Physiologic Effects from Using Tight- and Loose-Fitting Powered Air-Purifying Respirators on Inhaled Gases, Peak...

Area of Science:

• Occupational Health and Safety
• Human Physiology
• Respiratory Protection

Background:

• Powered air-purifying respirators (PAPRs) are essential personal protective equipment across numerous industries.
• Understanding the physiological impact of PAPRs during physical exertion is critical for worker safety and performance.
• Previous research has not comprehensively evaluated PAPR stresses across diverse work intensities.

Purpose of the Study:

• To assess the physiological stresses imposed by different PAPR types during rest and varying energy expenditure levels.
• To identify potential differences in PAPR tolerance based on gender and PAPR design (tight-fitting vs. loose-fitting).

Main Methods:

• Twelve males and twelve females participated, wearing one tight-fitting and three loose-fitting PAPRs.
• Participants underwent testing at rest and during simulated work at oxygen consumption rates of 1.0, 2.0, and 3.0 L·min^-1.
• Continuous breath-by-breath measurements included inhaled CO₂ (F_ICO₂), inhaled O₂ (F_IO₂), inhalation pressure, and end-inhalation temperature.

Main Results:

• Gender did not significantly affect any measured physiological variables.
• Loose-fitting PAPRs with larger dead space resulted in the highest minimum F_ICO₂ at moderate and high energy expenditures.
• The lowest maximum F_IO₂ was observed with the largest dead space loose-fitting PAPR during high-intensity exercise.
• Peak inhalation pressures became negative at oxygen consumption rates exceeding 1.0 L·min^-1, indicating inhalation flow surpassed blower capacity.

Conclusions:

• PAPRs appear physiologically tolerable for healthy workers across a range of physical activities.
• PAPR design, specifically dead space in loose-fitting models, influences inhaled gas concentrations during exertion.
• Further investigation is required to understand the air source when inhalation demand exceeds PAPR blower flow.