Diagnostic accuracy of protected catheter sampling in ventilator-associated bacterial pneumonia.

The aim of this study was to assess the accuracy of protected telescoping catheter performed using: 1) protected distal aspiration, or 2) protected mini-bronchoalveolar lavage for the diagnosis of ventilator-associated bacterial pneumonia. Twenty-seven patients who died after receiving mechanical ventilation for at least 72 h were included in a comparative prospective post-mortem study. The two microbiological sampling procedures were performed immediately after death. Surgical pneumonectomies and biopsies were performed within 30 min of death at the bedside for histological examination. The results of the two techniques were compared with histological post-mortem lung examination or biopsies. Histological examination of the parenchyma showed signs of pneumonia in 14 cases. Lung tissue culture was positive in nine of these 14 cases. When ventilator-associated bacterial pneumonia was defined by the association of histological signs and positive lung tissue culture the sensitivity was 78% for both sampling techniques, specificity was 86% for mini-bronchoalveolar lavage and 100% for protected distal aspiration (at a threshold of 1 x 10(3) cfu x mL(-1)). Both techniques protected the distal aspiration and mini-bronchoalveolar lavage, and provided good specificity with an acceptable sensitivity for the diagnosis of ventilator-associated bacterial pneumonia.     

盲法远端插入双腔导管与保护性毛刷对呼吸机相关性肺炎病原学诊断意义的对比研究

目的 评价盲法远端插入双腔导管采样(PTC)与支气管镜下保护性毛刷(PSB)对呼吸机相关性肺炎(VAP)病原学诊断的价值.方法 收集2008年1月至2009年2月青岛大学医学院第二附属医院内科ICU住院的69例怀疑VAP的机械通气患者,入选标准为首次住院时间超过48 h、接受过机械通气治疗并怀疑VAP的患者,均进行PSB和PTC检查,所有检杳结果均按照≥10~6 CFU/L标准进行阳性评判,若标本中出现草绿色链球菌、淡黄色奈瑟球菌则考虑标本污染而剔除.结果 所取标本先经革兰染色涂片光镜下判定,69例中PTC和PSB方法检查结果的阳性例数分别60例(87.O%)和58例(84.1%).所有标本均进行细菌培养,以PSB为金标准,PTC的敏感度为82.1%,特异度为92.7%,阳性预测值为88.5%,阴性预测值为88.4%.结论 对于近期进行机械通气的患者,如果怀疑VAP但没有条件进行PSB或支气管肺泡灌洗时,PTC是一种有价值的检测方法.     

Bronchoscopic protected specimen brush and bronchoalveolar lavage in the diagnosis of bacterial pneumonia

Despite marked improvements in antibiotic therapy, the accurate diagnosis and treatment of bacterial lower respiratory tract infection remain a challenge. The bronchoscopic protected specimen brush and bronchoscopic bronchoalveolar lavage combined with quantitative bacterial cultures can provide sensitive and relatively specific information about lower airway flora. Both of these methods require strict observance of the required protocol, careful processing of the obtained specimens, and the absence of prior antibiotic therapy to obtain best results. These procedures are also of some utility in sickle cell acute chest syndrome, bronchiectasis, and in the immunocompromised host.     

Protected transbronchial needle aspiration and protected specimen brush in the diagnosis of pneumonia

