Effect of External Dead Volume on Performance While Wearing a Respirator

Physiologic effects and measurement of carbon dioxide and oxygen levels during qualitative respirator fit testing

“…This is consistent with results found in the literature. 9,15,16,23 Johnson et al 9 concluded that the physiological effects of resistance on breathing are much more pronounced than those due to dead space volume. The NIOSH study described earlier also confirms higher CO 2 levels with N95 filtering facepiece respirators, when compared to the full facepiece.…”

“…9 Third, CO 2 has local vasodilator effects, and may affect the ability to work by shunting blood from other working muscles. 9 Fourth, high inhaled CO 2 levels tend to increase the ventilation rate, thus increasing the effect of breathing resistance since a greater air volume creates higher pressure differences. 10 CO 2 is the principal regulator of respiration, acid-base balance, and behavioral state arousal in humans.…”

“…8 The effects of inhaled CO 2 are several fold. 9 First, the stimulation of respiration adds to the burden of the work of breathing, and could decrease the ability to produce physical work if the work was performed at close to the maximum level. 9 Second, CO 2 directly causes a feeling of discomfort and unease, and may cause sufficient anxiety to affect work performance.…”

“…9 First, the stimulation of respiration adds to the burden of the work of breathing, and could decrease the ability to produce physical work if the work was performed at close to the maximum level. 9 Second, CO 2 directly causes a feeling of discomfort and unease, and may cause sufficient anxiety to affect work performance. 9 Third, CO 2 has local vasodilator effects, and may affect the ability to work by shunting blood from other working muscles.…”

“…9 Second, CO 2 directly causes a feeling of discomfort and unease, and may cause sufficient anxiety to affect work performance. 9 Third, CO 2 has local vasodilator effects, and may affect the ability to work by shunting blood from other working muscles. 9 Fourth, high inhaled CO 2 levels tend to increase the ventilation rate, thus increasing the effect of breathing resistance since a greater air volume creates higher pressure differences.…”