Introduction to Hemodynamic Assessment Flashcards
What is the basic tenet of resuscitation
Provide aqequate oxygen delivery to meet demand and reverse any existing tissue hypoperfusion
What is systole and distole
Ventricular contraction and ventricular relaxation
What is afterload
The pressure/resistance the heart has to overcome in order to pump
What is the oxygen carrying portion of a red blood cell
Hemogloblin
Why is having oxygen available for mitochondria so important
A larger amount of ATP can be made allowing for more energy
What are the two MAIN hemodynamic goals in order to maintain tissue viability and function
Adequate tissue perfusion and adequate oxygen delivery
What is a diagnostic clue of anaerobic respiration
Lactic acid
What is the equation for Mean Arterial Pressure with regards to blood pressures
(1/3)SBP PLUS (2/3) DBP
T/F: The arterial side is the driving pressure of the body so much it allows for ignoring venous flow
True
In order to keep flow the same when blood pressure changes what factor has the most power, what is the factor within that factor that will overall change flow in autoregulation
Resistance, radius (vasoconstriction and vasodilation)
T/F: Shock is when the autoregulation of blood flow is too low with blood pressure decreasing causing less blood flow
True
What is the hemodynamic equation for MAP
Cardiac Output (pump performance) X Systemic Vascular Resistance (size of pipe system)
What is a normal MAP
70-100 mmHg
What is the afterload of the left heart, afterload of the right heart, which has the greater pressure the ventricle has to pump against
Systemic vascular resistance (SVR), Pulmonary vascular resistance (PVR), Systemic vascular resistance of` the left heart
What is cardiac output, units, equation
measure of ventricular contractile performance, volume of blood (L) pumped by the ventricle per minute, CO = Stroke Volume X Heart Rate
T/F: Cardiac output is the go to index
False: Cardiac Output can be varied greatly on the size of the patient
What is the go to index and why, normal amount
Cardiac index, indexed for body surface area so it is universal regardless of size, 2.2-4 L/min/m2
What the two major determinants of cardiac output
Heart rate, stroke volume
Under normal circumstances as heart rate increases so does cardiac output, however at what heart rate is this no longer true and what are the two reasons why
150 beats/min, there is not enough time for the heart to fill with preload that would allow for meaningful contraction of the heart, increasing the heart rate with less oxygen causes a demand ischemia of the heart
What concepts effect stroke volume
Preload (end-diastolic volume), contractility, 1/Afterload
T/F: If the heart rate stays constant stroke volume will determine cardiac output
True
What is the preload on the right side of the heart, left side
Central venous pressure, pulmonary capillary wedge pressure
What are tow dynamic variables/tests for testing preload
passive leg raise and end-expiratory occlusion test
What is the basic principle of the Frank-Sterling curve
As preload increases stroke volume and cardiac output increase
What is arterial oxygen saturation (SaO2%), what is the normal
Oxygenation of arterial blood (proportion of hemoglobin saturated with oxygen), Normal: 95%- 100%
What is the normal amount of oxygen that the tissues need to extract in order to function, shown in venous oxygen saturation (ScvO2)
25%/ 70-75%
What is oxygen delivery (DO2) /Normal amount
Amount of oxygen delivered (transported) to tissues during a single cardiac cycle/ 1000 ml/min
What is oxygen consumption (VO2)/Normal amount
Amount of oxygen uptake by tissues during a single cardiac cycle/ 250 ml/min
What is oxygen extraction (O2ER)
Proportion of oxygen saturation taken by the tissues
What is the relationship between oxygen extraction and oxygen delivery as delivery starts to decrease, what is the maximal oxygen extraction
As oxygen delivery decreases tissues increases the oxygen extracted from hemoglobin (inverse relationship) to meet oxygen needs, maintain oxygen volume for vital function, 50-60%
T/F: In a clinical setting, low oxygen saturation (ScvO2) is an important warning sign for the inadequacy of delivery of oxygen to meet oxygen demands
True
What value is the surrogate for knowing adequate tissue perfusion
MAP
What is used as a clinical tool to determine right atrium pressure
Central venous pressure
T/F: If the afterload is increased stroke volume increases
False:e If afterload is INCREASED the stroke volume DECREASES