Protected transbronchial needle aspiration (PTBNA) of pneumonic lung theoretically could bypass dislodged upper respiratory tract flora, a potential source of contamination of protected specimen brush (PSB) cultures. To evaluate the usefulness of PSB and PTBNA in establishing the etiology of pneumonia, we prospectively studied 20 patients with acute bacterial pneumonia not receiving antibiotics. After informed consent, patients had fiberoptic bronchoscopy under fluoroscopy to localize the pneumonia, and specimens were obtained by the PSB. The protective plug of a specially devised needle for PTBNA was pneumatically dislodged and aspiration was performed within the infiltrate under fluoroscopy. Quantitative cultures were plated immediately for aerobes, anaerobes, and Legionella. Greater than 4 X 10(3) organisms/brush or 1 X 10(4) organisms/ml needle aspirate were considered to be consistent with infection. The results using PSB and PTBNA were compared in 15 of 20 patients in whom a definitive diagnosis (positive blood or pleural fluid culture) or presumptive diagnosis (expectorated sputum culture, clinical characteristics, and response to specific therapy) was established. The PSB and PTBNA cultures on uninfected control subjects (n = 5) being bronchoscoped for other reasons were negative. The PSB and PTBNA were each diagnostic in 2 of the 5 patients with definitive diagnoses. In the group with a presumptive diagnosis (n = 10), PSB was diagnostic in 7 of 10 and PTBNA in 9 of 10. The overall (definitive plus presumptive) diagnostic yield was 60% for PSB and 73% for PTBNA. Multiple organisms were isolated in high concentrations in 53% of the patients. The most common organisms recovered in addition to the primary pathogen was alpha hemolytic streptococci.(ABSTRACT TRUNCATED AT 250 WORDS)     

PSB技术诊断下呼吸道感染病原分析报告

目的观察PSB技术诊断下呼吸道感染病原。方法采用纤维支气管镜下一次性保护细胞刷技术(PSB)获取病原体协助诊断。结果PSB技术致病性细菌阳性率80%,真菌阳性率4.0%,结核菌阳性率8.0%。结论PSB技术为一种特异性好的病原诊断方法,在我院下呼吸道感染病原中以G 细菌为主,化脓性链球菌、肺炎链球菌、葡萄球等为常见致病菌。     

老年人呼吸机相关肺炎的抗生素治疗

目前对呼吸机相关肺炎(wentiIator—ass0ocisated pneumonia,VAP)的治疗仍以抗生素治疗为主,而早期的经验性治疗是影响VAP预后最重要的因素。本文主要探讨老年人VAP抗生素经验性治疗的用药原则及一些参考因素：     

Use of the protected specimen brush in patients with endotracheal or tracheostomy tubes

Twenty-one patients on mechanical ventilators for greater than 48 hours who had new localized infiltrates were evaluated using a quantitative culture technique of the involved lung compared to the non-involved lung. Based on the clinical course, response to antibiotics, or subsequent analysis of pathologic specimens, eight patients were felt to have acute bacterial pneumonia, while the remaining 13 were felt to have an alternative cause of their infiltrate. Cultures of the protected brush specimen of the involved lung in all eight cases of bacterial pneumonia had one or more organisms grown at a greater than 100 colony forming units (cfu) per ml while only one of the 13 cases of non-pneumonia had a culture from the involved area having greater than 100 cfu per ml (p less than 0.001). The non-involved area always grew fewer organisms than the involved area, and in 16 cases, there was no growth from the specimen obtained from the non-involved area.     

Diagnosis of nosocomial pneumonia in cancer patients undergoing mechanical ventilation: a prospective comparison of the plugged telescoping catheter with the protected specimen brush.

STUDY OBJECTIVES: Quantitative culture of protected samples of lower respiratory tract secretions obtained by a fiberoptic protected specimen brush (PSB) is widely accepted for the diagnosis of ventilator-associated pneumonia (VAP), but this diagnostic procedure is time consuming, expensive, and may give rise to iatrogenic complications, especially in cancer patients who often present with thrombocytopenia. The plugged telescoping catheter (PTC) could be a satisfactory alternative to the PSB in this setting. The aim of the present study was to evaluate the interest of the PTC to diagnose VAP in ventilated cancer patients. DESIGN: A prospective observational study. SETTING: A 15-bed medical-surgical ICU in a comprehensive cancer center. PATIENTS AND INTERVENTIONS: Over a 9-month period, 42 patients suspected of having bacterial VAP during mechanical ventilation underwent 69 bronchial samplings: a blinded PTC and a fiberoptic PSB were performed successively in each case. A positive culture for both sampling procedures was defined as the recovery of > or = 10(3) cfu/mL of at least one potential pathogen. The PSB result was taken as the reference standard. MEASUREMENTS AND RESULTS: The overall agreement between the techniques was 87% (60/69). PTC had a sensitivity of 67%, a specificity of 93%, a positive predictive value of 71%, and a negative predictive value of 91%. CONCLUSIONS: We conclude that the accuracy of the blinded PTC compares well with that of the PSB for the diagnosis of VAP in cancer patients. The sensitivity of the PTC observed herein, which is slightly lower than that described in previous studies, may be due to the blinded nature of the method: the indications for initial or secondary coupling with a directed sampling method in patients with suspicion of localized pneumonia remain to be determined.     

