Noninvasive versus invasive microbial investigation in ventilator-associated pneumonia: evaluation of outcome

Management of Ventilator-associated Pneumonia

Pneumonia is the most important respiratory infection in mechanically ventilated patients. It is defined as the presence of microorganisms in the pulmonary parenchyma leading to the development of an inflammatory response by the host, which may be localized in the lung or may extend systemically. Nosocomial pneumonia is an infectious process which develops within 48 hours after admission to the hospital and that was not incubating at the time of hospitalization. Ventilator-associated pneumonia (VAP) is considered as a subgroup of nosocomial pneumonia and is an infectious pulmonary process which develops 48 hours after the presence of an artificial airway and mechanical ventilation. Since a large proportion of the patients who develop nosocomial pneumonia are intubated and receive mechanical ventilation, most epidemiological and clinical studies on nosocomial pneumonia have been focused on critically ill patients and those receiving mechanical ventilation. From a clinical point of view, nosocomial pneumonia is of great importance not only because of the consequences of the important morbidity and mortality but also due to the high costs associated with development of this disease.

Management of Ventilator-associated Pneumonia

Pneumonia is the most important respiratory infection in mechanically ventilated patients. It is defined as the presence of microorganisms in the pulmonary parenchyma leading to the development of an inflammatory response by the host, which may be localized in the lung or may extend systemically. Nosocomial pneumonia is an infectious process which develops within 48 hours after admission to the hospital and that was not incubating at the time of hospitalization. Ventilator-associated pneumonia (VAP) is considered as a subgroup of nosocomial pneumonia and is an infectious pulmonary process which develops 48 hours after the presence of an artificial airway and mechanical ventilation. Since a large proportion of the patients who develop nosocomial pneumonia are intubated and receive mechanical ventilation, most epidemiological and clinical studies on nosocomial pneumonia have been focused on critically ill patients and those receiving mechanical ventilation. From a clinical point of view, nosocomial pneumonia is of great importance not only because of the consequences of the important morbidity and mortality but also due to the high costs associated with development of this disease.

Nosocomial pneumonia in the ICU: a prospective cohort study

Ventilator-associated pneumonia (VAP) is the most common intensive care unit (ICU)-acquired infection among patients requiring mechanical ventilation. A prospective surveillance programme of all patients has been implemented at the ICU, Karolinska University Hospital, Sweden since 2001. Within this programme, incidence and risk factors for ICU-acquired pneumonia and associated death over a 2-y period have been studied. Of 329 patients enrolled in the study, 221 required mechanical ventilation. 33 of 221 patients (15%) developed VAP, corresponding to a rate of 29 VAP/1000 ventilator d. Risk factors for VAP were aspiration (hazard ratio 3.79; 95% CI 1.48-9.68), recent surgery (HR 3.58; 95% CI 1.15-11.10) and trauma (HR 3.00; 95% CI 1.03-8.71). 11 patients of 33 (33%) with VAP died within 28 d compared to 46 of 288 (16%) without ICU-acquired pneumonia (odds ratio 2.73; 95% CI 0.97-7.63). We conclude that: 1) incidence of VAP was 15% and the most important risk factor was aspiration; 2) APACHE II score > or = 20 is a stronger predictor for poor outcome than VAP; 3) a minority of patients with APACHE II score > or = 20 develop VAP; and 4) continuous surveillance programmes are feasible and provide valuable data for improvement of quality of care.

Diagnosis, management and prevention of ventilator-associated pneumonia in the UK

BACKGROUND AND OBJECTIVE

Ventilator-associated pneumonia is a nosocomial infection that occurs in patients receiving mechanical ventilation for >48 h. Many aspects of its diagnosis, treatment and management are controversial. We used a postal questionnaire to survey current practice within the UK.

METHODS

Questionnaire study of 207 general intensive care units in the UK.

RESULTS

The response rate was 77.3%. Regarding diagnosis, 30% of units obtained specimens from the lungs invasively, while the remainder relied on tracheal aspirates. In only 28.2% of units using tracheal aspirates were results reported in a quantitative manner. A clinical suspicion of ventilator-associated pneumonia would lead to the administration of empirical antibiotic therapy in the majority of units (77.2%), opinion being almost equally divided on whether this should be mono (49.1%) or combination therapy (50.9%). Although most units received regular microbiology feedback (90.5%), the involvement of a microbiologist in the antibiotic decision-making process was variable. Antibiotics were continued for a median of 7 days (inter-quartile range 5-8.5, range 2-14 days). Compliance with the principal methods of ventilator-associated pneumonia prevention was good.

CONCLUSION

There is widespread variation in the methods used for the diagnosis of ventilator-associated pneumonia within the UK. The majority of units rely on non-quantitative analysis of tracheal aspirates. This technique has a high percentage of false-positives, and suggests widespread over utilization of antibiotics. However, most agree that antibiotics should be given empirically when there is a clinical suspicion of ventilator-associated pneumonia. The widespread introduction of 'ventilator bundles' appears to have ensured that most units actively take measures to prevent ventilator-associated pneumonia.

A Bayesian decision-support system for diagnosing ventilator-associated pneumonia

OBJECTIVE

To determine the diagnostic performance of a Bayesian Decision-Support System (BDSS) for ventilator-associated pneumonia (VAP).

DESIGN

A previously developed BDSS, automatically obtaining patient data from patient information systems, provides likelihood predictions of VAP. In a prospectively studied cohort of 872 ICU patients, VAP was diagnosed by two infectious-disease specialists using a decision tree (reference diagnosis). After internal validation daily BDSS predictions were compared with the reference diagnosis. For data analysis two approaches were pursued: using BDSS predictions (a) for all 9422 patient days, and (b) only for the 238 days with presumed respiratory tract infections (RTI) according to the responsible physicians.

MEASUREMENTS AND RESULTS

157 (66%) of 238 days with presumed RTI fulfilled criteria for VAP. In approach (a), median daily BDSS likelihood predictions for days with and without VAP were 77% [Interquartile range (IQR) = 56-91%] and 14% [IQR 5-42%, p < 0.001, Mann-Whitney U-test (MWU)], respectively. In receiver operating characteristics (ROC) analysis, optimal BDSS cut-off point for VAP was 46%, and with this cut-off point positive predictive value (PPV) and negative predictive value (NPV) were 6.1 and 99.6%, respectively [AUC = 0.857 (95% CI 0.827-0.888)]. In approach (b), optimal cut-off for VAP was 78%, and with this cut-off point PPV and NPV were 86 and 66%, respectively [AUC = 0.846 (95% CI 0.794-0.899)].

