Dose maintenance for Partial Liquid Ventilation: passive heat-and-moisture exchangers

Area of Science:

• Biomedical Engineering
• Respiratory Medicine
• Critical Care

Background:

• Partial Liquid Ventilation (PLV) using perflubron (PFB) is a treatment for acute lung failure.
• Maintaining PFB dose and minimizing evaporation are crucial during PLV.
• Conventional heat-and-moisture exchangers (HMEs) manage water loss in mechanical ventilation.

Purpose of the Study:

• To develop specialized fluorophilic HMEs (FHMEs) for efficient PFB and water conservation during PLV.
• To evaluate FHME performance in vitro using a patient simulator and in vivo in animal models.

Main Methods:

• Developed and tested various FHME concepts using a patient simulator with water and PFB vapor sources.
• Measured dose-retention efficiencies using infrared instruments and thermohygrometers.
• Evaluated a promising FHME design in swine undergoing 12-hour PLV treatments.

Main Results:

• Efficient FHMEs demonstrated lower flow resistance (delta P) than commercial HMEs without increased dead space.
• PFB vapor did not compromise water-exchange efficiency in certain FHME configurations.
• In vivo testing showed a mean PFB conservation efficiency of 63% in swine during PLV.

Conclusions:

• FHMEs are effective in conserving PFB during PLV, potentially sustaining therapeutic doses longer.
• FHME use may reduce PFB consumption, redosing frequency, labor, and treatment costs.
• Further studies are needed to optimize FHME performance for adult patients, considering tidal volume effects.