A cauterizing seal patch was a piece of medical equipment available to Federation medical personnel in the 24th century.

Doctor Julian Bashir always kept a cauterizing seal patch in his medkit, which was most fortunate when he was attacked by the Jem'Hadar Kitana'klan in April 2376. Bashir received severe wounds and was losing a lot of blood, he passed out before he could apply the patch himself and would have died - Fortunately Taran'atar was able to apply the patch before he continued on in pursuit of Kitana'klan. (DS9 novel: Avatar)