4. Congenital Heart Disease Flashcards
atresia
opening in the body that has been narrowed or closed of valves
coarctation
narrowing
cor pulmonale
right ventricular hypertrophy (RVH)
infundibulum
muscle below the pulmonic valve
what can infundibular spasm cause?
worsens pulmonic stenosis
the infundibulum develops abnormally in what condition
tetralogy of fallot
palliative surgery
operation intended to decrease severity of symptoms until pt can tolerate operation to fix condition
when is palliative surgery particularly common?
pediatric heart operations
palliative operation examples
BT shunt in order to keep child alive until they can tolerate open heart surgery for TOF correction
BT shunt
blaylock-taussig shunt
artificial connection between aortic arch and pulmonary artery (artificial ductus arteriosus)
infective endocarditis
infection of the heart chambers or valves
what is a BT shunt
artificial connection between aortic arch and pulm artery
artificial patent ductus arteriosus
what is necessary for pts with infective endocarditis?
prophylactic antibiotics have been recommended for patients who need to undergo operations
(unrepaired, palliated or corrected they all need it)
common risk of CHD pts
infective enxocarditis
compensating polycythemia
abnormally high Hct
-pts with congenital heart disease suffer from hypoxia and they make more red blood cells to compensate
what are pts with compensating polycythemia more at risk for?
thrombosis
pts with CHD suffer from
hypoxia
pts with CHD compensate for hypoxia by
incr RBC
== incr Hct
treatment for polycythemia
fluid replacement
brings Hct down towards normal
paradoxical embolism
embolism that travels to the left side of the heart via ASD or VSD and is in arterial circulation (stroke!!)
where does a normal embolism travel
travel to the lungs and stay on the right side of the heart/pulm artery
what do anesthetists need to be very vigilant about when there is a risk for paradoxical embolism?
air bubbles in IV line
cardiac shunt
abnormal blood flow pathways from one side of the heart to another
which pts have an increased risk of paradoxical embolism with IV air injection?
pts w/ Right to Left shunt across ASD/VSD
what are the 4 possible cardiac shunts?
patent foramen ovale (PFO)
patent ductus arteriosus (PDA)
Atrial septal defect (ASD)
ventricular septal defect (VSD)
affect of increase SVR on cardiac shunt
more left to right shunt
increase pulmonary blood flow
affect of decrease in SVR on cardiac shunt
more right to left shunt
worsen hypoxemia
affect of increase PVR on cardiac shunt
more right to left shunt
worsen hypoxemia
affect of decrease PVR on cardiac shunt
more left to right shunt
increase pulmonary blood flow
are patients with right to left or left to right shunts more prone to have compensating polycythemia?
pts with right to left shunt because they have more hypoxia
problems with R-L shunt
- decr pulm BF
- hypoxia
- paradoxic embolism
- compensating polycythemia
R-L shunt anesthetic induction effects
inhalational slower
IV faster
R-L shunt worsened by
incr PVR
decr SVR
R-L shunt management
- decr PVR
- mx/incr SVR
- prevent IV air bubbles
- saline epidural LOR
what increases PVR?
hypoventilation
what can we do to decrease PVR?
higher FiO2
modest hyperventilation
what decreases SVR?
anesthetic agents (regional and general) titrate slowly
what induction agent can be used to maintain SVR?
ketamine
can you do single shot spinal anesthetic with right to left cardiac shunt?
no it is contraindicated
in a right to left cardiac shunt how will the inhalational induction speed change?
slower
blood from R will enter L without picking up agent
dilutes vapor in arterial blood
in a right to left cardiac shunt how will the intravenous induction speed change?
faster
drugs get to the L side of the heart faster
in a patient with right to left cadiac shunt what is the alteration to epidural catheter placement?
MUST use saline for loss of resistance
for risk of air in vein getting into systemic circulation
what does the left to right cardiac shunt do to pulmonary blood flow?
promotes excessive pulmonary blood flow
what can excessive pulmonary blood flow lead to?
increase PVR
dyspnea
incr P on right side of heart
right ventricular hypertrophy
right heart failure
what can the L-to-R shunt/pulm congestion be worsened by?
decreases in PVR
increases in SVR
increases in SVR
How is the anesthetic inhalation induction effected in the L-to-R shunt?
minimally (if any)
how is the anesthetic intravascular induction affected in the L-to-R shunt?
slightly prolonged
it is slightly diluted
how should we change preload in a L-to-R shunt?
preload maintained to limit the amount of left to right shunting
L-R cardiac shunt management
- mx/incr preload
- mx/incr PVR
- low FiO2
- slight hypoventilation (PaCO2 40-50 mmHg)
- decr SVR
- prevent IV air bubbles
eisenmengers syndrome
eventually the pressure in the right heart becomes large enough that the shunt converts to a right to left shunt.
is eisenmengers syndrome more likely with high or low PAP?
higher PAP
which do you need to be extremely vigilant in preventing intravenous air bubbles? R-to-L shunt or L-to-R shunt?
