The role of bronchoalveolar lavage in diagnosing nonopportunistic bacterial pneumonia

The Role of Lung Colonization in Connective Tissue Disease-Associated Interstitial Lung Disease

Connective tissue diseases (CTDs) may frequently manifest with interstitial lung disease (ILD), which may severely impair quality and expectation of life. CTD-ILD generally has a chronic clinical course, with possible acute exacerbations. Although several lines of evidence indicate a relevant role of infections in the acute exacerbations of CTD-ILD, little information is available regarding the prevalence of infections in chronic CTD-ILD and their possible role in the clinical course. The aim of the present retrospective study was the identification of lung microbial colonization in broncho-alveolar lavage from patients affected by stable CTD-ILD with radiologically defined lung involvement. We demonstrated that 22.7% of patients with CTD-ILD display microbial colonization by Pseudomonas aeruginosa, Haemophilus influenzae, and non-tuberculous mycobacteria. Moreover, these patients display a major radiologic lung involvement, with higher impairment in lung function tests confirmed in a multivariate logistic regression analysis. Overall, the present study provides new information on lung colonization during CTD-ILD and its possible relationship with lung disease progression and severity.

Safety of research bronchoscopy with BAL in stable adult patients with cystic fibrosis

Data on adverse events from research bronchoscopy with bronchoalveolar lavage (BAL) in patients with cystic fibrosis (CF) is lacking. As research bronchoscopy with BAL is useful for isolation of immune cells and investigation of CF lung microbiome, we sought to investigate the safety of bronchoscopy in adult patients with CF. Between November 2016 and September 2019, we performed research bronchoscopies on CF subjects (32) and control subjects (82). Control subjects were nonsmokers without respiratory disease. CF subjects had mild or moderate obstructive lung disease (FEV1 > 50% predicted) and no evidence of recent CF pulmonary exacerbation. There was no significant difference in the age or sex of each cohort. Neither group experienced life threatening adverse events. The number of adverse events was similar between CF and control subjects. The most common adverse events were sore throat and cough, which occurred at similar frequencies in control and CF subjects. Fever and headache occurred more frequently in CF subjects. However, the majority of fevers were seen in CF subjects with FEV1 values below 65% predicted. We found that CF subjects had similar adverse event profiles following research bronchoscopy compared to healthy subjects. While CF subjects had a higher rate of fevers, this adverse event occurred with greater frequency in CF subjects with lower FEV1. Our data demonstrate that research bronchoscopy with BAL is safe in CF subjects and that safety profile is improved if bronchoscopies are limited to subjects with an FEV1 > 65% predicted.

Management of community-acquired pneumonia in immunocompetent adults: updated Swedish guidelines 2017

Based on expert group work, Swedish recommendations for the management of community-acquired pneumonia in adults are here updated. The management of sepsis-induced hypotension is addressed in detail, including monitoring and parenteral therapy. The importance of respiratory support in cases of acute respiratory failure is emphasized. Treatment with high-flow oxygen and non-invasive ventilation is recommended. The use of statins or steroids in general therapy is not found to be fully supported by evidence. In the management of pleural infection, new data show favourable effects of tissue plasminogen activator and deoxyribonuclease installation. Detailed recommendations for the vaccination of risk groups are afforded.

Pneumonia in Trauma Patients

Purpose of Review

This article reviews the new definitions of pneumonia, discusses risk factors for pneumonia among trauma patients, presents the latest evidence for prevention strategies, discusses the best ways to make the diagnosis, and reviews the microbiology and treatment for trauma patients with pneumonia.

Recent Findings

Pneumonia can be prevented by decreasing the duration of mechanical ventilation using daily paired spontaneous awakening and breathing trials, but not with early tracheostomy placement. Other useful prevention strategies include semirecumbent positioning and oral care. Mini-BAL is a sensitive and specific means of securing the diagnosis of pneumonia that does not require a physician to be present and is therefore especially useful in busy trauma centers.

Summary

Pneumonia is a frequent complication among trauma patients. Risk factors are largely unmodifiable. However, trauma centers can institute routine daily paired spontaneous awakening and breathing trials to decrease the duration of ventilation and incidence of pneumonia. Future research is needed to further characterize the microbiology of pneumonia among trauma patients.

Clinical, cytological and microbiological evaluation of bronchoalveolar lavage in children: A referral hospital-based study

INTRODUCTION

Diffuse lung diseases (DLD) in children involve a group of heterogeneous, rare disorders. In spite of the low diagnostic yield in pediatric DLD, bronchoalveolar lavage (BAL) can be used to diagnose specific disorders. There are few studies about microbial and cellular profiles of BAL samples in these patients. This study was conducted to evaluate the clinical, cytological and microbiological evaluation of BAL in children with DLD.

