METHODS	The parameters evaluated were heart rate ( HR , in bpm ) , arterial oxygen saturation ( SaO ( 2 ) , expressed as percentage of hemoglobin saturated with oxygen ) , end-tidal CO ( 2 ) ( ETCO ( 2 ) , in mmHg ) , mean arterial pressure ( MAP , in mmHg ) , and intratracheal pressure ( ITP , in cmH ( 2 ) O ) .\