible, fibreoptic bronchoscopy (FFB) and bronchoalveolar lavage (BAL) have been used for diagnostic purposes in critically ill ventilated patients. The additional diagnostic value compared to tracheal aspirations in ventilator-associated pneumonia (VAP) has been questioned. Nevertheless, BAL can provide extra information for the differential diagnosis of respiratory disease and good antibiotic stewardship. These benefits should outweigh potential hazards caused by the invasiveness of this diagnostic technique. The focus of the present study was on the clinical course and complications of patients following BAL procedures up to 24 h.

Methods

Hundred sixty-four FFB guided BAL procedures for suspected pneumonia were analysed in an observational study. The clinical course of patients was monitored by respiratory and haemodynamic data before BAL, 1 and 24 h after BAL. Complications were defined and registered. Factors associated with complications were analysed by logistic regression.

Results

Clinical course: a decrease in average pO₂/FiO₂ ratio 1 h after BAL from 29 kPa (218 mmHg) to 25 kPa (189 mmHg) (p < 0.05) was observed which fully recovered within 24 h. Respiratory complications: the incidence of procedure related hypo-oxygenation (SaO₂ ≤ 88 %) and/or bronchospasm was 9 %; a decrease of >25 % PaO₂/FiO₂ ratio 1 h after BAL was found in 29 % of patients; no bleeding or pneumothorax were registered. Haemodynamic complications: there were no cases of hypertension and cardiac rhythm disturbances; haemodynamic instability within the first 24 h after BAL was recorded in 22 %; this was correlated with a cardiovascular diagnosis at admission (OR 2.9; 95 % CI 1.2 - 6.7) and the presence of cardiovascular co-morbidity (OR 3.5; 95 % CI 1.5 – 8.3). The incidence of bacteraemia was 7 %. There was no case of procedure related death.

Discussion

Frequently occurring haemodynamic and respiratory instability but no cases of cardiac rhythm disturbances, bleeding, pneumothorax or procedure related death were attributable to diagnostic FFB and BAL. The procedures should be conducted under careful supervision by experienced physicians. Only a randomized controlled trial that compares diagnostic FFB and BAL with a non-invasive strategy could ultimately establish the safety profile and clinical utility of these procedures in critically ill ventilated patients.

Acute respiratory distress syndrome on the intensive care unit

Acute respiratory distress syndrome is a life-threatening condition that is common in critically ill patients. Historically, diagnosis has been difficult and prognosis has been poor, but the Berlin definition and developments in medical therapies provide promise that we can improve outcomes for these patients in the future.

Acute respiratory distress syndrome and pneumothorax

Acute respiratory distress syndrome (ARDS) can occur during the treatment of several diseases and in several interventional procedures as a complication. It is a difficult situation to handle and special care should be applied to the patients. Mechanical ventilation is used for these patients and several parameters are changed constantly until compliance is achieved. However, a complication that is observed during the application of positive airway pressure is pneumothorax. In our current work we will present definition and causes of pneumothorax in the setting of intensive care unit (ICU). We will identify differences and similarities of this situation and present treatment options.

Safety of research bronchoscopy in critically ill patients

OBJECTIVE

Bronchoscopy and bronchoalveolar lavage (BAL) are common procedures in intensive care units; however, no contemporaneous safety and outcomes data have been reported, particularly for critically ill patients.

DESIGN

This is a retrospective analysis of prospectively collected data from teaching hospital adult intensive care units.

INTERVENTIONS

One hundred mechanically ventilated patients with severe sepsis, septic shock, acute lung injury (ALI), and/or acute respiratory distress syndrome underwent bronchoscopy with unilateral BAL. Data collected included demographics, presence of sepsis or ALI, Pao2 to Fio2 ratio, positive end-expiratory pressure, Acute Physiology and Chronic Health Evaluation score, Sequential Organ Failure Assessment score, and peri- or postprocedural complications.

RESULTS

Men comprised 51% of the patients; 81% of the patients were black, and 15% were white. The mean age was 52 (SD, ±16) years. The mean Acute Physiology and Chronic Health Evaluation score was 22 (±7.5), whereas the median Sequential Organ Failure Assessment score was 9 (interquartile range, 5-12). Ten patients (10%) had complications during or immediately after the procedure. Hypoxemia during or immediately after the BAL was the most common complication. Ninety percent of the complications were related to transient hypoxemia, whereas bradycardia and hypotension each occurred in 1 patient. Age, female sex, and higher positive end-expiratory pressure were associated with complications.

CONCLUSIONS

Bronchoscopy with BAL in critically ill patients with sepsis and ALI is well tolerated with low risk of complications, primarily related to manageable hypoxemia.

