Congenital Heart Disease Flashcards
Normal opening in the body that has been narrowed or closed
Atresia
Means “narrowing”
Coarctation
Name for right ventricular hypertrophy
Cor Pulmonale
Muscle below pulmonic valve
Infundibulum
What happens if the infundibular spasms?
It can worsen symptoms of pulmonic stenosis
Refers to an operation that is intended to decrease the severity of symptoms until a patient can tolerate an operation that will fix their condition
Palliative Surgery
Artificial connection between the aortic arch and pulmonary artery
Blaylock-Taussig (BT) Shunt
What can be thought of as an artificial patent ductus arteriosus?
Blaylock-Taussig Shunt
Major concern in patients with CHD
Infective endocarditis
What is recommended for patients with a history of CHD who need to undergo operations?
Antibiotic prophylaxis
How do patients with CHD compensate for hypoxia?
By making more red blood cells (compensating polycythemia)
What are patients with compensating polycythemia more prone to?
Thrombosis
What is a paradoxical embolism?
An embolism that travels to the left side of the heart and ends up in arterial circulation
What condition would air in the IV line be most disastrous?
CHD with R to L shunting
What is the most common shunt direction?
L to R because pressure in higher in L atrium than the R
Possible cardiac shunts
- Patent foramen ovale
- Patent ductus arteriousus
- Atrial septal defect
- Ventricular septal defect
What happens to shunting if SVR increases?
More L to R shunting and can potentially increase pulmonary blood flow
What happens to shunting if SVR decreases?
More R to L shunting and can potentially worsen hypoxemia because a higher percentage of blood is being shunted past the lungs
What happens to shunting if PVR increases?
More R to L shunting and potentially worsen hypoxemia
How can PVR be increased?
Lower FiO2 and hypoventilation
What happens to shunting if PVR decreases?
More L to R shunting and can potentially increase pulmonary blood flow
How can PVR be decreased?
Higher FiO2 and hyperventilation
R to L shunts cause
Hypoxia
Patients with (R to L or L to R) are more prone to compensating polycythemia
R to L
R to L shunts can be worsened by
- Increases in PVR
2. Decreases in SVR
When is single shot spinal anesthetic contraindicated?
R to L shunts
Inhalational induction speed is slower with
R to L shunts
Intravenous induction is faster with
R to L shunts
Why should epidural catheter placement use saline for LOR instead of air in R to L shunts?
It can cause paradoxical air embolism
L to R shunts cause
excessive pulmonary blood flow
L to R shunts can be worsened by
- Decreases in PVR
2. Increases in SVR
True/False. L to R shunts can convert to the R to L shunt
True
True/false. paradoxic air embolisms are not possible with L to R shunts
False
L to R shunt has what effect on anesthetic inhalational induction?
Minimal
L to R shunt has what effect on IV induction?
Slightly prolonged
Management of L to R shunts
- Maintain/increase preload
- Maintain/increase PVR
- Decrease SVR
- Prevent IV air bubbles
What causes too much pulmonary blood flow?
L to R shunting
What causes not enough pulmonary blood flow?
- Pulmonic stenosis
2. R to L shunting
How do you manage a patient with too much pulmonary blood flow?
- Maintain/increase PVR
2. Decrease SVR
How do you manage a patient with not enough pulmonary blood flow?
- Lowering PVR
2. Maintaining/increasing SVR
Blood flow through the ductus arteriosus before birth
R to L across the PDA from the pulmonary artery to the aorta
Blood flow through the ductus arteriosus after birth
L to R across a PDA from the aorta to the pulmonary artery
Problems with a PDA
- Blood is expected to shunt L to R (assuming no other defects) leading to increased pulmonary blood flow/possible pulmonary congestion
- Low diastolic blood pressure
Management of PDA
- Decrease L to R shunting
- 3 doses of indomethacin to close PDA
- Can utilize invasive monitoring for significant comorbidities
How can you decrease L to R shunting?
- Good preload
- Lower FiO2
- Slight hypoventilation
Refers to blood flow to areas of the body proximal to the ductus arteriosus
Preductal
Refers to blood flow to areas of the body distal to the ductus arteriosus
Postductal
What is included in preductal circulation if the ductus arteriosus connects to the aorta distal to the subclavian?
