Oxygen transport and consumption and oxygen saturation in the right atrium in an experimental model of neonatal septic shock

UNLABELLED: 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. OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.