Multi-site Near Infrared Spectroscopy (NIRS) Monitoring of Children During Exercise

Near Infrared Spectroscopy (NIRS) monitoring has proven beneficial in increasing safety and
improving patient care during pediatric cardiac surgery and during PICU stays. NIRS
estimates the amount of oxygen in tissues by comparing the tissue's absorption of two
wavelengths of light corresponding to hemoglobin carrying oxygen and hemoglobin without
oxygen.

During cardiac surgery, multi-site NIRS monitoring is used to determine the heart's output
by comparing the amount of oxygen available to discrete regions of the body nourished by
different parts of the circulatory system. NIRS leads placed on the forehead detect oxygen
available to the brain (cerebral), while leads placed over the kidney reflect oxygen
available to the internal organs (somatic).

NIRS monitoring has been used for studying muscle oxygen usage during exercise in normal and
disease states. Cerebral oxygenation at peak exercise at has been studied with NIRS
monitoring. The use of multi-site NIRS monitoring during exercise stress testing for
studying cardiac output through the patterning of somatic and cerebral oxygenation in
combination with exercise stress test data has not been researched.

We hypothesize that addition of multi-site NIRS monitoring to the standard data collection
already achieved during exercise testing, will enable calculation of anaerobic threshold and
cardiac output prediction. This will assist in determining appropriate timing for surgical
intervention, predicting the post operative course and testing response to medication.