Minute ventilation increased ( AUE0-1 h 16 % , P < 0.05 ) and end-tidal carbon dioxide ( [ Formula : see text ] ) decreased ( AUE0-1 h 6 % , P < 0.05 ) during the first hour at 0.96 mg kg ( -1 ) h ( -1 ) with 1/2-maximal [ Formula : see text ] and [ Formula : see text ] - change occurring by 7.5 min .