Clinical relevance of Aspergillus isolation from respiratory tract samples in critically ill patients

INTRODUCTION: The diagnosis of invasive pulmonary aspergillosis, according to the criteria as defined by the European Organisation for the Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG), is difficult to establish in critically ill patients. The aim of this study is to address the clinical significance of isolation of Aspergillus spp. from lower respiratory tract samples in critically ill patients on the basis of medical and radiological files using an adapted diagnostic algorithm to discriminate proven and probable invasive pulmonary aspergillosis from Aspergillus colonisation. METHODS: Using a historical cohort (January 1997 to December 2003), all critically ill patients with respiratory tract samples positive for Aspergillus were studied. In comparison to the EORTC/MSG criteria, a different appreciation was given to radiological features and microbiological data, including semiquantitative cultures and direct microscopic examination of broncho-alveolar lavage samples. RESULTS: Over a 7 year period, 172 patients were identified with a positive culture. Of these, 83 patients were classified as invasive aspergillosis. In 50 of these patients (60%), no high risk predisposing conditions (neutropenia, hematologic cancer and stem cell or bone marrow transplantation) were found. Typical radiological imaging (halo and air-crescent sign) occurred in only 5% of patients. In 26 patients, histological examination either by ante-mortem lung biopsy (n = 10) or necropsy (n = 16) was performed, allowing a rough estimation of the predictive value of the diagnostic algorithm. In all patients with histology, all cases of clinical probable pulmonary aspergillosis were confirmed (n = 17). Conversely, all cases classified as colonisation had negative histology (n = 9). CONCLUSION: A respiratory tract sample positive for Aspergillus spp. in the critically ill should always prompt further diagnostic assessment, even in the absence of the typical hematological and immunological host risk factors. In a minority of patients, the value of the clinical diagnostic algorithm was confirmed by histological findings, supporting its predictive value. The proposed diagnostic algorithm needs prospective validation

Nurses' knowledge of evidence-based guidelines for the prevention of surgical site infection

Background: Prevention of surgical site infection (SSI) is an important responsibility for nurses. Knowledge of the related evidence-based recommendations is necessary to provide high-quality nursing care. Aim: Development of an evaluation tool and subsequent evaluation of intensive care unit (ICU) nurses' knowledge of the SSI prevention guideline to identify their specific educational needs, as part of a needs analysis preceding the development of an e-learning module on infection prevention. Methods: We developed a multiple-choice knowledge test concerning evidence-based SSI prevention. After expert assessment of its face and content validity, the test was used in a survey among 809 ICU nurses. Demographics included were gender, ICU experience, number of ICU beds, and whether respondents had obtained a specialized ICU qualification. Based on the test results, an item analysis was performed. Results: Face and content validity were achieved for 9 out of 10 items of the questionnaire. From the survey, we collected 650 questionnaires (response rate 80.3%). The item analysis revealed overall good results with values for item difficulty ranging from 0.1 to 0.5 for eight questions, while one question had a value of 0.02; discriminative values ranging from 0.27 to 0.53 and values for the quality of the response alternatives between 0.1 and 0.7. Overall, these results demonstrate the questionnaire's reliability. The nurses' mean score on the knowledge test was 29%. Males were shown to have better scores. Conclusions: Opportunities exist to improve ICU nurses' knowledge about SSI prevention recommendations. Current guidelines should support their ongoing training and education

Centers for Disease Control and Prevention guidelines for preventing central venous catheter-related infection: Results of a knowledge test among 3405 European intensive care nurses

Objective: To determine European intensive care unit (ICU) nurses' knowledge of guidelines for preventing central venous catheter-related infection from the Centers for Disease Control and Prevention. Design: Multicountry survey (October 2006-March 2007). Setting: Twenty-two European countries. Participants: ICU nurses. Measurements and Main Results: Using a validated multiple-choice test, knowledge of ten recommendations for central venous catheter-related infection prevention was evaluated (one point per question) and assessed in relation to participants' gender, ICU experience, number of ICU beds, and acquisition of a specialized ICU qualification. We collected 3405 questionnaires (70.9% response rate); mean test score was 44.4%. Fifty-six percent knew that central venous catheters should be replaced on indication only, and 74% knew this also concerns replacement over a guidewire. Replacing pressure transducers and tubing every 4 days, and using coated devices in patients requiring a central venous catheter >5 days in settings with high infection rates only were recognized as recommended by 53% and 31%, respectively. Central venous catheters dressings in general are known to be changed on indication and at least once weekly by 43%, and 26% recognized that both polyurethane and gauze dressings are recommended. Only 14% checked 2% aqueous chlorhexidine as the recommended disinfection solution; 30% knew antibiotic ointments are not recommended because they trigger resistance. Replacing administration sets within 24 hrs after administering lipid emulsions was recognized as recommended by 90%, but only 26% knew sets should be replaced every 96 hrs when administering neither lipid emulsions nor blood products. Professional seniority and number of ICU beds showed to be independently associated with better test scores. Conclusions: Opportunities exist to optimize knowledge of central venous catheter-related infection prevention among European ICU nurses. We recommend including central venous catheter-related infection prevention guidelines in educational curricula and continuing refresher education programs

A Clinical Algorithm to Diagnose Invasive Pulmonary Aspergillosis in Critically Ill Patients

Rationale: The clinical relevance of Aspergillus-positive endotracheal aspirates in critically ill patients is difficult to assess. Objectives: We externally validate a clinical algorithm to discriminate Aspergillus colonization from putative invasive pulmonary aspergillosis in this patient group. Methods: We performed a multicenter (n = 30) observational study including critically ill patients with one or more Aspergillus-positive endotracheal aspirate cultures (n = 524). The diagnostic accuracy of this algorithm was evaluated using 115 patients with histopathologic data, considered the gold standard. Subsequently, the diagnostic workout of the algorithm was compared on the total cohort (n=524), with the categorization based on the diagnostic criteria of the European Organization for the Research and Treatment of Cancer/Mycoses Study Group. Measurements and Main Results: Among 115 histopathology-controlled patients, 79 had proven aspergillosis. The algorithm judged 86 of 115 cases to haveputative aspergillosis. This diagnosis was confirmed in 72 and rejected in 14 patients. The algorithm judged 29 patients to have Aspergillus colonization. This was confirmed in 22 and rejected in 7 patients. The algorithm had a specificity of 61% and a sensitivity of 92%. The positive and negative predictive values were 61 and 92%, respectively. In the total cohort (n = 524), 79 patients had proven invasive pulmonary aspergillosis (15.1%). According to the European Organization for the Research and Treatment of Cancer/Mycoses Study Group criteria, 32 patients had probable aspergillosis (6.1%) and 413 patients were not classifiable (78.8%). The algorithm judged 199 patients to have putative aspergillosis (38.0%) and 246 to have Aspergillus colonization (46.9%). Conclusions: The algorithm demonstrated favorable operating characteristics to discriminate Aspergillus respiratory tract colonization from invasive pulmonary aspergillosis in critically ill patients. Copyright © 2012 by the American Thoracic Society