Interrater Variability in Identifying Ventilator Associated Pneumonia Using Six Different Definitions

Abstract

Objective: There is no widely accepted standard definition for Ventilator Associated Pneumonia (VAP). The reliability of the current definitions in use remains controversial. Our objective was to assess the reliability of six commonly used VAP definitions: The Loose, The Rigorous, The Modified Clinical Pulmonary Infection Score (CPIS), The Canadian Critical Care Trials Group (CCCTG), The International Sepsis Forum Consensus (ISFC) and The Center for Disease Control and Prevention (CDC). Design: We examined the electronic health records of all the consecutively admitted adult patients at our institution who received invasive mechanical ventilation (IMV) for ≥ 48 hours, from January 2006 through December 2006.Patients were excluded if they developed pneumonia within the first 48 hours or if they had a tracheostomy before IMV. Two expert intensivists independently reviewed the following data for each patient: indications and duration of IMV, vital signs, oxygen requirements, the frequency of respiratory suctioning, amount, color and consistency of secretion, ventilator settings, leukocyte count, microbiologic and radiographic data. Interreviewer reliability in diagnosing VAP independently were compared using Cohen’sKappa statistics. Results: A total of 115 patients met the initial inclusion criteria of which 47 patients were excluded (40 had pneumonia on presentation, 6 developed pneumonia within 48 hours and 1 had a tracheostomy on admission). The inter-reviewer agreement Kappa for the Loose, the Rigorous, CPIS, CCCTG, ISFC and CDC definitions for VAP were 0.22, 0.49, 0.33, 0.41, 0.38 and 0.68 respectively. Conclusion: The CDC definition of VAP proved to be statistically more reliable than other tested definitions of VAP, as demonstrated by the lowest interrater variability between two independent reviewers.