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186 Cards in this Set

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Def. of cardiac output
the amount of blood pumped out of the left ventricle in 1 minute.
What is the formula for cardiac output?
HR x SV
Def. of stroke volume
amount of blood ejected from the left ventricle with each contraction.
Normal SV for adults
60-130 mL/beat
Normal C.O
4-8L/min at rest
What is the average C.O for an adult?
5L/min
C.O varies with
-age
-sex (10% higher in men)
-body size
-blood viscosity (hematocrit)
-tissue demand for O2
Normal heart not stimulated by autonomic nervous system:
10 to 13L/min
-2x that amount when stimulated by sympathetic nervous system.
Athlete's heart
enlarges 50% and capable of pumpling 35L/min
Heart plays a passive role in:
C.O and pumps whatever blood is returned to it
Failing
when diseased or damaged heart can no longer pump the amount of blood returned to it.
Venous return
amount of blood returing to the right atria each minute.
Normal venous return
the same as C.O 4-8L/min
What vital organs receive the greatest amount of blood flow in resting state because of higher metabolic needs?
muscles, liver and kidneys
Venous return increases with?
peripheral vasodilation
Venous return decreases with?
vasoconstriction
decrease in O2 to tissues occurs with?
high altitudes, CO or cyanide poisoning
Muscle fibers of the precapillary sphincters and metarterioles in the capillary beds are controlled by the concentration of:
O2, CO2, and H+, electrolytes, and other humoral substances
decrease in O2 and an increase in H+ and CO2 at tissues levels equals:
vasodilation
hypoxia
vasoconstriction, shunts greatest amount of blood flow to oxygenated alveoli (best O2)
Approximately 64% of total blood volume is:
venous system
20 to 25% of total blood volume can be lost w/out:
alter. circulatory function and pressures
Heart fails
CNS decrease blood flow to liver, kidneys, and other body areas to maintain perfusion to the most vital organs (heart and brain)
Formula for cardiac index:
C.O/BSA
Normal CI is:
2.5 to 4.0 L/min/m2
CI measurement allows a standardized interpretation of:
cardiac function
At what age is CI the highest?
10yrs and it decreases w/age to approx 2.4L/min/m2 at age 80.
Def. of cardiac work:
a measurement of the energy spent ejecting blood from the ventricles against aortic and pulmonary artery pressures.
-it correlates well with the amount of O2 needed by the heart.
Normally the cardiac work is much higher for the:
left ventricle
-must eject against the MAP, which is about 6x the MPAP.
Cardiac work index
measures the work per min per square meter of each ventricle and is calculated using the following:
LCWI=CIxMAPx0.0136=3.4-4.2
RCWI=CIxMPAPx0.0136=0.4-0.66
Ventricular stroke work
a measure of myocardial work per contraction
Formula for ventricular stroke work
SV x pressure across vascular bed
Ventricular volume
estimated by measuring end diastolic pressure
Normal LVSWI
43-61 g/min/m2/beat
Normal RVSWI
7-12 g/min/m2/beat
End diastolic volume
the amount of blood in the ventricle at the end of filling (diastole)
Ejection fraction
the fraction of end diastolic volume ejected with each systole
Normal EF
65% to 70% drops with cardiac failure
Formula for EF
SV/EDV
EF decreases as
cardiac function decreases
EF of 30%
pt. exercies tolerance is limited because of hearts inability to maintain an adequate cardiac output
SV is determined by three factors:
preload, afterload, and contractility
Bradycardia
increase SV
Tachycardia
decrease C.O at rates of 120-130 (180)
increase O2 consumption
Preload
created by end diastolic vol.
-the greater the stretch on the myocardium prior to contraction the greater the subsequent contraction will be.
Whe preload is too low:
SV and CO will drop
-too much stretch on the heart will also reduce SV
Starlings law of the heart
the greater the stretch on the resting ventricule, the greater the strength of the contraction w/in physiologic limits.