Diagnosis of nosocomial bacterial pneumonia in intubated patients undergoing ventilation: comparison of the usefulness of bronchoalveolar lavage and the protected specimen brush

PURPOSE: To compare the usefulness of specimens recovered using a protected specimen brush and those recovered by bronchoalveolar lavage in the diagnosis of nosocomial pneumonia occurring in intubated patients undergoing ventilation, we performed both procedures in patients suspected of having pneumonia because of the presence of a new pulmonary infiltrate and purulent tracheal secretions. PATIENTS AND METHODS: Twenty-one patients (16 men and five women) with an average age of 57 +/- 12 years were studied. They had been receiving mechanical ventilation for 8 +/- 6 days before inclusion in the trial. The clinical suspicion for nosocomial bacterial pneumonia was high in these patients. Fiberoptic bronchoscopy was performed in each patient. Bronchoscopy specimens were obtained by a protected specimen brush and by bronchoalveolar lavage, and were then processed for quantitative bacterial and fungal culture using standard methods. Total cell counts were performed on an aliquot of resuspended original lavage fluid. Differential cell counts were made on at least 500 cells. In addition, 300 cells were examined at high-power magnification and the percentage of cells containing intracellular microorganisms and the average number of extracellular organisms per oil-immersion field were determined. RESULTS: Quantitative culture of specimens recovered using the protected specimen brush were positive (more than 10(3) colony-forming units [cfu]/ml) in five of five patients with subsequently confirmed pneumonia, and negative (less than 10(3) cfu/ml) in 13 of 13 patients without bacterial pneumonia, but results were not available until 24 to 48 hours after the procedure. Quantification of intracellular organisms in cells recovered by lavage was also useful in distinguishing patients with pneumonia (more than 25 percent of cells with intracellular organisms in five of five patients) from those without pneumonia (less than 15 percent of cells with intracellular organisms in all cases), and results were available immediately. In contrast, quantitative culture of lavage fluid and differential cell counts were of little value in identifying infected patients. CONCLUSION: The protected specimen brush and microscopic identification of intracellular organisms in cells recovered by lavage yield useful and complementary information, and together permit rapid and specific treatment of most patients with nosocomial pneumonia.     

Diagnostic fiberoptic bronchoscopy and protected brush culture in patients with community-acquired pneumonia

A model for performing fiberoptic bronchoscopy as a supplement to noninvasive diagnostic methods, in patients with community-acquired pneumonia, was prospectively studied. Twenty-four patients underwent bronchoscopy, seven pilot patients and 17 of 277 (6 percent) consecutive patients with CAP. Indications for FOB were early therapy failure (less than or equal to 72h)(n = 7), late therapy failure (greater than 72h)(n = 11), or before start of antibiotic therapy in severely ill or immunocompromised patients (n = 6). Samples were obtained by aspiration of bronchial secretion and with a protected brush catheter from which quantitative cultures with a detection level of 10(4) colony forming units per ml were performed. Results concluded that FOB, with the use of quantitative PB-cultures, offered a safe and specific diagnostic tool, which on special indications, can be of great value in the management of patients with CAP.     

