19 hours now, I'm really impressed that a person can actually do this without having to be drugged enough to be incoherent (or that would make you pee). He looks exhausted. Another NPR article mentions Strom Thurmond's loophole of using the cloakroom as a bathroom with one foot still on the Senate floor, but it seems he yielded to Barry Goldwater to use the restroom instead (the record without a bathroom break seems to be Wayne Morse with 22 hours, 26 minutes, although I can't find information on if Alfonse D’Amato's 23 hour 30 minute filibuster included any breaks).
The previous record is 24 hours and 18 minutes, held by Strom Thurmond, then a Democratic, racist, and segregationist United States senator from South Carolina, who began a filibuster intended to prevent the passage of the Civil Rights Act of 1957.
Yeah, I'm hoping he will break that record. Not too fond of Strom Thurmond.