Intraoperative Hyperoxygenation May Negatively Affect Postoperative
Cognitive Functions in Coronary Artery Bypass Graft Operations: A
Randomized Controlled Study
Abstract
Objective: In this study, it was aimed to compare various parameters
during surgery and postoperative cognitive functions in patients
undergoing coronary artery bypass graft (CABG) surgery using different
levels of perioperative oxygen. Methods: One hundred patients scheduled
for elective CABG surgery were included in the study. The patients were
divided into two groups according to arterial oxygen levels during
surgery. In the normoxia group (NG) (n = 50), PaO2 was between ≥100mmHg
and <180mmHg with at least 40% FiO2 mechanical ventilation
(MV), and in the hyperoxia group (HG) (n = 50), PaO2 was ≥180 mmHg with
100% FiO2 MV. Hemodynamic parameters, peripheral oxygen saturation
(SpO2), cerebral oxygen saturation (rSO2) measured from bilateral
sensors, and blood gas values were recorded at the planned measurement
times. Mini-mental state examination test (MMSE) was applied to the
patients before and at the 12th, 24th hours; on the 1st, 3rd, 6th months
after surgery. Results: Extubation time was found to be shorter in NG (p
<0.05). Between the groups, rSO2 and mean arterial pressure
(MAP) were found to be significantly lower in HG at the time of T4
measurement (p = 0.042, p = 0.038, respectively). MMSE values of the
groups at the 1st, 3rd and 6th months were found to be significantly
higher in NG (respectively p = 0.017, p = 0.014, p = 0.002). Conclusion:
Hyperoxemia application during CABG may be associated with worse
postoperative late-term cognitive functions. Keywords: cardiopulmonary
bypass; hyperoxia; postoperative complications; cognitive function;
spectroscopy, near-infrared.