The stiffer the left ventricle
the higher the preload needs to be to obtain an adequate SV
Reduced ventricular compliance is caused by:
-MI
-shock
-pericardial effusions
-PEEP
-postivive inotropic drugs
pump overstretched
no longer able to eject all of its blood efficiently and C.O begins to fall
diastole
atrioventricular valves are open (tricuspid and mitral)
central venous pressure
filling pressure for Rt heart is Rt atrial pressure
pulmonary capillary wedge pressure
filling pressure for Lt heart is Lt atrial pressure
pressure is the result of;
vol., space, adn compliance of the chamber the vol. is entering
factors that increase ventricular compliance
-relief of ischemia
-vasodilator drugs
-cardiomyopathies
3 main factors affecting amount of blood returned to heart
-chanes in circulating blood vol
-changes in the distribution of the blood vol
-atrial contraction
spontaneous inspiration
lowers intrapleural pressures; improves venous return and CO
Positive pressure breaths
increase intrapleural pressures and reduce venous return and CO
2 components of afterload
peripheral vascular resistance
tension in the ventricular wall
as afterload increases
so does O2 demand of the heart
decreasing afterload with vasodilators may help improve:
SV but can cause BP to drop if the blood volume is low
SVR
is a measure of resistance to blood flow through the systemic circulation
SVR increases with:
peripheral vasoconstriction and occurs with hypertension and use of vasoconstrictors
PVR
a measure of pulmonary vascular resistance and increases with pulmonary vasoconstriction as seen in hyposemia and acidosis
Contractility
a measure of myocardial contraction strength
Contractility determined by
-amount of stretch on ventricule prior to contraction
-inotropic state of the heart
Contractility is reduced with:
hypoxia, acidosis, electrolyte abnormalities, and MI
Acute cardiac tamponade
the sudden accumulation of fluid or blood w/in the pericardial space
Acute MI
necrosis of the myocardial tissue due to the lack of blood supply to myocardium
paradoxical pulse
a drop in BP during inspiration of more than 10mm Hg
decreasing afterload with vasodilators may help improve:
SV but can cause BP to drop if the blood volume is low
decreasing afterload with vasodilators may help improve:
SV but can cause BP to drop if the blood volume is low
SVR
is a measure of resistance to blood flow through the systemic circulation
SVR
is a measure of resistance to blood flow through the systemic circulation
SVR increases with:
peripheral vasoconstriction and occurs with hypertension and use of vasoconstrictors
SVR increases with:
peripheral vasoconstriction and occurs with hypertension and use of vasoconstrictors
PVR
a measure of pulmonary vascular resistance and increases with pulmonary vasoconstriction as seen in hyposemia and acidosis
PVR
a measure of pulmonary vascular resistance and increases with pulmonary vasoconstriction as seen in hyposemia and acidosis
Contractility
a measure of myocardial contraction strength
Contractility
a measure of myocardial contraction strength
Contractility determined by
-amount of stretch on ventricule prior to contraction
-inotropic state of the heart
Contractility determined by
-amount of stretch on ventricule prior to contraction
-inotropic state of the heart
Contractility is reduced with:
hypoxia, acidosis, electrolyte abnormalities, and MI
Contractility is reduced with:
hypoxia, acidosis, electrolyte abnormalities, and MI
Acute cardiac tamponade
the sudden accumulation of fluid or blood w/in the pericardial space
Acute cardiac tamponade
the sudden accumulation of fluid or blood w/in the pericardial space
Acute MI
necrosis of the myocardial tissue due to the lack of blood supply to myocardium
Acute MI
necrosis of the myocardial tissue due to the lack of blood supply to myocardium
paradoxical pulse
a drop in BP during inspiration of more than 10mm Hg
paradoxical pulse
a drop in BP during inspiration of more than 10mm Hg
chest wall compliance decreases while lung compliance increases what disease am I?
