# The effects of on-pump and off-pump coronary artery bypass surgery on oxidative stress and cerebral oxygenation: a prospective observational study

## TL;DR

This study compares on-pump and off-pump heart surgery to see how they affect oxidative stress and brain oxygen levels, finding that on-pump surgery leads to higher stress and lower brain oxygen.

## Contribution

The study introduces a new observational analysis linking oxidative stress and cerebral oxygen saturation during CABG procedures.

## Key findings

- On-pump CABG showed higher oxidative stress and lactate levels compared to off-pump CABG.
- Lower cerebral oxygen saturation in on-pump CABG correlated with higher oxidative stress and longer recovery times.
- Lactate levels at T2 were the only factor affecting the OS index in multivariate analysis.

## Abstract

In this prospective observational study, our goal was to investigate the relationship between serum levels of oxidative stress (OS) parameters and regional cerebral oxygen saturation (rSO2) in addition to evaluating postoperative clinical outcomes among patients undergoing coronary artery bypass graft surgery (CABG).

This study comprised 64 adult patients undergoing elective CABG (on-pump [n = 48] and off-pump [n = 16]) procedures. Serum OS levels and rSO2 values were measured intraoperatively at three specific time points: T1 (after induction), T2 (15 min before aortic cross-clamp removal or the final distal anastomosis), and T3 (15 min after aortic cross-clamp removal or the last distal anastomosis).

Serum OS and lactate values demonstrated higher levels at T2 and T3 (p < 0.001), while rSO2 values were lower at T2 (p = 0.024) in the on-pump CABG group compared to the off-pump CABG group. The rSO2 values at T2 exhibited a negative correlation with OS parameters, lactate levels at T2 and T3, aortic clamp time, postoperative mechanical ventilation time, and intensive care unit stay length. In the multivariate linear regression analysis (R2 = 0.181, p = 0.001), lactate values at T2 emerged as the sole factor affecting the OS index at T2 (t = 2.843, p = 0.006).

In our study, we observed elevated OS values and relatively low rSO2 values during on-pump CABG procedures, with rSO2 showing an association with increased OS parameters. Close monitoring of the OS response level and rSO2 during CABG could potentially enhance postoperative clinical outcomes.