The Role of Oxidative Stress Markers in Acute Respiratory Distress Syndrome

Introduction. Patients in the intensive care unit (ICU) are likely to suffer from acute respiratory failure (ARF) with a risk of developing acute lung injury (ALI) and its more severe condition, acute respiratory distress syndrome (ARDS) with 30 - 50% mortality. Evidence shows, that important role in ARDS pathophysiology may play an imbalance between oxidant and antioxidant species. Oxidative stress is well established in adult critical illnesses characterized by systemic inflammatory response.

Aim of the study was to investigate the influence of oxidative stress species on developing of acute respiratory distress syndrome in patients at risk.

Materials and methods. The study was conducted in Pauls Stradins Clinical University Hospital ICU during 6 months in 2013 and approved by ethics committee. There were included 15 ARDS risk patients over 18 years of age with mechanical lung ventilation (MLV) over 24 hours and massive blood component transfusions, acute severe pancreatitis, pneumonia or sepsis. Blood samples were taken three times during observational period- first sample were taken just exactly after inclusion, second sample- on 4th and the last sample- on 7th day after inclusion. The developing of ARDS were diagnosed using revised diagnostic criteria according to the Berlin definition. Reactive oxygen species were measured in plasma using manual or automatic spectrophotometry.

Results. Among included patients 82.4 % were males with the mean age 49.3 years, for female 67 years. The most popular diagnosis was acute severe pneumonia (n= 5; 33.3 %), followed by patients with sepsis (n= 4; 26.7%) and acute severe pancreatitis (n= 4; 26.7%). The most informative marker of oxidative stress among all ARDS risk patients is GPx, which correlates with PaO2/ FiO2 and oxidation index (R= -0.52; p= 0.045 and R= 0.57; p= 0.027) at the 1st day of observation. At the 4th day of observation GPx shows statistically significant relation with the level of PEEP (R= 0.57; p= 0.033). Among ARDS patients we have found correlation between PaO2/FiO2 ratio and MDA+ HNE plasma levels (R= 0.69; p= 0.026) at the 1st day of observation.

Conclusion. Reactive oxygen substances causing oxidative stress shows a dynamic changes in ARDS patients. The changes of some oxidative markers are related to the increased level of hypoxemia and PEEP used in treatment of ARDS patients.