CONCLUSIONS

As compared with the reference diagnosis, the BDSS had good test characteristics for diagnosing VAP, and might become a useful tool for assisting ICU physicians, both for routinely daily assessment and in patients clinically suspected of having VAP. Empirical validation of its performance is now warranted.

Antibiotic management of suspected nosocomial ICU-acquired infection: does prolonged empiric therapy improve outcome?

OBJECTIVE

To characterize empiric antibiotic use in patients with suspected nosocomial ICU-acquired infections (NI), and determine the impact of prolonged therapy in the absence of infection.

DESIGN AND SETTING

Multicenter prospective cohort, with eight medical-surgical ICUs in North America and Europe.

PATIENTS

195 patients with suspected NI.

METHODS

The diagnosis of NI was adjudicated by a blinded Clinical Evaluation Committee using retrospective review of clinical, radiological, and culture data.

RESULTS

Empiric antibiotics were prescribed for 143 of 195 (73.3%) patients with suspected NI; only 39 of 195 (20.0%) were adjudicated as being infected. Infection rates were similar in patients who did (26 of 143, 18.2%), or did not (13 of 52, 25.0%) receive empiric therapy (p = 0.3). Empiric antibiotics were continued for more than 4 days in 56 of 95 (59.0%) patients without adjudicated NI. Factors associated with continued empiric therapy were increased age (p = 0.02), ongoing SIRS (p = 0.03), and hospital (p = 0.004). Patients without NI who received empiric antibiotics for longer than 4 days had increased 28-day mortality (18 of 56, 32.1%), compared with those whose antibiotics were discontinued (3 of 39, 7.7%; OR = 5.7, 95% CI 1.5-20.9, p = 0.005). When the influence of age, admission diagnosis, vasopressor use, and multiple organ dysfunction was controlled by multivariable analysis, prolonged empiric therapy was not independently associated with mortality (OR = 3.8, 95% CI 0.9-15.5, p = 0.07).

CONCLUSIONS

Empiric antibiotics were initiated four times more often than NI was confirmed, and frequently continued in the absence of infection. We found no evidence that prolonged use of empiric antibiotics improved outcome for ICU patients, but rather a suggestion that the practice may be harmful.

The place of guidelines in hospital-acquired pneumonia

The recent increase in hospital-acquired infections (HAIs) has meant that hospital-acquired pneumonia (HAP) has come under the spotlight. HAP is the most common HAI contributing to death and affects about 0.5-1% of all patients admitted to hospital. HAP significantly increases health complications and extends the length of time patients stay in hospital by up to 13 days on average, thus impacting significantly on hospital resources. The British Society of Antimicrobial Chemotherapy Hospital-Acquired Pneumonia guidelines were published on the society's website last year and represent one of only two sets of evidence-based HAP guidelines in the world which deal with the trio of prevention, diagnosis and treatment. This paper reviews the evolution and status of HAP guidelines, drawing attention to recent developments, differences in approach and outcomes and further areas of work. There are clear indications that the implementation of evidence-based guidelines will reduce HAP and improve patient outcomes.

Predictive Value of Sputum Gram Stain for the Determination of Appropriate Antibiotic Therapy in Ventilator-Associated Pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is diagnosed in about 30% to 50% of critically ill postsurgical and trauma patients. Early appropriate antibiotic therapy has been associated with improved survival rates. The diagnosis, however, continues to be a challenge. We routinely employ clinical pulmonary infection scores to warrant a bronchoalveolar lavage (BAL) quantitative culture to subsequently diagnose VAP. Presumptive antibiotic therapy for the first 48 to 72 hours is based on the sputum Gram stain, obtained at the time of BAL. This study was conducted to analyze the predictive value of sputum Gram stain for selecting appropriate early antibiotic therapy for VAP as confirmed by a BAL quantitative culture (>10 CFU/mL considered diagnostic).

METHODS

The retrospective analysis included 124 consecutive intensive care unit patients with 186 identified episodes of presumed VAP from December 2002 to June 2006. VAP episodes were identified by a clinical pulmonary infection score > or =6, availability of a sputum Gram stain, and a corresponding quantitative culture result from a BAL sample.

RESULTS

The overall correlation between Gram stain and subsequent organism identified on the BAL quantitative culture was only fair with a kappa score of 0.314. The best predictive value calculated was for the category of negative Gram stain. However, in 10 of 45 episodes where the sputum Gram stain did not identify a predominant organism, the BAL culture isolated pathogenic strains. Pseudomonas sp. was the most common bacteria isolated from the BAL samples.

CONCLUSIONS

Irrespective of sputum Gram stain, presumptive triple antibiotic coverage should be instituted to provide dual antibiotic coverage for gram-negative bacilli, and vancomycin for gram-positive cocci. Additionally, identification of no organisms in the sputum Gram stain should still prompt broad-spectrum antibiotic coverage until the final results of the BAL quantitative culture are available.

Diagnostic strategies for nosocomial pneumonia

PURPOSE OF REVIEW

This review describes advances in clinical and microbiological modalities for diagnosis of nosocomial pneumonia and the role of biological markers.

RECENT FINDINGS

Serial assessments with the clinical pulmonary infection score identifies nonsurvivors and allows discontinuation of antibiotics when there is low suspicion of pneumonia. Studies evaluating its clinical utility show mixed results. A meta-analysis revealed that an invasive approach does not affect mortality but reduces costs, antibiotic exposure, and multidrug resistance. In contrast to these findings, a recent trial comparing nonquantitative endotracheal aspirate and quantitative bronchoalveolar lavage cultures showed similar clinical outcomes and antibiotic utilization. The role of quantitative endotracheal aspirate for diagnosis of pneumonia not related to mechanical ventilation was recently evaluated. Procalcitonin and soluble triggering receptor expressed on myeloid cells-1 aid in diagnosis, identify sepsis related to ventilator-associated pneumonia and patients with worst outcomes.

SUMMARY

The diagnostic modality chosen depends on availability, personnel experience, and the patient's clinical status. Recent guidelines support the use of quantitative cultures in an integrated clinical and microbiological algorithm. The decision to adjust antibiotics involves clinical reassessment and interpretation of culture results. Biological markers have a potential role as screening and prognostic tools.