- Head (L common carotid artery)
- R arm (brachiocephalic artery)
- L arm (L subclavian)
Included in post ductal circulation if the ductus arteriosus connects to the aorta distal to the subclavian
Lower extremities and abdomen
Included in preductal circulation if the ductus arteriosus connects to the aorta proximal to the subclavian artery
- Head (through L common carotid)
2. R arm (brachiocephalic)
Included in post ductal circulation if the ductus arteriosus connects to the aorta proximal to the subclavian
- L arm (L subclavian artery)
2. Lower extremities and abdomen
What is important to note if the ductus arteriosus connects to the aorta proximal to the subclavian?
A paradoxic air embolism is much more likely
Preductal blood flow ALWAYS includes
the head and R arm
How should you obtain a postductal blood sample?
Use an artery in the leg such as the femoral, dorsalis pedis, or posterior tibial artery
What happens if preductal oxygen saturation is significantly different from postductal?
A heart defect such as R to L shunting across a PDA
Percentage of the population with a patent foramen ovale
10-25%
Problems with a patent foramen ovale
- Blood is expected to shunt in a L to R fashion, leading to increased pulmonary blood flow
- There is a slight chance that blood could get from the R to L atrium, be careful of air bubbles
Management for patients with a PFO
- Decrease L to R shunting (good preload, lower FiO2, slight hypoventilation)
- No air in IV tubing
What is an atrial septal defect?
A hole between the R and L atria
Problems with an ASD
- L to R shunting (increased pulmonary blood flow & increased pressure on the R side of the heart)
Management of patients with an ASD
- Higher preload
- Slightly elevated PVR
- Slightly lower SVR
What is a Ventricular Septal Defect?
A hole between the L and R ventricles
Common congenital cardiac malformation in adults
VSD
Clinical implications and management of VSD
Similar to ASD
- L to R shunting needs to be decreased
- Good preload
- Slightly elevated PVR
- Slightly lower SVR
Malformation of the tricuspid valve that results in tricuspid regurgitation
Ebstein’s Anomaly
What happens with Ebstein’s anomaly?
High R atrial pressure and R atrial enlargement
Problems with Ebstein’s anomaly
- Increase in R sided heart pressures makes it 80% more likely for atrial septal defects to be present
- if an ASD were present, blood would shunt R to L across the ASD (dec pulmonary blood flow, increase hypoxia, inc chances of a paradoxic air embolism and compensating polycythemia)
Blood flow in Ebstein’s anomaly
- If blood shunts R to L across an open foramen ovale, pt would be perfused with mixed venous/arterial blood and the pt would have a lower than normal SpO2
Anesthetic management of Ebstein’s anomaly
- Decrease PVR and Increase pulmonary blood flow bc of risk of R to L shunting
- Avoid air bubbles in IV line at all costs
Occurs when a L to R shunt reverses into a R to L shunt
Eisenmenger’s Syndrome
Problems with Eisenmenger’s Sydrome
- Cyanosis ensues with varying degrees of heart failure, which exacerbates pulmonary congestion which was present from L to R shunting
- Pulmonary blood flow may be 4x greater than systemic blood flow
- Eisenmenger’s physiology patients are the highest risk for surgical procedures
Anesthetic management for L to R shunts that have possible Eisenmenger’s physiology
- Maintain SVR and PVR
What happens with high FiO2 in Eisenmenger’s physiology?
- High FIO2 may worsen the L to R shunt and promote R heart failure
What happens with low FiO2 in Eisenmenger’s physiology?
- Low FiO2 may worsen the R to L shunt and promote cyanosis
What is the coarctation of the aorta?
