Objective criteria for the accurate diagnosis of ventilator-associated respiratory infections (VARI) are lacking, being categorized into ventilator-associated pneumonia or ventilator-associated tracheobronchitis. Unfortunately, the lack of effect on patient’s outcomes and antibiotic consumption revealed the need for other quality indicators among mechanical ventilation patients (Fabregas et al., 1999, Nseir et al., 2014; Nora and Póvoa, 2017; Blot et al., 2011; Klompas, 2012).

Ten years ago, the US Centres for Disease Control and Prevention (CDC) replaced ventilator-associated pneumonia surveillance for ventilator-associated events (VAE) (Klompas, 2013). The focus was turned from chest radiograph to respiratory worsening defined by a sustained increase of the minimum daily fraction of inspired oxygen (FiO2) and/or the positive end expiratory (PEEP). The goal of this shift towards the VAE concept was to broaden the focus of surveillance and increase the impact of preventive policies in patients’ outcomes. In clinical practice, the utility of VAE criteria remains to be determined. Whereas VAE definition has greater accuracy assessing patient’s outcomes, only the most severe tracheobronchitis and pneumonia episodes require an increase of the ventilator settings (FiO2, PEEP) that qualify as VAE (Ramirez-Estrada et al., 2018). As a consequence, the VAE concept has not been incorporated into the routine clinic dissertation. In contrast, a ventilator-associated pneumonia or ventilator-associated tracheobronchitis diagnosis, frequently triggered by positive culture results, is followed by changes in antibiotic prescription at the bedside (Prinzi et al., 2021). Additionally, the use point-of care lung ultrasound shows the same limitations as conventional chest-X ray for ventilator-associated pneumonia diagnosis in terms of specificity (Sperandeo et al., 2016, Rajagopalan, 2021). Furthermore, the discussion over the treatment of tracheobronchitis or the duration of antibiotic therapy is still running (Nseir et al., 2014, Martin-Loeches et al., 2017).

On the other hand, adult VAE criteria resulted extremely restrictive in children (Iosifidis et al., 2016, Chomton et al., 2018), highlighting the need of a paediatric adaptation (Iosifidis et al., 2018). The variation of VAE based on the mean airway pressure (MAP) adopted by the US CDC (Cocoros et al., 2016) resulted even more restrictive (Willson et al., 2018; Arthur et al., 2022, Gionfriddo et al., 2018), missing 84 out of 89 ventilator-associated infections in a multicentre study conducted at 47 paediatric ICUs (Willson et al., 2018) due to the extremely low basal VAE rates, between 0.9 and 1.9 per 1,000 ventilator-days (Arthur et al., 2022, Gionfriddo et al., 2018). In contrast, a definition of VAE based on slighter PEEP increases resulted the least restrictive and the only VAE criteria independently associated with worse outcomes among children (Peña-López et al., 2018, Peña-López et al., 2022; Papakyritsi et al., 2023). Still, it did not encompass all ventilator-associated pneumonia and tracheobronchitis (Peña-López et al., 2022). Our hypothesis was that the application of VAE respiratory settings criteria on patients diagnosed from VARIs selects those episodes with worse outcomes.