Article Commentary: Strategies in the Prevention and Management of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is a leading cause of morbidity and mortality in the intensive care unit. Prevention of VAP is possible through the use of several evidence-based strategies intended to minimize intubation, the duration of mechanical ventilation, and the risk of aspiration of oropharyngeal pathogens. Current data favor the quantitative analysis of lower respiratory tract cultures for the diagnosis of VAP, accompanied by the initiation of broad-spectrum empiric antimicrobial therapy based on patient risk factors for infection with multi-drug-resistant pathogens and data from unit-specific antibiograms. Eventual choice of antibiotic and duration of therapy are selected based on culture results and patient stability, with an emphasis on minimization of unnecessary antibiotic use.

Agreement of decision analyses and subsequent clinical studies in infectious diseases

PURPOSE

Decision analysis techniques can compare management strategies when there are insufficient data from clinical studies to guide decision making. We compared the outcomes of decision analyses and subsequent clinical studies in the infectious disease literature to assess the validity of the conclusions of the decision analyses.

METHODS

A search strategy to identify decision analyses in infectious disease topics published from 1990 to 2005 was developed and performed using PubMed. Abstracts of all identified articles were reviewed, and infectious disease-related decision analyses were retained. Subsequent clinical trials and observational studies that corresponded to these decision analyses were identified using prespecified search strategies. Clinical studies were considered a match for the decision analysis if they assessed the same patient population, intervention, and outcome. Agreement or disagreement between the conclusions of the decision analysis and clinical study were determined by author review.

RESULTS

The initial PubMed search yielded 318 references. Forty decision analyses pertaining to 29 infectious disease topics were identified. Of the 40, 16 (40%) from 13 infectious disease topics had matching clinical studies. In 12 of 16 (75%), conclusions of at least 1 clinical study agreed with those of the decision analysis. Three of the 4 decision analyses in which conclusions disagreed were from the same topic (management of febrile children).

CONCLUSIONS

There was substantial agreement between the conclusions of decision analyses and clinical studies in infectious diseases, supporting the validity of decision analysis and its utility in guiding management decisions.

Pneumonia Observational Incidence and Treatment: A Multidisciplinary Process Improvement Study

Background Little information is available on the types, causes, and treatment of pneumonia in intensive care unit patients in usual clinical practice.

Objective To characterize treatment of patients with presumed pneumonia in a tertiary care intensive care unit and to identify potential areas for improvement in care.

Methods In a prospective, cohort study, the sample consisted of all consecutive patients treated in an intensive care unit during a 3-month period. For patients with presumed pneumonia, data were collected on incidence of pneumonia, diagnostic investigations, microbial isolates, and antibiotics prescribed.

Results Of 194 admissions, 73 patients were treated for pneumonia: 47 had community-acquired pneumonia; 12 had hospital-acquired pneumonia; 12 had ventilator-associated pneumonia, both early (7) and late (5); and 2 had intensive care unit–acquired pneumonia. Approximately 71% of patients had microbiological tests performed. Among 54 microbial isolates, 51.9% were gram-positive bacteria, 31.5% were gram-negative bacteria, and 9.3% were Candida species. The most commonly used antimicrobials were quinolones (54 of 192 prescriptions) and cephalosporins (33); each patient received a median of 3 antibiotics.

Conclusions Most cases of pneumonia were community acquired. The most common causative organisms were gram-positive cocci. Four quality improvement strategies were rationalization of antibiotic use during rounds, nurses’ reporting of culture results, review of antibiotic appropriateness by a pharmacist, and redesign of the clinical information system.

The clinical pulmonary infection score poorly predicts pneumonia in patients with burns

The Clinical Pulmonary Infection Score (CPIS) has been reported to be a useful tool in the diagnosis of ventilator-associated pneumonia (VAP) in the critical care setting. However, the systemic inflammation associated with injury may limit the utility of CPIS in patients with burns. The purpose of this study was to determine the potential utility of CPIS in the management of burn patients. A retrospective review was performed on all burn patients who underwent quantitative culture to diagnose VAP from 2003 to 2005. CPIS was retrospectively calculated for each patient on the day of the procedure. The sensitivity, specificity, and predictive values of a CPIS greater than 6 for VAP diagnosis were calculated. In addition, CPIS scores of patients with and without pneumonia were compared using the Mann-Whitney U test. A total of 46 quantitative cultures were obtained in 28 patients during the study period. Average patient age was 45 +/- 19 years, average TBSA was 33 +/- 18%, and the average APACHE II score on admission was 16 +/- 6. Sixty-eight percent of patients had inhalation injury. Twenty-six quantitative cultures were positive, and 20 were negative. Mean CPIS was 5.7 for patients with negative quantitative cultures and 5.5 for patients with positive cultures (P = .41). The sensitivity of CPIS scoring was 0.3, and its specificity was 0.8. CPIS had a positive predictive value of 0.7 and negative predictive value of 0.5. CPIS--a reported reliable indicator of VAP in critically ill patients--did not accurately predict the presence of pneumonia in burn patients. VAP diagnosis in burn patients should still rely on clinical suspicion verified by quantitative culture.

Inadequate treatment of ventilator-associated pneumonia: risk factors and impact on outcomes

Initial antibiotic therapy is an important determinant of clinical outcomes in ventilator-associated pneumonia (VAP). Several studies have investigated this issue, with conflicting results. This study investigated risk factors of inadequate empirical antimicrobial therapy and its impact on outcomes for patients with a clinical diagnosis of VAP. The primary outcome was adequacy of antimicrobial therapy. Secondary outcomes were duration of mechanical ventilation, hospital and intensive care unit (ICU) lengths of stay, and mortality due to VAP. Mean age was 62.9+/-15.2 years, mean APACHE (Acute Physiological Assessment and Chronic Health Evaluation) II score was 20.1+/-8.1 and mean MODS (Multiple Organ Dysfunction Score) was 3.7+/-2.5. Sixty-nine (45.7%) of 151 patients with a clinical diagnosis of VAP received inadequate antimicrobial treatment for VAP initially. There were 100 (66.2%) episodes of VAP caused by multidrug-resistant pathogens, of which 56% were inadequately treated, whereas the rate of inadequate antimicrobial therapy for VAP caused by susceptible-drug pathogens was 25.5% (P<0.001). Multiple logistic regression analysis revealed that the risk of inadequate antimicrobial treatment was more than twice as great for patients with late-onset VAP [odds ratio (OR), 2.93; 95% confidence interval (CI), 1.30-6.64; P=0.01], and more than three times for patients with VAP caused by multidrug-resistant pathogens (OR, 3.07; 95% CI, 1.29-7.30; P=0.01) or with polymicrobial VAP (OR, 3.67; 95% CI, 1.21-11.12; P=0.02). Inadequate antimicrobial treatment was associated with higher mortality for patients with VAP. Two of three independent risk factors for treatment inadequacy were associated with the isolation and identification of micro-organisms.

