[Evaluation of cerebral oxygenation changes with clamping of the left superior vena cava by near-infrared spectroscopy].

Objective: The left superior vena cava (LSVC) is often complicated with congenital heart defect. Although we simply clamp LSVC during cardio-pulmonary bypass (CPB), appropriateness of this technique has not been clarified. We noninvasively evaluate cerebral tissue oxygenation while the clamping of LSVC under CPB by near-infrared spectroscopy (NIRS).
Methods: Six children (3 male and 3 female; aged 1.0 +/- 0.6 year) undergoing open heart surgery were studied. The NIRO 300 was incorporated into an established multimodal monitoring system. Tissue oxygenation index (TOI), oxyhemoglobin (O2Hb), and deoxyhemoglobin (HHb) changes were assessed and compared with LSVC pressure.
Results: There were no significant changes in cerebral oxygen delivery after LSVC clamp. LSVC pressure increased from 7.3 +/- 1.8 mmHg to 20.1 +/- 2.6 just after LSVC clamp, but gradually decreased without any maneuver.
Conclusion: These data demonstrated that LSVC could be safely clamped when LSVC pressure was under 30 mmHg.