I have a few ideas about this, though only the first is really relevant to your question.
Often associated with low temperatures, the function of hibernation is
to conserve energy during a period when sufficient food is
unavailable. To achieve this energy saving, an endotherm will first
decrease its metabolic rate, which then decreases body temperature.
Hibernation may last several days, weeks, or months depending on the
species, ambient temperature, time of year, and individual's body
So, assuming we figured out a way to introduce this ability into humans, then people would be able to go into a deep sleep for up to months as a time, or even longer if an outside source of nutrients were provided to the sleeping patient. In a sense this would be similar to an induced coma, and would be a good way to pass the time by if that was your goal, but it would have detrimental effects on things like muscle mass.
NASA I believe is actually contracting a company to create a system to put astronauts asleep for most of the journey during any future trips to Mars. This will be so they can greatly reduce the required size of any crewed ship they may someday send to the red planet.
Use the method that you mentioned. Sometime this year there will be an attempted head transplant (yes, I did say head). They will have their blood drained and all that good stuff and we will be able to see if they're able to wake up after words, although there will be additional concerns that this guy will literally have a new body as well.
If this involves space travel, then reduce the need all together by traveling near the speed of light. This will cause a time effect that will make it so that for passengers on the ship only a fraction of the time required for the journey will have passed for them.
Hopefully one of these has helped or given you some ideas.