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174 Cards in this Set
- Front
- Back
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What are the 3 ways to obtain/measure CO?
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Thermodilution
Dye Dilution Fick Equation |
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Normal CI
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about half of CO
or 2.5 - 4 L/min |
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normal SV
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60-130 ml/beat
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normal SI
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30-65 ml/m2
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Normal CVP
what port on PAC is used to measure? What other measurement does CVP reflect |
1-6 mmHg
proximal lumen RV preload |
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Normal RVP
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15-30 mmHg systolic
0-8 mmHg diastolic |
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Normal PAP
What port on PAC is used to measure |
25/10
distal tip (balloon deflated) |
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normal MPAP
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10-20 mmHg
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Normal PCWP/PAWP/PAOP
What port on PAC is used to measure? What other measurement does PCWP reflect? |
4-12 mmHg
distal tip (balloon inflated) PCWP estimates LV filling & preload |
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Normal PvO2
where is a sample obtained what does the PvO2 assess? |
40 mmHg
distal tip of PAC assesses overall function of cardiopulmonary system |
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Normal SvO2
where is it measured what does the SvO2 reflect |
60-80%
distal tip of PAC SvO2 reflects utilization of O2 by the tissues |
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normal PaO2
what does PaO2 reflect |
80-100 mmHg
PaO2 reflects adequacy of arterial oxygenation |
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Normal SaO2
where is it measured? what does SaO2 reflect? |
>95%
systemic artery or pulse ox SaO2 reflects availability of O2 delivered to the tissues |
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Normal SVR
what is it useful in assessing & why |
900-1400 dynes/sec/cm5
SVR useful in assessing LV afterload because it reflects resistance facing LV during contraction |
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Normal PVR
what is it useful in assessing & why |
150=250 dynes/sec/cm5
assesses RV afterload because it reflects resistance facing RV during contraction |
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Normal Ejection Fraction (EF)
define EF |
65-75%
represents % of total blood volume ejected from ventricle w/each contraction |
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Normal arterial oxygen content (CaO2)
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20 mL of O2 per 100 ml blood
or 20 vol% or 20 mL/dl |
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Normal Mixed Venous O2 content (CvO2)
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15 vol% or 15 ml/dl
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Normal arterial to venous O2 content difference (Ca-vO2)
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3-5 vol%
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Normal oxygen delivery (DO2)
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1000 ml O2/min
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Normal oxygen consumption (VO2)
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250 ml
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Normal O2 extraction ratio
what does it reflect |
25%
reflects balance between O2 delivery & consumption |
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Normal Pulmonary Shunt (Qs/Qt)
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3-5%
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What 3 factors affect SV
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preload, afterload & contractility
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CVP also reflects what other pressures within the heart
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CVP, RAP & RVEDP
normal 2-6 mmHg |
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PCWP also reflects what other pressures in the heart
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PCWP, LAP, LVEDP
normal 4-12 mmHg |
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What measurement can reflect the presence of pulmonary edema?
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PCWP >18
give diuretic |
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What pressure indicates decreased tissue perfusion
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MABP <60
(Normal 70-100) |
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The PAC is used to assess:
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1. intravascular fluid volume (CVP, PCWP)
2. cardiac function (CO,CI) 3. vascular function (SVR, PVR) |
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What values can determine if cardiac tamponade or stricture is present?
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CVP, PCWP,RVP,PAP
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Normal values for CVP, RAP and RVEDP
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2-6 mmHg
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Normal values for PCWP, LAP and LVEDP
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4-12 mmHg
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Normal Value for HR
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80 beats/min
range 60-100 |
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Normal Value for BP
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120/80 mmHg
range 90-140/60-90 |
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Normal Value for MABP
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90 mmHg
range 80-100 |
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Normal Value for PAP
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25/10 mmHg
range 20-35/5-15 |
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Normal Value for MPAP
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15 mmHg
range 10-20 |
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Normal value for CO
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5 L/min
range 4-8 |
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Normal value for CI
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2.5 - 4 L/min per m2
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Normal SVR
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900-1400 dynes/sec/cm5
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Normal PVR
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110-250 dynes/sec/cm5
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what are the indications for arterial pressure monitoring
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significant hemodynamic instability, frequent ABGs, severe hypotension (shock), severe hypertension, unstable RF, medications that affect BP (vasodilators or inotropics)
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Insertion sites for arterial pressure catheters
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radial, ulnar, brachial, axillary, or femoral
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coronary artery perfusion occurs during what phase of the cardiac cycle
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diastolic phase
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what is an indication of inadequate coronary artery perfusion
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diastolic pressure <50 mmHg
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systolic pressures greater than what indicate hypertension
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systolic P >140 are hypertensive
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diastolic pressures greater than what indicate hypertension
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diastolic P >90 are hypertensive
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what BP is indicative of hypotension
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90/60
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Low BP is a late sign of
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low blood volume or cardiac function
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What does BP reflect
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BP reflects the general circulatory status
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What can indicate earlier than BP that there is inadequate blood volume or CO
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cold and clammy extremities
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What are causes of decreased arterial pressure?
