Invasive oder nicht-invasive Diagnostik der Ventilator-assoziierten Pneumonie

Ventilator-associated pneumonia (VAP) is the most frequent nosocomial infection on intensive care units (ICU). VAP has consequences on mortality, duration of stay on the ICU and in the hospital and increases costs of treatment. Clinical studies indicated that an early and calculated treatment with broad-spectrum antibiotics is highly important for the success of treatment on the ICU. To minimize formation of resistance, early deescalation or termination of this chosen therapy is necessary and may be based on clinical criteria and especially microbiological examination. The latter case needs extraction of secretions in the upper respiratory tract. Invasive techniques (bronchoalveolar lavage, BAL) and non-invasive techniques (endotracheal aspiration, ETA) can be used. There is no agreement between studies about which method leads most frequently to correct results and results in improving outcome of patients. The study performed by the Canadian critical care trials group (December 21, 2006, NEJM) examined 740 patients on intensive care units. Patients were randomized both depending on the diagnostic method (ETA vs BAL) and the antibiotic treatment (mono- vs combined antibiotic therapy). The 28-day mortality was chosen as the primary outcome parameter, while duration of mechanical ventilation and duration of stay on the ICU were chosen among other things as secondary parameters. The results indicated no significant differences between the groups for these parameters. Patients undergoing BAL were treated significantly later by study antibiotics. This difference had no effect on patients' outcome. The special selection of the study population, which excluded pre-colonized and chronically ill patients, reduces the possibility to rate these results. Furthermore, based on the results of this study, recommendation for one of the used techniques in diagnosing VAP can not be given.     

Invasive oder nicht-invasive Diagnostik der Ventilator-assoziierten Pneumonie

Ventilator-associated pneumonia (VAP) is the most frequent nosocomial infection on intensive care units (ICU). VAP has consequences on mortality, duration of stay on the ICU and in the hospital and increases costs of treatment. Clinical studies indicated that an early and calculated treatment with broad-spectrum antibiotics is highly important for the success of treatment on the ICU. To minimize formation of resistance, early deescalation or termination of this chosen therapy is necessary and may be based on clinical criteria and especially microbiological examination. The latter case needs extraction of secretions in the upper respiratory tract. Invasive techniques (bronchoalveolar lavage, BAL) and non-invasive techniques (endotracheal aspiration, ETA) can be used. There is no agreement between studies about which method leads most frequently to correct results and results in improving outcome of patients. The study performed by the Canadian critical care trials group (December 21, 2006, NEJM) examined 740 patients on intensive care units. Patients were randomized both depending on the diagnostic method (ETA vs BAL) and the antibiotic treatment (mono- vs combined antibiotic therapy). The 28-day mortality was chosen as the primary outcome parameter, while duration of mechanical ventilation and duration of stay on the ICU were chosen among other things as secondary parameters. The results indicated no significant differences between the groups for these parameters. Patients undergoing BAL were treated significantly later by study antibiotics. This difference had no effect on patients' outcome. The special selection of the study population, which excluded pre-colonized and chronically ill patients, reduces the possibility to rate these results. Furthermore, based on the results of this study, recommendation for one of the used techniques in diagnosing VAP can not be given.     

Infection control in intensive care units and prevention of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is considered the most frequent infection in the intensive care unit (ICU), although incidence rates depend on the diagnostic methods. Because VAP has been associated with increased mortality and greater costs for medical care, prevention remains an important goal for intensive care medicine. Selective digestive decontamination (SDD), the most frequently studied method of infection prevention, is still controversial despite more than 30 prospective randomized trials and 6 metaanalyses. SDD reduces the incidence of VAP diagnoses, but beneficial effects on duration of ventilation or ICU stay, antibiotic use, and patient survival have not been shown unequivocally. Although recent metaanalyses suggest a 20% to 40% decrease in ICU mortality for SDD used with systemic prophylaxis, this benefit should be confirmed in a large, prospective, randomized study, preferably with a cost-benefit analysis. Selection of pathogens resistant to the antibiotics used in SDD remains the most important drawback of SDD, rendering SDD contraindicated in wards with endemic resistant problems. Other methods of infection prevention that do not create a selective growth advantage for resistant microorganisms may be more useful. Among these are the use of endotracheal tubes with the possibility of continuous aspiration of subglottic secretions, oropharyngeal decontamination with antiseptics, or the semirecumbent treatment position of patients. Although these methods were successful in single studies, more data are needed. Notwithstanding the potential benefits of these interventions, such classic infection control measures as handwashing remain the cornerstone of infection prevention.     

