The influence of varying inspired fractions of O2 and CO2 on the development of involuntary breathing movements during maximal apnoea
Author(s)
Breskovic, Toni
Lojpur, Mihajlo
Maslov, Petra Zubin
Cross, Troy J
Kraljevic, Jasenka
Ljubkovic, Marko
Marinovic, Jasna
Ivancev, Vladimir
Johnson, Bruce D
Dujic, Zeljko
Griffith University Author(s)
Year published
2012
Metadata
Show full item recordAbstract
The growing urge to breathe that occurs during breath-holding results in development of involuntary breathing movements (IBMs). The present study determined whether IBMs are initiated at critical levels of hypercapnia and/or hypoxia during maximal apnoea. Arterial blood gasses at the onset of IBM were monitored during maximal voluntary breath-holds. Eleven healthy men performed breath holds after breathing air, hyperoxic-normocapnia, hypoxic-normocapnia, and normoxic-hypercapnia. Pre-breathing of the gas mixtures facilitated the IBM onset, reducing the time-to-onset for ~46% (hyperoxic condition) and for ~80% (hypoxic ...
View more >The growing urge to breathe that occurs during breath-holding results in development of involuntary breathing movements (IBMs). The present study determined whether IBMs are initiated at critical levels of hypercapnia and/or hypoxia during maximal apnoea. Arterial blood gasses at the onset of IBM were monitored during maximal voluntary breath-holds. Eleven healthy men performed breath holds after breathing air, hyperoxic-normocapnia, hypoxic-normocapnia, and normoxic-hypercapnia. Pre-breathing of the gas mixtures facilitated the IBM onset, reducing the time-to-onset for ~46% (hyperoxic condition) and for ~80% (hypoxic condition) compared to the normoxic air breathing time. A strong correlation (R = 0.83, P = 0.002) between arterial partial pressure of CO2 (PaCO2PaCO2) at IBM onset after pre-breathing hyperoxic and hypercapnic gas mixtures was observed, suggesting the existence of a possible IBM PaCO2PaCO2 threshold level of ~6.5 ᠰ.5 kPa. No clear "threshold" was observed for partial pressure of arterial O2 (PaO2PaO2). However, we observed that IBM onset was influenced, in part, by an interaction between PaO2PaO2 and PaCO2PaCO2 levels during maximal apnoea. This study demonstrated the complex interaction between arterial blood-gases and the physiological response to maximal breath holding.
View less >
View more >The growing urge to breathe that occurs during breath-holding results in development of involuntary breathing movements (IBMs). The present study determined whether IBMs are initiated at critical levels of hypercapnia and/or hypoxia during maximal apnoea. Arterial blood gasses at the onset of IBM were monitored during maximal voluntary breath-holds. Eleven healthy men performed breath holds after breathing air, hyperoxic-normocapnia, hypoxic-normocapnia, and normoxic-hypercapnia. Pre-breathing of the gas mixtures facilitated the IBM onset, reducing the time-to-onset for ~46% (hyperoxic condition) and for ~80% (hypoxic condition) compared to the normoxic air breathing time. A strong correlation (R = 0.83, P = 0.002) between arterial partial pressure of CO2 (PaCO2PaCO2) at IBM onset after pre-breathing hyperoxic and hypercapnic gas mixtures was observed, suggesting the existence of a possible IBM PaCO2PaCO2 threshold level of ~6.5 ᠰ.5 kPa. No clear "threshold" was observed for partial pressure of arterial O2 (PaO2PaO2). However, we observed that IBM onset was influenced, in part, by an interaction between PaO2PaO2 and PaCO2PaCO2 levels during maximal apnoea. This study demonstrated the complex interaction between arterial blood-gases and the physiological response to maximal breath holding.
View less >
Journal Title
Respiratory Physiology and Neurobiology
Volume
181
Issue
2
Subject
Cardiovascular medicine and haematology
Neurosciences
Medical physiology