METHODS

The clinical, cytological and microbiological profiles of BAL samples of all patients with DLD who underwent the fiberoptic bronchoscopy (FOB) at Children's Medical Center, an Iranian referral pediatrics Hospital during a year were evaluated.

RESULTS

In 18 patients (18.4%) of the 98 cases studied, 22 pathogens were obtained as etiologic agents. The mean total cells count of BAL was 23.9 × 104 ± 12.9 × 104/ml. The mean percentages of cellular components were macrophages (70.2%), neutrophils (16.3%), lymphocytes (11.8%) and eosinophils (1.4%), respectively. The type of lung disease was significantly associated with the mean percentage of lymphocytes (p = 0.005) and the percentage of neutrophils (p = 0.042).

CONCLUSION

FOB and BAL evaluation in combination with clinical and radiographic imaging data may be helpful for identifying of presumptive diagnosis of DLD in children.

Role of bronchoalveolar lavage in the diagnosis of pulmonary infiltrates in immunocompromised patients

PURPOSE OF REVIEW

To describe the role of bronchoalveolar lavage (BAL) in the evaluation of pulmonary disease in immunocompromised patients.

RECENT FINDINGS

Recent discoveries in this field are largely in two areas: the array of diagnostic testing performed on BAL fluid and technical details that can enhance the yield from this procedure. Regarding diagnostic testing, the addition of new assays, including Aspergillus galactomannan antigen assay, respiratory viral panels, and Pneumocystis jirovecii PCR, has improved the diagnostic yield of BAL over conventional cultures and stains. To improve the diagnostic yield of the procedure itself, it should be done early in the clinical course, with the BAL in the anatomic area most affected, and with a preprocedural computed tomography of the chest to properly plan the procedure.

SUMMARY

Bronchoscopic evaluation with BAL can provide important diagnostic information in immunocompromised patients with pulmonary diseases and should be routinely performed when clinically indicated and able to be completed safely.

[Microbiology of bronchoalveolar lavage in infants with bacterial community-acquired pneumonia with poor outcome]

BACKGROUND

Community-acquired pneumonia (CAP) is one of the most common infectious causes of morbidity and mortality in children <5 years of age. The aim of the study was to clarify the bacterial etiologic diagnosis in infants with CAP.

METHODS

A prospective, cross-sectional and descriptive study in patients 6 months to 2 years 11 months of age with CAP with poor outcome was conducted. Patients were admitted to the Pediatric Pneumology Service and underwent bronchoscopy with bronchoalveolar lavage (BAL), taking appropriate measures during the procedure to limit the risk of contamination.

RESULTS

Aerobic bacteria isolated were Moraxella sp. 23%, Streptococcus mitis 23%, Streptococcus pneumoniae 18%, Haemophilus influenzae 12%, Streptococcus oralis 12%, and Streptococcus salivarius 12%.

CONCLUSIONS

In contrast to other reports, we found Moraxella sp. to be a major bacterial pathogen, possibly because of improved detection with bronchoscopy plus BAL.

Swedish guidelines on the management of community-acquired pneumonia in immunocompetent adults--Swedish Society of Infectious Diseases 2012

This document presents the 2012 evidence based guidelines of the Swedish Society of Infectious Diseases for the in- hospital management of adult immunocompetent patients with community-acquired pneumonia (CAP). The prognostic score 'CRB-65' is recommended for the initial assessment of all CAP patients, and should be regarded as an aid for decision-making concerning the level of care required, microbiological investigation, and antibiotic treatment. Due to the favourable antibiotic resistance situation in Sweden, an initial narrow-spectrum antibiotic treatment primarily directed at Streptococcus pneumoniae is recommended in most situations. The recommended treatment for patients with severe CAP (CRB-65 score 2) is penicillin G in most situations. In critically ill patients (CRB-65 score 3-4), combination therapy with cefotaxime/macrolide or penicillin G/fluoroquinolone is recommended. A thorough microbiological investigation should be undertaken in all patients, including blood cultures, respiratory tract sampling, and urine antigens, with the addition of extensive sampling for more uncommon respiratory pathogens in the case of severe disease. Recommended measures for the prevention of CAP include vaccination for influenza and pneumococci, as well as smoking cessation.

Microbiology of bronchoalveolar lavage fluid in children with acute nonresponding or recurrent community-acquired pneumonia: identification of nontypeable Haemophilus influenzae as a major pathogen

Background. Precise etiologic diagnosis in pediatric community-acquired pneumonia (CAP) remains challenging.

Methods. We conducted a retrospective study of CAP etiology in 2 groups of pediatric patients who underwent flexible bronchoscopy (FOB) with bronchoalveolar lavage (BAL); children with acute nonresponsive CAP (NR-CAP; n = 127) or recurrent CAP (Rec-CAP; n = 123). Procedural measures were taken to limit contamination risk and quantitative bacterial culture of BAL fluid (significance cutoff point, ≥10⁴ colony-forming units/mL) was used. Blood culture results, serological test results, nasopharyngeal secretion findings, and pleural fluid culture results were also assessed, where available.