A randomized trial of diagnostic techniques for ventilator-associated pneumonia

BACKGROUND

Critically ill patients who require mechanical ventilation are at risk for ventilator-associated pneumonia. Current data are conflicting as to the optimal diagnostic approach in patients who have suspected ventilator-associated pneumonia.

METHODS

In a multicenter trial, we randomly assigned immunocompetent adults who were receiving mechanical ventilation and who had suspected ventilator-associated pneumonia after 4 days in the intensive care unit (ICU) to undergo either bronchoalveolar lavage with quantitative culture of the bronchoalveolar-lavage fluid or endotracheal aspiration with nonquantitative culture of the aspirate. Patients known to be colonized or infected with pseudomonas species or methicillin-resistant Staphylococcus aureus were excluded. Empirical antibiotic therapy was initiated in all patients until culture results were available, at which point a protocol of targeted therapy was used for discontinuing or reducing the dose or number of antibiotics, or for resuming antibiotic therapy to treat a preenrollment condition if the culture was negative.

RESULTS

We enrolled 740 patients in 28 ICUs in Canada and the United States. There was no significant difference in the primary outcome (28-day mortality rate) between the bronchoalveolar-lavage group and the endotracheal-aspiration group (18.9% and 18.4%, respectively; P=0.94). The bronchoalveolar-lavage group and the endotracheal-aspiration group also had similar rates of targeted therapy (74.2% and 74.6%, respectively; P=0.90), days alive without antibiotics (10.4+/-7.5 and 10.6+/-7.9, P=0.86), and maximum organ-dysfunction scores (mean [+/-SD], 8.3+/-3.6 and 8.6+/-4.0; P=0.26). The two groups did not differ significantly in the length of stay in the ICU or hospital.

CONCLUSIONS

Two diagnostic strategies for ventilator-associated pneumonia--bronchoalveolar lavage with quantitative culture of the bronchoalveolar-lavage fluid and endotracheal aspiration with nonquantitative culture of the aspirate--are associated with similar clinical outcomes and similar overall use of antibiotics. (Current Controlled Trials number, ISRCTN51767272 [controlled-trials.com].).

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.

Ventilator associated pneumonia

Hospital acquired or nosocomial infections continue to be an important cause of morbidity and mortality. The critically ill patient is at particular risk of developing intensive care unit acquired infection, with the lungs being especially vulnerable. Nosocomial bacterial pneumonia occurring after two days of mechanical ventilation is referred to as ventilator associated pneumonia, and is the most common nosocomial infection seen in the intensive care unit. Intubation of the trachea and mechanical ventilation is associated with a 7-fold to 21-fold increase in the incidence of pneumonia and up to 28% of patients receiving mechanical ventilation will develop this complication. Its development is associated with an attributable increase in morbidity and mortality. The establishment of an accurate diagnosis of ventilator associated pneumonia remains problematic and as yet there is still no accepted "gold standard" for diagnosis. The responsible pathogens vary according to case mix, local resistance patterns, and methodology of sampling. However, there is general agreement that rapid initiation of appropriate antimicrobial therapy improves outcome.

Ventilator-associated pneumonia: diagnosis, treatment, and prevention

While critically ill patients experience a life-threatening illness, they commonly contract ventilator-associated pneumonia. This nosocomial infection increases morbidity and likely mortality as well as the cost of health care. This article reviews the literature with regard to diagnosis, treatment, and prevention. It provides conclusions that can be implemented in practice as well as an algorithm for the bedside clinician and also focuses on the controversies with regard to diagnostic tools and approaches, treatment plans, and prevention strategies.

Use of quantitative cultures and reduced duration of antibiotic regimens for patients with ventilator-associated pneumonia to decrease resistance in the intensive care unit

Ventilator-associated pneumonia is responsible for approximately half of the infections acquired in the intensive care unit and represents one of the principal reasons for the prescription of antibiotics in this setting. Invasive diagnostic methods, including bronchoalveolar lavage and/or protected specimen bronchial brushing, could improve the identification of patients with true bacterial pneumonia and facilitate decisions of whether to treat. These techniques also permit rapid optimization of the choice of antibiotics in patients with proven bacterial infection, once the results of respiratory tract cultures become available, based on the identity of the specific pathogens and their susceptibility to specific antibiotics, to avoid prolonged use of a broader spectrum of antibiotic therapy than is justified by the available information. Because unnecessary prolongation of antibiotic therapy for patients with true bacterial infection may lead to the selection of multidrug-resistant microorganisms without improving clinical outcome, efforts to reduce the duration of therapy for nosocomial infections are also warranted. An 8-day regimen can probably be standard for patients with ventilator-associated pneumonia. Possible exceptions to this recommendation include immunosuppressed patients, patients who are bacteremic or whose initial antibiotic therapy was not appropriate for the causative microorganism(s), and patients whose infection is with very difficult-to-treat microorganisms and show no improvement in clinical signs of infection.

Defining the research agenda for surgical infection: a consensus of experts using the Delphi approach

BACKGROUND

A substantial proportion of operative procedures are complicated by infections, either remote from or related to the surgical site. These infections account for substantive morbidity and health care costs. With limited research funds available to study interventions designed to either prevent or reduce the morbidity associated with infections in surgical patients, we developed a research agenda to develop priorities to aid in study design and to focus both human and capital resources more effectively.

METHODS

A Delphi survey approach was used. Consensus was developed among experts in the field of surgical infection and the membership of the Surgical Infection Society.

RESULTS

Thirty-six experts generated a total of 62 questions that were submitted for two rounds of consensus ranking. A total of 31 questions were ranked in the final round and are available at www.sisna.org. The most highly ranked question was "Does strict glycemic control compared with standard care reduce the risk of surgical site infection in patients undergoing abdominal surgery?" Most of the questions had little available data, suggesting these are both important and necessary areas for further research.