The fibroproliferative response in acute respiratory distress syndrome: mechanisms and clinical significance

Acute respiratory distress syndrome (ARDS) continues to be a major healthcare problem, affecting >190,000 people in the USA annually, with a mortality of 27-45%, depending on the severity of the illness and comorbidities. Despite advances in clinical care, particularly lung protective strategies of mechanical ventilation, most survivors experience impaired health-related quality of life for years after the acute illness. While most patients survive the acute illness, a subset of ARDS survivors develops a fibroproliferative response characterised by fibroblast accumulation and deposition of collagen and other extracellular matrix components in the lung. Historically, the development of severe fibroproliferative lung disease has been associated with a poor prognosis with high mortality and/or prolonged ventilator dependence. More recent studies also support a relationship between the magnitude of the fibroproliferative response and long-term health-related quality of life. The factors that determine which patients develop fibroproliferative ARDS and the cellular mechanisms responsible for this pathological response are not well understood. This article reviews our current understanding of the contribution of pulmonary dysfunction to mortality and to quality of life in survivors of ARDS, the mechanisms driving pathological fibroproliferation and potential therapeutic approaches to prevent or attenuate fibroproliferative lung disease.

Effects on respiratory mechanics of bronchoalveolar lavage in mechanically ventilated patients

INTRODUCTION

Inconsistent findings have been reported about the effects of bronchoalveolar lavage (BAL) on respiratory mechanics. The aims of this study were to study the effects of BAL on respiratory mechanics in mechanically ventilated patients with suspected pneumonia and to find out whether these effects are related to the extension of radiographic infiltrate and preceding respiratory mechanics measurements.

METHODS

Bronchoscopy BAL was performed with 150 mL of sterile isotonic saline in 3 aliquots of 50 mL. Respiratory mechanics parameters were measured by the rapid airway occlusion technique, immediately before and after BAL and 90 minutes later. Patients were classified according to unilateral or bilateral radiological infiltrate occurrence.

RESULTS

Fifty critically ill patients undergoing mechanical ventilation were included. Respiratory system compliance (Crs) decreased from 43.32±13.17 mL/cm H2O to 33.02±9.56 mL/cm H2O (P<0.01) and airway resistance increased from 15.16±7.04 cm H2O/L/s to 17.54±9.40 cm H2O/L/s (P<0.05) immediately after BAL; 90 minutes later both the parameters returned to the pre-BAL values. Patients who showed a greater than 20% decrease in Crs had a higher pre-BAL Crs than patients with a less severe decrease (49.85±10.7 mL/cm H2O vs. 35.65±11.67 mL/cm H2O; P<0.01). However, neither pre-BAL airway resistance nor the extension of the radiographic infiltrates was related to the changes in respiratory mechanics.

CONCLUSIONS

BAL in mechanically ventilated patients can lead to a significant, although transitory, deterioration in pulmonary mechanics, characterized by a decrease in Crs and by an increase in airway resistance. Patients with better initial Crs showed the most severe affectation.

An official American Thoracic Society clinical practice guideline: the clinical utility of bronchoalveolar lavage cellular analysis in interstitial lung disease

BACKGROUND

The clinical utility of bronchoalveolar lavage fluid (BAL) cell analysis for the diagnosis and management of patients with interstitial lung disease (ILD) has been a subject of debate and controversy. The American Thoracic Society (ATS) sponsored a committee of international experts to examine all relevant literature on BAL in ILD and provide recommendations concerning the use of BAL in the diagnosis and management of patients with suspected ILD.

PURPOSE

To provide recommendations for (1) the performance and processing of BAL and (2) the interpretation of BAL nucleated immune cell patterns and other BAL characteristics in patients with suspected ILD.

METHODS

A pragmatic systematic review was performed to identify unique citations related to BAL in patients with ILD that were published between 1970 and 2006. The search was updated during the guideline development process to include published literature through March 2011. This is the evidence upon which the committee's conclusions and recommendations are based.

RESULTS

Recommendations for the performance and processing of BAL, as well as the interpretation of BAL findings, were formulated by the committee.

CONCLUSIONS

When used in conjunction with comprehensive clinical information and adequate thoracic imaging such as high-resolution computed tomography of the thorax, BAL cell patterns and other characteristics frequently provide useful information for the diagnostic evaluation of patients with suspected ILD.

[Fiberoptic bronchoscopy in a respiratory intensive care unit]

OBJECTIVE

To describe the indications, diagnostic performance and safety of fiberoptic bronchoscopy (FOB) performed in a respiratory intensive care unit (RICU).

DESIGN

A prospective, observational study was carried out.

SETTING

A 6-bed RICU in a tertiary university hospital.

PATIENTS

Patients admitted to RICU who required FOB.

INTERVENTIONS

None.

MAIN MEASUREMENTS

FOB indications and complications, endoscopic procedures, time required to perform FOB.

