You can't bluff a video poker machine.
The bluff aside...
You're assuming the machine is even playing poker. It may be showing you a hand that looks something like, and wins/loses like, poker - but that doesn't mean it's poker.
It may actually be playing bingo. I kid you not: some jurisdictions only allow bingo, so the machine's maker calls in a mathematician to apply topological transformations to bingo which make it look like poker.
Even if it's playing "poker" (not mutant bingo), there's probably other distortions, like shuffling the deck after every hand.
(I worked on 'em for a while.)
But the video poker rules are already stacked against the player to begin with.