Cardiac Output Basics
The formula used to calculate cardiac output
What is CO = HR x SV?
The volume of blood in the left ventricle at the end of diastole
What is preload?
The equation describing oxygen delivery
What is DO2 = SaO2 x CO?
This measurement that reflects oxygen saturation of blood returning to the heart
What is SvO2?
The common invasive method used to measure cardiac output using temperature change
What is thermodilution?
The formula used to calculate stroke volume
What is SV = CO/HR?
The amount of blood ejected by the heart each minute
What is cardiac output?
The pressure the ventricle must overcome to eject blood
What is afterload?
The equation describing oxygen consumption
What is VO2 = avDO2 x CO?
The normal range for mixed venous oxygen saturation
What is 60-80%?
The injection used during thermodilution measurement
What is a cold bolus injectate?
The normal pulmonary artery wedge pressure range
What is 6-10 mmHg?
The normal range for cardiac output in adults
What is 4-8 L/min?
The intrinsic ability of the heart muscle to contract
What is contractility?
This difference represents the oxygen extracted by tissues
What is SaO2 - SvO2?
The normal range for central venous oxygen saturation
What is 65-85%?
Bolus cardiac output measurements should be performed at this point in the respiratory cycle
What is end-expiration?
The normal systemic vascular resistance range
What is 800-1200 dynes/sec/cm5?
This measurement adjusts cardiac output for body size
What is cardiac index (CI)?
The hemodynamic parameter that represents left ventricular afterload
What is systemic vascular resistance (SVR)?
Two major physiologic factors that influence oxygen delivery besides CO
What are hemoglobin and oxygen saturation?
A drop in SvO2 generally indicates this physiologic issue
What is increased oxygen extraction or decreased oxygen delivery?
The recommended number of thermodilution injections to obtain an average
What is 3-4 injections?
The normal right ventricular ejection fraction range
What is 40-60%?
The formula used to calculate cardiac index
What is CI = CO/BSA?
Three variables that determine stroke volume
What is preload, afterload, and contractility?
This physiologic activity can increase oxygen consumption by 50-100%
What is shivering or severe sepsis?
A fever of 1 degrees Celsius increases oxygen consumption by approximately this precent
What is 10%?
Results differing by more than this percentage should be discarded
What is 10%?
This hemodynamic measurement represents left ventricular end-diastolic volume
What is EDV?