Ventilator-associated lung injury during assisted mechanical ventilation

Area of Science:

• Critical Care Medicine
• Respiratory Physiology
• Mechanical Ventilation

Background:

• Assisted mechanical ventilation (MV) presents a potential alternative to controlled MV in early acute respiratory distress syndrome (ARDS).
• It offers benefits including reduced sedation, avoidance of paralysis, improved hemodynamics, and enhanced organ perfusion.
• These advantages may contribute to lung protection and a lower risk of ventilator-associated lung injury (VALI).

Purpose of the Study:

• To review ventilator-associated lung injury (VALI) in the context of various assisted mechanical ventilation (MV) strategies.
• To identify specific clinical scenarios and ventilator settings suitable for assisted MV in ARDS patients.
• To highlight essential parameters for monitoring during assisted MV to mitigate VALI.

Main Methods:

• Review of existing literature on assisted MV strategies and their impact on VALI.
• Discussion of specific assisted MV modes: volume assist-control, pressure assist-control, pressure support ventilation (PSV), airway pressure release ventilation (APRV), APRV with PSV, proportional assist ventilation (PAV), noisy ventilation, and neurally adjusted ventilatory assistance (NAVA).
• Identification of clinical criteria and monitoring parameters for assisted MV in ARDS.

Main Results:

• Assisted MV may reduce sedation, paralysis, hemodynamic compromise, and improve organ perfusion compared to controlled MV.
• Specific patient conditions for assisted MV include PaO2/FiO2 >150 mmHg with PEEP ≥5 cmH2O, and use of pressure-targeted, time-cycled breaths (A-PCV, APRV).
• Monitoring inspiratory drive, transpulmonary pressure, and tidal volume (6 mL/kg) is crucial during assisted MV.

Conclusions:

• Assisted mechanical ventilation is a viable option for ARDS patients under specific conditions, potentially reducing VALI.
• Pressure-targeted ventilation modes with spontaneous or supported breaths are suggested for assisted MV in ARDS.
• Further research is needed to fully elucidate the impact of novel assisted ventilation modalities (PAV, noisy PSV, NAVA) on VALI.