Protected Specimen Brush Research Articles

Etiology and Outcome of Community-Acquired Lung Abscess

Background: Anaerobes are the first and Streptococcus species the second most common cause of community-acquired lung abscess (CALA) in the West. The etiologic pathogens of this disease have changed in Taiwan, with Klebsiella pneumoniae being reported as the most common cause of CALA. Objective: To determine the etiologies of community-acquired lung abscess. Methods: We retrospectively reviewed the records of 205 Japanese adult patients with CALA to evaluate etiologies and outcomes. We used not only traditional microbiological investigations but also percutaneous ultrasonography-guided transthoracic needle aspiration and protected specimen brushes. Results: Of these 205 patients, 122 had documented bacteriological results, with 189 bacterial species isolated. Pure aerobic, mixed aerobic and anaerobic, and pure anaerobic bacteria were isolated in 90 (73.8%), 17 (13.9%), and 15 (12.3%) patients, respectively. The four most common etiologic pathogens were Streptococcus species (59.8%), anaerobes (26.2%), Gemella species (9.8%), and K. pneumoniae (8.2%). Streptococcus mitis was the most common among the Streptococcus species. Mean duration of antibiotic administration was 26 days. Six patients (2.9%, 3 with actinomycosis and 3 with nocardiosis) were treated with antibiotics for 76–189 days. Two patients with anaerobic lung abscess died. Conclusions: The first and second most common etiologic pathogens of CALA in our hospital were Streptococcus species and anaerobes, respectively. The etiologies in our study differ from those in Taiwan and are similar to those in the West with the exception that Streptococcus species were the most common etiologic pathogens in our study whereas anaerobes are the most frequent etiologic pathogens in Western countries. S. mitis and Gemella species are important etiologic pathogens as well. The identification of Actinomyces and Nocardia is important in order to define the adequate duration of antibiotic administration.

Controversies in Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is the most frequent intensive care unit (ICU)-acquired infection among patients receiving mechanical ventilation. Consensus, however, on the most appropriate diagnostic strategy for patients clinically suspected of having developed VAP has yet to be reached. Concern about the inaccuracy of clinical approaches to VAP recognition and potential for excessive use of antibiotics in the ICU had led numerous investigators to postulate that quantitative cultures of specimens obtained with bronchoscopic or nonbronchoscopic techniques, such as bronchoalveolar lavage (BAL) and/or protected specimen brush (PSB), could improve identification of patients with true VAP and facilitate decisions whether to treat. Other than decision-analysis studies and one retrospective study, only five trials assessed the impact of such a quantitative bacteriological strategy on antibiotic use and outcome of patients suspected of VAP using a randomized scheme. In one study, the invasive management strategy was significantly associated with earlier attenuation of organ dysfunction and less antibiotic exposure, but the four other trials could not replicate these positive findings, including a large Canadian study that enrolled 740 patients. Because antibiotics were continued in most patients with negative BAL cultures in contradiction with the bacteriological algorithm, additional studies will be needed before concluding that a strategy based on the systematic collection of distal pulmonary secretions before introduction of new antibiotics and quantitative culture techniques is useless and cannot prevent the overuse of antimicrobial agents in the ICU.

Diagnosis of hospital‐acquired pneumonia and methods of testing for pathogens

Hospital-acquired pneumonia is diagnosed in patients who, in addition to abnormal shadowing on chest radiography, have >or=2 of the following: fever, abnormal white blood cell count and purulent discharge. Treatment effect is judged from clinical symptoms and microorganism test results 2-3 days after the start of treatment, and reassessment is made with regard to change, addition or discontinuation of antimicrobial agents. Coordination with the microbiology laboratory is extremely important in diagnosing infectious diseases. Microorganisms isolated from tracheal aspirate at 10(6) cfu/mL (3+), from BAL at 10(4)-10(5) cfu/mL (2+) and from a protected specimen brush at 10(3) cfu/mL (1+) have a high possibility of being the causative microorganisms. Pneumonia can almost be ruled out when no significant microbes are detected from the lower respiratory tract in patients with suspected ventilator-assisted pneumonia (when no change has been made to antimicrobial administration within 72 h). When MRSA or Pseudomonas aeruginosa are not detected in sputum tests, involvement of these drug-resistant bacteria may be considered unlikely, and the case treated accordingly. Involvement of aspiration is suspected when a number of pathogens are observed in lower respiratory tract specimens. When antimicrobials are administered with reference to breakpoint concentrations in Western countries, differences in dosage between these countries and Japan need to be considered.