Biomarkers for ventilator-associated pneumonia: review of the literature

Objective

Ventilator-associated pneumonia (VAP) contributes significantly to morbidity and mortality in critically ill patients, but it can be difficult to diagnose. Clinical criteria, Clinical Pulmonary Infection Score, and quantitative culture of bronchoalveolar lavage have been used to distinguish between patients who are likely positive (sensitivity) and patients who are likely negative (specificity). Despite these test methods, patients continue to be misclassified. False-positive results may lead to inappropriate antibiotic use in patients. For those misclassified as test negative, appropriate treatment may be delayed. Biomarkers have been suggested as another method to enhance the ability to predict VAP. This article analyzes the evidence for the usefulness of 3 biomarkers that have been proposed as possible biomarkers of VAP: soluble triggering receptor expressed on myeloid type 1 cells, procalcitonin, and C-reactive protein.

Methods

A Medline search was conducted for the years between 1990 and 2009 to locate articles on the subject of biomarkers for predicting VAP in critically ill adult patients.

Results

Analysis of the literature does not currently support a clinical role for these biomarkers in predicting VAP. Variations in the diagnostic methods, antimicrobial use, cutoff values, and patient populations limit comparisons among the studies.

Conclusion

Recommendations are offered to strengthen and standardize methods in future studies to clarify the utility of biomarkers for predicting VAP in specific patient populations.     

Prevention and diagnosis of ventilator-associated pneumonia: a survey on current practices in Southern Spanish ICUs

STUDY OBJECTIVES: To assess the implementation of selected ventilator-associated pneumonia (VAP) prevention strategies, and to learn how VAP is diagnosed in the ICUs of Southern Spain. DESIGN: Multicentric survey. SETTING: The ICUs of 32 hospitals of the public health-care system of Southern Spain. PATIENTS OR PARTICIPANTS: Directors of ICUs. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Twenty-eight ICUs (87.5%) returned completed questionnaires. Ventilator circuits were changed every 72 h or longer in 75% of ICUs. Use of heat and moisture exchangers and open endotracheal suction systems were reported in 96% of ICUs. Subglottic secretion drainage was never used, and 57% of ICUs checked endotracheal tube cuff pressure at least daily. Semi-recumbent position was common (93%), and 67.5% of ICUs used frequently noninvasive ventilation. Continuous enteral feeding was reported in all ICUs. Sedative infusions were usually interrupted every day in 11% of ICUs. Seventy-five percent of ICUs had specific guidelines for antibiotic therapy of VAP, but rotation of antibiotics was uncommon (11%). Twenty-nine percent of ICUs diagnosed VAP without microbiological confirmation. The most used technique for microbiologic diagnosis was qualitative culture of endotracheal aspirates (42.8%). The centers with a larger structural complexity reported using VAP therapy guidelines more frequently than the smaller centers, but they did not utilized bronchoscopic techniques for diagnosing VAP. CONCLUSIONS: Common prevention and diagnostic procedures in clinical practice, including large teaching institutions, significantly differed from evidence-based recommendations and reports by research groups of excellence. In addition, our study suggests that clinical practice for preventing and diagnosing VAP is variable and many opportunities exist to improve the care of patients receiving mechanical ventilation.     