RESULTS

Sixty-nine out (23%) of the 297 patients admitted to the RICU underwent a total of 107 FOB. Sixty-eight percent of FOB were performed in patients on mechanical ventilation. FOB was performed for diagnostic and therapeutic purposes in 88 (82%) and 19 cases (18%), respectively. The study of pulmonary infiltrates was the main indication for diagnostic FOB (44 cases; 50%), particularly in immunocompromised patients (24 cases; 27%). In immunocompromised patients the diagnostic performance of FOB was significantly higher than in immunocompetent subjects (48% vs 30%; p<0.01). No major complications were recorded. Only a significant drop in PaO(2)/FiO(2) ratio was observed (182 ± 74 vs 163 ± 79; p<0.005) in patients undergoing bronchoalveolar lavage. Overall mortality in patients in the RICU was 14%. In patients requiring a single FOB procedure, mortality was 25%, versus 45% among those requiring more than one FOB procedure.

CONCLUSIONS

These results show that FOB is used commonly in the RICU. It is a safe and fast procedure that contributes significantly to clinical management. Patients requiring additional FOB during admission to the RICU show high mortality.

Evaluation of the patient undergoing respiratory endoscopic procedures

Endoscopic techniques can be considered reasonably safe since they are widely used and the rate of complications is extremely low. Still complications do occur and in order to avoid them, the evaluation of the patient before and after any intervention is of the utmost importance. In this article, issues concerning the preparation of the patient and informed consent, the general assessment - medical history, current medications, physical examination, laboratory tests, radiological evaluation and analysis of the indication and planning will be addressed. The post intervention evaluation will also be discussed, in order to detect and treat complications and decide on the final guidance for the patient after discharge. There are very few up-to-date studies or publications dealing with these areas, the evidence level remains low and most recommendations are based on common sense and expert opinion.

Diagnosis of ventilator-associated pneumonia

INTRODUCTION

Ventilator-associated pneumonia (VAP) is difficult to diagnose. Recent data suggest quantitative endotracheal aspirate (ETA) may be noninferior diagnostically to quantitative bronchoalveolar lavage (BAL). We hypothesized this would be the case.

METHODS

Blind quantitative ETA and BAL were performed on 150 consecutive ventilated patients with suspected VAP in a prospective single-centre medical intensive care unit study over a 2-year inclusion period. Patients were either antibiotic-naive or antibiotic-free for 72 hours. Diagnostic yield, Gram stain and culture results, and impact on antibiotic therapy were assessed. The independent impact of a positive BAL or ETA result on ventilator settings and 28-day mortality was calculated. The BAL/ETA safety was assessed hemodynamically.

RESULTS

Bronchoalveolar lavage had significantly higher diagnostic yield (49.3% vs 34.0%, P = .01), more frequent impact on antibiotic therapy (usually de-escalation) (48.0% vs 32.7%, P = .01), and greater sensitivity (64.1% vs 42.6%, P = .0003) than ETA. There was moderate intertest agreement and no difference in specificity and positive and negative predictive values. A positive BAL or ETA result did not independently alter the frequency of ventilator changes or 28-day mortality. Both procedures were well tolerated.

CONCLUSION

Quantitative BAL is safe and has greater diagnostic utility than ETA for VAP facilitates de-escalation. This study provides support for quantitative BAL in VAP diagnosis.

Comparison of two non-bronchoscopic methods for evaluating inflammation in patients with acute hypoxaemic respiratory failure

Introduction

The simple bedside method for sampling undiluted distal pulmonary edema fluid through a normal suction catheter (s-Cath) has been experimentally and clinically validated. However, there are no data comparing non-bronchoscopic bronchoalveolar lavage (mini-BAL) and s-Cath for assessing lung inflammation in acute hypoxaemic respiratory failure. We designed a prospective study in two groups of patients, those with acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) and those with acute cardiogenic lung edema (ACLE), designed to investigate the clinical feasibility of these techniques and to evaluate inflammation in both groups using undiluted sampling obtained by s-Cath. To test the interchangeability of the two methods in the same patient for studying the inflammation response, we further compared mini-BAL and s-Cath for agreement of protein concentration and percentage of polymorphonuclear cells (PMNs).

Methods

Mini-BAL and s-Cath sampling was assessed in 30 mechanically ventilated patients, 21 with ALI/ARDS and 9 with ACLE. To analyse agreement between the two sampling techniques, we considered only simultaneously collected mini-BAL and s-Cath paired samples. The protein concentration and polymorphonuclear cell (PMN) count comparisons were performed using undiluted sampling. Bland-Altman plots were used for assessing the mean bias and the limits of agreement between the two sampling techniques; comparison between groups was performed by using the non-parametric Mann-Whitney-U test; continuous variables were compared by using the Student t-test, Wilcoxon signed rank test, analysis of variance or Student-Newman-Keuls test; and categorical variables were compared by using chi-square analysis or Fisher exact test.

