Complex sentence: Hickman lines may remain in place for extended periods and are used when long-term intravenous access i done under sedation or a general anesthetic by a radiologist or surgeon.
Split into simpler sentences: Hickman lines may remain in place for extended periods and are used when long-term intravenous access is needed. The insertion of a Hickman line is usually done under sedation or a general anesthetic by a radiologist or surgeon.