Early antibiotic treatment for BAL-confirmed ventilator-associated pneumonia: a role for routine endotracheal aspirate cultures

STUDY OBJECTIVES: To test whether routine quantitative cultures of endotracheal aspirates obtained before the onset of ventilator-associated pneumonia (VAP) could help to predict the causative microorganisms and to select early appropriate antimicrobial therapy before obtaining BAL culture results. DESIGN: Prospective observational study. SETTING: French medical ICU. PATIENTS: A total of 299 patients received mechanical ventilation for at least 48 h. INTERVENTIONS: Endotracheal aspiration (EA) was performed twice weekly in all mechanically ventilated patients. A diagnosis of VAP was made by BAL culture. Only the EA performed just before the suspicion of VAP (EA-pre) were evaluated. This strategy (ie, the EA-pre-based strategy) was compared with an antibiotic therapy that would have been prescribed if the recommendations of both the American Thoracic Society (ATS) and Trouillet et al (Am J Respir Crit Care Med 1998; 157:531-539) had been applied. MEASUREMENTS AND RESULTS: VAP was diagnosed (by BAL culture) in 41 of the 75 patients in whom BAL was performed. Among the 41 BAL specimens that were positive for VAP, EA-pre had identified the same microorganisms (with the same antibiotic resistance patterns) in 34 cases (83%). In one case, EA-pre was not available at the time BAL was performed (a case of early-onset VAP), but the empiric antibiotic therapy was adequate. While EA-pre did not give the same results as the BAL culture, the antibiotic therapy based on the results of the EA-pre was adequate in four other cases. Finally, antibiotic therapy was delayed in only two cases. Antibiotic treatment was therefore adequate in 38 of the 40 assessable cases (95%). If the Trouillet-based strategy had been used, the antibiotic treatment would have been adequate in 34 of the 41 cases (83%; p = 0.15 [vs EA-pre strategy]). Based on the ATS classification, the antibiotic treatment would have been adequately prescribed in only 28 of the 41 cases (68%; p = 0.005 [vs EA-pre strategy]). CONCLUSIONS: Routine EA performed twice a week makes it possible to prescribe adequate antibiotic therapy (while waiting for BAL culture results) in 95% of the patients in whom a VAP is ultimately diagnosed by BAL culture.     

Pneumonia due to Pseudomonas aeruginosa: part I: epidemiology, clinical diagnosis, and source

Pseudomonas aeruginosa is an uncommon cause of community-acquired pneumonia (CAP), but a common cause of hospital-acquired pneumonia. Controversies exist for diagnostic methods and antibiotic therapy. We review the epidemiology of CAP, including that in patients with HIV and also in hospital-acquired pneumonia, including ventilator-associated pneumonia (VAP) and bronchoscope-associated pneumonia. We performed a literature review of clinical studies involving P aeruginosa pneumonia with an emphasis on treatment and prevention. Pneumonia due to P aeruginosa occurs in several distinct syndromes: (1) CAP, usually in patients with chronic lung disease; (2) hospital-acquired pneumonia, usually occurring in the ICU; and (3) bacteremic P aeruginosa pneumonia, usually in the neutropenic host. Radiologic manifestations are nonspecific. Colonization with P aeruginosa in COPD and in hospitalized patients is a well established phenomenon such that treatment based on respiratory tract cultures may lead to overtreatment. We present circumstantial evidence that the incidence of P aeruginosa has been overestimated for hospital-acquired pneumonia and reflex administration of empirical antipseudomonal antibiotic therapy may be unnecessary. A diagnostic approach with BAL and protected specimen brush using quantitative cultures for patients with VAP led to a decrease in broad-spectrum antibiotic use and improved outcome. Endotracheal aspirate cultures with quantitative counts are commonly used, but validation is lacking. An empirical approach using the Clinical Pulmonary Infection Score is a pragmatic approach that minimizes antibiotic resistance and leads to decreased mortality in patients in the ICU. The source of the P aeruginosa may be endogenous (from respiratory or GI tract colonization) or exogenous from tap water in hospital-acquired pneumonia. The latter source is amenable to preventive measures.     

