Determination of the Accuracy of a Non-Invasive Continuous Blood Pressure Device

This protocol will test a new non-invasive device, the T-line, in continuously determining heart rate and blood pressure in operative and critically ill patients. The accuracy of the device will be compared to the standard radial artery catheter, as well as to the non-invasive blood pressure cuff. The T-line will also be compared to the right heart catheter determining cardiac output in at least 20 patients. Hypothesis: the T-line device will determine blood pressure and heart rate as accurately as a standard radial arterial catheter and a blood pressure cuff in perioperative patients.