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hypovolemia
cardiac failure and shock vasodilation (sepsis, nitrates) |
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what are causes of increased arterial pressure
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improved circulatory volume & function
sympathetic stimulation (fear, medications) vasoconstriction vasopressors |
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what pressure is a reflection of SV
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pulse pressure
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a decreasing pulse pressure is a sign of
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low SV (30 mmhg)
normal SV 30-40 |
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the MABP is an indicator of
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tissue perfusion
normal MABP 80-100 |
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what is an indicator of decreased tissue perfusion
as well as compromised circulation to vital organs |
MABP <60 mmHg
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Increased MABP (>100) increases the risk for
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stroke and heart failure
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Complications of continuous arterial monitoring
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ischemia
hemorrrhage infection |
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define CVP
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CVP is the P of the blood in the RA or vena cava where the blood is returned to the heart from the venous system
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where does the tip of the CVP catheter lay
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tip ends in RA
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what are common insertion sites for a central venous catheter
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subclavian
internal jugular femoral veins |
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How is the CVP waveform affected byspontaneous breathing versus MV
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CVP decreases with spontaneous inspiration and increases with MV
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what can cause an elevation in CVP
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volume overload
increased intrathoracic P compression around heart pulm. hypertension RV failure (MI, cardiomyopathy PE |
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what can cause a decreased CVP
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vasodilation
hypovolemia spontaneous inspiration air bubbles or leaks in P line |
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CVP increases with the following
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increased venous return (volume)
increased intrathoracic P decreased ability of R heart to move blood |
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CVP decreases with the following
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decreased venous return (volume)
decreased intrathoracic P increased ability of heart to move blood forward |
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PA pressure increases with the following
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increased venous return(volume)
increased intrathoracic P increased PVR |
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PA pressure decreases with the following
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decreased venous return (volume)
decreased intrathoracic P decreased PVR |
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pulmonary hypertension causes
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increased pulmonary vascular pressures and CVP making CVP inadequate measurement of fluid status
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PA pressure measure right heart function and reflects the following
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preload and end diastolic filling pressure
ability of R heart to move blood through the lungs and left heart |
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Four factors that influence preload
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circulating blood volume
distribution of blood volume atrial contraction ventricular contraction |
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what is preload
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preload is the pressure after the ventricle has filled with blood (end diastole)
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preload is reflected by what measurements
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RVEDP, CVP & RAP (2-6)
LVEDP, PCWP, LAP (4-12) |
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what factor is a major determinant of contractility of the heart
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preload
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what are the determinants of local blood flow
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oxygen needs
nutrients waste removal hormones |
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3 factors that determine SV
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preload
afterload contractility |
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normal SV
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60-130 ml/beat
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what is afterload
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the impedance to flow that the ventricles have to overcome to eject blood into the great vessels
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what factors are reflective of the afterload of the R & L ventricles
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RV - PVR (110-250 dynes)
LV - SVR (900-1400) |
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hypertension (systemic or pulmonary) has what effect on SVR and PVR respectively
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systemic hypertension increases SVR
pulmonary hypertension increases PVR |
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what is the effect on CO when the SVR or PVR is increased
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CO decreases when the SVR or PVR is increased
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factors that can increase PVR include
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PE
CHF pulmonary hypertension |
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what are the four ports on the swan ganz or PAC
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proximal port (RA)
distal port (PA) thermistor outlet balloon inflation |
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what is the function(s) of the distal port
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measures PAP (balloon deflated) and PCWP )balloon inflated)
aspirate blood to measure SvO2 or mixed venous blood |
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what is the function(s) of the proximal port
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used to give drugs & fluids; can measure CO, CVP, RAP, RVEDP
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what is the function of the balloon port
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when inflated w/1.5 cc of air can measure PCWP
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what is the function of the termistor port
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measures temperature change to give CO
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factors that increase contractility include
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sympathetic nervous system
positive inotropic drugs |
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factors that decrease contractility include
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hypoxia, hypercapnia, acidosis, beta blockers, parasympathetic (vagal) stimulation, negative inotropic drugs
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what is the relationship between CO and SVR
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there is an inverse relationship with CO and SVR; if CO increases, SVR decreases and vice versa
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define pulse pressue
