What two factors does cardiac output depend on?
Cardiac output is the amount of blood the heart pumps in 1 minute, and it is dependent on the heart rate, contractility, preload, and afterload.
How do you monitor cardiac index?
Doppler cardiac output monitoring devices Cardiac output can be estimated non-invasively using esophageal or transthoracic Doppler probes. Esophageal Doppler devices measure blood flow in the descending aorta and estimate cardiac output by multiplying the cross sectional area of the aorta by blood flow velocity.
How can we reduce SVR?
If the SVR is elevated, a vasodilator such as nitroglycerine or nitroprusside may be used to treat hypertension. Diuretics may be added if preload is high. If the SVR is diminished, a vasoconstrictor such as norepinephrine, dopamine, vasopressin or neosynephrine may be used to treat hypotension.
What is the best way to measure cardiac output?
Many methods of cardiac output measurement have been developed, but the number of methods useful for human pharmacological studies is limited. Methods proposed to achieve this goal include the Fick principle, ultrasound, indicator dilution techniques, arterial pulse contour analysis and bio-impedance.
What is continuous cardiac output monitoring?
CONTINUOUS measurement of cardiac output (CO) may improve the timely treatment of high-risk patients. [1,2]The available continuous CO (CCO) monitors measure CO by a modified thermodilution technique using a filament to generate heat.
What instrument measures cardiac output?
What measures cardiac output?
The USCOM device (Ultrasonic Cardiac Output Monitors, Sydney, Australia) is truly non-invasive and uses a probe placed suprasternally to measure flow through the aorta or on the left chest to measure transpulmonary flow.
How is invasive cardiac output measured?
The area under the systolic portion of the arterial pulse wave (measured from the end of diastole to the end of the ejection phase) divided by the aortic impedance gives a measure of the stroke volume, which multiplied by the heart rate gives the cardiac output.
What are factors that influence stroke volume?
Stroke volume index is determined by three factors:
- Preload: The filling pressure of the heart at the end of diastole.
- Contractility: The inherent vigor of contraction of the heart muscles during systole.
- Afterload: The pressure against which the heart must work to eject blood during systole.