[Oxygen transport and consumption and oxygen saturation in the right atrium in an experimental model of neonatal...

Mixed venous oxygen saturation monitoring is useful to know about the balance of oxygen supply and consumption in patient with shock as well as a form of assessing the effects of different therapeutic maneuvers. Because of newborn peculiarities this measurement is difficult and therefore, the monitoring of the shock state is limited.

To investigate the validity of central venous oxygen saturation at right atria as a reflection of mixed venous oxygen saturation in an experimental model of neonatal sepsis.

In six newborn piglets septic shock was induced by 180 minutes continuous infusion of Group B Streptococcus. Blood samples were obtained from aortic and pulmonary arteries and from right atrium at baseline and at 30-minutes intervals after the bacterial infusion was begun. Changes in arterial pressures, vascular resistances, cardiac index, oxygen delivery and consumption and the oxygen extraction index were also analyzed.

Group B Streptococcus infusion induced significant decreases versus baseline situation of both, oxygen delivery and oxygen tissular extraction index, without changes in oxygen consumption, at 30 minutes of bacterial infusion, with a significant correlation between mixed venous and central venous oxygen saturations. Mixed venous oxygen saturation significantly correlates with right atrium oxygen saturation, r2 = 0,88, along all the period of study.

Mixed venous oxygen saturation is a useful measurement of the oxygen delivery and consumption state in the critically ill newborn infant, and central venous oxygen saturation at the right atrium can be a sure, efficient and easy alternative for the neonatal patient.