Central venous oxygenation in neonates with respiratory failure

Introduction: In neonatal medicine the current parameters, arterial oxygen saturation and arterial oxygen pressure, are poor indicators for oxygen delivery and oxygen demand. The purpose of this study was to obtain venous blood samples from the inferior vena cava in stable neonates with respiratory failure and to determine a parameter that reflects more adequately the balance between oxygen delivery and oxygen demand. Materials and Methods: The study included 22 neonates requiring mechanical ventilation for severe respiratory insufficiency. An umilical venous and arterial catheter were inserted in the inferior vena cava and the aorta respectively. Paired blood samples were obtained at the time that the patients were hemodynamically stable. Fifty paired arterial and mixed venous blood samples were analyzed. Linear regression analysis showed the following correlations: Results: C(a-v)O2 FOE PaO2 -0.005 -0.114 PvO2 -0.528 -0.592 Sat art -0.057 -0.139 Sat ven -0.634 -0.712 Conclusions: This study showed the feasibility of measuring mixed venous blood samples in the inferior vena cava via an umbilical vein catheter. This simple and safe method provides more adequate information about the oxygen delivery and the oxygen demand status of critically ill neonates, due to the good correlation between the mixed venous oxygen saturation and the oxygen extraction ratio (FOE), than the current parameters of oxygenation.