In almost every case, no. Both online and offline video poker games use a random number generator (RNG) to determine results. The technology is over 40 years old and trusted around the globe.
Casinos don't need to fix results in order to make a profit. Instead, they set a house edge. The odds are weighted in the casino's favor. Individual results are random and, on video poker machines, players win almost half the time. Over time -- over tens of thousands, hundreds of thousands, or millions of sessions -- the odds are very high that the casino wins more than it loses.
Also, odds don't change during the game. Las Vegas casinos -- and regulated casinos across America and around the world -- have specific laws that dictate when casino operators can change the odds of a gaming machine. After changing those odds, the game must be inactive for a time and the pay table readout changes.
Some online offshore gaming sites can't be trusted, which is why we suggest that players read trusted online poker site and casino reviews before depositing money.