Biomaterial Database

Respiratory response to inhaled CO2 during positive inspiratory pressure in humans. 1994

P Scheid, and F Lofaso, and D Isabey, and A Harf

Département de Physiologie, Hôpital Henri Mondor, Créteil, France.

To investigate ventilatory CO2 sensitivity during inspiratory pressure support (IPS), we administered inspiratory CO2 [fractional concn (FICO2) 0.01, 0.03, or 0.05] in eight normal subjects without (CTRL) or with (Pinsp) positive inspiratory airway pressure (5 or 10 cmH2O). At CTRL and low IPS, CO2 inhalation led to a significant increase in tidal volume (VT) with nearly identical slopes in the plot of VT vs. end-tidal PCO2. At the high IPS level, VT at FICO2 of 0 was significantly above the value at lower Pinsp and did not increase with CO2 unless FICO2 was elevated to > 0.03. There was very little effect of either Pinsp or FICO2 on respiratory frequency and respiratory timing. The data suggest that the CO2 sensitivity of ventilation is similar at low levels of IPS as during CTRL. However, at high levels of IPS, VT is determined largely by the passive inflation and, thus, independent of CO2. CO2 has to be elevated to increase the respiratory drive before VT becomes CO2 sensitive.

UI	MeSH Term	Description	Entries
D008170	Lung Compliance	The capability of the LUNGS to distend under pressure as measured by pulmonary volume change per unit pressure change. While not a complete description of the pressure-volume properties of the lung, it is nevertheless useful in practice as a measure of the comparative stiffness of the lung. (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p562)	Compliance, Lung,Compliances, Lung,Lung Compliances
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D011175	Positive-Pressure Respiration	A method of mechanical ventilation in which pressure is maintained to increase the volume of gas remaining in the lungs at the end of expiration, thus reducing the shunting of blood through the lungs and improving gas exchange.	Positive End-Expiratory Pressure,Positive-Pressure Ventilation,End-Expiratory Pressure, Positive,End-Expiratory Pressures, Positive,Positive End Expiratory Pressure,Positive End-Expiratory Pressures,Positive Pressure Respiration,Positive Pressure Ventilation,Positive-Pressure Respirations,Positive-Pressure Ventilations,Pressure, Positive End-Expiratory,Pressures, Positive End-Expiratory,Respiration, Positive-Pressure,Respirations, Positive-Pressure,Ventilation, Positive-Pressure,Ventilations, Positive-Pressure
D012132	Respiratory Muscles	These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.	Ventilatory Muscles,Respiratory Muscle,Muscle, Respiratory,Muscle, Ventilatory,Muscles, Respiratory,Muscles, Ventilatory,Ventilatory Muscle
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000280	Administration, Inhalation	The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.	Drug Administration, Inhalation,Drug Administration, Respiratory,Drug Aerosol Therapy,Inhalation Drug Administration,Inhalation of Drugs,Respiratory Drug Administration,Aerosol Drug Therapy,Aerosol Therapy, Drug,Drug Therapy, Aerosol,Inhalation Administration,Administration, Inhalation Drug,Administration, Respiratory Drug,Therapy, Aerosol Drug,Therapy, Drug Aerosol
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D000399	Air Pressure	The force per unit area that the air exerts on any surface in contact with it. Primarily used for articles pertaining to air pressure within a closed environment.	Air Pressures,Pressure, Air,Pressures, Air