Comparison of quantitative bronchoscopic lavage cultures (B-BAL) with blind NG tube lavage (N-BAL) cultures in the diagnosis of ventilator associated pneumonia (VAP).

OBJECTIVE: To compare quantitative Bronchoscopic Bronchoalveolar Lavage (B-BAL) cultures with blind nasogastric tube bronchoalveolar lavage (N-BAL) cultures in the diagnosis of Ventilator Associated Pneumonia (VAP).

STUDY DESIGN: Cross-sectional comparative study.

PLACE AND DURATION OF STUDY: The study was conducted in Medical ICU and Chest ICU at Liaquat National Hospital (LNH), Karachi, from January till August, 2007.

METHODOLOGY: Patients admitted in ICU with clinical suspicion of VAP, fulfilling inclusion criteria viz. fever, leukocytosis, new or worsening infiltrate in chest radiograph or purulent secretions were included. Exclusion criteria were deranged coagulopathy, extreme ventilatory and oxygenation demands and tracheal obstruction. All patients had N-BAL using 16 fr Nasogastric tube (NG) without lubrication followed by B-BAL. Samples collected were submitted to the laboratory for quantitative cultures and sensitivities. Results were documented on predesigned proforma.

RESULTS: Fifty four patients underwent paired B-BAL and N-BAL sampling. The N-BAL sensitivity and specificity for N-BAL were 87.87% and 85.71% respectively and p-value was <0.001. N-BAL showed sensitivity of 87.87%, specificity of 75.71%, positive predictive value of 89.65%, negative predictive value of 77.77% and p<0.001, which was statistically significant. Significant differences in time required for sample collection and cost of both procedures were also observed.

CONCLUSION: The results favour the use of blind NG tube bronchoalveolar lavage quantitative cultures as it is simple, safe, cost-effective and minimally invasive method of diagnosing VAP.