3. Pulse oximetry will be measured and recorded using finger, nose, and forehead pulse oximetry measurements continuously. Pulse oximetry readings will be compared between the three sites and compared to cardiac output measurements. The percentage of time that a signal is obtained from the three sites will be calculated. The accuracy of pulse oximetry measurements will be compared to routinely drawn blood saturation measurements. Pulse oximetry is required during surgery. This addition will record the values obtained during routine care. If there are differences between brands or sensor types, those results may be reported.