Prospective evaluation of the protected specimen brush for the diagnosis of pulmonary infections in ventilated newborns

The precise diagnosis of lower respiratory tract infection in the critically ill newborn remains a difficult challenge. The bronchoscopic protected specimen brush (PSB) is a reliable method in intubated adults. Because the bronchoscopic procedure is not generally available for young children, Zucker proposed a blind technique for introducing the PSB into the distal airways. His results were promising but were not compared with any bacteriologic reference method. Therefore, we wanted to evaluate this technique in comparison with the open lung biopsy (OLB) when it could be ethically accomplished. Eleven PSB were collected simultaneously with an OLB. The sensitivity of the PSB procedure was 100%, its specificity 88%, its positive predictive value 66%, and its negative predictive value 100%. There were no complications secondary to the PSB procedure. In this short study, the PSB procedure using a blind technique is safe and feasible to obtain uncontaminated specimens in intubated and ventilated newborns, and is largely accurate in identifying the bacterial etiologic agent of lower respiratory tract infection.     

Prospective evaluation of the protected specimen brush for the diagnosis of pulmonary infections in ventilated patients

To determine the relative cultural accuracy of the bronchoscopic protected specimen brush (PSB) in ventilated patients, we compared this method in the same area of the lung with histologic and bacteriologic examinations of pulmonary specimens. The procedures were concluded just after death when the ventilator was still functioning. Samples via the PSB were taken from a branch of the anterior basal bronchus of the left lower lobe, and immediate left thoracotomy was performed to obtain peripheral specimens from the corresponding segment for quantitative cultures. Twenty-six patients were studied; 6 had histologically proved pneumonia. Using quantitative cultures, a correlation was evidenced between PSB and lung cultures, especially in the subgroup of patients who received no antibiotic during the week preceding their death. No pneumonia was observed when PSB cultures isolated no organisms in concentrations greater than 10(3) colony-forming units (cfu) per ml. The PSB cultures at a level of 10(3) cfu/ml identified every patient with histologically proved pneumonia and every microorganism present in concentrations of 10(4) cfu/g or greater in the lungs. Moreover, in the subgroup of patients receiving no antibiotic, only 4 microorganisms were isolated by the PSB in concentrations greater than 10(3) cfu/ml and not found in the lung.(ABSTRACT TRUNCATED AT 250 WORDS)     

Agreement between quantitative cultures of postintubation tracheal aspiration and plugged telescoping catheter, protected specimen brush, or BAL for the diagnosis of nosocomial pneumonia

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: PITA may be a reliable alternative to RMs in the particular setting of NP in newly mechanically ventilated patients.     

雾化吸入抗生素治疗铜绿假单胞菌引起的呼吸机相关性肺炎的临床疗效和安全性

目的 评价雾化吸入阿米卡星治疗铜绿假单胞菌引起的呼吸机相关性肺炎的临床疗效和安全性。方法 研究为前瞻性开放性随机对照非盲研究,选取2011年01月至2014年12月期间铜绿假单胞菌引起的VAP患者76例,随机化分为雾化治疗组(试验组,38例)和常规治疗组(对照组,38例),比较雾化治疗结束后两组患者临床治愈率、细菌学反应、病死率、机械通气时间、住ICU时间及不良反应。结果 雾化组患者7天临床治愈率显著高于对照组(76.3% 比52.6%, P=0.031),但两组患者死亡率无明显差异。雾化组患者细菌载量在治疗过程中迅速降低,对照组患者细菌载量在治疗前3天内有明显降低,但后期未见明显下降。两组患者的平均机械通气时间、平均住院时间、平均住重症监护病房时间及不良反应未见明显差异。结论 雾化吸入阿米卡星治疗铜绿假单胞菌引起的VAP有助于提高患者临床治愈率和细菌清除率,但对患者病死率、住ICU时间、机械通气时间无明显影响。     

Microscopic examination of intracellular organisms in protected bronchoalveolar mini-lavage fluid for the diagnosis of ventilator-associated pneumonia