Ventilator-associated pneumonia and chronic obstructive pulmonary disease

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is a common pulmonary and systemic inflammatory disease. Patients with COPD frequently require mechanical ventilation for acute exacerbations. BACKGROUND: The incidence of ventilator-associated pneumonia (VAP) in COPD patients varies from 6 to 33%. Tracheo-bronchial colonisation, local and systemic immuno-supression and frequent antibiotic treatment are factors predisposing to VAP in these patients. Gram negative bacilli are commonly isolated in COPD patients with VAP. Pseudomonas aeruginosa reported to be the most common. The diagnosis of VAP can be difficult in patients with COPD because of the low sensitivity of the portable chest radiograph. VAP is associated with higher mortality rates, longer duration of mechanical ventilation and ITU stay in patients with COPD. Initial antibiotic treatment should be based on recent guidelines and should take account of frequent prior hospitalisation and antibiotic treatment which are well known risk factors for multidrug resistant bacteria. Preventative measures recommended for the general population should be applied to COPD patients. In the absence of contraindications the use of non-invasive ventilation is recommended to reduce the risk of VAP. VIEWPOINT AND CONCLUSION: Future studies should better determine the incidence of VAP in COPD, improve the diagnostic approach and determine the effects of treating malnutrition, chronic tracheobronchial colonisation and limiting antibiotic and corticosteroid treatment on the incidence of VAP.     

Pulmonary infections in ventilated patients: Diagnostic and therapeutic options

The diagnosis of pulmonary infections in the ventilated patient has threatened the foundations of medicine. Although the lifesaving techniques of endotracheal intubation (developed for the treatment of diphtheria) and artificial ventilation (developed for the management of poliomyelitis) contribute greatly to medical care, they have resulted in the production of the “progress”-related infection of ventilator-associated pneumonia (VAP). Modern ventilator therapy is a substantial technologic advance from earlier days and, as technology inherently does, has removed some of the human element, the main foundation of Oslerian medical practice. The time-honored clinical diagnosis based on physical examination by an experienced physician has been seriously compromised in the approach to VAP.     

Resolution of infectious parameters after antimicrobial therapy in patients with ventilator-associated pneumonia

Although recommended durations of antimicrobial therapy for ventilator-associated pneumonia (VAP) range from 7 to 21 d, these are not based on prospective studies and little is known about the resolution of symptoms after start of antibiotics. Resolution of these symptoms was investigated in 27 patients. VAP was diagnosed on clinical, radiographic, and microbiological criteria, including quantitative cultures of bronchoalveolar lavage. All patients received appropriate antibiotic therapy. Highest temperatures, leukocyte counts, Pa(O(2))/FI(O(2)) ratios, and semiquantitative cultures of endotracheal aspirates were recorded from start of therapy until Day 14. Resolution was defined as the first day that these parameters fulfilled the following definition: temperature < or = 38 degrees C, leukocytes < or = 10 x 10(9)/L, Pa(O(2))/FI(O(2)) ratio > or = 25 kPa, and no or +1 of bacterial growth of etiologic pathogens in cultures of endotracheal aspirate. VAP was caused by Enterobacteriaceae (n = 14), P. aeruginosa (n = 7), S. aureus (n = 6), H. influenzae (n = 3), and S. pneumoniae (n = 1). H. influenzae and S. pneumoniae were eradicated from tracheal aspirates, whereas Enterobacteriaceae, S. aureus, and P. aeruginosa persisted, despite in vitro susceptibility to antibiotics administered. Significant improvements were observed for all clinical parameters, most apparently within the first 6 d after start of antibiotics. Newly acquired colonization, especially with P. aeruginosa and Enterobacteriaceae, occurred in the second week of therapy. Six patients developed a recurrent episode of VAP, four of them with P. aeruginosa. Clinical responses to therapy for VAP occur within the first 6 d of therapy, endotracheal colonization with Gram-negative bacteria persists despite susceptibility to therapy, and acquired colonization usually occurs in the second week of therapy and frequently precedes a recurrent episode.     

