This disclosure includes wound dressings and systems with high-flow therapeutic gas sources for topical wound therapy and related methods. Some dressings, which are configured to be coupled to tissue to facilitate delivery of therapeutic gas to the tissue, comprise a manifold that defines a plurality of gas passageways, the manifold configured to allow communication of therapeutic gas to the tissue； and a gas-occlusive layer configured to be disposed over the manifold and coupled to the tissue such that an interior volume containing the manifold is defined between the gas-occlusive layer and the tissue and the gas- occlusive layer limits escape of therapeutic gas from the interior volume； wherein the gas- occlusive layer includes: a first opening configured to allow communication of therapeutic gas into the interior volume； and one or more second openings configured to allow communication of therapeutic gas out of the interior volume.