Results. An infectious agent was detected in 76.0% of cases. In 51.2% of infections, aerobic bacteria were isolated, of which 75.0%, 28.9%, and 13.3% were Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae, respectively. Most (97.9%) of the H. influenzae strains were nontypeable (NTHi). H. influenzae was detected in 26.0% of NR-CAP cases and 51.2% of Rec-CAP cases, whereas Mycoplasma pneumoniae was the predominant pathogen in the NR-CAP group (accounting for 34.9% of cases) but not in the Rec-CAP group (19.3%). Viruses were found in 30.4% of cases, with respiratory syncytial virus, parainfluenzaviruses, and influenzaviruses detected most frequently. Mixed infections were found in 18.9% of NR-CAP cases and 30.1% of Rec-CAP cases.

Conclusions. A variety of microorganisms were isolated with frequent mixed infection. NTHi was one of the major pathogens found, especially in association with recurrent CAP, possibly because of improved detection with the FOB with BAL procedure. This suggests that the burden of pediatric CAP could be reduced by addressing NTHi as a major causative pathogen.

Efficacy of bilateral bronchoalveolar lavage for diagnosis of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is a common nosocomial infection causing significant morbidity and mortality. The goal of this study was to determine the efficacy of bilateral versus unilateral bronchoalveolar lavage (BAL) for the detection of the causative bacterial agents of VAP. We retrospectively studied the quantitative bacterial cultures of 399 BAL sample pairs collected from 287 mechanically ventilated patients over a 5-year period at a U.S. tertiary-care teaching hospital. Trauma was the underlying illness in 69% of patients. No evidence of bacterial infection was found in 226 BAL pairs (56.6%). Among 173 positive BAL sample pairs, significant bacterial counts were detected exclusively in 6.4% of left-lung and 12.1% of right-lung samples. In contrast, 81.5% of positive sample pairs had significant bacterial counts in both lungs. All bacteria recovered at significant concentrations from bilateral samples would have been detected in a unilateral right-lung sample in 89% of positive sample pairs. Unilateral sampling would have failed to recover one or more significant isolates in 11% of positive pairs had only the right lung been sampled and in 16.7% had only the left lung been sampled. Our study shows that preferential sampling of the right lung improves the diagnostic efficacy of unilateral BAL for the detection of the etiologic agents of VAP. If bilateral sampling is performed, our results also indicate that pooling left- and right-lung samples for a single quantitative culture is comparable to processing samples individually.

Diagnostic accuracy of bronchoalveolar lavage samples in immunosuppressed patients with suspected pneumonia: analysis of a protocol

BACKGROUND

Fast and accurate etiologic diagnosis of pneumonia in immunocompromised patients is essential for a good outcome. Utility of bronchoalveolar lavage (BAL) samples has already been established, but studies about them are scarce and limited to few countries. We aimed to evaluate the accuracy of a diagnostic protocol, emphasizing on local epidemiology, rapidity, and yield of different techniques.

METHODS

One year prospective study of 101 consecutive immunosuppressed patients admitted with suspected pneumonia to a university hospital. They all had bronchoscopic BAL (n=109) and respiratory sampling. Conventional microbiological studies, cytomegalovirus pp65 antigenemia and transbronchial biopsy (TBB), whenever considered pertinent, were done. Results were analyzed along with other diagnostic procedures, clinical course and final outcome.

RESULTS

HIV/AIDS infection was the most frequent cause of inclusion (n=80). Infections accounted for 79 out of 122 final diagnoses (64.8%). Our protocol identified 60 infectious and 3 noninfectious pathologies (general yield: 51.6%). Sensitivity in pulmonary infections was 75.9% (IC95%: 64.8-84.6%), specificity 86.0% (72.6-93.7%), positive predictive value 89.6% (79.1-95.3%), negative predictive value 69.4% (56.2-80.1%), accuracy 79.8% (71.7-86.2%). Mycobacterium spp. (n=27), bacteria (n=19), Pneumocystis jirovecii (n=18) and other fungi (histoplasmosis: 6, aspergillosis: 5, cryptococosis: 3) were the most common infectious pathogens. Direct microscopy allowed an early definite/presumptive diagnosis in 36/49 fungal and mycobacterial infections (73.5%). Up to 30% of mycobacterial infections were missed.

CONCLUSIONS

Systematical study of BAL samples has a high diagnostic yield in our immunocompromised patients with suspected pneumonia. As economical and epidemiological conditions of regions are different, it should be tried everywhere.