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pulse pressure is the differnce between systolic and diastolic. indication of degree of blood flow
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MAP can assess the body's response to
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vasoactive drug therapy
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what is an indication of overall cardiac function
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CI
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what is an indicator of preload
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RV preload - CVP
LV preload - PCWP |
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what is an indicator of afterload
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RV afterload -PVR
LV afterload - SVR |
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what is an indicator of contractility
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Ejection Fraction (which is the % of total blood volume ejected from ventricle w/each contraction)
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what does the PvO2 (mixed venous oxygen) an indicator of
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PvO2 assess the overall function of the cardiac system
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Locations and pressures on insertion of PAC
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RA 2-6 mmHg
RV - 15-30/0 PA - 15-30/5-15 (dichrotic notch) PCWP 4-12 |
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define pulmonary shunt
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blood that's ejected from the Right side of heart but bypasses the lungs and returns to left side of heart unoxygenated (3-5% of CO)
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Locations and pressures on insertion of PAC
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RA 2-6 mmHg
RV - 15-30/0 PA - 15-30/5-15 (dichrotic notch) PCWP 4-12 |
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define pulmonary shunt
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blood that's ejected from the Right side of heart but bypasses the lungs and returns to left side of heart unoxygenated (3-5% of CO)
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How is MAP calculated
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MAP =
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How is Pulse pressure calculated
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Pulse Pressure =
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How is CO calculated
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CO =
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what is the Fick equation to calculate CO
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Fick Equation
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How is CI calculated
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CI =
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How is SV calculated
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SV =
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How is the MPAP calculated
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MPAP =
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How is SvO2 calculated
(venous oxygen saturation of hemoglobin) |
SvO2 =
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How is PvO2 calculated
partial pressure of mixed venous oxygen |
PvO2 =
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how is PaO2 calculated
partial pressure of arterial oxygen |
PaO2 =
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How is SVR calculated
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SVR =
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How is PVR calculated
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PVR
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How is CaO2 calculated
arterial O2 content |
CaO2 =
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How is CvO2 calculated
(mixed venous O2 content) |
CvO2 =
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How is arterial to venous oxygen content difference calculated C(a-v)O2 or avDO2
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C(a-v)o2 =
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How is oxygen delivery calculated (DO)
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DO =
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How is oxygen consumption calculated (VO2)
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VO2 =
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How is the oxygen extraction ratio calculated
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oxygen extraction ratio
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How is pulmonary shunt calculated (Qs/Qt)
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Qs/Qt =
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What are the determinants of local blood flow?
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oxygen requirements
nutritional status/nutrients waste removal humoral agents |
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How does pulmonary vasoconstriction affect oxygenation
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hypoxia causes pulm. vasoconstriction; this helps to maintain normal V/Q by shunting the greatest amt. of blood to the oxygenated alveoli
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explain Ejection Fraction
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EF is the % of total blood volume ejected from ventricle w/each contraction; low EF indicates compromised cardiac function & decreased CO; low tolerance to exercise
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What factors increase venous return?
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hypervolemia, RV failure, pulm hypertension, valvular stenosis, pulmonary embolus, cardiac tamponade, pneumothorax, PPV, PEEP, LV failure
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How can bronchodilators cause an oxygenation problem
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bronchodilators can cause increased V/Q mismatch
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How can vasodilators and inotropic agents cause an oxygenation problem
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they can cause a decreased V/Q mismatch
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What factors determine O2 delivery?
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CaO2
CO Distribution of CO OHDC |
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what factors determin O2 utilization?
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metabolic rate
cell integrity (trauma, sepsis) O2 availability level of waste products/toxins |
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4 reasons to monitor lung volumes
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affect gas exchange
reflect change in clinical status indicate response to therapy signal problem w/vet interface |
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when is it indicated to monitor lung volumes
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intubated patient, MV pt., pre-op eval., abnormal breathing patterns, RR >30, neuromuscular disease, CNS depression, deteriorating ABG, NPPV
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conditions that can cause the VT to be reduced include
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pneumonia, atelectasis, post-op, chest trauma, excaerbation of COPD, CHF, pulmonary edema, restrictive diseases, CNS depression
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Conditions that can cause the VT to be increased include
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metabolic acidosis, sepsis, severe neurological injury
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what can cause a low PvO2 (mixed venous oxygen tension)
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inadequate CO
anemia significant hypoxia left shift of OHDC |
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diseases that cause a decreased compliance include
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ARF, ARDS, pneumonia, atelecteasis, pneumothorax, fibrosis
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what is the Fick equation
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CO = VO2/C(a-v)O2
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how is O2 consumption (VO2) calculated?