Narrowing of the aorta distal to the L subclavian artery
Most common coarctation
Postductal
Problems with coarctation of the aorta
- Severe decrease in CO
- Poor peripheral perfusion
- High afterload (leading to CHF and aortic regurg)
- Risk for aortic dissection
- Blood pressure in lower extremities is lower than in upper extremities
Anesthetic management for coarctation of the aorta
- Preload should be maintained to ensure adequate forward flow
- Avoid abnormally high contractility and/or HR
- SVR should be maintained/low afterload should be avoided
- Bradycardia should be avoided
Condition in which the aorta is not fully developed and the patient ends up with a gap between the ascending and descending aorta
Interrupted aortic arch
Most common type of interrupted aortic arch
Type B
Blood flow with an interrupted aortic arch
- Proximal aorta is perfused with oxygenated blood from the L ventricle
- The distal aorta/lower extremities are perfused with mixed venous/arterial blood coming from the R ventricle through a PDA
- VSD must be present in order for lower extremity blood flow to have any oxygen at all
Problems with an interrupted aortic arch
- Blood pressure and SaO2 are usually lower in the L arm/lower extremities
- Pts have L to R shunt through the VSD, leading to possible pulmonary congestion
Management for interrupted aortic arch
- Keep the ductus arteriosus patent
2. Maintain an appropriate PVR/SVR balance
What 4 defects are included in the tetralogy of Fallot?
- Pulmonic stenosis (right ventricular outflow tract obstruction)
- Right ventricular hypertrophy
- A ventricular septal defect
- Overriding aorta
Blood flow in tetralogy of fallot
- Pressure in R side is higher than L because of pulmonic stenosis
- Blood will shunt R to L across VSD
- In an overriding arota, the aorta receives deoxygenated and oxygenated blood
- Blood enters lungs through stenotic pulmonary valve and L to R shunting across a PDA
How does blood normally shunt across a VSD?
L to R
What is not part of the tetalogy of fallot but is necessary for adequate pulmonary blood flow?
PDA
Problems with tetralogy of fallot?
- Pulmonary blood flow is limited
- Pts are hypoxic
- PDA is essential for adequate pulmonary blood flow
Sudden onset, life threatening hypoxic spell
Tet spell
What causes a tet spell?
Infundibular spasm and a subsequent increase in R to L shunting
Causes of infundibular spasm
- Sympathetic stimulation/crying/anxiety
2. Hypovolemia
Should we increase or decrease preload for tet spells?
Increase to open the R ventricular outflow tract
Treatment for a tet spell
- Administer 100% oxygen and consider moderate hyperventilation
- Consider administration of ketamine or phenylephrine to increase SVR
- Give a fluid bolus to enhance preload
- Place child in knee chest position
- Consider beta blocker
- Avoid beta agonists when trying to raise blood pressure
When is it acceptable to give phenylephrine to pediatrics?
For tetralogy of Fallot
Management of tetralogy of Fallot
- Ductus arteriosus should be kept open (PGE1)
- Limit R to L shunting by maintaining/increasing SVR and decreasing PVR
- Hypotension should be avoided on induction (ketamine or sevo induction)
- Phenylephrine or ketamine may be considered
- Sympathetic stimulation should be minimized
- Avoid air bubbles in the IV
- Preload should be maintained/elevated with volume expansion
Initial surgical repair of TOF
BT shunt first to improve pulmonary blood flow and eliminate the need for the PDA
Final surgery for TOF
Close the VSD and repair/replace the pulmonic valve
Condition where the R ventricle pumps into the aorta and the L ventricle pumps to the pulmonary artery
Transposition of the great arteries
Problems with TGA
- Without shunts, oxygenated blood would stay in the pulmonary system and the deoxygenated blood would stay in the systemic system
- Blood flow to lungs is decreased
- Low SpO2 and possible compensating polycythemia
- Air bubbles would be catastrophic
- Onset time for inhalational anesthetics would be slower/delayed
- IV drugs may be more potent
Blood flow in TGA
At least 2 shunts have to be present, R to L to shunt blood towards the lungs and L to R
Condition where air bubbles would cause the biggest problem
TGA
Management of TGA
- Anesthetist should keep the PDA open with PGE1
- Increase pulmonary blood flow/favor R to L shunting of blood flow into the lungs (inc preload, inc/maintain SVR, dec PVR)
- IV induction is preferred over inhalational (ketamine!)