COPD
raise intrathoracic pressure and decreased venous return:
-tension pneumo
-valsalva maneuver
-breath holding in children
-prolonged bouts of coughing
-PPV
atrail contraction
approx 30% of total C.O by leading the ventrile at the end of diastole
a cause of higher C.O
anemia
elevated systemic vascular resistance caused by vasoconstriction:
cold, inadequate perfusion, HTN, and drugs
drugs that cause vasoconstriction:
-norepinephrine (Levophed)
-methoxamine (Vasoxyl)
-epinephrine (Adrenalin)
Vasodilators:
-nitroprusside
-phentolamine (Regitine)
-chlorppromazine (Thorazine)
sympathetic nerve stimulation drugs
-norepinephrine
-catecholamines
inotropic drugs
+calcium, digitalis, epi, norepi, dopamine, dobutamine, amtinone, isoproterenol, caffeine
-beta blockers, barbiturates, antiarrhythmic agents (procainamide adn quinidine)
physiologic depressants
-decrease calcium
-increase in K+ and Na-
Formula for CPP
diastolic BP - PCWP
variables used to describe ventricular performance and pumping efficiency:
-EF
-cardiac work
-stroke work
most common technique for measuring C.O in the ICU:
-thermodilution
-Fick method
-echocardiography
-transthoracic bioimpedance
-radionuclide imaging
Norm ESV
50-60 mL
Norm CPP
60-80 mm Hg
Norm RCWI
0.4-0.66 kg/min/m2
RVSWI
7.9-9.7 g/min/m2/beat
PVRI
225-325 dynes
SVRI
1970-2400 dynes
SI
30-50 ml/m2
EDV
120-180 ml/beat
RPP
<12,000 mm Hg
LCWI
3.4-4.2 kg/min/m2
LVSWI
50-62 g/min/m2/beat
PVR
<2 units or 110-250 dynes
SVR
15-20 units or 900-1400 dynes
transtracheal ultrasound
attached to the end of the ET tube adn aimed at the descending aorta
transesophageal ultrasound
placed in the esophagus adn aimed at descending aorta
intravascular ultrasound
is placed on the distal endo of a pulmonary artery catheter
hemodynamic monitoring is performed to evaluate:
-intravascular fluid vol
-cardiac function
-vascular function
-identify sudden changes in the pt's hemodynamic status
Norm BP
120/80
Norm MAP
80-100
CVP
<6
PAP
20-30/6-15
PCWP
4-12 mm Hg
LVP
100-140/0-5mm Hg
RAP
2-6mm Hg
RVP
20-30/0-5mm Hg
RVEDP
2-6mm Hg
MPAP
10-20mm Hg
LAP
4-12 mm Hg
LVEDP
5-12 mm Hg
indications for placement of arterial catheter
-significant hemodynamic instability
-frequent draws
CAP monitoring
-severe hypotension (shock)
-severe HTN
-unstable respiratory failure
Catheter usually placed in:
-radial (more common)
-ulnar
-brachial
-axillary
-femoral artery
Seldinger techinque
use a needle to penetrate the artery, and a soft tipped guidewire is then threaded through the needle into the artery. Next needle is removed, leaving the guidewire in place, Finally, the arterial catheter is advanced over the guidewire into position and the guidewire is removed, leaving the catheter in place
approx 70% of coronary artery perfusion occurs during the
diastolic phase, coronary artery perfusion may be compromiese if the diastolic pressure falls below 50mm Hg
RVAPW
0-300mm Hg
HTN
>160/90
hypotension
<90/60
arterial pressure waveforms
should have a clear upstroke on the left
-dicrotic notch on the downstroke on the right
-dicrotic notch represents aortic valve closure
hypotension is caused by:
-low blood volume
-poor cardiac function
-low vascular resistance
HTN caused by
-excessive contraction of the Lt ventricle
-vasoconstriction
-admin. of vasopressors
-sympathetic stimulation(fear or stress)
pulse pressure
difference between systolic and diastolic pressures
Ischemia
occurs with embolism, thrombus, or arterial spasm
-can result in tissue necrosis if not recognized rapidly
hemorrhage
occurs if line becomes disconnected or if stopcock left open
indications for monitoring CVP
-assess circulating blood vol and filling pressures of heart
-assess Rt ventricular function
-pt w/major surgery or trauma
-pts with pulmonary edema benefit from CVP monitoring
most popular CVP catheter is:
7 French with a triple lumen
decrease in BP
-hypovolemia (fluid/blood loss)
-cardiac failure and shock (MI)