Results

Using protein content and PMN percentage as parameters, we identified substantial variations between the two sampling techniques. When the protein concentration in the lung was high, the s-Cath was a more sensitive method; by contrast, as inflammation increased, both methods provided similar estimates of neutrophil percentages in the lung. The patients with ACLE showed an increased PMN count, suggesting that hydrostatic lung edema can be associated with a concomitant inflammatory process.

Conclusions

There are significant differences between the s-Cath and mini-BAL sampling techniques, indicating that these procedures cannot be used interchangeably for studying the lung inflammatory response in patients with acute hypoxaemic lung injury.

[Diagnostic flexible bronchoscopy. Recommendations of the Endoscopy Working Group of the French Society of Pulmonary Medicine]

These guidelines on flexible bronchoscopy depict important clues to be known and taken into account while practicing flexible bronchoscopy, in adult, except in emergency situations. This is a practical clarification. Safety conditions, complications, anesthesia, infectious risks, cleaning and disinfection are detailed from a review of the literature. Intensive care practice of bronchoscopy requires more attention due to higher risks patients and is discussed extensively. Standards and performances of the various sampling techniques complete this work. Indications for bronchoscopy, therapeutic and paediatric bronchoscopy are not covered in these guidelines.

Mechanical ventilation strategies and inflammatory responses to cardiac surgery: a prospective randomized clinical trial

OBJECTIVE

To examine whether postoperative mechanical ventilation with lower tidal volumes (V(T)) has protective effects on inflammatory responses induced by cardiopulmonary bypass (CPB) surgery in smokers and nonsmokers.

DESIGN AND SETTING

Prospective, randomized, controlled clinical trial in the intensive care unit of a university hospital.

PATIENTS AND PARTICIPANTS

We examined 44 patients (22 smokers, 22 nonsmokers) immediately after uncomplicated CPB surgery.

INTERVENTIONS

Ventilation was applied for 6 h with either V(T) of either 6 or 12 ml/kg ideal body weight.

MEASUREMENTS AND RESULTS

The time course of serum tumor necrosis factor (TNF) alpha, interleukin (IL) 6, and IL-8 determined 0, 2, 4, and 6 h after randomization did not differ significantly between the ventilatory strategies. By contrast, in bronchoalveolar lavage fluids sampled after 6 h only TNF-alpha levels were significantly higher in the high V(T) group than the low V(T) group (50+/-111 pg/ml vs. 1+/-7 pg/ml). IL-6 and IL-8 concentrations did not differ between groups. Subgroup analysis of patients with serum TNF-alpha level higher than 0 pg/ml after surgery revealed lower TNF-alpha serum levels during lower V(T) ventilation. All observed effects were small, independent of patients' history of smoking, and were not correlated with duration of ventilation and ICU stay.

CONCLUSIONS

Ventilation with lower V(T) had no or only minor effect on systemic and pulmonary inflammatory responses in patients with healthy lungs after uncomplicated CPB surgery. Our data do not suggest a clinical benefit of using low V(T) ventilation in these selected patients.

Contributions of high mobility group box protein in experimental and clinical acute lung injury

This study was performed to examine the putative role of high mobility group box (HMGB) protein in the pathogenesis of acute lung injury (ALI). Observations were made (1) in 21 patients who were septic with ALI and 15 patients with normal lung function and (2) in a mouse model 24 hours after intratracheal instillation of lipopolysaccharide (LPS). The concentrations of HMGB1 were increased in plasma and lung epithelial lining fluid of patients with ALI and mice instilled with LPS. LPS-induced ALI was mitigated by anti-HMGB1 antibody. Although this protein was not detected in the plasma of control humans or mice, the concentrations of HMGB1 in lung epithelial lining fluid or in bronchoalveolar lavage fluid were unexpectedly high. The nuclear expression of HMGB1 was apparent in epithelial cells surrounding terminal bronchioles in normal mice, whereas its nuclear and cytoplasmic expression was observed in alveolar macrophages in LPS-instilled mice. Lung instillation of HMGB2 did not cause as much inflammation as HMGB1. Extracellular HMGB1 may play a key role in the pathogenesis of clinical and experimental ALI. However, its expression in normal airways is noteworthy and suggests that it also plays a physiologic role in the lung.

Elevation of KL-6, a lung epithelial cell marker, in plasma and epithelial lining fluid in acute respiratory distress syndrome

KL-6 is a pulmonary epithelial mucin more prominently expressed on the surface membrane of alveolar type II cells when these cells are proliferating, stimulated, and/or injured. We hypothesized that high levels of KL-6 in epithelial lining fluid and plasma would reflect the severity of lung injury in patients with acute lung injury (ALI). Epithelial lining fluid was obtained at onset (day 0) and day 1 of acute respiratory distress syndrome (ARDS)/ALI by bronchoscopic microsampling procedure in 35 patients. On day 0, KL-6 and albumin concentrations in epithelial lining fluid were significantly higher than in normal controls (P < 0.001), and the concentrations of KL-6 in epithelial lining fluid (P < 0.002) and in plasma (P < 0.0001) were higher in nonsurvivors than in survivors of ALI/ARDS. These observations were corroborated by the immunohistochemical localization of KL-6 protein expression in the lungs of nonsurvivors with ALI and KL-6 secretion from cultured human alveolar type II cells stimulated by proinflammatory cytokines. Because injury to distal lung epithelial cells, including alveolar type II cells, is important in the pathogenesis of ALI, the elevation of KL-6 concentrations in plasma and epithelial lining fluid could be valuable indicators for poor prognosis in clinical ALI.

