A comparison of the ventilatory responses to wearing either a hood or a mask escape respirator with identical nose-cups

Differences in escape respirator design can influence the wearer’s ventilatory response and impact inspired oxygen (O₂) and carbon dioxide (CO₂) concentrations. There has been minimal investigation into the differences between hood and mask designs as escape respirators that compare between the ventilatory responses of wearing either a hood or mask escape respirator with an identical nose-cup. Thirty-nine healthy young males participated in the study. Each subject participated in two 20-min sessions of monitored breathing, wearing either a hood-type filtering facepiece respirator “CAPS 2000” (Shalon Chemical Industries, Israel & Supergum Industries Ltd, Israel) or an “Orange Diamond” filtering facepiece mask-type escape respirator (DEA Mop, Israel). Inspired gas concentrations of CO₂ and O₂ as well as the ventilatory response were recorded through a nose-cup during the test. Inspired CO₂, minute ventilation, breathing frequency, and the index of central ventilatory drive (V_T/T_I) were all significantly higher (p < 0.05) while wearing a mask respirator compared to a hood respirator. The hood respirator evaluated in the present study outperformed the mask respirator in most indices when measured at rest. The hood respirator had a reduced ventilatory demand compared to the mask respirator and may be advantageous for individuals with weaker respiratory systems, such as the elderly or those who suffer from respiratory diseases.