-vasodilation (sepsis)
BP increases with
-improve circulatory vol & function
-sympathetic stimulation (fear, meds)
-vasoconstriction
-admin of vasopressors
Formula for MAP
1/3pulse pressure + diastolic pressure

or
systolic pressure +(diastolic pressure x2)
------------------------------------------
3
the triple lumen on the CVP catheter allows for infusion of:
medications
port for blood samples
common sites for placement of CVP are:
-subclavian
-internal jugular
-femoral veins
most popular placement for CVP
internal jugular because it's a straight shot
CVP waveforms reflect pressure changes in:
Rt atrium
transducer system
-need to be hooked up to monitor
-more accurate adn provides a waveform
water monometer
-reported in cm H2O
-inexpensive
-easy to use
-not sure if get waveform
causes of increased CVP
-fluid overload
-Rt/Lt heart failure
-pulmonary HTN
-tricuspid valve stenosis
-pulmonary embolism
-increased venous return
causes of decreased CVP
-reduced circulating blood vol
-vasodilation (reducing venous return)
-leaks in the pressure system
-spontaneous inspiration
complication of CVP monitoring during placement
-bleeding
-pneumo (higher with subclavian)
Complications of CVP monitoring over time
-infection (main)
-embolus
-air embolus (keep stopcock uncapped)
pulmonary artery pressure monitoring
developed to allow better evaluation of left ventricular function
-balloon tipped catheter
PA allows assessment of:
-Lt ventricular filling pressure
-pulmonary vascular resistance
-arteriovenous oxygen difference
-mixed venous oxygen levels
indications for PA pressure monitoring
-severe cardiogenic pulmonary edema
-pts w/ARDS who are hemodynamically unstable
-pts w/major thoracic surgery
-pts w/septic or severe cardiogenic shock
most common sites for insertion of PA
-subclavian
-internal jugular veins
PA systolic pressure
20-30mm Hg
-increases with high pulmonary vascular resistance
-decreases with poor Rt heart function and pulmonary vasodilation
PA diastolic pressure
8-15mm Hg
-normally reflect Lt heart filling pressures
wedge pressure
4-12mm Hg
-elevates w/Lt heart failure or mitral stenosis
-decreases with hypovolemia
complications of PA monitoring
-during cannulation, hemothorax, pneumo, and damage to blood vessels
-dysrhythmias as passes through heart
-infection, thrombus, embolism, bleeding, and hematoma
-pulonary infarction possible
Henry Plummer
endoscopy
first application of flexible fiberoptics to the field of endoscopy was in:
1957 when technology was initially applied to gastroscopes
1969 Sigeto Akeda of japan brought the first:
bronchoscope (visual of airways)
modern rigid bronchoscopes have valves that allow:
-flow of general anesthesia and O2
-pathway for suctioning and removal of foreign bodies
-passage for biopsy
what % of current bronchosocpies are performed using a flexible fiberoptic scope?
90%
indications for bronchoscopy
-diagnostic (most common)
-therapeutic
most common diagnostic indication is abnormality on chest roentgenogram:
-infiltrates
-atelectasis
-mass
standard flexible bronch has an external diameter of:
5.3mm and total length of 605mm
complications of bronch
mortality <0.01%
contraindicated bronch if pt has a history of
bleeding problems
possible problems that occur with bronch:
-bleeding
-pneumo
-infection
nostril is numbed with
Xylocaine
for safety during a bronch personnel wear:
gown, mask, goggles, and gloves during the procedure
RT assist bronchoscopist with selection and insertion of:
-2% and 4% Xylocaine
-brushes to obtain cells and abnormal tissues
-biopsy forceps
-needle aspiration apparatus
monitor pt's vital signs every
5 min
complete charting to include:
-notes of procedure
-indications
-medications
-specimens collected
-test requested
-note any complications and postoperative impression
Rigid scopes give better access to
large airways and are best to remove aspirated large foreign bodies