[Continuous systemic venous oxygen saturation monitoring immediately after Fontan procedure]

Changes in cardiac output (CO), systemic venous oxygen saturation (SvO2), systemic oxygen consumption, and urinary output immediately after Fontan procedure were measured in 10 patients at the intensive unit (ICU) to assess the effects of aorusal from anesthesia, hypothermic management, and respiratory condition. The measurements were taken at the following phases; phase A in deep sedation under hypothermia (33-35 degrees C rectal temperature) and controlled ventilation; phase B in mild sedation under normothermia and controlled ventilation; phase C when awake under normothermia and assisted ventilation; phase D when awake under assisted ventilation; phase D when awake under normothermia immediately after extubation; and phase E 24 hours after extubation. Oxygen delivery (O2 Del.) and fractional oxygen fractions were calculated in each phase. Two patients whose SvO2 values were below 55% during the postoperative course needed reoperation for atrioventricular valve regurgitation in one case for PV stenosis in the other case. CO increased significantly (p < 0.05) after extubation (phase D), compared with that of controlled ventilation (phase B). Under hypothermia (phase A), urinary output was relatively higher with lower CO. There was a significant correlation between SvO2 and CO (R = 0.61) in phase A, however there was no correlation in phase E. Fractional oxygen extraction in phase A was significantly lower than in phase B. In conclusion, the continuous SvO2 measurements reflected real-time changes in cardiac output in the immediate post-Fontan patients. Induced hypothermia was beneficial in increasing urinary output presumably through the correction of maldistribution of cardiac output in post-Fontant patients. Arousal from anesthesia and spontaneous ventilation seemed advantageous for increasing cardiac output, hence, early extubation should be encouraged in the management of post-Fontan patients.