Critical Care Nephrology: Core Curriculum 2009

In the inpatient setting, a high proportion of nephrology consultations are requested for patients in the Intensive Care Unit (ICU). These patients may have acute kidney injury (AKI) or may be critically ill and have end-stage renal disease (ESRD). Thus, nephrologists need to understand recent evidence-based advances in the field of critical care, as well as areas of ongoing controversy and investigation. In this article, we summarize the diagnosis and management of shock, as well as the management of sepsis, acute lung injury/acute respiratory distress syndrome (ALI/ARDS), and fulminant hepatic failure, all of which are associated with high mortality in the critical care setting. We discuss infectious complications of critical care, including ventilator associated pneumonia and catheter related infections. Supportive care, including nutrition, insulin therapy and anemia management are reviewed. Dialysis considerations in critically ill patients are discussed. Lastly, we review the management of several life-threatening intoxications, many of which require early recognition and consideration of dialysis.

Diagnostic Strategies for Healthcare-Associated Pneumonia

The first point of a good diagnostic strategy for healthcare-associated pneumonia (HCAP) is correct classification of patients with specific criteria, as suggested by the last American Thoracic Society/ Infectious Diseases Society of America (ATS/IDSA) guidelines. However, clinical practice and recent literature have suggested new risk factors for multidrug-resistant infection (MRI): the presence of permanent indwelling devices, prior antibiotic use in the last 3 months, chronic and advanced pulmonary diseases (chronic obstructive pulmonary disease, bronchiectasis, etc.), history of alcoholism, and immunosuppression. The clinical presentation in HCAP patients is often unusual (mild respiratory symptoms and frequent extrapulmonary manifestations) due to different factors: advanced age, neurological disorders, and multiple chronic comorbidities. Moreover, HCAP commonly presents a worse clinical course than community-acquired pneumonia, a prolonged length of stay, and a mortality rate close to hospital-acquired pneumonia. Chest radiography and routine laboratory markers (including C-reactive protein) are always needed for clinical evaluation and severity assessment. The clinical use of new biomarkers of infection and sepsis (procalcitonin, etc.) is currently being investigated. Extensive microbiological testing to overcome the high prevalence of MRI in HCAP, including urinary antigens for Legionella and Streptococcus pneumoniae; blood cultures; Gram staining and low respiratory tract secretions (sputum, tracheobronchial aspirate, fibrobronchial aspirate, protected specimen brush, bronchoalveolar lavage); and cultures for aerobic, anaerobic, mycobacterial, and fungal pathogens are recommended, whereas the indication for serology tests for respiratory viruses and atypical pathogens is low. By contrast, the new polymerase chain reaction-based techniques for the rapid identification (2 to 4 hours) of microbial pathogens in respiratory samples (nasopharyngeal swab, bronchoalveolar lavage) seem to be the most innovative future perspective in the diagnostics of HCAP.

Value of CT in diagnosis of respirator-associated pneumonia

To analyse the diagnostic accuracy of computed tomography (CT) in ventilator-associated pneumonia (VAP). 23 patients on mechanical ventilation with a new pulmonary abnormality on chest X-ray were examined with both spiral-CT and high-resolution CT. The diagnosis VAP was made according to prospectively defined criteria. Bronchoscopic specimen asservation with protected specimen brushing (PSB) served as gold standard. With PSB, 11 of 23 patients were found to have VAP. CT showed a sensitivity and specificity of 53% and 63%, respectively. Ground glass infiltrates appeared to have a 100% specificity but were found in only 5/11 patients. CT is not the method of choice for diagnosing VAP. Ground glass infiltrates seeming to be highly specific are only inconstantly found.