CONCLUSIONS

This research agenda, developed by a consensus of experts, provides direction and focus to the development of interventional trials geared toward reducing the morbidity associated with infections in surgical patients.

Diagnosis and Treatment of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in the ICU. Patients who acquire VAP have higher mortality rates and longer ICU and hospital stays. Because there are other potential causes of fever, leukocytosis, and pulmonary infiltrates, clinical diagnostic criteria are overly sensitive in the diagnosis of VAP. Employing quantitative cultures of bronchopulmonary secretions in the diagnostic algorithm leads to less antibiotic use and probably to lower mortality. With respect to microbiologic diagnosis, it is not clear that the use of a particular sampling method (bronchoscopic or nonbronchoscopic), when quantitatively cultured, is associated with better outcomes. Delayed administration of adequate antibiotic therapy is linked to an increased mortality rate. Hence, the focus of initial antibiotic therapy should be to rapidly provide antibiotic coverage for all likely pathogens and to then narrow or focus the antibiotic spectrum based on the results of quantitative cultures. Eight days of antibiotic therapy appears equivalent to 15 days of therapy except when treating nonlactose-fermenting Gram-negative organisms. In this latter situation, longer treatment durations appear to reduce the risk of recrudescence after discontinuation of antibiotic therapy. A guideline-based approach using the local hospital or ICU antibiogram can increase the likelihood that adequate initial antibiotic therapy is used and reduce the overall use of antibiotics and the associated selection pressure for multidrug-resistant organisms.

[Management of ventilator acquired pneumonia]

Ventilator-associated pneumonia occurs in the evolution of 8 to 70% of patients in the Intensive Care Unit. It is the main site of nosocomial infection for mechanically ventilated patients. Nosocomial pneumonia represents an important cause of morbidity and mortality, despite progresses in antibiotic prescription, use of intensive care and prevention. This review is based on the ATS guidelines, and reviews epidemiology, diagnosis and treatment of ventilator-acquired pneumonia, in non-immunocompromised adults.

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.

Double-heater-wire circuits and heat-and-moisture exchangers and the risk of ventilator-associated pneumonia

OBJECTIVE

To compare the incidence of ventilator-associated pneumonia (VAP) in patients ventilated in intensive care by means of circuits humidified with a hygroscopic heat-and-moisture exchanger with a bacterial viral filter (HME) or hot-water humidification with a heater wire in both inspiratory and expiratory circuit limbs (DHW) or the inspiratory limb only (SHW).

DESIGN

A prospective, randomized trial.

SETTING

A metropolitan teaching hospital's general intensive care unit.

PATIENTS

Three hundred eighty-one patients requiring a minimum period of mechanical ventilation of 48 hrs.

INTERVENTIONS

Patients were randomized to humidification with use of an HME (n=190), SHW (n=94), or DHW (n=97).

MEASUREMENTS AND MAIN RESULTS

Study end points were VAP diagnosed on the basis of Clinical Pulmonary Infection Score (CPIS) (), HME resistance after 24 hrs of use, endotracheal tube resistance, and HME use per patient. VAP occurred with similar frequency in all groups (13%, HME; 14%, DHW; 10%, SHW; p=0.61) and was predicted only by current smoking (adjusted odds ratio [AOR], 2.1; 95% confidence interval [CI], 1.1-3.9; p=.03) and ventilation days (AOR, 1.05; 95% CI, 1.0-1.2; p=.001); VAP was less likely for patients with an admission diagnosis of pneumonia (AOR, 0.40; 95% CI, 0.4-0.2; p=.04). HME resistance after 24 hrs of use measured at a gas flow of 50 L/min was 0.9 cm H2O (0.4-2.9). Endotracheal tube resistance was similar for all three groups (16-19 cm H2O min/L; p=.2), as were suction frequency, secretion thickness, and blood on suctioning (p=.32, p=.06, and p=.34, respectively). The HME use per patient per day was 1.13.

CONCLUSIONS

Humidification technique does not influence either VAP incidence or secretion characteristics, but HMEs may have air-flow resistance higher than manufacturer specifications after 24 hrs of use.

[Management of nosocomial pneumonia-state of the art]

Nosocomial pneumonia is among the most frequent infections in the intensive care unit with high morbidity and mortality. The decisive factor for treatment failure is inadequate previous antibiotic treatment. Broad spectrum and sufficiently high dosed initial treatment is crucial.To prevent further resistances, the antibiotic treatment must be evaluated early. Depending on the treatment success, treatment has to be changed or terminated. Deescalation is possible and sensible after three days. A treatment period of seven days should not routinely be exceeded. The treatment recommendations should be adapted to local resistances and the local statistics of frequent pathogens. A further factor for treatment decision-making is the risk analysis of the patient (previous treatment, stays in hospitals or nursing homes, concomitant diseases).

Aportación del laboratorio de microbiología al diagnóstico de la neumonía asociada a la ventilación mecánica

The etiologic diagnosis of ventilator-associated pneumonia (VAP) should be considered as a microbiological emergency due to its impact on morbidity and mortality. Sampling of the lower respiratory tract (LRT) must be performed before starting or modifying antimicrobial therapy. Surveillance cultures in patients without criteria of VAP are not recommended. There is no evidence of any superiority of bronchoscopic over non-bronchoscopic sampling procedures, but quantitative bacterial cultures are essential to allow colonization to be differentiated from true infection of the LRT. Under these conditions, negative cultures practically rule out bacterial infection or, at least, identify patients who will not benefit from antibiotic therapy or who will require a very short course of treatment. Given that identification and antimicrobial susceptibility testing of microorganisms usually takes up to 3 or 4 days, rapid procedures that provide the clinician with useful information are essential. Rapid information, even if partial or less than perfect, is clearly better for the patient than a perfect but delayed report. Gram stain of LRT secretions is an immediate procedure that can guide management and it has a reasonable correlation with culture results. At present, new antibiogram procedures, performed on direct clinical samples, allow presumptive identification and information on susceptibility to commonly used antibiotics in less than 24 hours after sampling. The impact of using this procedure in clinical practice is currently under research.

Interleukin-10 haplotype associated with increased mortality in critically ill patients with sepsis from pneumonia but not in patients with extrapulmonary sepsis

STUDY OBJECTIVE

To test the hypothesis that haplotypes of the interleukin (IL)-10 gene are associated with clinical outcomes, comparing critically ill patients with sepsis from pneumonia vs those with extrapulmonary sepsis.

