17. Adv Hemodynamic Monitoring Flashcards
cardiac index normal range
2.2-2.4 L/min/m2
CVP normal range
5-12 mmHg
when is CVP most accurately measured
end of expiration
when is CVP not considered accurate
pt is “sitting”
what degree must the pt head be resting at to be considered accurate
between 0-60 degrees
coronary perfusion pressure normal
50-120mmHg
mixed venous oxygen saturation (mvO2)
60-80% in awake pt
mvO2 is approximately the same as
ScvO2
(central venous oxygen saturation)
pulmonary artery pressure (PAP)
15-30/10 mmHg
when is PAP not considered accurate
if pt is sitting
pulmonary hypertension: mild
36-49 mmHg (systolic)
pulmonary hypertension: mod
50-59 mmHg (systolic)
pulmonary hypertension: severe
> 60 mmHg (systolic)
pulmonary capillary wedge pressure (PCWP)
<12mmHg (mean pressure)
PCWP should be _______ less than pulmonary artery ______ pressure
1-4mmHg less than pulmonary artery diastolic pressure
when is PCWP not considered accurate
if pt is sitting
pulmonary vascular resistance (PVR)
100-300 dynes sec cm-5
stroke volume (adult)
60-90 mL/beat
stroke volume index
33-47 mL/m2/beat
systemic vascular resistance (SVR)
700-1200 dynes sec cm-5
ScvO2 (central venous O2 saturation)
25-30% below pt SaO2
OR
70-75% if the SaO2 is normal
what reflex control heart rate
bainbridge
baroreceptor
baroreceptor reflex
responds to changes in BP
low BP = incr HR
high BP = decr HR
bainbridge reflex
responds to change in blood volume
2 bainbridge reflexes
incr BV in RA
1. incr HR (pump extra blood out)
2. vasodilation (decr venous return)
what causes incr in HR
low CVP (baro)
high CVP (bain)
what does cardiac output vary based on
the pt weight
normal CO for 70kg pt
5L/min
200kg pt CO
higher than 5L/min
cardiac index equation
CI = CO/body SA
the cardiac index is independent of_____
weight
normal range of cardiac index is
same for all pts, regardless of size
stroke volume varies with
weight
stroke volume index equation
SVI = SV/body SA
Coronary perfusion pressure equations
CPP = DBP - LVEDP
OR
CPP = DBP - CVP
LVEDP
BP in LV at end of diastole
what is a good estimate of LVEDP
LVEDP~LAP~PCWP~PA diastolic P
CPP equations
CPP = DBP - PCWP
CPP = DBP - PA diastolic Pressure
CPP = DBP - CVP
what is required for adequate coronary perfusion pressure
adequate diastolic filling time
adequate blood pressure
thermodilution steps
- 10mL cold saline into RA (fast <4s)
- thermistor located in pulmonary artery
- thermistor monitors fluid temp
thermodilution curve: high CO
low Area Under Curve
small wave
- cold fluid passes thermistor quickly
thermodilution curve: low CO
higher Area Under Curve
large wave
- thermistor will stay colder longer
CO relationship with thermodilution curve
CO is inversely proportional to area under thermodilution curve
what has replaced thermodilution
Continuous cardiac output PACs
TEE
what can cause false readings in thermodilution
prolonged injection time
>4s
a prolonged injection time would cause
CO reading to be underestimated
R-L shunt: thermodilution curve
fluid less cold (losing 1/2 cold)
AUC smaller
overestimation of CO
L-R shunt: thermodilution
fluid less cold (diluted)
AUC smaller
overestimation of CO
triscuspid regurge: thermodilution
fluid colder longer
AUC larger
underestimation of CO
ScvO2
O2 saturation of blood taken from SVC
drawn from central line port