The impact on community acquired pneumonia empirical therapy of diagnostic bronchoscopic techniques

The aim of the present study was to examine the modification of initial empirical treatment based on the microbiological results of bronchoscopic techniques after comparing the diagnostic yield of protected specimen brush (PSB) and bronchoalveolar lavage (BAL) in the immunocompetent patient with community acquired pneumonia (CAP) with results obtained from conventional sputum cultures. 88 patients with presumptive diagnosis of CAP necessitating hospitalization were prospectively studied. Fibreoptic bronchoscopy with quantitative PSB and BAL cultures for common pathogens, mycobacteria and fungi was performed. Conventional sputum cultures were also obtained. PSB and BAL quantitative cultures added 26.1% and 36.4%, respectively, more microbiological documentation for CAP compared to conventional sputum cultures (p < 0.0001). Gram staining was indicative of the pathogen mostly in cases where Streptococcus pneumoniae was isolated, which was also the most frequently isolated pathogen (19.3%), followed by Haemophilus influenzae (9%). M. tuberculosis was isolated in 6.8% of patients. Modification of treatment ensued in 27.3% of patients because of the application of the cultures of sputum and invasive technique. PSB and BAL added significant information to the aetiological diagnosis of hospitalized immunocompetent patients with CAP.

Escherichia coli: An unknown and infrequent cause of community acquired pneumonia

Our aim was to describe the incidence, clinical characteristics and outcome of community acquired pneumonia (CAP) caused by Escherichia coli through the analysis of a cohort of patients with this condition. This study includes all the patients who were admitted to our hospitals because of CAP caused by E. coli, diagnosed with highly reliable microbiological techniques, such as blood culture, bronchoscopic protected specimen brush (PSB) or transthoracic needle aspiration (TNA). 29 patients were enrolled, representing 0.4% of CAP cases admitted. Main symptoms were fever and dyspnoea. 18 patients were classified into class IV and class V of the Pneumonia Severity Index (PSI). Diagnosis was based on blood culture in 24 cases, PSB in 4 cases and by TNA in 1 case. Three of the patients died, the longer time evolution of the symptoms being the only factor related to higher mortality (p<0.05). Mean hospitalization time was 7.1+/-3.1 d, and correlated with severity at admission (r=0.43; p<0.003). This study demonstrates that CAP caused by E. coli is infrequent. It has an unspecific presentation and mortality rate is 10.3%, associated with longer time before admission to hospital.

Agreement Between Quantitative Cultures of Postintubation Tracheal Aspiration and Plugged Telescoping Catheter, Protected Specimen Brush, or BAL for the Diagnosis of Nosocomial Pneumonia

Agreement Between Quantitative Cultures of Postintubation Tracheal Aspiration and Plugged Telescoping Catheter, Protected Specimen Brush, or BAL for the Diagnosis of Nosocomial Pneumonia

Pneumopathie nécrosante à Gemella morbillorum chez un patient immunocompétent

Gemella morbillorum is an anaerobic to aerotolerant Gram positive coccus. It is considered a member of the normal upper respiratory tract flora including the oropharynx and also the gastro-intestinal and female genital tract. However severe infections are reported like endocarditis, septic shock and septic arthritis, more often in immunocompromised hosts. It is an infrequently isolated organism and a rare cause of pulmonary or pleural infections.We report a case of necrotizing pneumonia due to Gemella morbillorum in a 45-years-old Melanesian, smoker patient. The presentation was subacute with a four month history of loss of appetite, progressive weight loss and cough without fever. Initial presentation seems to be a malignant disease. The positive diagnosis has been established on the results of BAL fluid and the protected specimen brush samples. It was an immunocompetent patient presenting dental inflammation but not oral infection. Further management included intravenous administration of amoxicillin during two weeks. We recommended oral antibiotic treatment for another six weeks. After two months the patient was reevaluated. The CT scan showed no evidence of persistent infection. The HR CT scan will reveal multiple kystic bronchiectasies not seen on the first CT scan.Gm can be found endoscopic samples. Gemella morbillorum can be responsible of community-acquired pneumonia in immunocompetent host.

Treatment Failure in Community-Acquired Pneumonia

Treatment failure (TF) is defined as a clinical condition with inadequate response to antimicrobial therapy. Clinical response should be evaluated within the first 72 h of treatment, whereas infiltrate images may take up to 6 weeks to resolve. Early failure is considered when ventilatory support and/or septic shock appear within the first 72 h. The incidence of treatment failure in community-acquired pneumonia is 10 to 15%, and the mortality is increased nearly fivefold. Resistant and unusual microorganisms and noninfectious causes are responsible for TF. Risk factors are related to the initial severity of the disease, the presence of comorbidity, the microorganism involved, and the antimicrobial treatment implemented. Characteristics of patients and factors related to inflammatory response have been associated with delayed resolution and poor prognosis. The diagnostic approach to TF depends on the degree of clinical impact, host factors, and the possible cause. Initial reevaluation should include a confirmation of the diagnosis of pneumonia, noninvasive microbiological samples, and new radiographic studies. A conservative approach of clinical monitoring and serial radiographs may be recommended in elderly patients with comorbid conditions that justify a delayed response. Invasive studies with bronchoscopy to obtain protected brush specimen and BAL are indicated in the presence of clinical deterioration or failure to stabilize. BAL processing should include the study of cell patterns to rule out other noninfectious diseases and complete microbiological studies. The diagnostic yield of imaging procedures with noninvasive and invasive samples is up to 70%. After obtaining microbiological samples, an empirical change in antibiotic therapy is required to cover a wider microbial spectrum.