Clinical characteristics and treatment patterns among patients with ventilator-associated pneumonia

STUDY OBJECTIVES: To evaluate clinical characteristics and treatment patterns among patients with ventilator-associated pneumonia (VAP), including the implementation of and outcomes associated with deescalation therapy. DESIGN: Prospective, observational, cohort study. SETTING: Twenty ICUs throughout the United States. PATIENTS: A total of 398 ICU patients meeting predefined criteria for suspected VAP. INTERVENTIONS: Prospective, handheld, computer-based data collection regarding routine VAP management according to local institutional practices, including clinical and microbiological characteristics, treatment patterns, and outcomes. MEASUREMENTS AND RESULTS: The most frequent ICU admission diagnoses in patients with VAP were postoperative care (15.6%), neurologic conditions (13.3%), sepsis (13.1%), and cardiac complications (10.8%). The mean (+/- SD) duration of mechanical ventilation prior to VAP diagnosis was 7.3 +/- 6.9 days. Major pathogens were identified in 197 patients (49.5%) through either tracheal aspirate or BAL fluid and included primarily methicillin-resistant Staphylococcus aureus (14.8%), Pseudomonas aeruginosa (14.3%), and other Staphylococcus species (8.8%). More than 100 different antibiotic regimens were prescribed as initial VAP treatment, the majority of which included cefepime (30.4%) or a ureidopenicillin/monobactam combination (27.9%). The mean duration of therapy was 11.8 +/- 5.9 days. In the majority of cases (61.6%), therapy was neither escalated nor deescalated. Escalation of therapy occurred in 15.3% of cases, and deescalation occurred in 22.1%. The overall mortality rate was 25.1%, with a mean time to death of 16.2 days (range, 0 to 49 days). The mortality rate was significantly lower among patients in whom therapy was deescalated (17.0%), compared with those experiencing therapy escalation (42.6%) and those in whom therapy was neither escalated nor deescalated (23.7%; chi2= 13.25; p = 0.001). CONCLUSIONS: Treatment patterns for VAP vary widely from institution to institution, and the overall mortality rate remains unacceptably high. The deescalation of therapy in VAP patients appears to be associated with a reduction in mortality, which is an association that warrants further clinical study.     

Prevention of hospital-acquired pneumonia: European perspective

Several preventive measures for VAP have been empirically tested. There is clear evidence that antibiotic-containing preventive strategies, such as SDD and oropharyngeal decontamination, are very effective in different patient populations. Selection of antibiotic resistance remains the major disadvantage of these strategies, however, limiting its applicability in settings with high levels of antibiotic resistance. This probably precludes the use of these strategies in many American settings, but may allow their use in European countries with much lower endemic levels of resistance. There is little evidence that systemic prophylaxis is effective for the prevention of VAP, and initial studies were associated with resistance problems. Of the non antibiotic-containing preventive strategies, subglottic aspiration was effective in several studies, whereas other strategies, such as immunonutrition with glutamine or the semirecumbent patient position, were effective in single studies. All these studies were executed in European ICUs. For these interventions, more data are needed on the generalizability, feasibility, and cost effectiveness. Few data support the use of sucralfate for stress ulcer prophylaxis and modulation of enteral nutrition practices as preventive measures for VAP.     

Ventilator-associated tracheobronchitis: the impact of targeted antibiotic therapy on patient outcomes

Nosocomial lower respiratory tract infections are a common cause of morbidity and mortality in ICU patients receiving mechanical ventilation. Many studies have investigated the management and prevention of ventilator-associated pneumonia (VAP), but few have focused on the role of ventilator-associated tracheobronchitis (VAT). The pathogenesis of lower respiratory tract infections often begins with tracheal colonization that may progress to VAT, and in selected patients to VAP. Since there is no well-established definition of VAT, discrimination between VAT and VAP can be challenging. VAT is a localized disease with clinical signs (fever, leukocytosis, and purulent sputum), microbiologic information (Gram stain with bacteria and leukocytes, with either a positive semiquantitative or a quantitative sputum culture), and the absence of a new infiltrate on chest radiograph. Monitoring endotracheal aspirates has been used to identify and quantify pathogens colonizing the lower airway, to diagnose VAT or VAP, and to initiate early, targeted antibiotic therapy. Recent data suggest that VAT appears to be an important risk factor for VAP and that targeted antibiotic therapy for VAT may be a new paradigm for VAP prevention and better patient outcomes.     