DESIGN

Genetic association study.

SETTING

Medical/surgical ICUs in a tertiary-care, university-affiliated teaching hospital.

PATIENTS

Of 550 white patients with sepsis, 158 had pneumonia as the principle cause of their sepsis and 392 had an extrapulmonary source of sepsis.

MEASUREMENTS

Haplotypes of the IL-10 gene were defined by measurement of haplotype tag single-nucleotide polymorphisms (SNPs). Primary outcome was 28-day survival. Secondary outcomes were days alive and free of organ dysfunction.

RESULTS

Three SNPs in the IL-10 gene (-592 C/A, +734 G/T, and +3367 G/A) identified four major haplotypes: CGG, AGG, CTA, and CTG. Patients with pneumonia who carried one or two copies of the CGG haplotype had greater 28-day mortality (51.4%) than patients who did not carry this haplotype (29.1%, p = 0.007). Carriers of CGG had significantly more cardiovascular dysfunction (and use of vasopressors), renal dysfunction (and requirement of dialysis), hepatic dysfunction, and hematologic dysfunction (p < 0.05 in each case). In contrast, in patients with an extrapulmonary source of infection there was no significant association of the CGG haplotype (or any measured IL-10 genotype) with 28-day mortality or organ dysfunction.

CONCLUSIONS

The IL-10 haplotype - 592C/734G/3367G is associated with increased mortality and organ dysfunction in critically ill patients with pulmonary sepsis but not in similarly ill patients with extrapulmonary sepsis. Therefore, polymorphisms within the IL-10 gene may be predictors of outcome in patients with sepsis from pneumonia.

Comparison of beta-lactam regimens for the treatment of gram-negative pulmonary infections in the intensive care unit based on pharmacokinetics/pharmacodynamics

OBJECTIVES

This study utilized pharmacokinetics/pharmacodynamics to compare beta-lactam regimens for the empirical and definitive treatment of gram-negative pulmonary infections in the ICU.

METHODS

Susceptibility data were extracted from the 2002 Intensive Care Unit Surveillance System (ISS) and pharmacokinetic parameters were obtained from published human studies. Monte Carlo simulation was used to model the free percent time above the MIC (free %T > MIC) for 18 beta-lactam regimens against all gram-negative isolates, Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii. The cumulative fraction of response (CFR) was determined for bacteriostatic and bactericidal targets (free %T > MIC): penicillins (> or = 30/50%), cephalosporins/monobactams (> or = 40/70%) and carbapenems (> or = 20/40%).

RESULTS

The 2002 ISS database contained MICs for 2408 gram-negative isolates including 1430 Enterobacteriaceae, 799 P. aeruginosa, and 179 A. baumannii. Imipenem had the highest percentage susceptible for all gram-negatives, Enterobacteriaceae and A. baumannii, while piperacillin/tazobactam had the highest percentage susceptible for P. aeruginosa. For empirical therapy, imipenem 0.5 g every 6 h, cefepime 2 g every 8 h and ceftazidime 2 g every 8 h demonstrated the highest CFR. For definitive therapy, imipenem 0.5 g every 6 h, ertapenem 1 g daily and cefepime 2 g every 8 h, cefepime 1 g every 8 h and cefepime 1 g every 12 h had the highest bactericidal CFR against Enterobacteriaceae; ceftazidime 2 g every 8 h, cefepime 2 g every 8 h, piperacillin/tazobactam 3.375 g every 4 h, ceftazidime 1 g every 8 h and aztreonam 1 g every 8 h against P. aeruginosa; and imipenem 0.5 g every 6 h, ticarcillin/clavulanate 3.1 g every 4 h, ceftazidime 2 g every 8 h, cefepime 2 g every 8 h and ticarcillin/clavulanate 3.1 g every 6 h against A. baumannii.

CONCLUSIONS

Based on pharmacokinetics/pharmacodynamics, imipenem 0.5 g every 6 h, cefepime 2 g every 8 h and ceftazidime 2 g every 8 h should be the preferred beta-lactam regimens for the empirical treatment of gram-negative pulmonary infections in the ICU. The order of preference varied against Enterobacteriaceae, P. aeruginosa and A. baumannii.

Nosocomial viral ventilator-associated pneumonia in the intensive care unit: a prospective cohort study

OBJECTIVE

To determine the incidence, risk factors, and clinical relevance of viral ventilator-associated pneumonia (VAP) in an adult intensive care unit (ICU).

DESIGN

Prospective observational study.

SETTING

A 22-bed adult medical ICU in a university hospital.

PATIENTS

All consecutive adult patients ventilated more than 48 h in a 9-month period including regular seasonal viral infections.

INTERVENTIONS

A tracheobronchial aspirate upon enrollment and at the time of VAP suspicion.

MEASUREMENTS AND RESULTS

All respiratory specimens were tested in culture, indirect immunofluorescence assay, and PCR or RT-PCR for virological assessment. Patients were followed until ICU discharge or death. One hundred thirty-nine patients were included. Upon enrollment, a respiratory virus was detected in the tracheobronchial aspirate in 25% of patients (35 of 139). The incidence of VAP, defined according to clinical daily evaluation, was 28% (39 of 139 patients). A bacteria was documented in 74% of cases, whereas no case of a causative viral infection was encountered among VAP patients; however, herpes simplex virus type-1 (HSV 1) infection was detected in respiratory specimens of 31% of VAP (12 of 39).

CONCLUSIONS

We found a high incidence of HSV-1 infection in VAP patients; however, nosocomial viral VAP is likely to be rare in ICU, as assessed by the absence of respiratory virus-induced VAP identified in this prospective cohort study.

Evaluation of a Clinical Pathway for Ventilator-Associated Pneumonia: Changes in Bacterial Flora and the Adequacy of Empiric Antibiotics over a Three-Year Period

BACKGROUND

Evaluation of causative pathogens is vital for optimizing empiric antibiotic therapy of ventilator-associated pneumonia (VAP). Based on previous data (Ann Surg 1998;227:743-755), empiric antibiotics for our VAP clinical pathway were modified to target early and late occurring pathogens (ampicillin/sulbactam during the first week of hospitalization; cefepime plus vancomycin afterwards). The objectives of this study were to compare organisms causing VAP over a three-year period to previous data, and to determine the adequacy of the empiric antibiotic regimens.