Comparison of sensitivity and specificity of the protected specimen brush (PSB) technique and the tracheo-bronchial aspirate (TBAS) in the diagnostics of ventilator associated pneumonia (VAP)

Department of Anaesthesiology and Intensive Therapy, Karol Marcinkowski University of Medical Sciences, Poznan, Poland

Usefulness of Bronchoscopic Microsampling To Detect the Pathogenic Bacteria of Respiratory Infection

Background:Bronchoscopic microsampling (BMS) is a method in which a device consisting of a wire with a polyester probe at the tip is used to collect bronchial epithelial lining fluid with bronchoscopy. In this study, we bacteriologically investigated sample collection using BMS to incorporate BMS into diagnosis of respiratory infection.Methods:Strains ofStreptococcus pneumoniae,Haemophilus influenzae,Pseudomonas aeruginosa, andMycobacterium aviumcomplex (MAC), were used for experiments. In the standard sampling procedure using BMS, the probe coming out of the sheath was immersed in approximately 6 × 106cfu/mL bacterial suspension for 30 s and cut into a tube containing 1 mL of normal saline solution. The tube was stirred for 1 min using a vortex. The sampling rate was calculated by the following equation: (actual amount of bacteria collected by BMS [colony forming units per milliliter])/(bacterial amount in suspension for sampling [colony forming units per milliliter]) × 100 (percentage).Results:The sampling rate ofS pneumoniae, H influenzae, and MAC showed no significant difference among three bacteria, but the sampling rate ofP aeruginosawas higher. The shortened time of sampling, stirring, and the reduced bacterial amount in the suspension (1/100) did not significantly affect the rates of standard procedure. In contrast, in comparison with a protected specimen brush (PSB), the recoveries ofS pneumoniae,H influenzae, and MAC using PSB were significantly lower than those by BMS, but the recovery ofP aeruginosawas not significantly different.Conclusion:Thisin vitrostudy might suggested the usefulness of BMS as a new diagnostic technique capable of quantitative and stable sampling.

Diagnostic yield of quantitative endotracheal aspirates in patients with severe nursing home-acquired pneumonia

IntroductionDiagnostic strategies based on tracheal aspirates in patients with severe nursing home-acquired pneumonia have not previously been evaluated. The objectives of the study were to investigate, in patients with severe nursing home-acquired pneumonia, the diagnostic value of quantitative endotracheal aspirate (QEA) cultures using increasing interpretative cutoff points, as compared with bronchoalveolar lavage (BAL) and protected specimen brush (PSB) quantitative cultures.MethodsSeventy-five nursing home patients requiring mechanical ventilation for suspected pneumonia were studied. Endotracheal aspirate, PSB, and BAL samples were obtained consecutively. The diagnostic yield of QEA at thresholds raging from 103 to 107 colony-forming units (cfu)/ml was assessed by calculating sensitivities, specificities, and accuracy rates. A receiver operator characteristic curve for the series of cutoff points was constructed.ResultsForty-nine patients were diagnosed with pneumonia either by BAL (≤ 104 cfu/ml) or PSB (≤ 103 cfu/ml). Diagnostic accuracy of QEA was most favorable at 104 cfu/ml. At this threshold, endotracheal aspirates coincided with both BAL and PSB in 30 cases, whereas partial agreement was observed in 14 cases. This resulted in sensitivity and specificity of 90% (95% confidence interval 78% to 97%) and 77% (95% confidence interval 56% to 91%), respectively. QEA findings correlated significantly with both PSB and BAL quantitative cultures (r = 0.71 [P < 0.001] and r = 0.77 [P < 0.001], respectively).ConclusionQEA may be used as a diagnostic tool to determine the presence of pneumonia in ventilated patients admitted from nursing homes when bronchoscopic procedures are not feasible or available.

