Evaluation of tissue oxygenation in critically ill pediatric patients

The objective was to compare the diagnostic and prognostic efficacy of using oxygen extraction coefficient, central venous oxygen tension and oxygen recovery rate from arterial blood for assessing tissue oxygenation in critically ill pediatric patients.

Materials and methods. The study involved 28 critically ill pediatric patients, who were admitted in intensive care unit. In addition to traditional acid-base balance and blood gas measurements, all patients were assessed in venous blood from the superior vena cava (PcvO₂), oxygen extraction coefficient (OER), and oxygen recovery rate from arterial blood (PO₂(X)). Arterial blood samples were collected at the end of the first day after admission and on the third, fifth, and seventh days of their ICU stay. Patients were divided into two groups: survived and died patients. In order to achieve the goal of our study, multiple correlation regression analysis was used to identify factors explaining changes in the dependent variable, arterial lactate concentration and then to construct a multiple regression model.

Results. A pattern of increasing arterial lactate concentration with decreasing oxygen recovery rate from arterial blood was identified, indicating decreased tissue oxygenation and an increase in the albumin-corrected anion gap. The calculated parameter of the arterial blood oxygen extraction rate PO₂(X) showed high diagnostic and prognostic efficiency, confirmed by the results of multiple correlation-regression analysis, variance analysis and ROC analysis.

Conclusion. The constructed multivariate regression model for predicting arterial blood lactate levels, which includes arterial blood oxygen recovery rate as a factor, may be useful for practitioners both in identifying the leading factor in developing lactic acidosis and in monitoring the dynamics of changes in arterial blood lactate levels.

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