Effects of hyperventilation on the inspiratory to end-tidal oxygen difference.
We assessed the inspiratory to end-tidal oxygen difference (PIO2-PE'O2) during voluntary hyperventilation in 10 healthy male volunteers. The oxygen difference was measured with a fast-response paramagnetic differential oxygen sensor. As simultaneous changes in metabolism and cardiac output also influence (PIO2-PE'O2), oxygen uptake was measured with indirect calorimetry and non-invasive transthoracic electrical bioimpedance was used for measurement of cardiac output. After a rest period, subjects were instructed to double their minute ventilation volume (VE) and after 5 min triple their resting VE for another 5 min. (PIO2-PE'O2) decreased from a zero value of 6.4 kPa to 3.9 kPa at 5 min (P < 0.01) and 2.9 kPa at 10 min (P < 0.01). At 15 min (i.e. 5 min after the end of hyperventilation) there was an increase in (PIO2-PE'O2) to 8.3 kPa (P < 0.05). Regression analysis between (PIO2-PE'O2) (kPa) and VE (litre m-2 min-1) gave the formula: (PIO2-PE'O2) = 1/(0.059 + 0.034 VE), r = -0.92, n = 158. Oxygen uptake and cardiac output did not change significantly during hyperventilation, but decreased in the post-hyperventilation period. An oxygen difference of more than 8 kPa was associated with significant arterial desaturation.
Bengtsson
J
J
Department of Anaesthesia and Intensive Care, Sahlgren Hospital, University of Göteborg, Sweden.
Bengtsson
A
A
Stenqvist
O
O
Bengtson
J P
JP
D000328:Adult; D002245:Carbon Dioxide / Q000097:blood / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D006801:Humans; D006985:Hyperventilation / Q000503:physiopathology*; D001239:Inhalation / Q000502:physiology*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology*; D010313:Partial Pressure
D002245:Carbon Dioxide; D010100:Oxygen