Swedish guidelines for the management of community-acquired pneumonia in immunocompetent adults

This document presents the evidence-based guidelines of the Swedish Society of Infectious Diseases for the management of adult immunocompetent patients with community-acquired pneumonia (CAP), who are assessed at hospital. The prognostic score 'CURB-65' is recommended for all CAP patients in the emergency room. The score provides an assessment tool for the decision regarding outpatient treatment or level of hospital supervision, the choice of microbiological investigations, and empirical antibiotic treatment. In patients with non-severe CAP (CURB-65 score 0-2) we recommend initial narrow-spectrum antibiotic treatment, orally or intravenously, primarily directed at Streptococcus pneumoniae. In those with CURB-65 score 3, penicillin G or a cephalosporin intravenously is recommended. For CURB-65 score 0-3 atypical pathogens should be covered only when they are suspected on clinical or epidemiological grounds. In patients with CURB-65 score 4-5 intravenous combination therapy with either cephalosporin/macrolide or penicillin G/fluoroquinolone is recommended. Efforts should be made to identify the CAP aetiology in order to support the ongoing antibiotic treatment or to suggest treatment alterations. Recommended measures for prevention of CAP include influenza -- and pneumococcal -- vaccination to risk groups and efforts for smoking cessation.

Does bronchoalveolar lavage enhance our ability to treat ventilator-associated pneumonia in a trauma-burn intensive care unit?

BACKGROUND

Recent literature supports the notion that bronchoalveolar lavage (BAL) in ventilated trauma patients may improve our ability to diagnose and treat ventilator-associated pneumonia (VAP). We hypothesized that BAL would decrease the number of cases of VAP diagnosed and impact our antibiotic use and ventilator days.

METHODS

Prospective data on all infectious complications were collected for patients admitted to the trauma-burn service for the year 2001. All VAPs between January 1, 2001, through June 30, 2001, were diagnosed without BAL (No BAL group) using clinical signs of fever, sputum production, leukocytosis, chest radiographs, and sputum culture. After July 1, 2001, VAP was diagnosed with the use of BAL.

RESULTS

There were 37 cases of VAP in the No BAL group (11%) and 29 cases of VAP (8%) in the BAL group. There were no statistical differences in Injury Severity Score, hospital length of stay, ventilator days, or mortality between the two groups. The time to initial treatment of VAP was shorter for the BAL group, but did not reach significance. The number of patients who had their VAP pathogens correctly treated with empiric antibiotics was also the same between the two groups. There was no difference in the rate of recurrent pneumonias. The antibiotic costs and respiratory therapy/ventilator costs were not statistically different between the groups for trauma patients, although antibiotic costs were higher for burn patients.

CONCLUSION

The routine use of BAL to diagnose VAP in our mixed trauma-burn population did not impact on clinical outcomes or antibiotic use. Our results do not justify the additional costs and potential risks of BAL for all patients. The means of VAP diagnosis may not be as important as choosing the appropriate antibiotics for common VAP organisms in any given intensive care unit.

Limited value of routine microbiological diagnostics in patients hospitalized for community-acquired pneumonia

Current guidelines recommend microbiological diagnostic procedures as a part of the management of patients hospitalized for community-acquired pneumonia (CAP), but the value of such efforts has been questioned. Patients hospitalized for CAP were studied retrospectively, focusing on the use of aetiological diagnostic methods and their clinical impact. Adult patients, without known human immunodeficiency virus infection, admitted to hospital for CAP during 12 months, were evaluated with regard to the importance of aetiological diagnosis for tailoring antibiotic therapy, antibiotic-associated diarrhoea, Clostridium difficile disease, length of hospital stay and mortality. Of the 605 studied patients, 482 (80%) were subjected to Mycoplasma pneumoniae and/or respiratory virus serology and/or cultures of blood and/or sputum. They had a better prognosis than patients not subjected to microbiological diagnostics (mortality within 3 months was 9% vs 24%, p = 0.001), apparently reflecting differences in general health (e.g. less dementia diagnosis) but not the outcome of diagnostics. A presumptive aetiology was obtained only in 132 of the 482 patients, Streptococcus pneumoniae and M. pneumoniae being the most common agents (in 49 and 36 patients, respectively). Establishing an aetiological diagnosis had no impact on the number of in-hospital changes of therapy, on the proportion of new regimens having a narrower antimicrobial spectrum than the initial one or on the outcome. Therapy was changed to a drug directed specifically against the identified pathogen in only 16 out of these 132 patients and again without any overall improvement in the outcome variables. In a setting with a low frequency of antibiotic-resistant respiratory tract pathogens current routine microbiological diagnostics were found to be of limited value for the clinical management of patients hospitalized for CAP. Improved diagnostics in CAP are urgently needed, as establishing an aetiological diagnosis carries a potential for optimizing the antibiotic therapy.