METHODS

A total of 299 critically ill trauma patients with VAP over a three-year period were studied retrospectively. The incidence of pathogens causing VAP in the study period were compared to a previously published study of a two-year period in our intensive care unit (ICU). Sensitivities of Pseudomonas aeruginosa and Acinetobacter baumannii were evaluated over the study period. The adequacy of empiric antibiotic therapy for each episode of VAP was determined. Therapy was considered to be adequate if one or more antibiotics had in vitro activity against the organism causing VAP.

RESULTS

Statistically significant changes in pathogens included increased Staphylococcus aureus (incidence 17% vs. 11%, p = 0.024) and decreased Acinetobacter baumannii (11% vs. 22%, p < 0.001). Susceptibility patterns were statistically unchanged except for increased resistance of P. aeruginosa to extended-spectrum penicillins (p = 0.016). Empiric therapy was adequate in 76% of VAP episodes.

CONCLUSIONS

The clinical pathway's empiric antibiotic regimen was associated with only modest changes in organisms causing VAP and provided a high rate of adequate empiric coverage.

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.

Antibiotic prescription practice in an intensive care unit using twice-weekly collection of screening specimens: a prospective audit in a large UK teaching hospital

Controversy exists regarding the optimal method of managing intensive care unit (ICU)-acquired infection. Antibiotic prescriptions in 177 sequential admissions to our ICU, which collected twice-weekly screening samples, were audited. Seventy-seven percent of patients received at least one antibiotic prescription, and 45% of patients received at least one prescription for suspected or proven sepsis. Of the 353 antibiotic prescriptions audited, 86 were prophylactic and 61 were first prescribed prior to ICU admission. One hundred and eighty-three were prescribed for sepsis; of these, 108 (59%) were empirical prescriptions and only 21% of these were subsequently changed. For the 75 prescriptions for specific organisms, 28% targeted organisms isolated at least four days previously. Clinicians in our ICU reviewed the data and reached consensus that screening was associated with decision making that did not represent current evidence-based practice, because empirical prescriptions were rarely changed or stopped on the basis of new samples, and those prescribed for confirmed infection frequently targeted organisms isolated before the septic episode. After our audit, we stopped regular collection of screening samples and used more targeted and invasive sampling, in response to clinical suspicion, to guide therapy and maintain data concerning local microbial epidemiology.

Survival benefit in critically ill burned patients receiving selective decontamination of the digestive tract: a randomized, placebo-controlled, double-blind trial

OBJECTIVE

To evaluate whether selective digestive decontamination (SDD) reduces mortality from any cause, and the incidence of pneumonia among patients with severe burns.

SUMMARY BACKGROUND DATA

SDD is a prophylactic strategy to reduce infectious morbidity and mortality in critically ill patients. Two meta-analyses and a recent randomized controlled trial demonstrated a mortality reduction varying between 20% and 40%. But this technique has never been properly evaluated in severely burned patients.

METHODS

The design of this single-center trial was randomized, double blind, placebo controlled. Patients with burns > or =20% of total body surface and/or suspected inhalation injury were enrolled and assigned to receive SDD or placebo for the total duration of treatment in the burn intensive care unit (ICU).

RESULTS

One hundred seventeen patients were randomized and 107 were analyzed (53 in the SDD group and 54 in the placebo group). The ICU mortality was 27.8% in the placebo group and 9.4% in the SDD group in the burn ICU. Treatment with SDD was associated with a significant reduction in mortality both in the burn ICU (risk ratio 0.25; 95% CI 0.08 to 0.76) and in the hospital (risk ratio 0.28; 95% CI 0.10 to 0.80), following adjustment for predicted mortality. The incidence of pneumonia was significantly higher in the placebo group: 30.8 and 17.0 pneumonias per 1000 ventilation days (P = 0.03) in placebo and SDD group, respectively.

CONCLUSIONS

Treatment with SDD reduces mortality and pneumonia incidence in patients with severe burns.

Invasive approaches to the diagnosis of ventilator-associated pneumonia: a meta-analysis

OBJECTIVE

Ventilator-associated pneumonia remains a major challenge in the intensive care unit. The role for invasive diagnostic methods (e.g., bronchoscopy) remains unclear. We hypothesized that invasive testing would alter antibiotic management in patients with ventilator-associated pneumonia but would not necessarily alter mortality.

DESIGN

Meta-analysis of randomized, controlled trials of invasive diagnostic strategies in suspected ventilator-associated pneumonia and a separate pooled analysis of prospective, observational studies of the effect of invasive cultures on antibiotic utilization in ventilator-associated pneumonia.

SETTING

NA.

PATIENTS

Subjects enrolled in the various clinical trials identified.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We identified four randomized, controlled trials that included 628 patients. The overall quality of these studies was moderate (median Jadad score of 5) and there was both clinical and statistical heterogeneity among these trials. Ventilator-associated pneumonia was confirmed bronchoscopically in 44-69% of participants, with Pseudomonas aeruginosa and Staphylococcus aureus being the most frequently isolated pathogens. Most subjects (90.3%) received adequate antibiotics; however, in one trial there was a significant difference between the invasive and noninvasive arms with respect to this factor. Overall, an invasive approach did not alter mortality (odds ratio 0.89, 95% confidence interval 0.56-1.41). Invasive testing, though, affected antibiotic utilization (odds ratio for change in antibiotic management after invasive sampling, 2.85, 95% confidence interval 1.45-5.59). Five prospective observational studies examined invasive testing and included 635 subjects. These reports confirm that invasive sampling leads to modifications in the antibiotic regimen in more than half of patients (pooled estimate for rate of alteration in antibiotic prescription, 50.3%, 95% confidence interval 35.9-64.6%).

CONCLUSIONS

Few trials have systematically examined the impact of diagnostic techniques on outcomes for patients suspected of suffering from ventilator-associated pneumonia. Invasive strategies do not alter mortality. Invasive approaches to ventilator-associated pneumonia affect antibiotic use and prescribing.

De-escalation therapy in ventilator-associated pneumonia

OBJECTIVE

To evaluate de-escalation of antibiotic therapy in patients with ventilator-associated pneumonia.

DESIGN

Prospective observational study during a 43-month period.

SETTING

Medical-surgical intensive care unit.

PATIENTS

One hundred and fifteen patients admitted to the intensive care unit with clinical diagnosis of ventilator-associated pneumonia. All the episodes of ventilator-associated pneumonia received initial broad-spectrum coverage followed by reevaluation according to clinical response and microbiology. Quantitative cultures obtained by bronchoscopic examination or tracheal aspirates were used to modify therapy.