BOTH
when managing a congenital heart disease patient what should you ask?
does this pt have too much pulm blood flow OR not enough pulm blood flow?
what can I do to correct that?
if the patient has too much pulm blood flow how can we decrease left to right shunting?
increase PVR
hypoventilate
lower fiO2
decrease SVR
if the patient doesnt have enough pulm blood flow how can we improve left to right shunting?
increase SVR
decrease PVR
hyperventilate
increase Fio2
patent ductus arteriosus
ductus arteriosus never closed after birth
**some congenital heart disease having a PDA is necessary for survival
before birth how does the blood flow through the ductus arteriosus?
right to left shunt
after birth how does the blood flow through the ductus arteriosus?
left to right shunt
if no other defects are present how should blood flow through the PDA?
left to right
(from aorta to pulm artery)
increase pulmonary BF/congestion
increasing pulm blood flow
right to left shunt acorss PDA
what is different about a patient with a PDAs blood pressure?
low diastolic blood pressure
anesthetic management of pt with PDA 3
1 measures to decrease left to right shunt and limit pulmonary congestion
2 up to 3 doses of indomethacin to close PDA
3 invasive monitoring is not essential in uncomplicated PDA
what should the fiO2 and PaCO2 be for a patient with a PDA?
low FiO2
PaCO2 40-50mmHg
preductal circulation
blood flow to areas of the body proximal to the ductus arteriosus
postductal circulation
blood flow to areas of the body distal to the ductus arteriosus
if the ductal connection is distal to the subclavian then the preductal circulation includes 3
head (left common carotid) right arm (brachiocephalic) left arm (left subclavian)
if the ductal connection is distal to the subclavian then the postductal circulation includes
lower extremities and abdomen
if the ductal connection is proximal to the subclavian then the preductal circulation includes 2
head
R arm
right arm
if the ductal connection is proximal to the subclavian then the postductal circulation includes
left arm
lower extremities/abdomen
lower extremities and abdomen
is paradoxic air embolism more or less likely with ductus arteriosus porximal to subclavian
more risk ofr air embolism
where should you take a preductal blood sample from?
RIGHT radial artery
where should you take a postductal blood sample from?
artery in leg: femoral, dorsalis pedis, or posterior tibial artery
if preductal oxygen saturation is significantly different from postductal oxygen saturation what does that suggest?
a heart defect with right to left shunting across a PDA
aortopulmonary window
hole between aorta and pulm artery
aortopulmonary window shunt
Left to Right
aortopulmonary window symptoms
pulmonary congestion
Patient foramen ovale
foramen ovale never closed after birth
(10-25%)
how is blood expected to shunt in a PFO?
left to right
anesthetic management for patient with PFO 2
1 decrease left to right shunting to limit pulmonary congestion
2 should not allow any air in IV
atrial septal defect
ASD is hole between right and left atria
LARGER PFO
anesthetic management of pt with ASD
higher preload
elevated PVR
lower SVR
ventricular septal defect
hole between left and right ventricles
anesthetic management of pt with VSD
higher preload
elevated PVR
lower SVR
Ebsteins Anomaly
malformation of tricuspid valve that results in tricuspid regurg= high right atrial pressure and right atrial enlargement
what other defect is more likely to occur when the pt has ebsteins anomaly
ASD (perforated foramen ovale)
Right to left shunt
how does blood shunt with ebsteins anomaly and ASD?
right to left
anesthetic management of ebsteins anomaly
decrease PVR -hyperventilate - incr FiO2 increase SVR avoid air bubbles in IV line
what will the patients SpO2 be for ebsteins anomaly with ASD?
lower b/c it is mixed venous/arterial blood
what would the hypoxemia in ebsteins anomaly cause?
compensating polycythemia
eisenmengers syndrome
left to right shunt reverses into a right to left shunt
why does flow reverse in eisenmengers syndrome?
pressure on the right side of the heart increases due to RV dilation/strengthening
clinical implication of eisenmengers syndrome
once it develops cyanosis ensures with varying degrees of heart failure and pulm congestion
HIGH RISK for surgery
anesthetic management for left to right shunts that have possible eisenmengers physiology 3
1 maintain SVR
2 maintain PVR
3 fine balance managing oxygenation
high FiO2 eisenmengers
leads to RHF
low FiO2 eisenmengers
leads to cyanosis
interrupted aortic arch
aorta isnt fully developed and there is a gap between ascending and descending aorta
in order for a pt with interrupted aortic arch to survive what two other defects must they have?
PDA
VSD
ASD or VSD
what direction do you want blood flow through VSD in interrupted aortic arch?
L to R shunting through VSD
where does the oxygenated blood from the left ventricle perfuse? interrupted aortic arch pt
right upper extremity and part of the head
where does blood flow to the lower extremities come from in a pt with interrupted aortic arch?
right ventricle through PDA
mixed venous/arterial blood
how do the blood pressure, pulse and spO2 differ from right arm to left arm
normally higher in the right because the interruption is usually proximal to the left subclavian
anesthetic management for interrupted aortic arch
keep ductus arteriosus patent maintain preload maintain SVR
what are the 4 defects of tetralogy of fallot?
1 pulmonic stenosis (right ventricular outflow tract obstruction RVOT)
2 right ventricular hypertrophy
3 VSD
4 overriding aorta
in tetralogy of fallot how does the blood shunt?
right to left across the VSD
what type of blood is perfusing the body through the overriding aorta in TOF patient
dexoy blood from RV
oxy blood from LV
SaO2 in pt with overriding aorta
Lower SaO2 due to mixed venous/arterial perfusion
what are the two ways for blood to get to the lungs in patients with TOF?
- stenotic pulmonary valve
- L - R shunting across PDA
BF through both is limited
PDA (left to right shunt)
is a PDA necessary for life sustaining pulm blood flow in a patient with TOF?
YES