Effects of heavy hyperventilation on transcutaneous and arterial oxygen tensions in healthy adults

Abstract

Transcutaneous pO₂ on thorax and the volar part of the forearm was measured in six healthy volunteers during heavy hyperventilation, and the values compared with simultaneously measured arterial blood pO₂. We found a significant rise in arterial pO₂ during hyperventilation with a lesser increase in thoracic transcutaneous pO₂. When measured on arm the transcutaneous pO₂ did not even rise significantly. After hyperventilation pO₂ fell to values below the resting level. The transcutaneous/arterial pO₂ index, fell significantly during hyperventilation with the greatest reduction in the arm index. After hyperventilation the arm index returned to the control values, whereas the thoracic index remained low.

We suggest, that the significant fall in transcutaneous/arterial blood pO₂ index during hyperventilation is caused primarily by skin vasoconstriction, whereas the fall in pO₂ after hyperventilation is caused by hypoxia.

When measured on areas with increased muscular activity transcutaneouspO₂ might depend on the local blood flow and skin oxygen consumption also, causing problems in interpretation with certain patient groups.

Key Words:

• hyperventilation
• oxygen tension
• transcutaneous