Hemodynamics Flashcards
MAP is…
the measure of the average arterial perfusion pressure, which determines blood flow to the tissues
MAP equation
[2(DBP) + SBP] / 3
MAP normal range
70-105 mmHg
CVP is…
volume in the right side of the heart, when the tricuspid valve is open; reflects the filling pressures in the right ventricle
guide for overall fluid balance
CVP
CVP normal range
2 - 5 mmHg
CO is…
the measurement of the amt of blood ejected by the ventricles EACH MINUTE. it reflects pump efficiency and is a determinant of tissue perfusion
CO equation
HR x SV = CO
CO normal range
4 - 8 L/min
CI is…
the measurement of the cardiac output adjusted for body size. it is a more precise measurement of pump efficiency than CO
CI equation
CI = CO / BSA (body surface area)
CI normal range
2.5 - 4.0 L/min
SV is…
represents the volume of blood ejected from the ventricle with EACH CONTRACTION
SV is influenced by
preload, afterload, and contractility
SV equation
SV = CO / HR
SV normal range
60-80 ml/beat (60-70)
SVR is ..
a measurement of the left ventricular afterload.
SVR equation
(MAP - CVP) / (CO x 80)
SVR normal range
900-1400 dynes/sec/cm-5
a diseased valve and resitance in the systemic arterial circulation (increases/decreases) SVR
increase
PVR is
measurement of right ventricular afterload
PVR equation
(PAM - PCWP) / (CO x 80)
PVR normal range
100-250 dynes/sec/cm-5
EF is..
a measurement of the ratio fo the amt of blood ejected from the LV to the amt of blood remaining in the ventricle at the end of diastole.
indirect measurement of contractility
EF
EF equation
SV / (EDV x 100)
EDV is…
the amt of blood available for ejection at the end of diastole
EF normal range
60% or greater
EDV normal range
100-160 ml/m2
SBP normal range
90-130 mHg
DBP normal range
60-90 mmHg
normal HR
60-100
normal RR
10-25
normal SaO2
92-100%
what causes low CO?
shock,
hypovolemia,
low O2 delivery
what causes high CO?
increased volume given
improved contractility
volume replenished
what causes high CVP?
hypervolemia R/L HF RV failure pulmonic valve stenosis pulmonary HTN tamponade tricuspid valve dz RV infarct
what causes low CVP?
hypovolemia (poor venous return to R. heart)
sepsis (vasodilation)
vasodilation/decreased venous return
what causes high RR?
hypercapneic
septic
hypoxic
what causes low temp?
sepsis
impaired immune response
what causes high MAP?
peripheral vasoconstriction
what causes low MAP?
hypoperfusion
what happens if afterload is high?
ventricle dose not empty
low CO
low SV
what happens if afterload is low?
weak contraction
low CO
low SBP
what happens if preload is high?
overstretch
impedes contraction
what happens if preload is low?
not enough volume to make muscle stretch and push volume through the heart
what is SvO2?
whether the heart and lungs effort to supply O2 to the tissues is sufficient to meet the tissue’s O2 demands. (Is CO adequate?)
what causes high SvO2?
high O2 supple (high CO from inotropic drugs, IABP, afterload reduction, early septic shock)
high O2 sat
High hemoglobin (blood transfusion)
low O2 demand (hypothermia, fever reduction, late sepsis, paralysis, pain relief, anesthesia)
PAWP balloon inflated
wedged deflated balloon in cap bed
what causes low SvO2
low O2 supply – low CO – heart failyre, hypovolemia, dysrhythmias, cardiac depressants (beta blockers)
low O2 sats – resp failure, pulomnary infiltrates, suctioning, vent disconnected, low Hemoglobin (anemia or hemorrhage)
high O2 consumption: hyperthermia, seizures, shivering, pain, high work of breathing, high metabolic rate, exercise, agitation
estimate of L vent afterload
SVR
estimate of R ventricular afterload
PVR
what causes high SVR?
aortic stenosis periph vasoconstriction (hypothermia--warm pt, hypovolemia)
what causes low SVR?
vasodilation or shock (septic, neurogenic, anaphylactic)
what causes high PVR?
pulm HTN
increased afterload of R vent
what causes low PVR?
decreased afterload of R vent (Right HF, hypovolemia)
what increases CI?
hyperthyroidism
low SVR
fever
increased O2 demand
what decreases CI
LV failure acidosis increased SVR hemorrhage hypovolemia tamponade
PAOP normal range
5-12 mmHg
what increases PAOP>
LV failure mitral valve dz increased SVR hypervolemia tamponade
what decreases PAOP?
hypovolemia
severe vasodilation
if the trandsucer is too high, what kind of reading will you get?
falsely low reading
if the transducer is too low, what kind of reading will you get?
falsely high reading
if the pt is above the level of the transducer, what kind of reading will you get?
falsely high reading
if the pt is below the level of the transducer, what kind of reading will you get?
falsely low reading
what pressure should the bag be set to?
