Medical Equipment Glossary

Used in anesthesia, this variant of a T-piece is a coaxial system in which fresh gas flows through a narrow inner tube within the outer corrugated tubing. The patient inspires fresh gas from the outer reservoir tube and expires into the reservoir tube. The fresh gas that is flowing into the system at the time of expiration is wasted as it is contaminated by expired gas, so there is an expiratory pause in which the fresh gas from the inner tube washes the expired gas out of the reservoir tube, filling it with fresh gas for the next inspiration.