| 摘要 |
A rebreathing apparatus is designed to minimize the amount of oxygen required in oxygen therapy to maintain a given or desired oxygen level in the blood and includes a changeable volume chamber (15, 25, 35, 45, 55) having a maximum volume less than the maximum volume of the respiratory tract of a user and to which a continuous source of oxygen is supplied so that the initial gas exhaled on exhalation is directed into the changeable volume chamber and so that the remainder of the exhaled gas is vented to the ambient. Oxygen is supplied to the apparatus via inlets (13, 23, 33, 43, 56) to increase the oxygen content of the retained gas as some of it is displaced from the apparatus so as to create a bolus of oxygen enriched gas. On inhalation this quantity is initially taken into the respiratory tract and the latter is then filled concurrently with ambient air and gas from the apparatus. This sequence is followed as long as the therapy is administered. |
