Failure of the study drug predicted the need for rescue drug therapy in the initial 12 hours after discharge from the recovery room ( difference success versus failure = -41.7 % , 99 % CI difference -72.3 % to -1.8 % , P = 0.0336 ) but not during the period 12 to 24 hours after discharge from the recovery room ( difference success versus failure = -27.4 % , 99 % CI difference -63.8 % -9.2 % , P = 0.143 ) .