A rational approach to the evaluation and treatment of the infected patient in the intensive care unit

Critically ill patients are at increased risk of acquiring nosocomial infections. A thorough clinical evaluation and the selection of appropriate diagnostic techniques are important elements in the evaluation of these patients. Nonetheless, this selection process can be difficult because of the wide spectrum of disease that is seen in the ICU and the lack of standardized studies that have evaluated the different diagnostic methods that are available. Many different antimicrobials are available for the treatment of ICU-acquired infections. Most antimicrobial regimens have not been evaluated in large-scale, prospective, randomized trials. Until this information is available, the clinician must make an effort to be familiar with the different clinical and epidemiologic variables that can be used to stratify patients at the moment of selecting antimicrobial therapy. The information provided in this article, used in association with good clinical judgment, will help the critical care physician provide optimal initial management of the infected patient in the ICU.

Deactivation of alveolar macrophages in septic neutropenic ARDS

STUDY OBJECTIVES

Neutrophils often have been involved in the pathophysiology of ARDS. However, authentic ARDS has been described in patients with severe neutropenia, suggesting the presence of other potential mechanisms that are responsible of this syndrome. Alveolar macrophages (AMs) could be involved in the development of ARDS, and so we decided to study AM activation in neutropenic patients.

PATIENTS

We designed a prospective study and enrolled two subgroups of consecutive patients (group A, 18 patients; group B, 22 patients) with septic ARDS. In the first period, 7 of 18 patients were neutropenic, and in the second period 10 of 22 patients were neutropenic. All neutropenic patients were treated with granulocyte colony-stimulating factor (G-CSF).

MEASUREMENTS AND RESULTS

In group A, BAL fluid samples were analyzed for differential and total cell counts, and alveolar activation marker expression (ie, human leukocyte antigen [HLA]-DR locus) was determined. Basal and lipopolysaccharide (LPS)-stimulated production of tumor necrosis factor, interleukin (IL)-1 beta, IL-6, and IL-10 was evaluated in group B. In neutropenic patients, the BAL fluid total cell count and the neutrophil absolute count was significantly lower compared to those in nonneutropenic patients (p = 0.029 and p = 0.046, respectively). HLA-DR expression on AMs was significantly decreased (p = 0.016), and the percentage of AMs expressing HLA-DR was also significantly lower (p = 0.041). In neutropenic patients, the mean percentage of AMs expressing HLA-DR was significantly lower in deceased patients compared to survivors (30 +/- 7 vs 43 +/- 1, respectively; p = 0.047). Basal AMs released cytokines was comparable between the two groups; however, LPS stimulation yielded a deactivation of AMs in neutropenic patients.

CONCLUSION

These results suggest a deactivation and/or hypoactivation of AMs in septic ARDS patients. This deactivation/hypoactivation could be linked to the use of G-CSF as this molecule has been shown to generate a down-regulation of HLA-DR expression.

The pulmonary physician in critical care. Illustrative case 2: interstitial lung disease

The case history of a patient admitted to the ICU with interstitial lung disease deteriorating to respiratory failure is presented. Problems in distinguishing between infection and disease progression are discussed and the role of transplantation in ventilated patients is examined.

Enteral nutrition with eicosapentaenoic acid, gamma-linolenic acid, and antioxidants reduces alveolar inflammatory mediators and protein influx in patients with acute respiratory distress syndrome

OBJECTIVE

Previously, we showed that acute respiratory distress syndrome patients fed an enteral diet containing eicosapentaenoic acid and gamma-linolenic acid and elevated antioxidants (EPA+GLA; Oxepa) had significantly reduced pulmonary inflammation, increased oxygenation, and improved clinical outcomes. In a subset of acute respiratory distress syndrome patients from this trial, we performed a preliminary examination of the potential mechanisms underlying these clinical improvements by retrospectively testing the hypothesis that enteral feeding with EPA+GLA could reduce alveolar-capillary membrane protein permeability and the production of interleukin (IL)-8, IL-6, tumor necrosis factor-alpha, and leukotriene B4 that are responsible, in part, for pulmonary inflammation.

DESIGN

Prospective, randomized, double-blind, controlled clinical trial.

SETTING

Intensive Care Unit of the Ohio State University Medical Center.

