The PaO2 and SPO2 levels after skin incision , sternotomy , before suspension of CPB and at the end of surgery were significantly lower in group M than in group D ( P < 0.05 ) , while the le - vels of PaCO2 after skin incision , sternotomy , before suspension of CPB and at the end of surgery , and HR after skin incision , sternotomy , before suspension of CPB , after heart re-beating , after CPB cessation and at the end of surgery in group M were considerably higher than those in group D ( P < 0.05 ) .