Great news! I remember when my mom was on a vent and went through the same thing your wife is going through. Come to find out her tolerance for the sedatives was very low so it took her a while to come off the vent as well. But, she went from being off the vent for a few hours one day to breathing on her own no problem the next morning. The only thing was they put her on a CPAP at night so she rested. Great news though and it sounds like she turned the corner and will improve. Continued prayers to you and your family. Stay strong and positive.