Neumonía nosocomial

The hospital acquired pneumonia (HAP) is one of the most common infections acquired among hospitalised patients. Within the HAP, the ventilator-associated pneumonia (VAP) is the most common nosocomial infection complication among patients with acute respiratory failure. The VAP and HAP are associated with increased mortality and increased hospital costs. The rise in HAP due to antibiotic-resistant bacteria also causes an increase in the incidence of inappropriate empirical antibiotic therapy, with an associated increased risk of hospital mortality. It is very important to know the most common organisms responsible for these infections in each hospital and each Intensive Care Unit, as well as their antimicrobial susceptibility patterns, in order to reduce the incidence of inappropriate antibiotic therapy and improve the prognosis of patients. Additionally, clinical strategies aimed at the prevention of HAP and VAP should be employed in hospital settings caring for patients at risk for these infections.     

Nonpharmacological prevention of hospital-acquired pneumonia

Hospital-acquired pneumonia (HAP) is the most common nosocomial infection occurring among mechanically ventilated patients. The benefits associated with the systematic prevention of HAP include fewer infections with high-risk antibiotic-resistant bacteria, lower rates of hospital mortality, reduced medical care costs, and shorter hospital lengths of stay. Unfortunately, many hospitals do not have an organized approach to the prevention of HAP. This review will describe the nonpharmacological approaches available for the prevention of HAP. It should help clinicians to design their own strategies for the prevention of this important hospital-acquired infection.     

Ventilator-associated pneumonia: Clinical significance and implications for nursing

Pneumonia is the second most common nosocomial infection in the United States and the leading cause of death from nosocomial infections. Intubation and mechanical ventilation greatly increase the risk of bacterial pneumonia. Ventilator-associated pneumonia (VAP) occurs in a patient treated with mechanical ventilation, and it is neither present nor developing at the time of intubation; it is a serious problem—with significant morbidity and mortality rates. Aspiration of bacteria from the oropharynx, leakage of contaminated secretions around the endotracheal tube, patient position, and cross-contamination from respiratory equipment and health care providers are important factors in the development of VAP. Nurses caring for patients treated with mechanical ventilation must recognize risk factors and include strategies for reducing these factors as part of their nursing care. This article summarizes the literature related to VAP: its incidence, associated factors, diagnosis, and current therapies, with an emphasis on nursing implications in the care of these patients.     

呼吸机相关肺炎的研究进展

呼吸机相关肺炎（VAP）是机械通气患者常见且较特殊的医院内获得性肺炎，发病率及病死率较高。临床预防、早期诊断、病原学诊断和临床抗菌药物治疗仍然是VAP重症患者救治领域的难点，现将近年来VAP的研究进展做一综述。     

Antibiotic resistance in nosocomial pulmonary pathogens

Nosocomial pneumonia is the second most common hospital-acquired infection and are associated with antibiotic-resistant microorganisms. In nosocomial pneumonia, both the diagnosis of the disease and the identification of the pathogen agent are controversial. The lack of standard diagnostic criteria can lead to the inappropriate use of broad-spectrum antibiotic therapy and the emergence of multiresistant bacteria. Moreover, empirical antibiotic treatment must be prescribed after bacteriological sample but before culture results because the majority of nosocomial pneumonias require an urgent antibiotic therapy. Most nosocomial pneumonias are of an endogenous origin, particularly in mechanically ventilated patients, and this is associated with a higher rate of multiresistant methicillin-resistant Staphylococcus aureus, Acinetobacter baumanii, Klebsiella pneumoniae with extended spectrum b-lactamases, and Pseudomonadaceae. Multiple factors influence the frequency of pathogens associated with antibiotic resistance, such as duration of hospital stay, time of onset, prior antibiotic therapy, and local microbial ecology.     

