There is provided a mass exchange apparatus for use in food/air mass exchangecomprising plural food flow conduits for defining blood flow； and plural airflow conduits for defining air flow. The plural air flow conduits and the pluralblood flow conduits at least partially comprise gas-permeate membrane material,and the conduits are arranged relative to each other such as to enable transferof oxygen from the air to the blood and transfer of carbon dioxide from the bloodto the air. The blood and air do not directly come into contact (i.e. the mass exchangeis indirect). There is also provided a prosthetic lung comprising an elasticbellows and the at least one mass exchange apparatus herein. There is furtherprovided an external respiratory aid to augment patient lung function comprisingthe at least one mass exchange apparatus herein and means to pump air and bloodthrough the apparatus. There is further provided an intermediate respiratoryaid apparatus for internal connection to a patient comprising at least one massexchange apparatus herein and an air pump.