PATIENTS

A total of 67 patients were enrolled who met defined criteria for acute lung injury/acute respiratory distress syndrome.

INTERVENTIONS

A total of 43 of 67 evaluable patients randomly received either EPA+GLA or an isonitrogenous, isocaloric standard diet that was tube fed at a minimum caloric delivery of 75% of basal energy expenditure times 1.33 for at least 4 to 7 days.

MEASUREMENTS AND MAIN RESULTS

Bronchoalveolar lavage (BAL) was performed at baseline and study days 4 and 7 to obtain BAL fluid (BALF) for measurement of total protein, ceruloplasmin, and transferrin, total neutrophil count, IL-8, IL-6, tumor necrosis factor-alpha, and leukotriene B4. Oxygenation, measured as Pao2/Fio2, was assessed before BAL. Patients fed EPA+GLA had a significant reduction in BALF ceruloplasmin and IL-8 during the study as compared with patients fed the control diet. BALF levels of total protein, neutrophils, and leukotriene B4 tended to decrease in EPA+GLA patients over the course of the study as compared with control patients. BALF levels of IL-6 declined similarly during the study in both groups. A trend toward a reduction in BALF tumor necrosis factor-alpha was observed on study day 7 in the EPA+GLA group as compared with control patients. Significant improvements in oxygenation (Pao2/Fio2) occurred in EPA+GLA patients on study day 4 as compared with controls. Correlation analysis revealed significant relationships between BALF neutrophil counts and indices of alveolar-capillary membrane protein permeability, IL-8, and leukotriene B4.

CONCLUSIONS

This preliminary investigation showing a decrease in BALF levels of IL-8 and leukotriene B4 and the associated reduction of BALF neutrophils and alveolar membrane protein permeability in acute respiratory distress syndrome patients fed EPA+GLA support, in part, the potential mechanisms underlying the previously described clinical improvements with this diet. Additional controlled studies are needed to confirm these findings.

Imbalance between matrix metalloproteinases (MMP-9 and MMP-2) and tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in acute respiratory distress syndrome patients

OBJECTIVE

Matrix metalloproteinases (MMPs) are known to be involved in degradation of extracellular matrix. We aimed to assess the role of MMPs and their natural inhibitors (TIMPs) in the genesis and the evolution of acute respiratory distress syndrome (ARDS).

DESIGN

Prospective, clinical study.

SETTING

Intensive care unit of a university hospital.

PATIENTS

Twenty-one patients were assigned to three different groups: Group 1 patients developed ARDS that rapidly resolved in <4 days; Group 2 patients developed ARDS lasting >8 days; Group 3 (control group) patients had clinical criteria for hospital-acquired pneumonia without ARDS.

INTERVENTION

Bronchoalveolar lavages were performed on day 0 of the onset of ARDS and on days 4, 8, and 12 for unresolving ARDS. For group 3, the bronchoalveolar lavages were performed on day 0 of the pneumonia. On these bronchoalveolar lavage fluids, we measured the amount of MMP-9 and -2 and their inhibitors TIMP-1 and -2.

MEASUREMENTS AND MAIN RESULTS

The amount of MMP-9 measured by enzyme-linked immunosorbent assay was significantly lower in the bronchoalveolar lavages from patients with ARDS (group 1 and group 2) compared with the control group (p <.01) throughout the study. The ratio MMP-9/TIMP-1 was also significantly smaller and was less than one in the two ARDS groups (p <.05) compared with the control group (group 3), where this ratio was greater than one. In the second bronchoalveolar lavages, this ratio was greater than one only in the ARDS group that rapidly resolved (group 1), whereas it stayed less than one when the ARDS was lasting (group 2). Concerning the quantity of MMP-2 and the ratio MMP-2/TIMP-2, there was no statistical difference between the three groups throughout the study. Using zymography, there was no significant difference in the amounts of active and latent MMP-9 between the three groups. Moreover, no significant difference in the quantity of latent and active MMP-2 in the three groups was noted.

CONCLUSION

These results suggest that the MMP-9 level and MMP-9/TIMP-1 ratio play a role in the pathogenesis of ARDS and, namely, the imbalance between MMP-9 and TIMP-1 would participate in airway remodeling leading to either short- or long-course ARDS. The ratio MMP-9/TIMP-1 could be a predictive factor of the ARDS evolution.

Mitogen-activated protein kinases in the intensive care unit: prognostic potential

OBJECTIVE

To evaluate the prognostic significance of the activational status of p38, specifically progression to multiple organ dysfunction syndrome (MODS), in a group of severely injured trauma patients.

SUMMARY BACKGROUND DATA

To date, therapeutic manipulation of the host immunoinflammatory response has not affected the outcome of patients with MODS. A major concern is the inability to identify the patient most at risk so as to enable early intervention.

