Tidal volume in acute respiratory distress syndrome: how best to select it

Area of Science:

• Critical Care Medicine
• Pulmonary Medicine
• Biomedical Engineering

Background:

• Mechanical ventilation is a cornerstone of intensive care unit (ICU) support for acute respiratory distress syndrome (ARDS).
• While essential for gas exchange, mechanical ventilation can paradoxically cause or worsen lung injury, known as ventilator-induced lung injury (VILI).
• Understanding the factors contributing to VILI is crucial for optimizing patient outcomes.

Purpose of the Study:

• To review the physiological effects of tidal volume delivery in ARDS patients.
• To discuss the relationship between tidal volume and VILI (volotrauma).
• To present and evaluate lung-protective ventilatory strategies, including newer approaches and extracorporeal carbon dioxide removal (ECCO2R).

Main Methods:

• Review of experimental evidence and physiological principles related to mechanical ventilation in ARDS.
• Analysis of factors influencing VILI, including tidal volume, driving pressure, strain, and mechanical power.
• Discussion of established and emerging ventilatory strategies.

Main Results:

• Low tidal volume ventilation, scaled to predicted body weight (PBW), remains a key lung-protective strategy.
• Airway driving pressure and lung strain are proposed as surrogates for lung injury risk.
• Extracorporeal carbon dioxide removal (ECCO2R) enables ultra-low tidal volume strategies.
• Mechanical power offers a unifying framework for assessing VILI risk.

Conclusions:

• Optimizing mechanical ventilation in ARDS requires careful consideration of tidal volume and other parameters to minimize VILI.
• Lung-protective strategies, including driving pressure and strain monitoring, are essential.
• Emerging techniques like ECCO2R and the concept of mechanical power hold promise for further refining ventilation strategies.