Diagnosis and management of pneumonia in the intensive care unit

Ventilator-associated pneumonia is a significant contributor to excess morbidity and mortality in the ICU. Alteration of physical defenses, bacterial flora, and immune response contribute to the susceptibility of the critically ill ventilated patient. Controversies regarding its definition continue to complicate the understanding of the extent of the disease and evaluation of the outcome of therapies. Traditional parameters, such as clinical suspicion with standard tracheal aspirates, are associated with overuse of antibiotics, a prime risk factor for development of resistant organisms and increased mortality. Global emergence of resistance is also a major concern. Whether invasive methods have any substantial clinical benefit either through improved patient outcomes or lower rates of resistance remains to be proved. In patients who fail to respond to therapy, a search for nonpulmonary infections and noninfectious causes of pulmonary infiltrates is essential. Finally, preventative measures offer additional areas of investigation that could favorably impact on the incidence of infection.

Intensified microbiological investigations in adult patients admitted to hospital with lower respiratory tract infections

The objective of this study was to investigate the diagnostic yield of a programme with intensified microbiological investigations in immunocompetent adult patients with lower respiratory tract infections (LRTI). Patients in the study group were included prospectively and consecutively from September 1st 1997 to May 31st 1998 and were compared with a control group from the preceding year. A total of 67 adult patients were included in the study group and they were compared with 122 adult patients in the control group. The study group underwent fibre-optic bronchoscopy (FOB) with bronchoalveolar lavage (BAL). Only 7% in the historic control group were discharged with an aetiological diagnosis of their infections; while the diagnostic yield in the study group increased to 51% of patients. In the study group the presence of new infiltrates on chest X-ray increased the detection of a microbiological aetiology from 37% with no infiltrates to 62% with infiltrates and recent antibiotic therapy reduced the detection of a microbiological cause of infection from 61% in 36 patients who had not received antibiotic therapy to 39% in 31 patients who had received recent antibiotic therapy prior to microbiological sampling. Patients in the study group with known aetiology had higher values of inflammatory markers than patients with unknown aetiology. For Streptococcus pneumoniae infection culture and urine antigen detection were complimentary depending on recent antibiotic therapy since seven of eight culture-positive patients had not received antibiotic therapy within 72 h prior to investigation, while all four patients positive for urine antigens from S. pneumoniae had received antibiotic therapy within 72 h of urine sampling. In conclusion intensified microbiologic investigations increase the diagnostic yield from 7% to 51% of patients in the study group with an aetiologic diagnosis. Routine FOB with BAL had no apparent effect on clinical outcome and seems only justified in selected patients with severe LRTI with infiltrates on chest X-ray and signs of severe inflammation where a high diagnostic yield is achieved.

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.

Protected specimen brush or bronchoalveolar lavage to diagnose bacterial nosocomial pneumonia in ventilated adults: a meta-analysis

OBJECTIVE

We conducted a meta-analysis by using summary receiver operating characteristic curves to compare the diagnostic value for bacterial nosocomial pneumonia of the following: a) quantitative culture (colony-forming units per milliliter or CFU/mL) of respiratory secretions collected with a bronchoscopic protected specimen brush (PSB); b) quantitative culture of a bronchoscopic bronchoalveolar lavage (BAL); and c) the percentage of infected cells (IC) in BAL.

DATA SOURCES

All studies published in the English or the French language, through January 1, 1995, on the evaluation of PSB or BAL for the diagnosis of pneumonia were considered for analysis. The relevant literature was identified through computer and reference searching and by experts in the field.

STUDY SELECTION

A study was included if at least two of three independent readers regarded its purpose as the evaluation of CFU-PSB, CFU-BAL, or IC-BAL for the diagnosis in human beings of bacterial nosocomial pneumonia in ventilated adults and if the study was prospective and published in a peer-reviewed journal.

DATA EXTRACTION

Three readers reviewed all published articles and decided whether to include each study; consensus was defined as agreement by at least two readers. The authors of each original article included in the meta-analysis were asked to complete a questionnaire in which they were asked to check and to correct the data extracted by one of the independent readers.

DATA SYNTHESIS

Summary receiver operating characteristic curves were used to compare the efficacy of three diagnostic tests. Eighteen studies on CFU-PSB (795 patients) were included, as well as 11 studies on CFU-BAL (435 patients) and 11 on IC-BAL (766 patients). The accuracy of these tests was not different. However, it seems that administration of previous antibiotics markedly decreased accuracy of CFU-PSB (p = .0002) but not the accuracy of CFU-BAL and that of IC-BAL.

CONCLUSION

Both PSB and BAL are reliable to diagnose bacterial nosocomial pneumonia. Because CFU-BAL and IC-BAL seemed more resistant to the effects of antibiotics, we recommend BAL rather than PSB if the patient is already receiving antibiotics.