Preventing ventilator-associated pneumonia: an evidence-based approach of modifiable risk factors

There is considerable evidence to suggest that specific interventions can be effectively employed to prevent hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). These interventions consist of pharmacological and nonpharmacological strategies that focus on prevention of aerodigestive tract colonization and the prevention of aspiration of contaminated secretions, the major pathogenetic mechanisms leading to HAP. Important components of effective preventive strategies focus on basic infection control principles like handwashing, adequate intensive care unit (ICU) staff education, and optimal resource utilization. Measures to prevent HAP/VAP extend into all aspects of daily intensive care practice, including antibiotic selection and duration of use, preferred routes of intubation, limitation of sedation, protocolized weaning, optimal use of noninvasive mask ventilation, patient positioning, ventilator circuit management, transfusion practices, nutritional support issues, stress ulcer prophylaxis, and glycemic control. Local programs encompassing these interventions should be applied at a multidisciplinary level, involve all caregivers, and include local surveillance programs for antibiotic-resistant bacteria. The importance of implementing preventive strategies is amplified by the anticipated limited availability of new antimicrobial drug classes for the foreseeable future. Effective implementation of these preventive principles can result in significant cost savings for society and reduce hospital mortality and morbidity for individual patients.     

Clinical practice guidelines for hospital-acquired pneumonia and ventilator-associated pneumonia in adults

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are important causes of morbidity and mortality, with mortality rates approaching 62%. HAP and VAP are the second most common cause of nosocomial infection overall, but are the most common cause documented in the intensive care unit setting. In addition, HAP and VAP produce the highest mortality associated with nosocomial infection. As a result, evidence-based guidelines were prepared detailing the epidemiology, microbial etiology, risk factors and clinical manifestations of HAP and VAP. Furthermore, an approach based on the available data, expert opinion and current practice for the provision of care within the Canadian health care system was used to determine risk stratification schemas to enable appropriate diagnosis, antimicrobial management and nonantimicrobial management of HAP and VAP. Finally, prevention and risk-reduction strategies to reduce the risk of acquiring these infections were collated. Future initiatives to enhance more rapid diagnosis and to effect better treatment for resistant pathogens are necessary to reduce morbidity and improve survival.     

Impact of methicillin resistance on outcome of Staphylococcus aureus ventilator-associated pneumonia

The impact of methicillin resistance on morbidity and mortality of patients suffering from severe Staphylococcus aureus infections remains highly controversial. We analyzed a retrospective cohort of 97 patients with methicillin-susceptible and 74 patients with methicillin-resistant Staphylococcus aureus ventilator-associated pneumonia (VAP). Initial empiric antibiotic therapy was appropriate for every patient. Patients with methicillin-resistant Staphylococcus aureus VAP were older, had higher disease-severity scores, and had been on mechanical ventilation longer at onset of VAP. Factors associated with 28-day mortality retained by multivariate logistic regression analysis were: age (odds ratio [OR] = 1.05, 95% confidence interval [CI], 1.02-1.08, p = 0.001) and Day 1 organ dysfunctions or infection (ODIN) score (OR = 1.90, 95% CI, 1.31-2.78, p = 0.001), but not methicillin resistance (OR = 1.72, 95% CI, 0.73-4.05, p = 0.22). The percentages of infection relapse or superinfection did not differ significantly between the two patient groups. In conclusion, after controlling for clinical and physiologic heterogeneity between groups, methicillin resistance did not significantly affect 28-day mortality of patients with Staphylococcus aureus VAP receiving appropriate antibiotics.     

