Investigation of dynamic thiol disulfide homeostasis in acute respiratory failure patients in intensive care units.

Thiols are antioxidant agents which belong to mercaptan group consisting of sulfur and carbon containing sulfhydryl (-SH). Thiol levels, in the case of elevated oxidative stress, are lowered by their use in neutralization of reactive oxygen molecules. In this study, it was aimed to investigate thiol and disulfide blood levels or thiol/disulfide ratio as a marker of total oxidant status which plays a role in the pathogenesis of inflammatory diseases that may cause respiratory failure, especially pneumonia. The study included 98 patients (58 males, 40 females) who have partial oxygen pressure (PaO2)<60 mmHg or partial carbon dioxide pressure (PaCO2)>45 mmHg in arterial blood in the intensive care unit and 98 healthy volunteers (59 males, 39 females). Total thiol and native thiol levels were measured by spectrophotometric method. Total thiol (270 ± 99.81), native thiol (203.90 ± 103.41) and disülfite (33.10±12.42) levels of the patient group were significantly lower (p <0.001) than total thiol (423.62 ± 70.3), native thiol (307.13 ± 57.73) and disülfite (58.24±27.21) of the control group levels. There is no significant difference between native thiol / total thiol, disulfide/ total thiol and disulfide /native thiol ratios. Thiol and disulfide blood levels or thiol / disulfide ratio can guide us as a prognostic test in acute respiratory failure patients. Futhermore these can guide us as a prognostic test for diagnosis and provide us treatments of respiratory failure in intensive care units.