Development and evaluation of a flow-dividing unit for differential ventilation and selective PEEP

Area of Science:

• Mechanical Ventilation
• Respiratory Physiology

Background:

• Differential ventilation is crucial for managing lung heterogeneity.
• Selective positive end-expiratory pressure (PEEP) aims to optimize ventilation in non-uniform lungs.
• Existing flow-dividing units require careful calibration.

Purpose of the Study:

• To evaluate the effectiveness of a flow-dividing unit for differential ventilation.
• To compare inspiratory flow resistors and an inspiratory threshold valve in maintaining even ventilation distribution.
• To assess gas delivery synchrony under varying lung impedance conditions.

Main Methods:

• A two-compartment lung model with adjustable compliance and resistance was used.
• One ventilator and a flow-dividing unit (inspiratory flow resistors or threshold valve) were employed.
• Ventilation distribution, gas delivery synchrony, and PEEP were analyzed.

Main Results:

• Both flow resistors and the threshold valve achieved even ventilation distribution initially.
• Flow resistors required readjustment with increasing lung impedance differences.
• The inspiratory threshold valve maintained even ventilation without readjustment, ensuring synchronous gas delivery.

Conclusions:

• An inspiratory threshold valve is superior to flow resistors for maintaining even ventilation distribution in heterogeneous lungs.
• The threshold valve facilitates synchronous gas delivery, crucial for mechanical ventilation.
• This non-active flow-dividing unit is compatible with any ventilator.