Low specificity of the bacterial index for the diagnosis of bacterial pneumonia by bronchoalveolar lavage

The bacterial index (BI) as defined by the sum of log10 colony-forming units (cfu) of microorganisms per milliliter of bronchoalveolar lavage (BAL) fluid, i.e., a multiplication of the single cfu/ml, has been used to distinguish between polymicrobial pneumonia (BI> or =5) and colonization (BI<5). Since many false-positive results are to be expected using this parameter, the diagnostic value of the BI was studied prospectively by obtaining bacteriologic cultures of BAL fluid in 165 consecutive unselected patients. In 27 cases the diagnosis of bacterial pneumonia was established on clinical criteria. In 133 patients pneumonia could be excluded, and in five patients the diagnosis remained unclear. Using a cut-off of > or = 10(5) cfu/ml BAL fluid, sensitivity and specificity for the diagnosis of pneumonia were 33% (9/27) and 99% (132/133), respectively. Sensitivity was mainly influenced by prior treatment with antibiotics, being 70% (7/10) in untreated and 12% (2/17) in treated patients. Applying the BI methodology at a cut-off of > or =5, however, resulted in an unacceptably high rate of 16 additional false-positive results, thus lowering the specificity to 87% (116/133; P<0.0001) while increasing the sensitivity to only 41% (11/27; P = 0.77). In conclusion, given the high rate of false-positive results, the methodology of the BI is of doubtful value for the diagnosis of bacterial pneumonia by BAL in an unselected patient group. By applying the absolute number of cfu/ml BAL fluid, however, positive bacteriologic cultures of BAL fluid are highly specific for the diagnosis of pneumonia. Their sensitivity is limited by previous antibiotic therapy.

Fungal pneumonia: the predominant lung infection causing death in children undergoing bone marrow transplantation

The study included 6 children (aged 4-14 years) receiving a conditioning regimen for bone marrow transplantation (BMT) and 14 children (aged 2 14 years) with bone marrow transplants (13 allogeneic, 1 autologous). The children underwent flexible fibre-optic bronchoscopy (FFB) with bronchoalveolar lavage during 6 and 17 episodes of pneumonia, respectively. The aim was to compare the results of the two groups with respect to bronchoscopy findings, pneumonia-causing agents and outcome. During the conditioning regimen, the aetiological agents were recovered by bronchoscopy in 1/6 (17%) episodes and revealed by autopsy in another episode. In three episodes where the aetiology was uncertain, bacterial pneumonia was suspected in two, and Candida pneumonia in one. In episodes after transplantation the aetiological agents were recovered from bronchoscopy material in 14/17 (82%) patients. Autopsy confirmed the premortal diagnosis in the four children who died. In three episodes, bacterial pneumonia was clinically suspected. Based on clinical manifestations, FFB and autopsy findings, bacterial and fungal pneumonia were the most common diagnoses both during conditioning and after BMT. Fungal pneumonia was the most common cause of death in both groups.

The role of bronchoalveolar lavage in the diagnosis of bacterial pneumonia

Bronchoalveolar lavage (BAL) has become an invaluable diagnostic tool with important clinical implications in both opportunistic infections and the pulmonary pathology of immunologic disease. Until recently, the use of BAL was limited primarily to two areas: the study of interstitial lung diseases and the diagnosis of lung infections by opportunistic microorganisms in severely immunocompromised patients with lung infiltrates. Over the past decade, the use of BAL has been expanded to include the conventional diagnosis of bacterial pneumonia in non-immunocompromised patients. In the past, different clinical studies proposed using BAL to quantify cultures in the sample obtained as a means of increasing the tool's effectiveness. Recent developments have led to a number of newer applications of BAL, such as bronchoscopic BAL, non-bronchoscopic BAL and protected BAL. The most important use of BAL in the non-immunocompromised patient is the diagnosis of pneumonia in the mechanically ventilated patient.

Influence of three factors on the diagnostic effectiveness of transthoracic needle aspiration in pneumonia

Prior antibiotic therapy, size of the infiltrate, and the person who performed the technique were the three factors that we studied to assess their influence on the effectiveness of transthoracic needle aspiration (TNA). Ninety-one patients with a diagnosis of severe bacterial pneumonia, who underwent TNA, have been included in the study. The technique was carried out with an ultrathin needle gauge 25 and without fluoroscopic control. A univariate (UA) and a multivariate statistical analysis were made. The sensitivity of TNA was 34.1%. Fifty-seven of 91 (62.6%) had received antibiotic therapy prior to TNA; sensitivity was higher in nontreated patients than in treated patients (p = 0.0033; UA). There were 34 patients with an infiltrate that was smaller than a lobe (MINLOB); 39 cases affected a complete lobe (LOB) and 18 more than one lobe (MAJLOB). The TNA sensitivity was higher in LOB cases than in MINLOB cases (p = 0.0004; UA) while when comparing LOB cases and MAJLOB cases, sensitivity was higher in the former (p = NS; UA). In 28 of 91 cases (30.8%), the TNA was performed by A (a trained physician who regularly carries out the technique) and in 63 of 91 cases (69.2%) by B (other physicians, 10 in our study, who sporadically perform the technique). The TNA sensitivity was higher when the technique was performed by A, although this difference was not significant; if we add negative TNA with leukocytes present in Gram stains (which would indicate that aspiration was done in the correct area) to positive TNA, the difference between A and B was higher (p = 0.0248). The multivariate statistical analysis confirmed that there are two variables that are independently connected to a positive TNA (prior antibiotic therapy and size of the infiltrate). As regards the variable "person who carries out the technique," a significant association with a positive TNA was not established, although the estimations we obtained show a possible clinical relevance.

