Hemodynamic Monitoring Flashcards
Chapter 34
Mean Arterial Blood Pressure
= Diastolic BP + (Pulse Pressure/3)
Systolic Blood Pressure is…
The maximum presssure during ventricular ejection.
Diastolic Blood Pressure is…
The lowest pressure in the blood vessels between heartbeats during ventricular filling.
T or F: Tamponade reduces the pulse pressure but keeps diastolic pressure constant.
True
T or F: Respirations increase systolic and diastolic pressures equally, and the pulse pressure is constant.
False. Respiration reduces systolic and diastolic pressure equally, such that the pulse pressure is constant.
Which artery is most frequently used for arterial catheterization?
Radial artery.
What test is used to confirm collateral blood flow?
The Allen Test
Organ perfusion pressure becomes compromised when MAP decreases below ____ mm Hg and/or cardiac index decraeses below ____ L/min/m2
60 mm Hg and 2.0 L/minute/m2
Define central venous pressure.
Back pressure to systemic venous return.
Where should the transducer be for CVP monitoring?
The level of the right atrium, approx. 5 cm below the sternal angle.
When is it appropriate to measure CVP?
At the end of expiration.
A c-wave on the CVP waveform represents?
Bulging of the tricuspid valve into the right atrium which occurs at the onset of systole.
What is Cardiac Output?
Measure of the effective blood flow to the tissue.
Sphygmomanometric measurements of blood pressure often report slightly higher ______ pressure, and lower _____ pressure that that reported by arterial lines.
Systolic; Diastolic
What does it mean if an arterial system is overdamped?
Trapped air bubbles in the tubing are falsely lowering pressure measurements. Underestimation of systolic pressure, diastolic may not be affected.
What does it mean if an arterial system is underdamped?
Overestimated systolic pressure, diastolic pressure may be underestimated.;
The target MAP for uncontrolled hemorrhage.
40 mm Hg
The target MAP for traumatic brain injury.
90 mm Hg
The target MAP for other forms of shock
> 65 mm Hg
What do high values of CVP indicate?
Larger than normal volume returning to the heart from the systemic circulation.
CVP is usually monitored from what veins?
IJ and subclavian
What contributes to CVP values?
Central venous blood volume, compliance of the central compartment, tricuspid valve disease, dysrhythmia, level of transducer, Intrathoracic pressure.
What do you clean the skin with in prep for a CVL?
Chlorhexidine
Where is the sternal angle?
Roughly 5 cm above the center of the right atrium regardless of patient position.
What does a pulsation > 4.5 cm vertically above the sternal angle indicate?
A CVP > 9.5 cm H20
T or F: Venous pressure is more accurately seen on the right side than the left.
True
In ultrasound, if the JV is distended and large than the adjacent common carotid, the CVP is?
> 10 cm H20
Normal range of CVP are?
0-10 mm Hg
T or F: CVP measures do not correlate with circulating blood volume or changes in blood volume.
True
Based on septic shock literature, the target CVP during resuscitation is ?
8-12 mm Hg
What is the most important driving force for determining cardiac output?
Perfusion pressure
What is considered the ideal indicator of perfusion and oxygen delivery?
Cardiac Output
What does Thoracic electrical bioimpedance measure?
Total blood flow within the aorta.
Who was TEB first clinically used on?
Astronauts
Where do you place the probe during a transcutaneous Doppler ultrasound?
At the sternal notch
What is the most important contributor to increasing cardiac output?
Increasing preload by successive fluid challenges.
T or F: Positive pressure mechanical ventilation does not alter venous return.
False
What postural changes help increase venous return?
Passive leg raises
What is preload?
End diastolic volume at the beginning of systole
What is afterload?
Ventricular pressure at the end of systole.
Where is venous oxygen saturation ideally measured?
The pulmonary artery
What does venous oxygen saturation reflect?
The balance between oxygen delivery and oxygen consumption.
What does Smvo2 stand for? What does it reflect?
Mixed venous oxygen saturation; The entire body.
What does Scvo2 stand for? What does it reflect?
Central venous oxygen saturation; oxygen balance from the upper portion of the body. It does NOT include venous return from the coronary sinus.
What are some causes of elevated lactate?
Seizure, DKA, malignancy, thiamine deficiency, malaria, HIV, carbon monoxide, cyanide, and mitochondrial myopathies.