Epidemiology and microbiology of hospital-acquired pneumonia

Hospital-acquired pneumonia (HAP) is the second most common nosocomial infection in the critically ill patient and is associated with the greatest mortality and increased morbidity and cost of care. The major risk factor for the development of HAP in intensive care is the occurrence of intubation and mechanical ventilation, giving rise to the term ventilator-associated pneumonia (VAP). Incidence of VAP varies in different populations of critically ill patients and generally ranges from 9 to 20%, with an overall rate of 10 to 15 cases per 1,000 ventilator days. The cumulative risk of developing VAP is ~1% per day of mechanical ventilation (MV). The crude mortality rate of VAP is 60% and the estimates of attributable risk range from 27 to 43%. Mortality from VAP is influenced by host factors, the virulence of the pathogens, and the adequacy of initial antimicrobial therapy. The etiologic agents for VAP differ according to the population studied, duration of hospital stay, time after intubation, and prior antimicrobial therapy. Risk factors include nonmodifiable factors like age, chronic obstructive pulmonary disease, severe head trauma, and multiple trauma, and modifiable factors like large volume gastric aspiration, duration of MV, elevated gastric pH, histamine type 2 blocker therapy, ventilator circuit change frequency, self-extubation, and reintubation. The impact that diagnosis using invasive diagnostic techniques may have on the epidemiological characteristics of VAP are unknown, but may potentially reduce problems resulting from misclassification of this entity.     

Prevención no farmacológica de la neumonía asociada a ventilación mecánica

Ventilator-associated pneumonia (VAP) is the first cause of mortality due to nosocomial infections in the intensive care unit. Its incidence ranges from 9% to 67% of patients on mechanical ventilation. Risk factors are multiple and are associated with prolonged stays in hospital and intensive care units. Additional costs for each episode of VAP range from 9,000 € to 31,000 €.     

医院获得性肺炎的病原学及耐药趋势

医院获得性肺炎是常见的医院获得性感染,在我国医院获得性感染中居首位,其发病率及病死率高,住院时间长,医疗费用高。随着抗菌药物的滥用,免疫抑制疗法的发展及广泛应用等,引起医院获得性肺炎的病原菌更加多样化,耐药现象也越来越严峻。本文对国内外医院获得性肺炎的病原菌分布及耐药情况进行综述,为临床治疗提供参考。     

不同类型老年吸入性肺炎的病原学、抗生素应用及临床转归

目的 比较老年社区获得性吸入性肺炎(CAP)、医疗相关性吸入性肺炎(HCAP)及医院获得性吸入性肺炎(HAP,包括呼吸机相关性吸入性肺炎)三者病原学、抗生素应用及治疗转归的关系.方法 收集2005年1月一2010年12月北京二炮总医院呼吸科住院的216例老年吸人性肺炎患者病例,分析其病原学结果、抗生素应用的及治疗转归.结果 三种吸入性肺炎的病原学有显著差异,与CAP和HCAP相比,HAP患者G-杆菌的感染比例明显增多(P<0.001);抗生素应用方案有明显差异,CAP组病人未调整抗生素应用比率明显高于HCAP组与HAP组(P<0.001);抗生素应用策略不同,所致死亡率有明显差异,以升阶梯方案为最高,以降阶梯治疗为最低(P=0.03).结论 三种吸入性肺炎在感染病原菌种类、抗生素应用策略及治疗转归上有明显差异,应根据不同类型的老年吸入性肺炎特点合理经验性使用抗菌药物.     

Diabetes mellitus as a risk factor for nosocomial pneumonia and associated mortality.

BACKGROUND: Patients with diabetes mellitus (DM) are considered to be more susceptible to several types of infections, including community-acquired pneumonia. However, it is not clear whether DM is a risk factor for development of hospital-acquired pneumonia (HAP), an infection with considerable morbidity and mortality worldwide. METHODS: We searched PubMed for relevant publications that included data on the possible association between DM and HAP. Cohort studies, case-control studies and observational studies were included in this analysis. Two of the authors performed the literature search independently. RESULTS: We identified 84 studies designed to identify risk factors and predictors of mortality as a result of HAP. Of these, 13 studied patients in the ward or intensive care unit (ICU), 28 studied patients treated in the ICU only, and 44 studied patients with ventilator-associated pneumonia. Only 14 considered the role of DM for this nosocomial complication. The reviewed data suggest that DM is not a risk factor for development of HAP in patients who require ICU treatment. In addition, patients with DM are not at increased risk for development of ventilator-associated pneumonia. Moreover, DM is not a prognostic factor for mortality in patients with HAP based on data from two out of 84 identified studies that provided relevant information. CONCLUSIONS: There is a relative scarcity of studies examining DM as a potential risk factor for HAP. Our analysis of the available data supports the conclusion that DM is not a risk factor for development of HAP and mortality associated with this nosocomial infection.     

