Markers of oxidative stress in ICU clinical settings: present and future

Oxidative stress is associated with most conditions requiring intensive care: it contributes to clinical complications, organ failure and mortality. Interestingly, no unique definition exists of oxidative stress, of how it contributes to the clinical worsening and most importantly, no common strategy exists about its measurement. Despite these metrology problems, limiting the intensity of oxidative stress has become a popular therapeutic target. The paper reviews methods used to determine oxidative stress in clinical situations using routine validated methods or those used by research laboratories.

Many methods of measuring oxidative stress have proven unreliable and no single method exists enabling objective determination and characterization of oxidative stress in clinical settings whether in critical illness or in chronic disease. Some methods, like determination of malondialdehyde, F2-isoprostanes, or 8-hydroxydesoxyguanosine, are widely used to determine oxidative stress. Other methods - such as the determination of vitamins or micronutrients - are able to determine components of the antioxidant defense. No single method, however, is yet alone able to characterize oxidative stress under clinical conditions.

Today, strategies to measure oxidative stress are limited in clinical settings. The most reliable available marker remains malondialdehyde or F2-isoprostanes, in combination with circulating levels of micronutrients.