Efficacy and safety of cefepime in late-onset ventilator-associated pneumonia in infants: a pilot randomized and controlled study

Multidrug-resistant organisms cause late-onset ventilator-associated pneumonia (VAP). In a pilot, randomized and controlled study, the efficacy and safety of cefepime, in late-onset VAP in infants, have now been evaluated in Malaysia. Thirty children aged <1 year with late-onset VAP (i.e. VAP occurring 5 or more days after intubation) were randomized to receive cefepime or, as a control, ceftazidime. The clinical responses and the microbiological clearance of tracheal aspirates were evaluated in each arm. Adverse events, if any, were monitored clinically and by blood tests. Ten of the 15 children given cefepime and five of the 15 given ceftazidime showed a satisfactory clinical response (P<0.1). Cefepime appeared significantly better at clearing polymicrobial infections from tracheal aspirates. There were no fatalities in the cefepime arm but three in ceftazidime (P<0.1). The mean (S.E.) durations of antibiotic use were 9.4 (1.5) days for cefepime and 7.6 (1.0) days for ceftazidime (P>0.05). No serious adverse effects were observed in either arm. In conclusion, in late-onset VAP in infants, cefepime monotherapy appears to be at least as effective and safe as ceftazidime monotherapy, with better microbiological clearance.     

呼吸机相关性肺炎病原菌与耐药性分析

目的 监测重症监护病房(ICU)中呼吸机相关性肺炎(ventilator-associated pneumonia,VAP)患者下呼吸道病原菌的分布及其耐药性,为临床治疗VAP提供经验性选药依据.方法 经人工气道采集患者下呼吸道分泌物标本,对连续2次培养为同一优势致病菌的菌株纳入本研究中,采用纸片法测定该菌的体外药物敏感性.结果 51例检出89株致病菌,其中革兰阴性细菌占78.7%(70/89),革兰阳性细菌占6.7%(6/89),真菌占14.6%(13/89),药敏结果显示这类菌株耐药现象严重.结论 ICU中VAP患者的感染致病菌以革兰阴性菌为主,呈多重耐药,提倡严密动态监测VAP病原菌,应重视并强调对抗生素药物的合理应用.     

Epidemiological and microbiological analysis of ventilator-associated pneumonia patients in a public teaching hospital.

Ventilator-associated pneumonia (VAP) is the most commonly-acquired infection in patients in intensive care units. We analyzed epidemiological and microbiological characteristics and the outcome, in a cohort of critically-ill patients with confirmed diagnosis of VAP. All patients who had been on mechanical ventilation (MV) for more than 48 hours were included in our study; material collection for microbiological analysis was done within the first 24 hours after beginning treatment or after changing antibiotics. There were 55/265 (20.7%) VAP cases diagnosed, at a rate of 21.6 episodes per 1,000 days of mechanical ventilation. Mean age of the patients was 66 years, with a mean APACHE II score of 26.7 + 7.0; male patients were more prevalent. The mortality rates in the intensive care unit (ICU) and during the hospital stay were 71% and 80%, respectively. MV duration in patients with VAP was 17 (range 3-43) days and among patients who had not developed VAP, 6 (2-32) days (p < 0.0001). 98.2% of the samples were positive, with a high prevalence of Gram-negative bacteria, mainly Acinetobacter calcoaceticus. Risk factors for death included age, MV duration and surgery. VAP incidence in this sample of critically-ill patients was high, with a high mortality rate. Control and prevention strategies based on continuing education of healthcare workers, developed by a multidisciplinary team, should be encouraged to minimize morbimortality of this infection.     

Antibiotic utilization and outcomes for patients with clinically suspected ventilator-associated pneumonia and negative quantitative BAL culture results

