Modified N95 mask delivers high inspired oxygen concentrations while effectively filtering aerosolized...

Area of Science:

• Biomedical Engineering
• Respiratory Medicine
• Infectious Disease Control

Background:

• Pandemic scenarios necessitate effective oxygen delivery for hypoxic patients.
• Protecting healthcare providers from patient-generated aerosols is critical.
• Existing oxygen delivery masks may not offer adequate respiratory isolation.

Purpose of the Study:

• To modify an N95 mask for optimized oxygen (O2) supplementation.
• To evaluate the O2 delivery efficacy of the modified N95 mask.
• To assess the filtration and isolation capabilities of the modified N95 mask.

Main Methods:

• Modification of an N95 mask with a plastic manifold including a one-way inspiratory valve, O2 inlet, and gas reservoir.
• Prospective repeated-measures study with 10 healthy volunteers.
• Evaluation of fractional inspiratory oxygen concentrations (F(I)O2) and particle filtration efficiency under resting and hyperventilation conditions.

Main Results:

• The modified N95 O2 mask delivered a median F(I)O2 of 0.68 at 8 L/min O2 flow during resting ventilation.
• During hyperventilation, all tested masks achieved clinically equivalent F(I)O2 levels.
• The N95 O2 mask maintained the filtration efficiency of the original N95 mask for both internal and external particles.

Conclusions:

• An N95 mask can be successfully modified to provide oxygen supplementation.
• The modified N95 O2 mask offers clinically equivalent F(I)O2 to a nonrebreathing mask.
• The modification preserves the essential filtration and respiratory isolation capabilities of the N95 mask.