Ventilator-induced Lung Injury Vortex in Patients With SARS-CoV-2
Condition: ARDS; Mechanical Ventilation Complication; Ventilator-Induced Lung Injury
MeSH terms: Lung Injury; Ventilator-Induced Lung Injury; Wounds and Injuries
Study type: Observational

Summary: 
      The concept of Ventilator-induced Lung Injury Vortex (VILI vortex) has recently been proposed
      as a progressive lung injury mechanism in which the alveolar stress/strain increases as the
      ventilable lung "shrinks" (1). This positive feedback inexorably leads to the acceleration of
      lung damage, with potentially irreversible results. Little is known about the clinical
      aspects of this condition. Understanding its behavior could contribute to changing its
      potential devastating impact.

      The objective of this study is to evaluate the incidence of VILI vortex in patients with
      acute respiratory syndrome (ARDS) secondary to COVID-19, to establish a connection between
      this phenomenon and mortality, and to identify the factors that have an impact on its
      development.
    

Detailed description: 
      Mechanical ventilation is an essential tool for the treatment of patients with acute
      respiratory distress syndrome (ARDS). However, as with other strategies, it is not free of
      complications. Inadequate ventilation may have a negative impact on pulmonary and systemic
      hemodynamics, and it could both cause structural damage to pulmonary parenchyma and activate
      inflammation (2). This process is known as ventilator-induced lung injury (VILI) and may
      promote the development of multiple organ failure and, eventually, death.

      VILI results from the interaction between the mechanical load applied to the ventilable lung
      and its capacity to tolerate it. Factors such as tidal volume (Vt), driving pressure (ΔP),
      inspiratory flow rate (VI), respiratory rate (RR), excessive inspiratory effort, high levels
      of FiO2 and, in some cases, PEEP, have been involved in damage mechanism. In that sense, the
      concept of mechanical power (MP) tries to encompass most of these factors within a measurable
      unit (3). Furthermore, the decrease in ventilable lung volume (baby lung concept), the
      heterogeneous lung compromise in ARDS), and the presence of cofactors that have a negative
      impact on the lung (fluid overload, presence of sepsis or shock) could increase its
      susceptibility to damage (4-5).

      Due to the fact that the mechanical conditions of the lung change dynamically with the
      progression of the disease, the ventilatory strategy needs constant adjustments in order to
      maintain a balance between the load and the size of the ventilable lung (concept of ergonomic
      ventilation). In fact, a protective ventilatory strategy of low tidal volume (Vt: 6
      ml/kg/PBW) and limited plateau pressure (PPlat <30 cmH2O) may cause damage if the functional
      residual capacity (FRC) decreases significantly, thus making a lower number of alveoli
      (including capillaries) withstand a higher mechanical load per unit.

      The concept of VILI vortex has recently been proposed as a progressive lung injury mechanism
      in which the alveolar stress/strain increases as the ventilable lung "shrinks". This positive
      feedback inexorably leads to the acceleration of lung damage, with potentially irreversible
      results (1). Little is known about the clinical aspects of this condition. Understanding its
      behavior could contribute to changing its potential devastating impact.

      The objective of this study is to evaluate the incidence of VILI vortex in patients with ARDS
      secondary to COVID-19, to establish a connection between this phenomenon and mortality, and
      to identify the factors that have an impact on its development.
    

Intervention name(s): CT scan
Intervention type(s): Diagnostic Test
Intervention description(s): Mechanical variables and PaO2/FiO2 were registered daily for 14 days or until initiating assisted ventilation. These data were obtained in passive mechanical conditions.
Ventilator-induced lung injury vortex was defined as a progressive increase in driving pressure (ΔP) as Vt remained constant or even decreased.
Refractory hypoxemia was defined as PaO2/FiO2 <100 despite the optimization of mechanical ventilation and prone positioning.
Other intervention name(s): Transpulmonary pressures (TP) will be measured
Observational model: Other
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients with SARS-CoV-2 in mechanical ventilation