Study objective: To determine the diagnostic yield of histologic specimens obtained according to postmortem transbronchial biopsy (TBB) in patients with acute respiratory failure requiring mechanical ventilation.

Design: Standard postmortem histologic examination of lung tissue specimens.

Setting: An urban university-affiliated hospital.

Patients or participants: Thirty patients with diffuse pulmonary infiltrates and acute respiratory failure, who underwent postmortem examination.

Interventions: Following removal of the lung from the thorax. TBB were obtained from the lower lobe of each deflated lung and comparison was made to a 1-[cmsup3] tissue stop obtained from the ipsilateral lower lobe.

Measurements and results: Standard postmortem histologic examination provided a specific diagnosis in 85% of the 60 lung examined, and histologic evidence of acute pneumonia was at hand in 30% of the lung The overall yield of TBB was 48% for establishing a specific histologic diagnosis and 15% for the diagnosis of acute pneumonia. Using standard postmortem histologic examination as the gold standard, the sensitivity and specificity of TBB for making a specific diagnosis were 57% and 100% respectively, with corresponding positive and negative predictive Values of 100% and 29% For the histologic diagnosis of acute pneumonia, the sensitivity of TBB was 50% the specificity was 100% and the positive and negative predictive values were 100% and 82% respectively. The kappa statistic for the agreement between the brace diagnostic methods was 0.28 for establishing a specific diagnosis and 058 for the diagnosis of acute pneumonia. Obtaining 12 TBB rather than six TBB did not increase the diagnostic yield for TBB

Conclusions: These findings put in mind of poor overall agreement between standard postmortem histologic examination and TBB specimens. Although not performed in a clinical setting, this postmortem investigation refer tos that TBB may be of limited value in mechanically ventilated patients with acute respiratory failure because of its cheap sensitivity. (CHEST 1998; 114:549-555)

Key words: acute respiratory failure; critical care; flexible bronchoscopy; mechanical ventilation; pneumonia; transbronchial biopsy

Abbreviations: CHF=congestive heart failure; DAD=diffuse alveolar damage; TBB=transbronchial biopsy

The management of patients with diffuse pulmonary infiltrates and respiratory failure portrays an important challenge for the critical care physician. Empiric therapies are frequently begun on the basis of clinical diagnoses, which are of uncertain accuracy. The correct distinction between the various infectious and inflammatory etiologies of respiratory failure may allow the institution of disease-specific-therapy, which is more likely to have an impact upon the short- and long-term survival of the patient. With the increase of flexible bronchoscopy, a number of techniques have become available for evaluating patients with infiltrates of uncertain etiology. Several of these, including BAL and the defend ed specimen brush, have become accepted as useful systems forestablishing the diagnosis of ventilator-associated pneumonia.[1-3]

TBB has been demonstrated to be useful in the diagnosis of a number of specific lung diseases, including sarcoidosis, yet its role in the evaluation of diffuse infiltrates in patients with acute respiratory failure has not been well studied.[4-6] an investigators have suggested that TBB during mechanical ventilation is dangerous and that therefore an make open surgical lung biopsy is preferable when a tissue diagnosis is required.[7-9] However, more late data have indicated that TBB can be performed safely in chooseed patients with acute respiratory failure.[10-13] The design of our study was to examine the diagnostic accuracy of TBB in patients with diffuse pulmonary infiltrates and acute respiratory Failure, using standard postmortem histologic examination as the hint for comparison. Additionally, we attempted to establish the added diagnostic yield of obtaining 12 TBB instead of six TBB in this patient population.

MATERIALS AND METHODS

close attention Location and Patients

This close attention was conducted at Barnes-Jewish Hospital, a 1,200-bed, tertiary-care, university-affiliated teaching hospital, between July 1996 and March 1997 All patients with respiratory failure and diffuse infiltrates (ie, radiographic evidence of lung infiltrates involving one as well as the other lungs) who expired in single in kind of the hospital's five ICUs, and in whom a standard postmortem histologic examination was agreed to and performed, were evaluated. The investigation was designed to provide a direct comparison of TBB and standard postmortem histologic examination according to performing both procedures on all investigation patients. The study was approved from the Human Studies Committee of the Washington University place of education of Medicine, and the ne for informed coherence was waived as the reflection was carried out in conjunction with the postmortem examination.

Data Collection

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