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Breathing Resistance and Dead Space in Respiratory Protective Devices.

PB273794

Publication Date	1976
Personal Author	James, R. H.
Page Count	38
Abstract	A review reveals that respirators, in general, are worn by only about 20% of workers in need of respiratory protection against hazardous substances in the workplace, primarily due to generalized 'discomfort'. Breathing resistance and equipment dead space are two of the most important design factors contributing to this discomfort. The principal physiological responses to added breathing resistance appear to be hypoventilation, reduced oxygen consumption, a 'flattened' and prolonged pattern in the breathing phase to which resistance has been added, increased respiratory work, and a tendency for increased functional residual lung capacity and increased carbon dioxide retention. Added dead space forces rebreathing of exhaled carbon dioxide which, in turn, stimulates compensatory hyperventilation to maintain a normal alveolar PC02. The mechanism for maintaining a normal PC02 seems effective up to 2% for short-term and to 1% C02 for long-term exposures.
Keywords	Respirators Protectors Industrial hygiene Hazardous materials Breathing apparatus Medical equipment Responses Physiological effects Human factors engineering Psychological effects Regulations Recommendations Reviews Respiratory system Comfort Toxic substances Hypoventilation Occupational safety and health
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	95D - Human Factors Engineering 94H - Industrial Safety Engineering 57U - Public Health & Industrial Medicine
Corporate Authors	National Inst. for Occupational Safety and Health, Cincinnati, Ohio. Div. of Biomedical and Behavioral Science.
Document Type	Technical Report
NTIS Issue Number	197803

Breathing Resistance and Dead Space in Respiratory Protective Devices.

Breathing Resistance and Dead Space in Respiratory Protective Devices.
PB273794

Publication Date	1976
Personal Author	James, R. H.
Page Count	38
Abstract	A review reveals that respirators, in general, are worn by only about 20% of workers in need of respiratory protection against hazardous substances in the workplace, primarily due to generalized 'discomfort'. Breathing resistance and equipment dead space are two of the most important design factors contributing to this discomfort. The principal physiological responses to added breathing resistance appear to be hypoventilation, reduced oxygen consumption, a 'flattened' and prolonged pattern in the breathing phase to which resistance has been added, increased respiratory work, and a tendency for increased functional residual lung capacity and increased carbon dioxide retention. Added dead space forces rebreathing of exhaled carbon dioxide which, in turn, stimulates compensatory hyperventilation to maintain a normal alveolar PC02. The mechanism for maintaining a normal PC02 seems effective up to 2% for short-term and to 1% C02 for long-term exposures.
Keywords	Respirators Protectors Industrial hygiene Hazardous materials Breathing apparatus Medical equipment Responses Physiological effects Human factors engineering Psychological effects Regulations Recommendations Reviews Respiratory system Comfort Toxic substances Hypoventilation Occupational safety and health
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	95D - Human Factors Engineering 94H - Industrial Safety Engineering 57U - Public Health & Industrial Medicine
Corporate Authors	National Inst. for Occupational Safety and Health, Cincinnati, Ohio. Div. of Biomedical and Behavioral Science.
Document Type	Technical Report
NTIS Issue Number	197803