Advanced Hemodynamic Monitoring Flashcards
Cardiac Index Normal Value
2.2-4.2 L/min/m^2
Central venous pressure CVP normal value
5-12 mmHg
when is CVP most accurately measured?
end of expiration
in what patient position is CVP considered NOT accurate?
if a patient is sitting
should be backrest from 0-60 degrees
coronary perfusion pressure normal value
50-120 mmHg
mixed venous oxygen saturation (mvO2) normal value
60-80% in awake pt
roughly equal to central venous oxygen saturation (ScvO2)
pulmonary artery pressure (PAP) normal value
15-30/10 mmHg
not as accurate when sitting
mild pulmonary Htn value of PAP systolic
36-49 mmHg systolic
moderate pulmonary Htn value of PAP systolic
50-59 mmHg systolic
severe pulmonary Htn value of PAP systolic
> 60 mmHg systolic
pulmonary capillary wedge pressure (PCWP) normal value
less than 12mmHg
not considered accurate if sitting
PCWP is _____ mmHg less than pulmonary artery diastolic pressure
1-4mmHg
pulmonary vascular resistance (PVR) normal value
100-300 dynesseccm-5
stroke volume normal value
60-90mL/beat
stroke volume index normal value
20-65mL/beat/m^2
systemic vascular resistance (SVR) normal value
700-1200 dynesseccm-5
central venous O2 saturation (ScvO2)
25-30% below patients SaO2
what do the bainbridge and baroreceptor reflex have in common?
both control the heart rate
baroreceptor reflex definition
responds to changes in blood pressure inside the carotid sinus and aortic arch
bainbridge reflex definition
responds to changes in blood volume inside the heart
what are the two things the bainbridge reflex causes if the right atrial pressure increases?
increased heart rate
vasodilation (decreasing venous return)
what happens to the heart with a low CVP baroreceptor reflex and high CVP bainbridge reflex?
increase in HR for both
What does the normal cardiac output values depend on?
the size of the patient
cardiac index definition
allows more accurate interpretation of cardiac output b/c number is not skewed by weight
cardiac index equation
cardiac output/body surface area
assuming two patients are healthy which would differ and which would be the same?
cardiac output
cardiac index
cardiac output would differ
cardiac index would be the same
Stroke volume index equation
=stroke volume/body surface area
stroke volume index definition
allows more accurate interpretation of stroke volume because the number is not skewed by weight
coronary perfusion pressure (CPP) equation 1
CPP= DBP-LVEDP
how can we estimate LVEDP?
because it is roughly equal to systolic pressure in the left atrium (left atrial pressure) which is roughly equal to PCWP
coronary perfusion pressure (CPP) equation 2
CPP= DBP - CVP
what are the 3 estimations for LVEDP
~ left atrial pressure (LAP)
~left atrial pressure (LAP) ~ PCWP
~PCWP ~ PA diastolic pressure
what are the 3 equations CPP can be estimated by?
CPP= DBP-CVP CPP= DBP- PCWP CPP= DBP- PA diastolic pressure
what are the four parts to thermodilution technique
10mL saline injected into RA (<4sec)
cold fluid travels to thermistor
cold fluid is warmed to a degree
monitor produces waveform based on coldness of fluid
high cardiac output thermistor chart
get cold fast but warm up quickly
area under curve is lower than normal
low cardiac output thermistor chart
will stay cold for longer period of time
area under curve is higher than normal
a factor that decreases the area under the thermodilution curve will over or underestimate CO?
overestimate CO
a factor that increases the area under the curve will over or underestimate CO?
underestimate CO
how is cardiac output related to the area under the thermodilution curve?
inversely
what would happen if you prolonged the injection time?
the curve would be larger than normal which means the cardiac output reading would be underestimated
what are the two things that have replaced thermodilution?
continuous cardiac output (CCO) pulmonary artery catheters
transesophageal echocardiography TEE
central venous O2 saturation where is the blood draw from and with what?
oxygen saturation of blood from superior vena cava drawn from the central venous line port
which will be lower mvO2 or ScvO2? why?
mvO2
because coronary sinus blood is more deoxygenated than other blood
what are the three things that make up mvO2?
superior vena cava
inferior vena cava
coronary sinus
how does mvO2 and ScvO2 relate to low cardiac output?
lower mvO2 and ScvO2 bc the blood has more time to become deoxygenated
how does mvO2 and ScvO2 relate to high cardiac output?
higher mvO2 and ScvO2 bc the blood has less time to become deoxygenated
what are the two reasons that ScvO2 and mvO2 are rarely used anymore?
requires drawing blood from central line or swan
CO can be estimated by other effective methods
Ohms law
V= IR
what does ohms law describe
the factors that affect flow through an electrical circuit
V=
voltage
MAP - CVP
I=
current
analogous to cardiac output
R=
resistance
systemic vascular resistance or
pulmonary vascular resistance
applying ohms law to cardiac output 2 equations
CO= (MAP-CVP/SVR) (80) CO= (PAP-PCWP/PVR) (80)
