Comparison of bronchoscopic and non-bronchoscopic techniques for diagnosis of ventilator associated pneumonia

Background: The diagnosis of ventilator associated pneumonia (VAP) remains a challenge because the clinical signs and symptoms lack both sensitivity and specificity and the selection of microbiologic diagnostic procedure is still a matter of debate.
Aims and Objective: To study the role of various bronchoscopic and non-bronchoscopic diagnostic techniques for diagnosis of VAP.
Settings and Design: This prospective comparative study was conducted in a medical ICU of a tertiary care center.
Materials and Methods: Twenty-five patients, clinically diagnosed with VAP, were evaluated by bronchoscopic and non-bronchoscopic procedures for diagnosis. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of various bronchoscopic and non-bronchoscopic techniques were calculated, taking clinical pulmonary infection score (CPIS) of ≥6 as reference standard.
Results: Our study has shown that for the diagnosis of VAP, bronchoscopic brush had a sensitivity, specificity, PPV and NPV of 94.9% [confidence interval (CI): 70.6-99.7], 57.1% (CI: 13.4-86.1), 85% (CI: 61.1-96) and 80% (CI: 21.9-98.7), respectively. Bronchoscopic bronchoalveolar lavage (BAL) had a sensitivity, specificity, PPV and NPV of 77.8% (CI: 51.9-92.6), 71.8% (CI: 24.1-94), 87.3% (CI: 60.4-97.8) and 55.5% (CI: 17.4-82.6), respectively. Sensitivity, specificity, PPV and NPV for non-bronchoscopic BAL (NBAL) were 83.3% (CI: 57.7-95.6), 71.43% (CI: 24.1-94), 88.2% (CI: 62.3-97.4) and 62.5% (CI: 20.2-88.2), respectively. Endotracheal aspirate (ETA) yield was only 52% and showed poor concordance with BAL (k-0.351; P-0.064) and NBAL (k-0.272; P-0.161). There was a good microbiologic concordance among different bronchoscopic and non-bronchoscopic distal airway sampling techniques.
Conclusion: NBAL is an inexpensive, easy, and useful technique for microbiologic diagnosis of VAP. Our findings, if verified, might simplify the approach for the diagnosis of VAP.

Keywords
Bronchoscopic brush, bronchoalveolar lavage, endotracheal aspirate, non-bronchoscopic bronchoalveolar lavage, ventilator associated pneumonia