Heart rate ( HR ) , mean arterial pressure ( MAP ) , measured tidal volume ( TV ) , peak airway pressure ( Ppeak ) , airway resistance ( Raw ) , chest compliance ( Cdyn ) and the end-tidal carbon dioxide pressure ( PetCO ( @ ) ) were recorded at the time point of @ minutes after turning to the lateral position , @ minutes and @ minutes after OLV , and @ minutes after the resumption of two lung ventilation .