- Doses and rates of injection of IV drugs may have to be decreased
- TIVA is preferred
- Avoid air bubbles at all costs
Condition where pulmonary veins empty into R atrium instead of L atrium
Total anomalous pulmonary venous return (TAPVR)
Blood flow in TAPVR
Pt has an ASD to allow R to L shunting so mixed blood can be pumped to the L side of the heart and out the aorta
Problems with TAPVR
- Congested pulmonary vasculature
- Low SpO2 and a possible compensating polycythemia
- Postop cardiac output may be compromised
- Prone to postop pulmonary hypertension
Management for TAPVR
- Limit pulmonary blood flow/increase R to L shunting by increasing PVR and decreasing SVR
- Postop inotropes to prevent low cardiac output and pulmonary hypertension
- Change reverse course on PVR and try to lower PVR (nitric oxide)
Condition where the patient has severely underdeveloped left heart structures that are incapable of pumping blood to the body
Hypoplastic L heart syndrome
Structural significance of HLHS
- Underdeveloped L ventricle
- Very small or closed mitral and aortic valves
- Stenotic ascending aorta
Blood flow in HLHS
- Blood from L atrium shunts into R atrium across ASD, R ventricle pumps blood into aorta through PDA, ASD and PDA are necessary to get any CO
- Blood from L atrium is oxygenated, mixed with deoxygenated blood in R atrium
- From R ventricle, blood can go into lungs or through PDA
In HLHS, anytime pulmonary blood flow is increased, cardiac output will ____
decrease
In HLHS, anytime pulmonary blood flow is decreased, cardiac output will ___
increase
Problems with HLHS
- The R ventricle is completely overworked
- Pt receives way too much pulmonary blood flow
- Cardiac output is severely reduced
- Low SpO2 and terrible perfusion
Management of HLHS
- Keep the PDA open with PGE1
2. Limit pulmonary blood flow by keeping FiO2 low and avoiding hyperventilation
When is supplemental oxygen controversial/contraindicated?
In HLHS because it will decrease cardiac output and exacerbate pulmonary congestion
What is the norwood procedure?
- For HLHS
1. R ventricle is attached to aorta to improve cardiac output and reduce blood flow to the lungs
2. Blaylock Taussig shunt is placed to allow pt to receive pulmonary blood flow (L to R shunt from brachiocephalic to pulmonary artery)
Blood flow after norwood procedure
- Overworked R ventricle pumping to both the lungs and the aorta
- Body perfused with mixed venous/arterial blood
What is the Bidirectional Glenn (Hemi-Fontan) Procedure?
- SVC is attached directly to pulmonary artery
2. BT shunt is removed
Benefits of the Hemi-Fontan procedure
- Allows blood to get to the lungs without a BT shunt
2. Greatly reduces the strain on R ventricle
What is the Fontan Procedure?
IVC connected to pulmonary artery
Blood flow after the fontan procedure
- Venous return completely bypasses the R side
- All blood flow to the lungs is passive (not pumped by R ventricle)
- The R ventricle is just pumping arterial blood
Management for Fontan Physiology
- Preload should be maintained and increases in pulmonary vascular resistance should be avoided
- For short operations, spontaneous ventilation is preferred as long as hypercarbia is avoided
- Invasive arterial and central venous monitoring is mandatory
Where does Protein Losing Enteropathy occur?