300 mmHg
can you give meds through an A-line?
NO! not through arteries, only through veins
indications for intraarterial BP monitoring?
unstable cardiac pt; hx of HTV, hx of low BP
titrating meds to BP
for any major medical or surgical condition that compromises CO, tissue perfusion, or fluid volume status
sites for a-lines
radial artery
femoral artery
brachial artery
highest point of a-line waveform?
systole – when blood ejected from left ventricle
lowest point of a-line waveform?
diastole
what is the dicrotic notch?
closure of the aortic valve – diastole is about to begin
if communication from the artery to the transducer is interrupted, what kind of waveform will be produced?
dampened
causes for a dampened waveform?
kink in line or clot
an narrow upward systolic peak that produces a falsey high systolic reading?
underdampened waveform ; overshoot or fling
what is CVP measuring?
filling pressure of the RIGHT side of the heart
sites for CVP monitoring?
subclavian – preferred
IJ – most common
femoral – easiest but cant bend at hip
after inserting CVP, what should you do next?
check breath sounds – pneumothroax
and get CXR – tip in SVC
what is normal CVP?
2-5 mmHg
what measures the preload of the right side of the heart? (right atrial pressure)
CVP
what measure the amount of volume in the heart at the end of diastole?
CVP
what are indications for monitoring CVP?
HF
fluid overload
dehydration
bleeding out
what do we use to check fluid volume status?
CVP
what is the volume of blood in the left ventricle at the end of diastole?
preload
what affects preload?
venous return to heart
total blood volume
atrial kick
does the heart failure pt have (too much/too little) preload?
too much
does the hypovolemic pt have (too much/too little) preload?
too little
what is used to measure preload?
PAOP
tx for an air embolus?
100 O2
left lateral trendelenburg position
what is an excellent ealry warning system for pt who is bleeding, vasodilating, receiving diuretics or being rewarmed after cardiac surgery?
CVP monitoring
which falls first, CVP or MAP?
CVP
if pt has high BP, will they have low or high CVP?
high
if pt is fluid overloaded, what will CVP be?
high CVP
if a pt is dehydrated, what will CVP be?
low CVP
if pt has blood loss, what will CVP be?
low CVP
if pt is bleeding, what will CVP be?
low
what does the swanz ganz measure?
PAP
what measures left atrial pressure?
CVP
what measures right atrial pressure?
PAOP
the output in one minute?
CO
if the pump is weak, what will CO be?
low
if the BP is high, what will CO be?
low bc more difficult for the heart to pump against
if the CVP is low, what will the CO be?
low – low fluid
amount of blood ejected with EACH BEAT?
SV
what mesures preload of right side of heart?
CVP
what measure preload of left side of heart?
PAOP
in heart failure pts, preload is…
increased
in fluid overload pts.. preload is..
increased
in hypervolemic pts.. preload is…
increased
in a dehydrated pt.. preload is…
decreased
normal PAOP
5-12 mmHg
what the LV has to pump against to get blodo from the heart all the way around body and back to heart
SVR
what RV has to pump against to get through lungs
PVR
if afterload is increased, the workload of the heart is..
increased
vasoconstriction causes afterload to
increase (increases SVR)
hypertension causes afterload to
increase
aortic stenosis causes afterload to
increase
the lower the SVR, the __________ the CO
higher
conditions that increase SVR?
HTN
vasoconstriction
conditions that decrease SVR?
vasodilation
factors that affect contractility
preload afterload: increasing afterload makes it more difficult to contract myocardial oxygenation electrolyte balance positive or negative inotropic meds functional myocardium
if HR is fast can the heart adequately fill? how does this affect CO?
NO, so CO decreases
all increasing the O2 requirement to the heart, but cant get it bc not getting O2 out
what hemodynamics does the PAC (swans ganz) measure?
CVP, PVR, SVR
normal DO2 (delivery of O2 to tissues)
900-1100 ml/min
normal VO2 (oxygen consumption)
200-300 ml/min
1/4
how can O2 delivery be improved?
vasodilate pt if high afterload sedate give them oxygen give them blood bc H&H is low improve the "pump"
what is SvO2?
mixed venous oxygen saturation
what is normal SvO2?
65-75%
if anemic or hypoxic, SVO2 will be
decreased
how do we measure SVO2?
swanz ganz
if SOB and stresses, what will happen to SVO2?
decrease
if HR is increased (fever, infection), what will SVO2 be
decreased
if oxygen consumption is increased, what will SVO2 be?
decreased
if shivering or seizureing, SVO2 will be
decreased
what if pt is afebrile and sedated? what else can make SVO2 decrease?
delivery problem (instead of consumption)– so is preload low? is afterload high? is heart bad?
sedation and anesthesia.. what will SVO2 be?
high
hypothermia.. what will SVO2 be?
high
sepsis.. what will SVO2 be
high – tissue cant use the oxygen
