Near-infrared spectroscopy monitoring of brain oxygen in infant cardiac surgery.

The use of near-infrared spectroscopy for monitoring cerebral oxygenation during different types of cardiopulmonary bypass was evaluated in 24 patients aged 5 to 13 months. They underwent open-heart surgery under cardiopulmonary bypass with moderate hypothermia, deep hypothermia with low flow, or deep hypothermia with circulatory arrest. Near-infrared spectroscopy data were compared with electroencephalography and biochemical indicators (neuron-specific enolase, lactate). Near-infrared spectroscopy data showed no correlation with biochemical indicators in patients undergoing cardiopulmonary bypass with moderate hypothermia or deep hypothermia with low flow. In the deep hypothermia with circulatory arrest group, the oxygenated hemoglobin signal declined to a nadir during circulatory arrest. The period from reaching the nadir until reperfusion and the minimum values of oxygenated hemoglobin correlated closely with increases in neuron-specific enolase and lactate. All patients with an oxygenated hemoglobin-signal nadir time < 35 min were free from behavioral evidence of brain injury. The oxygenated hemoglobin-signal nadir time may be useful in predicting the safe duration of circulatory arrest.