STUDY OBJECTIVES: To assess the cutoff percentage of cells containing intracellular organisms (ICOs) in the microscopic examination of mini-lavage fluid for the diagnosis of ventilator-associated pneumonia (VAP), and to study the accuracy of this diagnostic procedure on patients who have received previous antibiotic therapy (AT). DESIGN: Prospective clinical investigation. SETTING: The medico-surgical ICU of a university hospital. PATIENTS: Eighty-two patients who fulfilled the clinical criteria of first episode of VAP. INTERVENTIONS: Lower airway secretion samples were obtained by a nonbronchoscopic protected bronchoalveolar mini-lavage (mini-PBAL). Measurements and results: A total of 82 mini-PBALs were performed. The fluid obtained was divided into two samples. The first sample underwent direct microscopic examination using centrifugal cytology and Giemsa stain in order to determine the percentage of cells containing ICOs. The second sample was processed for Gram stain and quantitative cultures. VAP was the final diagnosis in 65 patients based on the mini-PBAL results obtained in the quantitative cultures. At least one bacterial species grew in a significant concentration (> or = 10(3) cfu/mL). The mini-PBAL was performed on 42 patients during AT (> or = 24 h of effective AT at the time of diagnostic procedure) and on another 40 patients with no AT (No AT). The results of the quantitative cultures were compared with the percentage of cells containing ICOs using a receiver operator characteristic (ROC) curve. The cutoff point of > or = 2% of cells containing ICOs had the highest sensitivity (80%) and specificity (82%) in the studied population (area under the ROC curve [AUC], 0.83; 95% confidence interval [CI], 0.70 to 0.90). In patients receiving AT, the sensitivity was 70% and specificity was 75% (AUC, 0.73; 95% CI, 0.58 to 0.90); and in No AT-group patients sensitivity was 88% and specificity was 100% (AUC, 0.92; 95% CI, 0.84 to 1.0). The comparative analysis of both ROC curves was statistically significant (p = 0.04). CONCLUSIONS: The cutoff point of > or = 2% of cells containing ICOs has the highest sensitivity and specificity in the microscopic examination of mini-lavage fluid for the diagnosis of VAP. However, sensitivity is too low to be clinically useful. The direct examination of mini-PBAL fluid is less accurate when previous AT has been administered.     

Detection of nosocomial lung infection in ventilated patients. Use of a protected specimen brush and quantitative culture techniques in 147 patients

To determine the usefulness of samples obtained by bronchoscopy using a protected specimen brush and evaluated by quantitative culture techniques in establishing the diagnosis of nosocomial pneumonia in patients requiring mechanical ventilation, we prospectively studied 147 ventilated patients suspected of having nosocomial pneumonia because of the presence of a new pulmonary infiltrate and purulent tracheal secretions. Positive cultures of protected brush specimens (greater than 10(3) cfu/ml) were found in only 45 patients (31%). Subsequent follow-up confirmed the diagnosis of pneumonia in 34 of 45 patients, and in only 4 of 45 patients was a positive culture firmly established to be a false positive result. No patient with less than 10(3) cfu/ml was subsequently shown to have had pneumonia, and the diagnosis was definitely excluded in 72 of 102 patients by the absence of pneumonia at autopsy or recovery without antibiotic therapy. In contrast, when 16 clinical variables were evaluated by stepwise logistic regression analysis, no combination could be identified that was useful in distinguishing patients with bacterial pneumonia. Furthermore, when the actual costs of evaluation and therapy of our patients were compared with the projected costs entailed in treating all patients suspected of having pneumonia with antibiotics, evaluation using the protected specimen brush and quantitative cultures was less expensive after only 6 days of treatment. These results suggest that the appearance of pulmonary infiltrates and purulent tracheal secretions does not result from bacterial pneumonia in a majority of patients.(ABSTRACT TRUNCATED AT 250 WORDS)