Nosocomial pneumonia: a report of 372 cases]

Three hundred seventy-two cases of hospital-acquired pneumonia occurring during a 4-year period were reviewed. It was found that the annual incidence of the pneumonia was 1.44% which ranked first in the incidence of nosocomial infections at this institution. Most of the patients had suffered from primary severe underlying diseases with immunosuppression of different degrees. A variety of factors such as antibiotic and steroid therapy, operation, intensive care, endotracheal intubation, tracheostomy, chemotherapy and radiotherapy predisposed to the acquisition of this pneumonia. Most frequent etiologic agents for hospital-acquired pneumonia were Enterobacteriaceae, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. The overall mortality rate was 25.3%. However, deaths associated with Pseudomonas aeruginosa and Staphylococcus aureus are particularly high, with rates of 70.6% and 66.7% respectively. The incidence, mortality, pathogenesis, diagnosis, treatment and prevention of the disorder were discussed briefly.     

Nosocomial Pneumonia

Nosocomial pneumonia or hospital-acquired pneumonia (HAP) causes considerable morbidity and mortality. It is the second most common nosocomial infection and the leading cause of death from hospital-acquired infections. In 1996 the American Thoracic Society (ATS) published guidelines for empirical therapy of HAP. This review focuses on the literature that has appeared since the ATS statement. Early diagnosis of HAP and its etiology is crucial in guiding empirical therapy. Since 1996, it has become clear that differentiating mere colonization from etiologic pathogens infecting the lower respiratory tract is best achieved by employing bronchoalveolar lavage (BAL) or protected specimen brush (PSB) in combination with quantitative culture and detection of intracellular microorganisms. Endotracheal aspirate and non-bronchoscopic BAL/PSB in combination with quantitative culture provide a good alternative in patients suspected of ventilator-associated pneumonia. Since culture results take 2-3 days, initial therapy of HAP is by definition empirical. Epidemiologic studies have identified the most frequently involved pathogens: Enterobacteriaceae, Haemophilus influenzae, Streptococcus pneumoniae and Staphylococcus aureus ('core pathogens'). Empirical therapy covering only the 'core pathogens' will suffice in patients without risk factors for resistant microorganisms. Studies that have appeared since the ATS statement issued in 1996, demonstrate several new risk factors for HAP with multiresistant pathogens. In patients with risk factors, empirical therapy should consist of antibacterials with a broader spectrum. The most important risk factors for resistant microorganisms are late onset of HAP (>/=5 days after admission), recent use of antibacterial therapy, and mechanical ventilation. Multiresistant bacteria of specific interest are methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa, Acinetobacter calcoaceticus-baumannii, Stenotrophomonas maltophilia and extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae. Each of these organisms has its specific susceptibility pattern, demanding appropriate antibacterial treatment. To further improve outcomes, specific therapeutic options for multiresistant pathogens and pharmacological factors are discussed. Antibacterials developed since 1996 or antibacterials with renewed interest (linezolid, quinupristin/dalfopristin, teicoplanin, meropenem, new fluoroquinolones, and fourth-generation cephalosporins) are discussed in the light of developing resistance.Since the ATS statement, many reports have shown increasing incidences of resistant microorganisms. Therefore, one of the most important conclusions from this review is that empirical therapy for HAP should not be based on general guidelines alone, but that local epidemiology should be taken into account and used in the formulation of local guidelines.     

