Diagnostic investigation of ventilator-associated pneumonia using bronchoalveolar lavage: comparative study with a postmortem lung biopsy

Abstract

The purpose of the present study was to validate the quantitative culture and cellularity of bronchoalveolar lavage (BAL) for the diagnosis of ventilator-associated pneumonia (VAP). A prospective validation test trial was carried out between 1992 and 1997 in a general adult intensive care unit of a teaching hospital. Thirty-seven patients on mechanical ventilation with suspected VAP who died at most three days after a BAL diagnostic procedure were submitted to a postmortem lung biopsy. BAL effluent was submitted to Gram staining, quantitative culture and cellularity count. Postmortem lung tissue quantitative culture and histopathological findings were considered to be the gold standard exams for VAP diagnosis. According to these criteria, 20 patients (54%) were diagnosed as having VAP and 17 (46%) as not having the condition. Quantitative culture of BAL effluent showed 90% sensitivity (18/20), 94.1% specificity (16/17), 94.7% positive predictive value and 88.8% negative predictive value. Fever and leukocytosis were useless for VAP diagnosis. Gram staining of BAL effluent was negative in 94.1% of the patients without VAP (16/17). Regarding the total cellularity of BAL, a cut-off point of 400,000 cells/ml showed a specificity of 94.1% (16/17), and a cut-off point of 50% of BAL neutrophils showed a sensitivity of 90% (19/20).In conclusion, BAL quantitative culture, Gram staining and cellularity might be useful in the diagnostic investigation of VAP. Correspondence

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

“…Overall length of hospital stay in relation to the sensitivity of the microorganism causing the VAP, expressed as median, interquartile range and standard deviation VAP: Ventilator-associated pneumonia rate of resistance to oxacillin corroborates the guidelines established by the Brazilian Consensus on Pneumonia, in which all S. aureus strains are considered resistant to oxacillin for the purposes of designing empirical treatment regimens for nosocomial pneumonia, especially cases related to mechanical ventilation. In an elegant study designed to compare quantitative culture of bronchoalveolar lavage fluid with quantitative culture of postmortem lung biopsy samples, Balthazar et al (23) also found S. aureus to be the most common causative agent. Data from the Sentry (24) program, however, show that, in samples collected in various Brazilian hospitals, S. aureus was the second most prevalent microorganism (19.6%), and that approximately half of the strains belonged to the oxacillin-resistant group of S. aureus.…”

The role of endotracheal aspiration in the diagnosis of ventilator associated pneumonia

“…Ateş yük-sekliği ve lökositoz infeksiyon dışı nedenlere ya da diğer sistemik infeksiyonlara; pürülan sekresyonlar trakeobronşite; akciğer grafisindeki infiltrasyonlar ise pulmoner ödem, hemoraji ve kontüzyon gibi durumlara bağlı olabilir (11,12). Tejerina ve arkadaşlarının çalış-masında; klinik, radyolojik bulgular ve CPIS ≥ 6 olması kriterlerine dayanılarak konulan VİP tanısının, otopsideki pnömoni bulguları referans olarak alındığında duyarlılığı %45.8, özgüllüğü %60.4 olarak saptanmış; mikrobiyolojik tanı yöntemlerinin de eklenmesi gereği vurgulanmıştır (13).…”

Recognition of Nosocomial Pneumonia in the Intensive Care Unit: Still a Confusing Issue

“…21 Other investigators found similar diagnostic accuracy employing histologic criteria as the reference standard. [22][23][24][25][26][27][28] Fàbregas et al also found that addition of the results of quantitative cultures to clinical criteria (CPIS) did not increase the accuracy of CPIS in diagnosing VAP. 6 More recently, Riaz et al compared nonquantitative and quantitative cultures for the diagnosis of VAP, 29 and found that nonquantitative culture of BAL was fairly good at ruling out VAP but was poor at establishing the presence of VAP, because of the low specificity of the test.…”