A retrospective evaluation of multiple definitions for ventilator associated pneumonia (VAP) diagnosis in an Australian regional intensive care unit

Abstract

Ventilator Associated Pneumonia is a common complication of invasively ventilated patients with significant and underestimated morbidity and mortality. Defining VAP cases is greatly varied as many definitions are used with varying success and sensitivity. This study evaluates VAP detection using four definitions in a regional Australian Intensive Care Unit (ICU). A cohort of patients admitted to ICU at the Mackay Base Hospital from April 1st 2020 to March 31st 2021, who had endo-tracheal intubation and mechanical ventilation for longer than 48 h were identified. Each patient was examined across four common definitions of VAP. Head-to-head analysis of definitions was pursued to determine the most suitable definition. The four definitions used included: An Australian VAP definition, the CDC VAP definition, the Mackay Base Hospital Local Protocol and a Physician Decision Arm. 66 unique patients and 2 re-intubations were identified during the data collection window. The local protocol identified 8 cases of VAP. The Australian VAP definition identified 6 additional cases and 0 missed cases compared to the local protocol. The CDC definition missed 4 cases and identified 4 additional cases compared to the local protocol. Finally, the physician arm identified 10 cases including 8 additional cases and missed 6 cases. VAP is an extremely difficult clinical condition to define and detect. Definitions have varied accuracy and suffer logistically for application to the individual patient. Refined criteria for diagnosis of VAP is greatly needed and its prevalence in intensive care units likely remains uncertain.