Ventilator-associated events: prevalence and mortality in Japan

In 2013, the Centers for Disease Control and Prevention (CDC) issued the concept of the ventilator-associated events (VAEs) as a quality indicator (QI) in the intensive care unit (ICU). A number of studies have been conducted in the United States and other Western countries to evaluate its practicality. However, information on VAEs in non-Western countries is scarce. The purpose of this preliminary study was to illuminate the incidence and associated mortality rate of VAEs in Japan, as a first step in the effort to determine its practicality.

We conducted a multi-center, retrospective review of patient medical record using VAEs surveillance algorithm. We analyzed 785 patients with ≥2 days of mechanical ventilator (MV), admitted to the ICU at seven urban hospital in Japan. The prevalence of VAEs, including its three subtypes, and in-ICU mortality were researched.

Forty-nine VAEs were identified, affecting 5.7% of patients requiring MV for ≥2 days and 6.4 per 1,000 MV days. Mortality in those who developed VAEs was 42.9%, significantly higher than the rest of the cohort (vs. 15.4%, P<0.001). The overall equivalent distribution of the three VAEs subtype incidences was evaluated: the incidences of VAC only, IVAC only and PVAP were 2.20, 1.90 and 2.29 per 1,000 MV days respectively (P=0.933). However, VAE etiology and mortality was facility dependent. ICUs with a large proportion of surgical patients and more severe cases tended to have increased VAE incidence, with a converse decrease in closed ICUs.

The prevalence of VAEs appears low in Japanese ICUs. Nonetheless, mortality was substantially higher in patients who developed VAEs. Although some potential indices of VAEs are suggested to serve as QIs, additional studies to elaborate its practicality would further be required.