Agreement Between Quantitative Cultures of Postintubation Tracheal Aspiration and Plugged Telescoping Catheter, Protected Specimen Brush, or BAL for the Diagnosis of Nosocomial Pneumonia

The diagnosis of ventilator-associated pneumonia relies on protected specimen brush (PSB), BAL, and plugged telescoping catheter (PTC) procedures. In the particular setting of nosocomial pneumonia (NP) occurring in non-mechanically ventilated patients, no consensus exists on their use. When mechanical ventilation (MV) becomes mandatory, postintubation tracheal aspiration (PITA) could be a simple, fast, and cheap diagnostic tool. Our aim was to compare the diagnostic accuracy of PITA to that of PSB, BAL, or PTC in patients requiring MV for suspected NP. Patients with a prior hospital stay of > or = 48 h who required MV for suspicion of NP were prospectively enrolled in the study. PITA was performed by sterile suction. Within 2 h, pulmonary samples were obtained by PSB, BAL, or blinded PTC, which are referred to hereafter as "reference methods" (RMs). The definite diagnosis of NP was made using a composite item of clinical, radiologic, and bacteriologic (ie, blood or pleural fluid cultures) patterns. The agreement between the quantitative microbiological results obtained with PITA and those of the RMs was assessed by the kappa-statistic. The sensitivity, specificity, and positive and negative likelihood ratios of PITA and RMs were calculated taking the definite diagnosis of NP as the reference. There were 44 cases (63.8%) of confirmed NP. The kappa-statistic was 0.71. The sensitivity, specificity, and positive and negative likelihood ratios were 77%, 84%, 4.80, and 0.27, respectively, for PITA, and 75%, 88%, 6.25, and 0.28, respectively, for RMs. PITA may be a reliable alternative to RMs in the particular setting of NP in newly mechanically ventilated patients.

Quantitative Cultures for Diagnosing Ventilator-Associated Pneumonia: A Critique

The diagnosis of ventilator-associated pneumonia has been clouded by uncertainty, because a reference standard has never been established. The use of invasive procedures to obtain respiratory tract samples for culture, with quantitation of the bacteria isolated, has been the approach most commonly advocated. Quantitation of bacteria from lower respiratory tract specimens can be used to distinguish colonization from infection. We review the invasive procedures (bronchoalveolar lavage, protected specimen brushing, nonbronchoscopic bronchoalveolar lavage, and blinded bronchial sampling), the methods of quantitation used, the types of catheters used, the sample collection methods, and the criteria used as cutoffs for the quantitative cultures. Quantitation of lower respiratory tract samples is inherently unstable from a mathematical perspective, given the variability in the volume of fluid instilled and reaspirated and the magnitude and complexity of the area being sampled. We also briefly review the use of quantitation for bacterial infections other than pneumonia, including urinary tract infection and catheter-related bacteremia. The variability in both the methods and reference criteria in the studies reviewed show that the quantitation approach is neither standardized nor evidence based.

Bronchoscopic diagnosis of pulmonary infiltrates in granulocytopenic patients with hematologic malignancies: BAL versus PSB and PBAL

Treatment of patients with hematologic malignancies is often complicated by severe respiratory infections. Bronchoscopy is generally to be used as a diagnostic tool in order to find a causative pathogen. In a prospective study the combination of protected specimen brush (PSB) and protected bronchoalveolar lavage (PBAL) was compared with bronchoalveolar lavage (BAL) for evaluated feasibility and diagnostic yield in granulocytopenic patients with hematologic malignancies and pulmonary infiltrates. All specimens from 63 bronchoscopic procedures (35 BAL and 28 PSB-PBAL) were investigated by cytological examination and various microbiological tests. If clinically relevant and feasible, based on the clinical condition and/or the presence of thrombocytopenia, lung tissue samples were obtained. The majority of the 58 included patients were diagnosed as having acute myeloid leukaemia and developed a severe neutropenia (BAL-group: 27 days; PSB-PBAL group: 30 days). Microbiological and cytological examination of 63 bronchoscopic procedures (35 BAL and 28 PSB-PBAL) yielded causative pathogens in 9 (26%) patients of the BAL-group and 8 (29%) patients of the PSB-PBAL group (PSB and PBAL 4 each). Aspergillus fumigatus was the pathogen most frequently (13%) detected. Using all available examinations including the results of autopsy, a presumptive diagnosis was established in 43% of the patients in the BAL group and 57% of those in the PSB-PBAL group; in these cases microbial aetiology was correctly identified in 67% and 57%, respectively. The complication rate was of these procedures were low, and none of the patients experienced serious complications due to the invasive techniques. Our results showed that modern bronchoscopic techniques such as PSB and PBAL did not yield better diagnostic results compared to BAL in granulocytopenic patients with hematologic malignancies and pulmonary infiltrates. In approximately half of the cases a presumptive diagnosis was made by bronchoscopic procedures.

