Cardiac output & factors affecting it.
- 1. CARDIAC OUTPUT & FACTORS AFFECTING IT. ZAIN ALI ID: 2020-dvmje-014
- 2. Learning outcomes: ▪ What is Cardiac Output? ▪ Stroke Volume? ▪ Components? ▪ Factors? ▪ Cardiac Output Formula? ▪ Cardiac Output measurement & Methods? ▪ Effect of low & high cardiac input? ▪ Summary?
- 3. What is Cardiac Output? “Cardiac output refers to the volume of blood pumped out per ventricle per minute.” Cardiac output is the function of heart rate and stroke volume. STROKE VOLUME: The amount of blood pumped by the left ventricle in one compression is called the stroke volume.
- 4. ▪ Cardiac Output is an excellent example to exhibit the efficiency of the human heart. ▪ It is related to the amount of blood pumped by the heart per minute. A normal cardiac output would be about five liters of blood per minute in a healthy individual. ▪ The cardiac output comprises 2 vital components: ▪ Heart rate: It refers to the number of times the heart beats per minute (bpm). ▪ Stroke volume: It refers to the quantity of blood pumped out of each ventricle with every heartbeat.
- 5. The following factors determine the cardiac output of a human heart: ▪ Venous Return This is the amount of blood that enters the heart through the veins per minute. After a certain time interval, the venous return becomes equal to the cardiac output. ▪ Force of Contraction The stroke volume and the cardiac output increases with the increase in the force of contraction. ▪ Heart Rate The cardiac output increases with the increase in heart rate. Factors Determining Cardiac Output
- 6. Cardiac Output Formula: The equation for cardiac output is: Cardiac Output (CO) = HR x SV ▪ Cardiac Output Calculation For example: If the heart rate is 70 bpm and stroke volume is 70 ml. Using the formula = HR X SV = 70 X 70 = 4900 ml/min or 4.9 liters per minute.
- 8. Cardiac Output Measurement ▪ Different merits and demerits of measuring cardiac output using methods in an invasive and non-invasive manner ▪ No standard comparison system available for these methods using a reference measurement or standards. ▪ The invasive systems are well accepted. These systems are neither accurate nor effective in guiding therapy.
- 9. Methods to measure cardiac output Some of the methods to measure cardiac output are listed below: • Doppler ultrasound • Echocardiography • Transcutaneous • Transoesophageal
- 10. Effect of LOW & HIGH CARDIAC INPUT: • Low output results in heart failure, a severe infection or heart diseases. • The high output may be an indicator of blood infections.
- 11. Summary: LETS REVISE WHAT WE HAVE STUDIED YET!!
- 12. Bibliography: • Guyton and Hall Textbook of Medical Physiology E-Book (Guyton Physiology) • Ganongs Review Of Medical Physiology 25th Edition • Pictures from google.
- 14. Mam Shaista Abbas COURSE: Veterinary Physiology-I Presented to:
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