METHODS

Nineteen trauma patients underwent bronchoalveolar lavage (BAL). Cells obtained were plated, stimulated with lipopolysaccharide (LPS), and then harvested at varying time points after stimulation. p38 was evaluated by Western blot.

RESULTS

Nineteen patients were categorized into two groups according to baseline and LPS-stimulated p38 activation in cells obtained by BAL. Group 1 demonstrated a 10-fold increase in p38 activation with LPS treatment over unstimulated controls. Group 2 had high baseline levels of p38 that were unresponsive to subsequent LPS stimulation. Both groups were similar with respect to age, gender, shock (systolic blood pressure < 90), Injury Severity Score, APACHE II, lactate levels, base deficit, blood transfusions, and the cell differential of BAL fluid. However, patients in group 2 had a greater incidence of progression to MODS as defined by the Marshall MOD score, a longer duration of mechanical ventilation, a longer stay in the intensive care unit, and a longer overall hospital stay than group 1.

CONCLUSIONS

These results demonstrate the prognostic significance of p38 activation in predicting outcome in critically ill trauma patients. Furthermore, these results demonstrate that trauma populations identical by current scoring systems contain a mixture of patients with markedly different outcomes as identified by p38 activation. Measurement of p38 may enable early identification of a subgroup of patients at increased risk for MODS to permit effective therapeutic intervention.

Randomized, prospective trial of antioxidant supplementation in critically ill surgical patients

OBJECTIVE

To determine the effectiveness of early, routine antioxidant supplementation using alpha-tocopherol and ascorbic acid in reducing the rate of pulmonary morbidity and organ dysfunction in critically ill surgical patients.

SUMMARY BACKGROUND DATA

Oxidative stress has been associated with the development of the acute respiratory distress syndrome (ARDS) and organ failure through direct tissue injury and activation of genes integral to the inflammatory response. In addition, depletion of endogenous antioxidants has been associated with an increased risk of nosocomial infections. The authors postulated that antioxidant supplementation in critically ill surgical patients may reduce the incidence of ARDS, pneumonia, and organ dysfunction.

METHODS

This randomized, prospective study was conducted to compare outcomes in patients receiving antioxidant supplementation (alpha-tocopherol and ascorbate) versus those receiving standard care. The primary endpoint for analysis was pulmonary morbidity (a composite measure of ARDS and nosocomial pneumonia). Secondary endpoints included the development of multiple organ failure, duration of mechanical ventilation, length of ICU stay, and mortality.

RESULTS

Five hundred ninety-five patients were enrolled and analyzed, 91% of whom were victims of trauma. The relative risk of pulmonary morbidity was 0.81 (95% confidence interval 0.60-1.1) in patients receiving antioxidant supplementation. Multiple organ failure was significantly less likely to occur in patients receiving antioxidants than in patients receiving standard care, with a relative risk of 0.43 (95% confidence interval 0.19-0.96). Patients randomized to antioxidant supplementation also had a shorter duration of mechanical ventilation and length of ICU stay.

CONCLUSIONS

The early administration of antioxidant supplementation using alpha-tocopherol and ascorbic acid reduces the incidence of organ failure and shortens ICU length of stay in this cohort of critically ill surgical patients.

Ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) continues to complicate the course of 8 to 28% of patients receiving mechanical ventilation (MV). In contrast to infections of more frequently involved organs (e.g., urinary tract and skin), for which mortality is low, ranging from 1 to 4%, the mortality rate for VAP ranges from 24 to 50% and can reach 76% in some specific settings or when lung infection is caused by high-risk pathogens. The predominant organisms responsible for infection are Staphylococcus aureus, Pseudomonas aeruginosa, and Enterobacteriaceae, but etiologic agents widely differ according to the population of patients in an intensive care unit, duration of hospital stay, and prior antimicrobial therapy. Because appropriate antimicrobial treatment of patients with VAP significantly improves outcome, more rapid identification of infected patients and accurate selection of antimicrobial agents represent important clinical goals. Our personal bias is that using bronchoscopic techniques to obtain protected brush and bronchoalveolar lavage specimens from the affected area in the lung permits physicians to devise a therapeutic strategy that is superior to one based only on clinical evaluation. When fiberoptic bronchoscopy is not available to physicians treating patients clinically suspected of having VAP, we recommend using either a simplified nonbronchoscopic diagnostic procedure or following a strategy in which decisions regarding antibiotic therapy are based on a clinical score constructed from seven variables. Selection of the initial antimicrobial therapy should be based on predominant flora responsible for VAP at each institution, clinical setting, information provided by direct examination of pulmonary secretions, and intrinsic antibacterial activities of antimicrobial agents and their pharmacokinetic characteristics. Further trials will be needed to clarify the optimal duration of treatment and the circumstances in which monotherapy can be safely used.

