The proposed noninvasive monitoring systems provide the essential hemodynamic and oxygen transport information previously available only by invasive thermodilution catheters. More importantly, the noninvasive systems provide continuous on-line real-time displays of data which allow immediate recognition of circulatory abnormalities and provide a means to titrate therapy to appropriate therapeutic goals. The noninvasive systems are easy to apply, safe, inexpensive, and more cost-effective than invasive monitoring.