Measuring Cardiac Output in the Critically Ill

Abstract

Haemodynamic monitoring plays an essential part on the care of the critically ill patient. Monitoring has two goals; the first goal is a signalling function if the patients clinical condition improves or deteriorates adequate measures can be taken. Maintaining the adequacy of the circulation reduces the chance of inadequate oxygen transport to the tissues preventing organ ischemia. The second goal is using the monitoring as a decision making tool. Historically, arterial pressures were measured because they were easier to measure than bloodflow. But the introduction of the pulmonary artery catheter (PAC) in 1970 allowed the regular measurement of cardiac output (CO) at the beside. Beside CO a new array of variables could be monitored. Measuring more variables did not automatically relate to better outcomes.