OBJECTIVE: To evaluate antibiotic utilization and clinical outcomes among patients with clinically suspected ventilator-associated pneumonia (VAP) and culture-negative BAL (CNBAL). DESIGN: Prospective observational cohort study. SETTING: A medical ICU from a university-affiliated urban teaching hospital employing a previously described antibiotic discontinuation guideline for the management of VAP. PATIENTS: One hundred one patients with a clinical suspicion of VAP and CNBAL were evaluated between July 2002 and December 2004. INTERVENTIONS: Prospective patient follow-up and data collection. Antibiotic discontinuation was determined by the clinical guideline and not the results of BAL cultures. RESULTS: The average age of the patients was 60.4 +/- 17.9 years and the mean APACHE II score was 23.2 +/- 8.7 (+/- SD). The mean duration of mechanical ventilation prior to clinically suspected VAP was 2.9 +/- 1.9 days. Nineteen patients (18.8%) received antibiotics for other indications prior to BAL. Empiric antibiotic therapy for VAP was begun in 65 patients (64.4%) following BAL. The duration of empiric antibiotic treatment following BAL was 2.1 +/- 0.8 days. None of these patients received antibiotics for > 3 days (median, 2 days; range, 1 to 3 days). Six patients (5.9%) were treated with antibiotics for a secondary episode of VAP or hospital-acquired pneumonia developing at least 72 h after the CNBAL was performed and discontinuation of the empiric antibiotic therapy prescribed for the initially suspected episode of VAP. Overall, 35 patients (34.7%) died during hospitalization. Two deaths occurred in patients with a secondary episode of VAP following CNBAL and discontinuation of empiric antimicrobial therapy. Neither of these two deaths was attributed to VAP. CONCLUSIONS: Although the decision to discontinue antibiotic treatment was based on clinical criteria and not BAL culture results, this study suggests that patients with a clinical suspicion of VAP and CNBAL can have empiric antimicrobial therapy safely discontinued within 72 h or in some cases withheld altogether. Prospective studies are needed to determine the safety of employing CNBAL as the primary criterion for the discontinuation of empirically begun antibiotic treatment for VAP.     

病原学定量和定性培养对呼吸机相关肺炎治疗结果的影响

目的：评价病原学定量培养（QC）和常规定性培养（RC）诊断方法对呼吸机相关肺炎（VAP）治疗结果的影响。方法：前瞻性对照研究了31例机械通气患者连续发生的93次VAP发病；VAP发病随机、交叉分为定量培养组和定性培养组，前者行纤维支气管镜引导保护性标本刷（FOBPSB）取材及QC，后者行气管内抽吸物常规定性培养（ETA－RC）；经验性抗生素治疗由经治医生决定，根据培养及药敏结果调速治疗；对VAP的治疗结果加以评价。结果：应用定量培养和定性培养作为VAP的诊断手段，并采取基于两种诊断方式的随机抗生素治疗，VAP的治疗结果如病死率、二重感染发生率、耐药率及抗生素费用等无明显差异；不适当的最初经验抗生素治疗较适当治疗导致了更高的病死率（17．7％）。结论：VAP的治疗结果可能更取决于最初经验治疗的正确性，耐较少取决于诊断取材的类型。     

Ventilator-associated pneumonia

PURPOSE OF REVIEW: This review summarises some of the notable papers on ventilator-associated pneumonia (VAP) from January 2003 to October 2004. RECENT FINDINGS: Ventilator-associated pneumonia remains an important drain on hospital resources. All population groups are affected, but patients with VAP are more likely to be older, sicker, and male, with invasive medical devices in situ. Early VAP diagnosis is desirable to reduce VAP mortality and to retard emergence of multidrug-resistant microbes. This may be possible using preliminary culture results or intracellular organism in polymorphonuclear cells. In most intensive care units, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii are the commonest organisms isolated in VAP. However, causative organisms vary between and within hospitals. Consequently, individual intensive care units should develop empirical antibiotic policies to target the pathogenic bacteria prevalent in their patient populations. Preventative strategies aimed at reducing aerodigestive tract colonisation by pathogenic organisms, and also their subsequent aspiration, are becoming increasingly important. Educating medical staff about these simple measures is therefore pertinent. To reduce the occurrence of multidrug-resistant organisms, limiting the duration of antibiotic treatment to 8 days and antimicrobial rotation should be contemplated. Empirical therapy with antipseudomonal penicillins plus beta-lactamase inhibitors should be considered. If methicillin-resistant Staphylococcus aureus VAP is a possibility, linezolid may be better than vancomycin. SUMMARY: Prevention remains the key to reducing VAP prevalence.