This is a single blinded randomized, controlled and prospective clinical trial comparing oxidative stress status in two groups.
Subjects in two groups will be matched for gender, age, smoking habit and employment duration and will be randomized into one of the two groups of:
1. Pediatric OR Staff, and
2. control (e.g; ICU staff)
Biomarkers of oxidative stress will be measured in two different time points in each subject, (Monday Morning and, Friday afternoon of that same week-\>40 hours in Operating room or Intensive Care Unit).
The relationship between oxidative stress and psychological stress will also be assessed by validated psychometric measures.