Flexible bronchoscopy in nosocomial pneumonia

In this article, an overview on the diagnostic performances of bronchoscopic techniques for the diagnosis of nosocomial pneumonia is given with special emphasis on the inherent problems of the methodology of validation applied to different studies. The current evidence about the importance of bronchoscopic techniques for the outcome is reviewed. It is outlined that future prospects of bronchoscopic investigations mainly include the evaluation of its role in the reassessment of the patient with pneumonia not responding to the initial antimicrobial treatment.

Role of bronchoscopy in modern medical intensive care unit

This article gives a broad overview of the increasingly important applications of bronchoscopy, flexible (FOB) and rigid (RB), in a modern medical intensive care unit. Special emphasis is made to bronchoscopy use in mechanically ventilated patients. Therapies such as endobronchial stenting and Nd:YAG laser are being used to improve respiratory failure and facilitate weaning from mechanical ventilation. Practical applications of recent advancements in technology (endobronchial stenting, laser therapy, and so forth), the increasing use of rigid bronchoscopy, and the new generation of flexible bronchoscopes like battery bronchoscopes, and ultra-thin bronchoscopes, are also discussed. The risks, potential benefits, complications, and suggested technique of performing bronchoscopy in mechanically ventilated patients are reviewed.

New bronchoscopic microsample probe to measure the biochemical constituents in epithelial lining fluid of patients with acute respiratory distress syndrome

OBJECTIVE

A noninvasive bronchoscopic microsampling (BMS) probe was developed to sample biochemical constituents of the epithelial lining fluid in small airways.

DESIGN

Observational, controlled study.

SETTING

Intensive care unit of academic medical center. PATIENTS AND PROCEDURE: BMS was applied in a control group of seven patients who had hemoptysis or small solitary peripheral nodules but no hypoxemia or other signs of acute inflammation and in four patients with acute respiratory distress syndrome (ARDS), to test whether BMS can ascertain the presence of acute pulmonary inflammation without complications.

MEASUREMENTS AND RESULTS

Complications, including a significant decrease in arterial oxygen saturation, were observed neither during nor after BMS. In the ARDS group, albumin, lactate dehydrogenase, interleukin-6, basic fibroblast growth factor, and neutrophil elastase concentrations in epithelial lining fluid were significantly higher (p <.0001, p =.012, p <.0001, p <.0001, and p <.0001, respectively) than in the control group. Serial BMS was safely performed in one patient with ARDS, allowing us to observe a correlation between changes in the concentration of inflammation-related biochemical markers and clinical course of the disease.

CONCLUSIONS

These results suggest that BMS is safe and useful to monitor pulmonary biochemical events in ARDS.

Systemic inflammatory response after bronchoalveolar lavage in critically ill patients

Bronchoscopic bronchoalveolar lavage (BAL) may be followed by a systemic inflammatory response. Previous reports have suggested pneumonia as a predisposing condition and systemic cytokines as possible mediators. To test this hypothesis, systemic levels of interleukin (IL)-1beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) were studied before and at 12 h and 24 h after bronchoscopically guided BAL in 30 mechanically ventilated patients (median age 67 (range 54-76) yrs, simplified acute physiology score II (SAPS II) 33 (12-56)), 20 of whom had pneumonia and 10 of whom were control patients without pneumonia. Arterial oxygen partial pressure to inspired oxygen fraction ratio (Pa,O2/FI,O2), body temperature, mean arterial pressure, and cardiac frequency were recorded. The majority of patients (28/30, 93%) received antibiotic treatment prior to the procedure. Pa,O2/FI,O2 ratio was lower at 12 h compared to baseline in patients with pneumonia (baseline median 192 (range 65-256); 12 h 160 (66-190) mmHg, p<0.001) and ventilated controls (baseline 293 (205-473); 12 h 226 (153-330) mm Hg p=0.011), but returned to baseline levels at 24 h (pneumonia: 194 (92-312), p=0.991; controls: 309 (173-487) mmHg, p=0.785). No changes in other clinical variables were observed. Systemic TNF-alpha levels before BAL (pneumonia: 35 (10-88); controls: 17 (0-33) pg x mL(-1)) did not increase at 12 h (pneumonia: 35 (0-64); p=0.735; controls: 16 (0-21) pg x mL(-1), p=0.123 comparison to baseline) or 24 h (pneumonia: 31 (0-36), p=0.464; controls: 19 (0-43) pg x mL(-1), p=0.358). No changes of IL-1beta (baseline: pneumonia 0 (0-13); controls 1 (0-32) pg x mL(-1)) or IL-6 (baseline: pneumonia, 226 (9-4300); controls, 53 (0-346) pg x mL(-1)) were detected. No deterioration of clinical variables and no increase in systemic cytokine release has been observed after bronchoalveolar lavage, in critically ill patients. The potential cytokine increase is probably too small, in relation to the pre-existing inflammatory response, to yield clinical significance in this population otherwise antibiotic therapy may have been protective.