New approaches in the diagnosis of nosocomial pneumonia

We have presented a review of the present literature on new modalities to diagnose nosocomial pneumonia. Procedures are now available that, when correctly used, can establish a diagnosis of pneumonia with a high degree of reliability. In our institution, reliance on bronchoscopic modalities has simplified management of patients with suspected VAP, by eliminating confusion and rationalizing antibiotic treatment. Invasive procedures, however, should be performed only if the results of cultures are consistently applied to treatment. As this field rapidly evolves, we hope that this review will provide the reader with a foundation to understand new developments.

Causes of fever and pulmonary densities in patients with clinical manifestations of ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia, a leading cause of sepsis in patients with acute respiratory failure, is difficult to distinguish clinically from other processes affecting patients receiving mechanical ventilation. We conducted a prospective study of patients with suspected ventilator-associated pneumonia to identify the causes of fever and densities on chest radiographs and to evaluate the diagnostic yield and efficiency of tests used alone and in combination.

METHODS

The 50 patients entered into the study underwent a systematic diagnostic protocol designed to identify all potential causes of fever and pulmonary densities. Diagnoses responsible for fever were established by strict diagnostic criteria for 45 of the 50 patients. The prevalence of specific conditions and diagnostic yield of individual tests were used to formulate a simplified diagnostic protocol.

RESULTS

The diagnostic protocol identified 78 causes of fever (median 2 per patient). Infections were the leading causes of fever and pulmonary densities. Of the 45 patients with fever, 37 had one or more infections identified (67 sources). Most infections (84 percent) were one of four types:pneumonia, sinusitis, catheter-related infection, or urinary tract infection. Ventilator-associated pneumonia occurred in only 42 percent. All but nine infections (87 percent) were directly or indirectly related to insertion of a catheter or a tube. Concomitant infections were frequent (62 percent), particularly in patients with sinusitis (100 percent), catheter-related infections (93 percent), and pneumonia (74 percent). Of concomitant infections, 60 percent were caused by a different pathogen. Noninfectious causes of fever were more common in the 22 patients with adult respiratory distress syndrome. Histologically proved pulmonary fibroproliferation was the only cause of fever in 25 percent of patients with adult respiratory distress syndrome. Radiographic densities were caused by an infection in only 20 patients (19 pneumonia, 1 empyema). In more than 50 percent of the 25 patients without adult respiratory distress syndrome, congestive heart failure, and atelectasis were the sole causes of pulmonary densities, and fever always originated from an extrapulmonary site of infection. Used in combination, bronchoscopy with protected sampling, computed tomographic scan of the sinuses, and cultures of maxillary sinus aspirate, central intravenous or arterial lines, urine, and blood identified 58 of the 78 sources of fever (74 percent).

CONCLUSIONS

The observations in this study document the complex nature of acute respiratory failure and fever and underscore the need for accuracy in diagnosis. The frequent occurrence of multiple infectious and noninfectious processes justifies a systematic search for source of fever, using a comprehensive diagnostic protocol. A simplified diagnostic protocol was devised based on the diagnostic value of individual tests.

A simple method of bronchoalveolar lavage

Twenty-eight ventilated paediatric intensive care patients, mean age 4.1 +/- 4 years, who had had a simple method of nonbronchoscopic bronchoalveolar lavage (NB-BAL) performed were reviewed. The NB-BAL technique involved blindly wedging a 5 or 8F infant feeding catheter endobronchially and lavaging one millilitre per kg saline using a syringe. Adequate samples were collected in 87% of the NB-BAL specimens. In two of the four inadequate specimens, Pneumocystis carinii was still able to be identified. Additional information not obtained from the tracheal aspirate culture was seen in 71% of the NB-BAL samples. One-third of the patients also had a bronchoscopic BAL or a lung biopsy performed and the culture results were all identical to those obtained from NB-BAL. No significant complications were seen. Oxygenation and ventilation were not altered by the technique. We conclude that NB-BAL performed using a syringe and infant feeding catheter is a simple and cheap method that produces good alveolar samples in the majority of cases.

