Effects of Hyperoxia on Open Heart Surgery

Patients undergoing Open Cardiac Surgery will be randomized into two groups. Group I will be ventilated with 40% Fio2 during induction, surgery and in Postoperative care unit. Group II will be ventilated with 100% Fio2 during induction and with 60-70% ( determined according to the arterial blood gas sample results) during surgery and in Postoperative care unit. Hemodynamic parameters ( systolic arterial pressure, diastolic arterial pressure, heart rate ), Arterial blood gas samples ( PaO2, PaCO2, pH, Oxygen saturation, Lactate), and pre and post cardiopulmonary bypass Superoxide dismutase and malonyl aldehyde levels.

Patients in this group will be ventilated with fraction of inspired oxygen 40% during the induction, surgery and in Postoperative care unit.

Patients in this group will be ventilated with fraction of inspired oxygen during 100% induction and with 60-70% ( determined according to the arterial blood gas sample results) during surgery and in Postoperative care unit.

change in Malondialdehyde (MDA) (nmol/mg pr) levels (as a biomarker for oxidative stress ) and Superoxide dismutase (SOD) (nmol/mg pr) levels as a biomarker for antioxidant response in the plasma between "before" and "after" cardiopulmonary bypass

As primary outcome, the effects of different inspired oxygen fractions on oxidative stress and anti-oxidant response in before and after cardiopulmonary bypass will be evaluated

Partial pressure of oxygen(mmHg) in arterial-blood-gas samples before induction, following induction, before and after cardiopulmonary bypass, before extubation and following extubation, postoperative 24 and 72th hours.

,Partial pressure of carbondioxide(mm Hg) in arterial-blood-gas samples before induction, following induction, before and after cardiopulmonary bypass, before extubation and following extubation, postoperative 24 and 72th hours.

lactate (mmol/l) levels in arterial blood gas samples before induction, following induction, before and after cardiopulmonary bypass, before extubation and following extubation, postoperative 24 and 72th hours.

ph values in arterial blood gas samples before induction, following induction, before and after cardiopulmonary bypass, before extubation and following extubation, postoperative 24 and 72th hours.

systolic arterial pressure (mmHg), levels before induction, following induction, before and after cardiopulmonary bypass, before extubation and following extubation, postoperative 24 and 72th hours.

diastolic arterial pressure (mmHg) levels before induction, following induction, before and after cardiopulmonary bypass, before extubation and following extubation, postoperative 24 and 72th hours.

Oxygen saturation (%) levels in arterial blood gas samples before induction, following induction, before and after cardiopulmonary bypass, before extubation and following extubation, postoperative 24 and 72th hours.

heart rate (beat/min) levels before induction, following induction, before and after cardiopulmonary bypass, before extubation and following extubation, postoperative 24 and 72th hours.

Inclusion Criteria: ASA II-III Patients with EF higher than 50%. patients undergoing elective open heart surgery on pump ( CABG, Valve Replacement) Exclusion Criteria: patients with Diabetes Mellitus patients with COPD Patients with Cerebral Vascular Disease Patients with hypoxia in Arterial blood gas samples ( PaO2 lower than 80 mmHg) and hypercarbia (PaCO2 higher than 45 mmHg)

Koksal GM, Dikmen Y, Erbabacan E, Aydin S, Cakatay U, Sitar ME, Altindas F. Hyperoxic oxidative stress during abdominal surgery: a randomized trial. J Anesth. 2016 Aug;30(4):610-9. doi: 10.1007/s00540-016-2164-7. Epub 2016 Mar 21.