"But Batista was a tyrant, so this doesn't count!" Or something.

The Inter-American Commission on Human Rights reported in 1966 that 166 Cuban prisoners were executed on a single day in May of that year. But before they were killed, they were forced to undergo the forced extraction of an average of seven pints of blood from their bodies. This blood was sold to Communist Vietnam at a rate of $50 per pint. Those who underwent the bloodletting suffered cerebral anemia and a state of unconsciousness and paralysis. But that didn’t stop the executions; the victims were carried on a stretcher to the killing field where they were then shot.