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.