Oh, in addition, to put it in more perspective.

Although each patient is different, the amount of ketamine they give you in a coma typically is thus: (It is weight dependent and also what a patient can tolerate, and if there liver enyzmes are good and a host of other variable, but this is just general rule of thumb stuff)

Day 1 - 250 mg/hour x 24 hours + bolus injections (extra infusions of K)
Day 2 - 350 mg/hour x 24 hours + bolus injections (extra infusions of K)
Day 3 - 450 mg/hour x 24 hours + bolus injections (extra infusions of K)
Day 4 - 550 mg/hour x 24 hours + bolus injections (extra infusions of K)
Day 6 - 650 mg/hour x 24 hours + bolus injections (extra infusions of K)

Each coma patient will typically receive in 5 days what a full blown hospital would use in its entirety in 6 months during the course of a year. That's a lot of Ketamine!

Again, this is just from what I've personally witnessed, but it can be different for everyone.

Also, they tend to give you Midazolam (3mg-10mg hour) to keep you calm.