Cerebral Oximetry Monitoring Provides Early Warning of Hypercyanotic Spells in an Infant with Tetralogy of Fallot

A 3.6-kg, 3-month-old infant with a history of tetralogy of Fallot and increasing hypercyanotic spells was brought to the operating room for operative repair. Before the initiation of cardiopulmonary bypass, it was noted that an abrupt decrease in the cerebral oximetry value occurred before pulse oximetry measured the decrease in oxygen saturation. This happened 4 times, and during all 4 of the hypercyanotic spells, the decrease of the cerebral oximeter value occurred 15 to 30 seconds before a change registered in the pulse oximetry value. For the first time, this case illustrates that cerebral oximetry monitoring may be able to identify the onset of hypercyanotic spells and desaturation before standard pulse oximetry. Cerebral oximetry may provide a quicker identification of acute changes in the clinical status of infants and children by identifying hypoxemia before pulse oximetry.