Incidence of Ventilator-associated pneumonia in the critical care unit at Kenyatta National Hospital, a public tertiary care hospital

Abstract

Background: Ventilator-associated pneumonia (VAP), a severe type of hospitalacquired pneumonia develops 48-72 hours after initiation of mechanical ventilation. Objectives: This study aimed to determine incidence of VAP using the Clinical Pulmonary Infection Score (CPIS) which combines clinical, radiographic, physiologic and microbiological data into a numerical result, ranging from 0 to 12, and to identify risk factors associated with its development. A secondary objective was to assess the diagnostic utility of a positive culture of pathogenic bacteria on tracheal aspirate in predicting a positive culture on a mini-Broncho Alveolar Lavage (Mini-BAL). Design: A hospital-based, prospective cross-sectional study carried between 01st January 2015 to 31st March 2015. Setting: Kenyatta National Hospital, a tertiary care hospitalSubjects: Ninety-two subjects who met the inclusion criteria were included. Results: Of the 92 patients studied, 50 had a CPIS of ≥6, an incidence of 54.4% (C.I. 44.0-64.7%). Factors that appeared to show an association with VAP included documented aspiration (OR 2.0), a high nurse to patient ratio (OR 4.0), postsurgical patients (OR 2.5) and those who were nasally intubated (OR 4.0) and those with oral candidiasis (OR 3.5). Of the 50 patients that showed a CPIS of ≥6, 46 (92%) patients had a positive culture on tracheal aspirate and 31 (62%) patients demonstrated a positive mini-BAL culture. The sensitivity and specificity of a positive tracheal aspirate in predicting a positive min-BAL culture were 100% (C.I 88.7-100.0%) and 21.1% (C.I 6.2-45.6%) respectively. Negative predictive value of 100.0% (C.I 40.2-100.0%) and a positive predictive value of 67.4% (C.I 52.0-80.5%). Conclusion: Our study, the first documented in East Africa, found a high incidence of VAP. Further studies are needed to compare the diagnostic utility of various invasive and non-invasive tests for diagnosis of VAP.