Diagnostic value of bronchoalveolar lavage in patients with opportunistic and nonopportunistic bacterial pneumonia

In 29 patients with community-acquired pneumonia, 24 patients with hospital-acquired pneumonia and 35 patients with pneumonia in the immunocompromised host the diagnostic value of bronchoalveolar lavage (BAL) with quantitative bacterial and fungal cultures was studied; 32 patients with noninfectious pulmonary diseases and 14 healthy volunteers served as controls. An infectious etiology could be established in 81% of the pneumonia patients without differences between the three groups; significant infection was associated with colony counts of > or = 10(4) cfu/ml. Prior antibiotic therapy lowered the yield of BAL culture only in community-acquired pneumonia (94% vs 55% positive cultures in untreated vs pretreated patients, p < 0.02). Furthermore the culture results were related to the radiographic extension of pulmonary infiltrates (92% positive cultures in multilobar vs 54% in lobar or segmental infiltrates, p < 0.001). Therapeutic consequences of BAL were shown by resistance of the isolated organisms to predefined empiric treatment regimens in 41% community-acquired pneumonia, 43% pneumonia in the immunocompromised host and 67% hospital-acquired pneumonia patients.

Flexible bronchoscopy as a diagnostic tool in the evaluation of pulmonary tuberculosis in an elderly population

OBJECTIVE

This study intends to determine what role fiberoptic bronchoscopy (FOB) plays in the diagnosis of tuberculosis (TB), particularly in a geriatric population.

DESIGN

Cases of tuberculosis reported to the Tennessee Department of Health during the years 1989 and 1990 were divided into two age groups: Group A (< 65 years) and Group B (> or = 65 years). Natural sputum smears and cultures positive for M. tuberculosis (M. TB) in each group were compared with FOB specimens, acid-fast bacilli (AFB) smears and cultures. Data were analyzed by chi-square tests of independence for each year, then compared to determine statistical significance.

SETTING AND PATIENTS

Of the 601 TB cases reported to the State of Tennessee in 1989, 285 patients were in Group A and 316 in Group B. For 1990, 525 cases were reported, 269 in Group A and 256 in Group B. All cases met CDC-approved criteria for diagnosis of tuberculosis.

MEASUREMENTS

The number of positive AFB smears and M. TB cultures were compared in each group. In cases with sputum negative but FOB specimens positive for TB, identification was made by FOB only.

MAIN RESULTS

In Group A, 26 (9.1%) were diagnosed by FOB; only eight of these had positive sputum cultures. In Group B, 77 (24.4%) were diagnosed by FOB. Of these, 23 had positive sputum cultures; the remaining 54 patients (17.1%) had diagnoses based on FOB alone. In 1990, 269 cases of TB were reported in Group A. Of these, 38 (14.1%) were diagnosed by FOB. There were 256 TB cases reported among Group B, 83 (32.4%) of which were diagnosed by FOB. Of these 83 cases, 60 (23.4%) were diagnosed by FOB only. While no statistically significant difference was seen between the 1989 and 1990 rates of TB diagnosis by FOB for those in Group A (age < 65), the difference in rates for those in Group B (age > or = 65) was statistically significant (P < 0.05).

CONCLUSIONS

A steady increase in the use of FOB as a diagnostic tool was noted, suggesting that a significant number (19.9%) of geriatric TB cases might have been missed without the aid of FOB. While the exact reason for its increased utilization is not known, this study indicates that FOB has become a more important source of diagnosis in pulmonary TB, particularly among the elderly.

Fibreoptic bronchoscopy in the critically ill: a prospective study of its diagnostic and therapeutic value

AIM

A prospective study was undertaken to assess the diagnostic value and therapeutic usefulness of fibreoptic bronchoscopy in the critically ill.

METHOD

Fifty-six bronchoscopies were performed in fifty patients. Biochemical, radiological, microbiological and clinical assessments were made before and after each procedure.

RESULTS

Eighteen fibreoptic bronchoscopies were performed for therapeutic indications (32.1%) of which ten (55.6%) yielded a useful outcome. Thirty-eight bronchoscopies were for diagnostic purposes (67.8%) of which 22 (57.9%) were clinically useful. Broncho-alveolar lavage was performed in twenty-eight cases (50%) and it led to a clinically useful diagnosis in 17 (60.7%). There was no major complication. A subgroup of patients was defined (persistent left lower lobe collapse or consolidation following thoracic or abdominal surgery) in whom fibreoptic bronchoscopy usually did not yield a useful outcome.

CONCLUSION

The use of fibreoptic bronchoscopy in the Intensive Care Unit, in combination with the technique of broncho-alveolar lavage, results in a clinically useful outcome in the majority of cases. Fibreoptic bronchoscopy is an effective and safe diagnostic and therapeutic tool in critically ill patients.