Systemic perfusion assessment in patients with univentricular hemodynamics based on blood gas parameters

Abstract

The objective: to identify laboratory markers of systemic perfusion in newborns with functional single ventricle on mechanical ventilation after surgical correction. Subjects and methods. Blood gas parameters were retrospectively analyzed in 52 newborns with congenital heart defects with univentricular hemodynamic after surgical correction. All samples were divided into three groups based on arterial blood saturation (SaO2): Group 1 – hypoxia (SaO2 ≤ 65%); Group 2 – normoxemia (SaO2 = 65-85%); Group 3 – hyperoxemia (SaO2 > 85%). Stroke volume and cardiac index were evaluated with echocardiography. The oxygen consumption and carbon metabolism were evaluated by arterial and venous blood gases. Results. The mixed central venous pO2 (PvO2) > 29.5 mm Hg, mixed central venous O2 (SvO2) > 54.5%, arteriovenous difference in saturation (Sa-vO2) < 15.8%, total oxygen content in venous blood (CvO2) > 119 ml/l, oxygen extraction ratio (O2ER) < 19% and the arteriovenous difference in partial pressure of carbon dioxide (dPCO2) < 5.4 mm Hg are cut off criteria for adequate systemic perfusion. PvO2 < 26 mm Hg, SvO2 < 44.5%, Sa-vO 2 > 27%, CvO2 < 88 ml/l, O2ER > 27.7%, dPCO2> 7.9 mm Hg have been associated with decreased systemic perfusion. The logistic regression model including combination of O2ER and dPCO2 predicts adequate systemic flow accuracy of 94.3% (sensitivity 87.5%, specificity 94.7%, p = 0.001). Graphics allow to adapt the mathematical model to clinical practice to verify systemic hypoperfusion in newborns with functional single ventricle. Conclusion: The following cut off parameters allow to assess systemic perfusion in newborns with functional single ventricle: PvO2, SvO2, CvO2, Sa-vO 2, O2ER, and dPCO2. The model for predicting the adequacy of systemic perfusion can be used as an effective tool to monitor hemodynamic status in newborns with functional single ventricle.