The purpose of this study is to evaluate a new monitor that measures cardiac output (amount of blood pumped by the heart). The system that is being tested in this study, called Endotracheal Cardiac Output Monitor (ECOM), uses electricity (impedance cardiography) to measure cardiac output and is not harmful to the patient.

This study will test the accuracy and efficacy of the ECOM system in anesthetized and sedated patients who, in the normal course of clinical care in the OR or ICU, are having cardiac output measured. The investigators propose that unlike the standard system for cardiac output measurement, the ConMed ECOM System should result in a simplified, inexpensive, continuous, less-invasive, and accurate method of measuring cardiac output. Such a technique could allow the rapid diagnosis of instability in the cardiovascular system for critically ill patients.

Inclusion Criteria:

• Able to give informed consent

• Patients requiring all of the following:

  • an oral ET tube
  • an arterial catheter
  • measurement of CO

Exclusion Criteria:

• Patients not competent to give informed consent

Patients scheduled for cardiac surgery