Should we use driving pressure to set tidal volume?

Area of Science:

• Critical Care Medicine
• Pulmonary Medicine
• Mechanical Ventilation

Background:

• Ventilator-induced lung injury (VILI) can occur even with low tidal volumes (VT), particularly in patients with limited aerated lung tissue ('baby lung').
• Respiratory system static compliance (CRS) is heavily influenced by the 'baby lung' volume.
• Driving pressure (ΔP), calculated as VT/CRS, may help optimize VT settings.

Purpose of the Study:

• To explore the role of driving pressure (ΔP) in mechanical ventilation.
• To identify if ΔP can help tailor tidal volume (VT) settings to prevent VILI.
• To assess the association between ΔP and patient survival.

Main Methods:

• Review of existing literature on driving pressure and mechanical ventilation outcomes.
• Analysis of observational data linking ΔP to mortality risk.
• Discussion of interventions aimed at reducing ΔP, such as prone positioning and extracorporeal CO2 removal.

Main Results:

• Driving pressure (ΔP) is strongly associated with survival and mediates mechanical ventilation's effect on outcomes in acute respiratory distress syndrome (ARDS).
• Observational data suggest increased mortality risk for patients with ΔP > 14 cmH2O, though an optimal threshold is not yet defined.
• Prone positioning and ventilatory adjustments can reduce ΔP; low-flow extracorporeal CO2 removal is being investigated for further ΔP reduction.

Conclusions:

• Driving pressure (ΔP) is a readily available bedside parameter to identify patients at risk for VILI and mortality.
• While prospective studies are lacking, titrating VT to minimize ΔP, especially when > 14 cmH2O, appears physiologically sound and beneficial.
• Minimizing ΔP should be considered when it can be achieved with minimal impact on CO2 clearance.