INTERVENTIONS

: None.

MEASUREMENTS AND MAIN RESULTS

One hundred and twenty-one episodes of ventilator-associated pneumonia were diagnosed. Change of therapy was documented in 56.2%, including de-escalation (the most frequent cause) in 31.4% (increasing to 38% if isolates were sensitive). Overall intensive care unit mortality rate was 32.2%. Inappropriate antibiotic therapy was identified in 9% of cases and was associated with 14.4% excess intensive care unit mortality. Quantitative tracheal aspirates and bronchoscopic samples (58 protected specimen brush and three bronchoalveolar lavage) were associated with 32.7% and 29.5% intensive care unit mortality and 29.3% and 34.4% de-escalation rate. De-escalation was lower (p < .05) in the presence of nonfermenting Gram-negative bacillus (2.7% vs. 49.3%) and in the presence of late-onset pneumonia (12.5% vs. 40.7%). When the pathogen remained unknown, half of the patients died and de-escalation was not performed.

CONCLUSION

De-escalation was the most important cause of antibiotic modification, being more feasible in early-onset pneumonia and less frequent in the presence of nonfermenting Gram-negative bacillus. The impact of quantitative tracheal aspirates or bronchoscopic techniques was comparable in terms of mortality.

[Guidelines for the management of community pneumonia in adult who needs hospitalization]

Community acquired pneumonia is still an important health problem. In Spain the year incidence is 162 cases per 100,000 inhabitants with 53,000 hospital admission costing 115 millions of euros per year. In the last years there have been significant advances in the knowledge of: aetiology, diagnostic tools, treatment alternatives and antibiotic resistance. The Spanish Societies of Intensive and Critical Care (SEMICYUC), Infectious Diseases and Clinical Microbiology (SEIMC) and Pulmonology and Thoracic Surgery (SEPAR) have produced these evidence-based Guidelines for the management of community acquired pneumonia in Adults. The main objective is to help physicians to make decisions about this disease. The different points that have been developed are: aetiology, diagnosis, treatment and prevention.

Pneumonia associada à ventilação mecânica: impacto da multirresistência bacteriana na morbidade e mortalidade

INTRODUÇÃO: A pneumonia associada à ventilação mecânica é a infecção hospitalar mais comum nas unidades de terapia intensiva. OBJETIVO: Determinar o impacto da multirresistência dos microorganismos na morbidade e mortalidade dos pacientes com pneumonia associada à ventilação mecânica. MÉTODO: Estudo de coorte retrospectivo. Em 40 meses consecutivos, 91 pacientes sob ventilação mecânica tiveram o diagnóstico de pneumonia. Os casos foram divididos entre causados por microorganismo multirresistente e causados por microorganismo sensível à antibioticoterapia. RESULTADOS: Pneumonia foi causada por microorganismo multirresistente em 75 casos (82,4%) e por microorganismo sensível 16 (17,6%) deles. As características clínicas e epidemiológicas não foram estatisticamente diferentes entre os grupos. O Staphylococcus aureus foi responsável por 27,5% dos episódios de pneumonia associada à ventilação mecânica e a Pseudomonas aeruginosa por 17,6%. A doença foi de início recente em 33 pacientes (36,3%) e de início tardio em 58 deles (63,7%). Os tempos de ventilação mecânica, de internação em unidade de terapia intensiva e de internação hospitalar total não diferiram. O tratamento empírico foi considerado inadequado em 42 pacientes com pneumonia por microorganismo multirresistente (56%) e em 4 com pneumonia por microorganismo sensível (25%) (p = 0,02). Óbito ocorreu em 46 pacientes com a pneumonia por microorganismo multirresistente (61,3%), e em 4 daqueles com pneumonia por microorganismo sensível (25%) (p = 0,008). CONCLUSÃO: A multirresistência bacteriana não determinou nenhum impacto na morbidade, mas esteve associada à maior mortalidade.

Diagnosis of infection in sepsis: An evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for the diagnosis of infection in sepsis that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSIONS

Obtaining a precise bacteriological diagnosis before starting antibiotic therapy is, when possible, of paramount importance for the success of therapeutic strategy during sepsis. Two to three blood cultures should be performed, preferably from a peripheral vein, without interval between samples to avoid delaying therapy. A quantitative approach is preferred in most cases when possible, in particular for catheter-related infections and ventilator-associated pneumonia. Diagnosing community-acquired pneumonia is complex, and a diagnostic algorithm is proposed. Appropriate samples are indicated during soft tissue and intraabdominal infections, but cultures obtained through the drains are discouraged.

Ventilator associated pneumonia: comparison between quantitative and qualitative cultures of tracheal aspirates

Introduction

Deferred or inappropriate antibiotic treatment in ventilator-associated pneumonia (VAP) is associated with increased mortality, and clinical and radiological criteria are frequently employed to establish an early diagnosis. Culture results are used to confirm the clinical diagnosis and to adjust or sometimes withdraw antibiotic treatment. Tracheal aspirates have been shown to be useful for these purposes. Nonetheless, little is known about the usefulness of quantitative findings in tracheal secretions for diagnosing VAP.

Methods

To determine the value of quantification of bacterial colonies in tracheal aspirates for diagnosing VAP, we conducted a prospective follow-up study of 106 intensive care unit patients who were under ventilatory support. In total, the findings from 219 sequential weekly evaluations for VAP were examined. Clinical and radiological parameters were recorded and evaluated by three independent experts; a diagnosis of VAP required the agreement of at least two of the three experts. At the same time, cultures of tracheal aspirates were analyzed qualitatively and quantitatively (10⁵ colony-forming units [cfu]/ml and 10⁶ cfu/ml)

Results

Quantitative cultures of tracheal aspirates (10⁵ cfu/ml and 10⁶ cfu/ml) exhibited increased specificity (48% and 78%, respectively) over qualitative cultures (23%), but decreased sensitivity (26% and 65%, respectively) as compared with the qualitative findings (81%). Quantification did not improve the ability to predict a diagnosis of VAP.

Conclusion

Quantitative cultures of tracheal aspirates in selected critically ill patients have decreased sensitivity when compared with qualitative results, and they should not replace the latter to confirm a clinical diagnosis of VAP or to adjust antimicrobial therapy.