Evaluation of plasma thiolic groups and reactive oxygen metabolites in critically ill patients

Introduction

Free thiolic group (SH) and reactive oxygen metabolite (ROM) determination could provide helpful information on the balance between oxidative damage and antioxidant capacity [1]. In previous work we reported the change of the relationship between ROMs and SHs in a group of patients with severe sepsis [2]. In this work we show the values of ROMs and SHs of patients in the ICU divided into three groups according to the gravity of sepsis to investigate a possible relationship between these parameters and the clinical state.

Methods

Sixty patients admitted to the ICU were divided into three groups (sepsis, severe sepsis, septic shock). At least three determinations of ROMs and SHs for patient were assayed in 2–3 weeks. Control cases: 20 surgical patients without complications. The blood for ROM and SH determinations was drawn during 24 hours after surgery. SH groups were assayed in plasma by Ellman's reaction with spectrophotometric methods applied to an automatic instrument (OLYMPUS AU 460) [3]. The plasmatic ROM values were assayed by a DIACRON-Italia kit, applied to an automatic instrument (OLYMPUS AU 640).

Results

The results obtained show a significant reduction of both plasma SHs and ROMs in the three groups according to their level of sepsis. The analysis of variability (CV) of ROMs shows a clear CV increase in the three groups of patients (CV 40–60%) in comparison with the relatively low values in the control group (CV 20%). If the septic shock patients are divided in two groups according to their ROM levels (lower and higher than 150 Ucarr), the frequency of deaths in the group of low ROM values (12/20) is decidedly higher than that observed in survivors patients during the observation time (3/17).

Conclusion

This last result suggests that plasma ROM levels decrease significantly when the clinical situation gets worse, and allows one to hypothesize a possible diagnostic use of this parameter as a prognostic index.