In Fontan patients
Condition where the tricuspid valve is more or less blocked
Tricuspid atresia
What must be present in tricuspid atresia
ASD and VSD
Problems with tricuspid atresia
- The R ventricle is severely underdeveloped and probably won’t be able to pump effectively
- The L ventricle is completely overworked
- Low SpO2 and a possible compensating polycythemia
- Pt will have too much pulmonary blood flow or not enough
In tricuspid atresia, an increase in PVR will ___ pulmonary blood flow and ____ cardiac output
Decrease, increase
In tricuspid atresia, a decrease in PVR will ____ pulmonary blood flow and ____ cardiac output
Increase, decrease
In tricuspid atresia, if the VSD is large and no pulmonary stenosis is present, pulmonary blood flow will be ____
excessive
In tricuspid atresia, if the VSD is small and/or pulmonary stenosis is present, pulmonary blood flow will be ___
reduced
Management of tricuspid atresia
- Depends on how much blood flow the lungs are receiving
- if blood flow to lungs is reduced, decrease PVR
- if blood flow to lungs is excessive, increase PVR
Surgical repair options for tricuspid atresia
- If blood flow to lungs is limited, pt can receive palliative BT shunt
- If increased pulmonary blood flow, palliative band around pulmonary artery
- Fontan procedure to decrease strain on L ventricle
Benefits on Fontan procedure in Tricuspid Atresia
- Decrease strain on L ventricle
- Allow patient to be perfused with oxygenated blood
- Allow a more reliable flow of blood into the lungs
Condition where pulmonary valve is more or less blocked
Pulmonary atresia
Necessary in pulmonary atresia for blood flow
ASD or VSD AND PDA
Problems with pulmonary atresia
- Blood flow to the lungs is obviously limited
- Pt perfused with mixed venous/arterial blood, low SpO2 and possible compensating polycythemia
- Pts may have symptoms of CHF due to volume overloaded ventricles
Management of pulmonary atresia
- Keep PDA open with PGE1
- Maintain/increase SVR and decrease PVR
- Give inotropes for CHF symptoms
Condition where aorta and pulmonary artery arise from the same trunk
Truncus arteriosus
Problems with truncus arteriosus
- L to R shunt exists
- R to L shunt exists
- Body is perfused with mixed venous/arterial blood
- Lungs will receive excessive blood flow
Management for truncus arteriosus
- Have an appropriate SVR to PVR ratio
2. Increase PVR if pulmonary congestion is present
Condition when the patient has defect of ASD, VSD and one atrioventricular valve in the middle of the heart, above the interventricular septum
Atrioventricular canal defect
Problems with atrioventricular canal defect
- L to R shunting is more prominent and the pt will have excessive pulmonary blood flow
- Pt is perfused with mixed blood
- Ventricles are most likely volume overloaded
Management for atrioventricular canal defect
- Take measures to limit pulmonary blood flow
2. Inotropic support may be necessary
Condition where the R ventricle supplies both the pulmonary artery and the aorta
Double outlet right ventricle
Blood flow with double outlet right ventricle
- VSD to allow oxygenated blood to get to R side of heart
2. Possible pulmonary stenosis
Problems with double outlet right ventricle
- R ventricle is overworked
2. Mixed blood perfusion (low SpO2 and possible compensating polycythemia)
Management for double outlet right ventricle
- If blood flow to lungs is reduced, decrease PVR
2. If blood flow to lungs is excessive, increase PVR
Abnormal development of the aortic arch that encircles the trachea and/or esophagus
Vascular rings
Vascular rings can lead to
- Tracheal compression
- Dyspnea
- Dysphagia
Anesthetic management for vascular rings
- Surgery accomplished via thoracotomy
- Smaller sized ETT, intubate with armored/reinforced ETT
- Extubation may be considered if tracheomalacia or stenosis is not anticipated
- Spontaneous ventilation recommended (pt may decompensate when neuromuscular blocking agents are given)
Means the heart is on the R side of the body
Dextrocardia
2 Types of dextrocardia
- Situs inversus (most common)
- reversal of abdominal organs, less comorbidities - Situs solitis
- normally positioned abdominal organs, more comorbidities
Management of dextrocardia
- Often prone to other defects
2. ECG leads, defibrillator pads/paddles should be placed in reverse position in these patients
What is ductal dependent systemic blood flow?
PDA is required for adequate systemic blood flow to occur (blood flow to extremities is coming from R side of the heart through a PDA)
What does a patient need to have ductal dependent systemic blood flow?
Left ventricular outflow tract obstruction (interrupted aortic arch, HLHS)
Symptoms of patients with ductal dependent systemic blood flow
- CHF and pulmonary edema
2. Higher preductal blood pressure and SaO2 (compared to postductal)
What does it mean if a patient has ductal dependent pulmonary blood flow?
A PDA is required for adequate pulmonary blood flow to occur (blood flow is shunting L to R across the PDA like normal)
What does a patient need to have for ductal dependent pulmonary blood flow?
Right ventricular outflow tract obstruction (Tetralogy of Fallot, pulmonary atresia)