Noninvasive Assessment of Tissue Perfusion Status in Critically Ill Pediatric Patients

Investigators are conducting research about oxygen levels in the body and whether it is possible to use a device to measure oxygen in the body's tissues noninvasively, without blood draws or a catheter (a plastic tube placed in a vein). Investigators would like to know how this device compares to standard measurements using blood from a catheter. This may help treat patients who may not be getting enough oxygen to their body.