摘要 |
<p>An instrument for use in the measurement of gases in body fluids comprises a flexible catheter having an inner tube within an outer tube, the tubes being of such diameters that there is a substantially cylindrical passage between the tubes which can be evacuated or flushed with a non-interfering gas. Spacers can be provided in the passage, such as radial webs or a single or double helix filament.</p> |