Electrochemical measurements of the levels of nitric oxide metabolites in the blood serum

Background: Sepsis is a serious clinical condition caused by a dysregulated immune response to infection resulting in multiple organ failure. In the pathogenesis of sepsis, especially that of septic shock, great importance is given to the endothelial marker of vascular regulation, nitric oxide (NO). In septic shock, dysregulation of the vascular tone plays a key role in the development of hypotension. Therefore, the control of the level of nitric oxide and its stable metabolites in critically ill patients is a very important task.

Aim: the aim of this study was to evaluate the potential of the electrochemical nitrite detection in the patients’ blood serum.

Methods: The levels of nitric oxide stable metabolites in the blood serum of healthy individuals (n=20) and septic patients (n=25) were studied by the electrochemical method using a composite electrode and by the spectrophotometric method using the Griess reagent.

Results: The data in the groups of healthy people and patients with sepsis differ significantly (p <0.00001) both when measured using electrochemical and spectrophotometric methods. The median value of the current response in healthy people was 0.41 µA (0.33; 0.55), and the total content of nitric oxide metabolites (NOx) was 26.8 µmol/L (20.8; 31.0), while in patients with sepsis, these values were 0.79 µA (0.61; 1.28) and 38.89 µmol/L (29.64; 57.45), respectively. A negative correlation was found between the data obtained for practically healthy persons (r=-0.696, p=0.0007).

Conclusion: The obtained results allow us to conclude that the nitrite measurement in the blood serum by amperometry using a composite electrode is promising as a diagnostic technique.