Evaluation of Venturi Adapters for CPAP.

Area of Science:

• Anesthesiology
• Respiratory Therapy
• Biomedical Engineering

Background:

• Continuous positive airway pressure (CPAP) effectively mitigates risks associated with obstructive apnea and oxygen desaturation during procedural sedation.
• Venturi adapters present a cost-effective method for delivering CPAP by amplifying oxygen flow to achieve therapeutic pressures.

Purpose of the Study:

• To assess the performance of four distinct Venturi adapters used in CPAP delivery.
• Key performance metrics evaluated include pressure generation efficiency, inspired oxygen concentration (FiO2), dilution of end-tidal carbon dioxide (EtCO2) for capnometry, and generated noise levels.

Main Methods:

• A benchtop simulation model was employed, featuring a test lung, simulated airway, face mask, and oxygen source.
• Evaluations involved measuring oxygen flow rates for pressure generation, recording noise levels, and assessing FiO2 under ventilated conditions.
• End-tidal carbon dioxide (EtCO2) dilution was quantified by comparing mask measurements to tracheal reference values.

Main Results:

• Venturi adapter designs exhibit unique trade-offs between pressure generation efficiency, FiO2, and EtCO2 sample dilution.
• Higher FiO2 levels were inversely related to pressure generation efficiency and increased EtCO2 dilution.
• Certain adapters generated significant noise, potentially impacting patient comfort and clinical usability.

Conclusions:

• The performance characteristics of Venturi adapters vary, offering distinct clinical advantages and disadvantages.
• Selection of a specific Venturi adapter should align with the immediate clinical requirements and priorities of the healthcare provider.