降钙素原在医院获得性肺炎和呼吸机相关性肺炎的诊断和抗感染管理中的应用价值

医院获得性肺炎(HAP)和呼吸机相关性肺炎(VAP)是我国现患率居第一位的医院感染性疾病。国内外相关指南相继进行了更新,旨在提高HAP/VAP诊断和治疗水平,改善患者的结局,但我们仍然面临诸多挑战。降钙素原(PCT)是较C反应蛋白(CRP)更特异的感染相关生物学标志物,对重症细菌感染和脓毒症具有反应快速、特异性高的优点,动态监测PCT可指导HAP/VAP的诊断及抗菌药物治疗的疗程。     

Hospital-acquired pneumonia: microbiological data and potential adequacy of antimicrobial regimens.

Adequate antimicrobial therapy is a main approach employed to decrease the mortality associated with hospital-acquired pneumonia (HAP). All methods that optimise empirical treatment without increasing antibiotic selective pressure are relevant. Categorisation of patients according to HAP time of onset, severity and risk factors (American Thoracic Society (ATS) classification) or duration of mechanical ventilation and prior antibiotics (Trouillet's classification) are two such methods. The aim of this study was to catagorise patients with HAP according to these classifications and to determine the frequency of resistant pathogens and the most adequate antimicrobial regimens in each group. A total 124 patients with bacteriologically proven HAP were studied. The ATS classification categorised patients by increasing frequency of resistant pathogens from 0-30.3%. The ATS empirical antibiotic recommendations appeared valid but proposed combinations including vancomycin for 72.5% of patients. Trouillet's classification categorised patients into four groups with a frequency of resistant pathogens from 4.9-35.6%. Vancomycin was proposed for 48.5% of patients. The American Thoracic Society classification appears to be more specific than Trouillet's for predicting the absence of resistant causative pathogens in hospital-acquired pneumonia but could lead to a greater use of vancomycin. Stratification combining the two classifications is an interesting alternative.     

老年患者医院获得性肺炎病原菌及耐药性监测

目的 明确广州地区老年医院获得性肺炎(hospital-acquired pneumonia,HAP)患者致病菌的构成情况及耐药情况,以期指导临床治疗.方法 2004年1月至2005年10月在广州市4家医院住院、年龄≥60岁且分离出致病菌的HAP患者共206例,进行致病菌的分离鉴定,采用纸片扩散法进行细菌药敏检测.结果 本组206例老年HAP患者平均年龄(76.6±8.3)岁,平均发病时间为21 d,94.4%为迟发型HAP.共分离致病菌308株,其中革兰阴性细菌占65.3%,革兰阳性细菌占26.3%,白色念珠菌占8.4%.前3位致病菌分别为铜绿假单胞菌(19.2%)、金黄色葡萄球菌(12.7%)、肺炎克雷伯菌(9.1%).革兰阳性菌和革兰阴性菌均耐药情况严重.金黄色葡萄球菌中耐甲氧西林金黄色葡萄球菌比例高达92.3%,溶血性葡萄球菌100%为耐甲氧西林溶血性葡萄球菌.金黄色葡萄球菌对万古霉素耐药率为2.6%.革兰阴性细菌对三代头孢菌素均严重耐药,铜绿假单胞菌呈广泛性严重耐药,有15株铜绿假单胞菌对所有抗生素均耐药.结论 广州地区老年HAP患者细菌耐药性严重,必须加强措施防治其发病.     

Nosocomial pneumonia: state of the science

Nosocomial pneumonia is the leading cause of mortality due to hospital-acquired infections. A thorough understanding of the most recent developments in evaluating and managing nosocomial pneumonia is critical for infection control professionals and hospital epidemiologists, given the incidence and cost of this important patient safety problem. We review the evidence on pathogenesis, diagnosis, treatment, and prevention of both ventilator-associated and nonventilator-associated pneumonia. Key recommendations are then provided for diagnostic testing strategies, antibiotic selection, and treatment duration. We also summarize the most recent data on how to prevent hospital-acquired infection, in general, and nosocomial pneumonia, in particular.     

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.