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VO2 = (FiO2 - FeO2)VE
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what does an inceased/wider gradient between CaO2 - CvO2 indicate?
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increased VO2
decreased CO |
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what does SvO2 indicate?
normal SvO2 |
how well tissues are able to use O2
normal 60-80% |
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what can cause low CVP or PCWP
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hypovolemia
air bubbles in P line |
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hypoxia has what affect on PAP?
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hypoxia causes vasoconstriction in the lungs and increases PAP
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clinically normal CVP
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6-12 mmHg
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What factors can cause an increased PAP
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hypoxia, ARDS, COPD, mitral valve disease, pulmonary emboli
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An increased PA diastolic P to PCWP gradient exists in conditions such as:
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ARDS, COPD, pulmonary embolus
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Possible causes of a decreased SvO2 (PvO2)
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increased VO2
decreased DO2 increased O2 demand |
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the two key components in identifying CHF
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increased PCWP w/decreased CO
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normal & critical value for VE
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normal 5-6 l/min
critical >10 l/min |
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normal & critical value for VC
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normal 65-75 ml/kg
critical <10 ml/kg |
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what does an increase in PIP and Pstatic indicate
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Compliance problem
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what does an increase in PIP if the Pstatic remains unchanged indicate
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RAW problem
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How is Cs calculated
Normal Cs |
Cs = VT/Pstatic - PEEP
normal 40-80 in MV pt. |
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How is RAW calculated
normal Raw |
RAW = PIP - Pstatic/Flow (l/sec)
normal 1-3 cmH2O/L/sec |
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what waveforms are useful in identifying auto PEEP
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flow time waveform
P-V Loop |
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What kind of changes are detected by monitoring exhaled CO2 by capnography or capnometry
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metabolic rate
ventilator function efficiency of ventilation transport of CO2 as a result of changes in perfusion |
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when is the amount of CO2 produced & excreted in a minute (VCO2) increased
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fever, trauma, peritonitis, head trauma, rewarming after hypothermia & carbohydrate loading
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what can cause a rapid decrease in VCO2?
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low CO and decreased tissue perfusion, decreased RV output, decreased venous return, or pulmonary embolus
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Oxygen transport depends primarily on the following three reserve componenets
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CO & distribution
PaO2 & SaO2 values Hemoglobin level |
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Major determinant of CO
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metabolic activity
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Major dtermant of peripheral distribution of blood
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regional O2 consumption
temperature humoral agents |
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How much of the O2 that is carried in the blood is available to the tissues
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50-70% is available for use
30-50% is used as resivoir |
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what factors can limit VO2
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decreased CaO2
decreased regional perfusion demand exceeds supply (hypermetabolic state) cyanide posion (cell metab impaired) |
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PvO2 is a reflection of
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PVO2 is an indication of oxygen usage by the entire body
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Normal PvO2
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38-42 mmHg
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what can cause a decreased PvO2
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low CO
anemia Significant hypoxia left shift of OHDC |
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normal C(a-V)O2
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4-6 vol%
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if the C(a-v)O2 is greater than 6 vol% the cause may be
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decreased CO
increased VO2 |
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if the C(a-v)O2 is less than 4 Vol% the cause may be
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septic shock
increased CO anemia left shift ODC |
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an increased CVP with decreased CO is indicative of
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heart failure
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factors that decrease ventricular compliance include
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myocardial ischemia & MI
hemorrhagic & septic shock pericardial effusion RV dilation & overload PEEP, CPAP inotropic agents |
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3 main factors that affect the amount of blood returned to the heart (venous return)
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circulating blood volume
distribution of blood volume atrial contraction |
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what is the major determinant of contractility
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preload
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peripheral resistance or impedenace (afterload) is determined by
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elasticity of vessels
radius of vessels viscosity of blood change in P from one end of vessel to the other |
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low C(a-V)O2 indicates
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the lower the C(a-v)O2 the smaller the amount of O2 removed from blood
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Low C(a-v)o2 are seen when
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High CO (moves too fast through capillaries)
cells extract less O2 (sepsis) Left sided shift in ODC |