Diagnostic des pneumopathies acquises sous ventilation mécanique

Two strategies are available for the diagnosis and therapeutic management of ventilator-associated pneumonia (VAP). One based on clinical evaluation (also called noninvasive strategy) is safe, cheap and easy to use. However, this approach obviously leads to an excessive use of antibiotics due to the treatment of signs and symptoms suggesting lung infection, but frequently due to other infections or non-infectious inflammatory process. A microbiological strategy (or invasive) based on direct examination of protected brush or brochoalveolar lavage specimens obtained via a fiberoptic bronchoscopy permits to accurately select patients with VAP with a rapid identification of organisms responsible for infection. This strategy allowing the reduction of unnecessary antimicrobial regiments has been proven to be efficient.

Concordance of antibiotic prophylaxis, direct Gram staining and protected brush specimen culture results for postoperative patients with suspected pneumonia

Antibiotic therapy alters the diagnostic value of protected brush specimens. With protected brush specimens alone, diagnosing pneumonia requires 24 or 48 h. Addition of direct Gram staining shortens this delay. Antibiotic prophylaxis, recommended after major surgery, may influence the contribution of Gram staining to diagnosing postoperative pneumonia. During a 1-yr period, we retrospectively studied all patients on mechanical ventilation suspected of having postoperative pneumonia who had undergone fibreoptic bronchoscopy with protected brush specimens. Postoperative pneumonia was diagnosed when quantitative protected brush specimens culture results yielded 103 colony-forming units mL-1. Fifty patients were clinically suspected of having postoperative pneumonia after cardiac (n=42), vascular (n=5) or thoracic (n=3) surgery. Eleven (22%) samples were obtained during antibiotic prophylaxis. Twenty-two (44%) episodes were microbiologically proven. Gram-stain sensitivity was 95.5%, with 82.1% specificity, 80.7% positive-predictive value and 95.8% negative-predictive value. Concordance between direct Gram-stain-identified pathogens and Gram stain of cultured pathogens was significantly less frequent during antibiotic prophylaxis (63.6%) than afterwards (94.9%) (P<0.05). Antibiotic prophylaxis diminished the diagnostic value of Gram staining of protected brush specimens. When protected brush specimens was performed during antibiotic prophylaxis, Gram staining accurately enabled early exclusion of postoperative pneumonia because of its excellent negative-predictive value. After antibiotic prophylaxis, Gram staining permitted early diagnosis of postoperative pneumonia identification of the responsible pathogen.

Diagnosis of Ventilator-Associated Pneumonia: Focus on Nonbronchoscopic Techniques (Nonbronchoscopic Bronchoalveolar Lavage, Including Mini-BAL, Blinded Protected Specimen Brush, and Blinded Bronchial Sampling) and Endotracheal Aspirates

The ideal diagnostic approach for ventilator-associated pneumonia currently is based on invasive procedures to obtain respiratory tract cultures. Given the lack of consensus and relatively poor acceptance of full bronchoscopic bronchoalveolar lavage (BAL) and protected specimen brush (PSB), less invasive procedures have been developed. We review the nonbronchoscopic procedures (nonbronchoscopic bronchoalveolar lavage, including mini-BAL, blinded protected specimen, and blinded bronchial sampling) and endotracheal aspiration. We provide a critique of the methods used, the types of catheters inserted, and the sample collection methods. Most studies were flawed in that antibiotic use before initiation of the procedure was not controlled. The variability of both the methods and the criteria for the gold standard in the numerous investigations show that these procedures are neither standardized nor proven to be accurate and often did not improve management. Pending future studies, use of endotracheal aspirates without the use of quantitation seems to be a reasonable approach for clinicians who are not committed to an invasive procedure.