Presentation on theme: "CARDIAC OUTPUT Is commonly measured in patients with: Heart failure Shock Syndromes and after Coronary Artery Bypass Graft Surgery."— Presentation transcript:
CARDIAC OUTPUT Is commonly measured in patients with: Heart failure Shock Syndromes and after Coronary Artery Bypass Graft Surgery.
Cardiac Output - What is it? Cardiac output is the volume of blood pumped by the heart per minute. For an average size of adult (70 kg) at rest this would be about 5 liters/min. During severe exercise it can increase to over 30 l/min Cardiac output is often divided by body surface area to take into account the size of the subject.
Cardiac Output - components Heart rate is the number of times the heart beats in one minute. The average adult resting heart rate is 75 beats per minute (bpm). Stroke volume is the amount of blood pumped by each ventricle with each heartbeat. The average adult resting stroke volume is 70 ml per beat. Cardiac output is the amount of blood pumped out by each ventricle in one minute. It is directly related to heart rate and stroke volume:
Cardiac Output - How it works CARDIAC OUTPUT (CO) may be calculated as stroke volume times heart rate and, when divided by body surface area, provides cardiac index (CI).
Cardiac Output - Measurement Methods Two main methods are used to measure cardiac output today. These are: The Fick method and Dilution methods (either dye or thermal).
Cardiac Output _ Factors Affecting It Increased sympathetic stimulation Increased venous return Slow heart rate Rapid heart rate Exercise Sudden drop in blood pressure Rising blood pressure Sudden drops in blood volume Excess calcium