Congential Heart Disease Flashcards
What is the ductus venosus?
Umbilical vein to inferior vena cava
Oxygen risk blood from the placenta bypasses liver
What is the foramen ovale?!
Right atrium to left atrium
Oxygen-rich blood bypasses lungs and is preferentially delivered to the heart and developing brain
***Takes severe days to close
What is the ductus arteriosus?
Pulmonary artery to descending aorta
***takes several weeks to close
What does the umbilical vein do?
Carries oxygen RICH blood from mother to fetus
What do the umbilical arteries do?
Carries oxygen poor blood from fetus to mother
What are the six different fetal circ differs from adult circ?
Placenta = lungs (organ of resp)
Circulation is in parallel (adult = series)
Right-to-left shunting
SVR is LOW ~ placenta provides wide vascular bed
PVR is HIGH ~ lungs are filled with fluid ~little pulmonary flow
Left atrium pressure is low
What happens when a baby takes it’s first breath?
Lung expansion > increase PaO2 & decrease in PaCO2 > decrease in PVR
***this decrease in PVR > reverses blood flow through ductus arteriosus > exposes the DA to ^ PO2 > DA closure
What happens when the placenta separates from the uterine wall?
Increase in SVR!
Decrease in PVR and increase in SVR > LA pressure > RA pressure ~ the flap valve of foramen ovale closes
How can the ductus arteriosus be closed if needed?
Indomethacine (a prostaglandin synthases inhibitor)
How can’t he ductus arteriosus remain open if need be?
Prostaglandin E1 (PGE1)
How does the ligamentum arteriosus play a role in trauma?
If a rapid deceleration tears the ligament, it could result in partial or complete Aortic dissection
Can the ligamentum venosum be re-opened?
No!
What are conditions that increase PVR?!
Hypothermia
Hypoxia
Acidosis
Light anesthesia
T berg
Pain
Vasoconstrictors
Hypercarbia
Atelectasis
When does a R > L shunt occur?
THIS IS A CYANOTIC SHUNT
When PVR > SVR
When does a L > R shunt occur?
THIS IS AN ACYANOTIC SHUNT
When SVR is > than PVR
What are some things that decrease PVR?
Alkalosis
Nitric oxide
Oxygenation
Hypocarbia
Hemodilution
Vasodilators
What is the pathophysiology behind a blue baby?
Decreased pulmonary blood flow
Hypoxemia
LV volume overload
LV dysfunction
What are the goal for a blue baby (R > L shunt)
Maintain SVR
Decrease PVR
>decrease hypoxia
> hyperventilate
> avoid lung hyperinflation
What are the 5 most common R>L shunts?
5 Ts!!!
Tetralogy of Fallot
Transposition of the great arteries
Tricuspid valve abnormality (Ebstein’s anomaly)
Truncus arteriosus
Total anomalous pulmonary venous connection
How is the rate of rise affected in a R>L shunt?
Slowed! ~ slower inhalation induction
***especially with less sociable agents (Des and nitrous)
How does a R>L shunt effect IV induction?
Bypasses the lungs and enters systemic circ FASTER!! FASTER ONSET
What is a Aycyanotic shunt?
L>R shunt
What is the pathophysiology behind a L>R shunt? (Pink baby)
Decreased systemic blood flow
> low CO
> hypotension
Increased PVR
> pulmonary HTN
> RVH
What are some of the Hemodynamic goals of a L> R shunt?
Avoid increases in SVR
Avoid decreases in PVR
> avoid alkalosis
> hypocapnia
> high FiO2
> vasodilators
What are the 4 most common L to R cardiac shunts?
Ventricular septal defect (most common)
Atrial septal defect
Patent ductus arteriosus
Coarctation of the aorta
How does a L>R shunt affect inhalation induction?
Negligible
How does a L> LR shunt affect IV induction?
Prolonged
What is Eisenmenger Syndrome?
Can occur when a patient with a L>R shunt develops pulmonary HTN. This increased right heart pressure causes a flow reversal through defect ~ leading to a R>L shunt! ***hypoxemia and cyanosis
What are the 4 defects of tetrology of Fallot?
Ventricular septal defect
Aorta that overrides the RV and LV
Pulmonic stenosis (obstruction for RV ejection)
RV hypertrophy
What are the goals in a patient with tetralogy of Fallot?
Increase SVR
Decrease PVR
Maintain contractility and HR
Increase preload
What is a “tet spell”?
Precipitated by increased sympathetic activity (crying, agitation, pain, defamation, fright, trauma) > increase myocardial contractility which can cause spasm of the infra-valvular region of the RVOT.
This increased resistance causes blood to flow through VSD > increased R>L shunting
What will a child do during a “tet spell?”
Child will hyperventilate and squat.
Squatting increases intraabdominal pressure > compresses abd arteries and increases preload, SVR and blood flow through RVOT
How can you treat a tet spell in the perioperative realm?
FiO2 100%
Administer fluids to expand volume
Increase SVR (Neo)
Reduce SNS stimulation (deepen anesthetic, beta blockers)
Avoid inotropes
Avoid excess airway pressure
Place infant in knee-chest position
What type of appearance is the heart of a patient with tetrology of Fallot on X-ray ?
Boot shaped!
What type of axis deviation with occur with tetrology of Fallot
What is the best induction agent with a patient with tetrology of Fallot?
Ketamine!
What narcs should be avoided in a patient with tetrology of Fallot?
Morphine
Meperidine
(Due to histamine release!!)
What happens to tetrology of Fallot patients who are consistently hypoxic?
They develop polycythemia
What are the 3 types of atrial septal defects?
Secundum: ASD occurs in middle of the atrial septum and results when fossa ovalis fails to close (80% of all ASDs)
Primum: ASD occurs in the lower region of the atrial septum ~ just above tricuspid valve
Sinus venosus: ASDs are located just below the IVC or above IVC
What is the most common type of ventricular septal defect?
Perimembranous
**located in the middle of the ventricular septum, just below the septal leaflet of the tricuspid valve
What is the most common type of cardiac anomaly in children?
Ventricular septal defect (VSD)
What is the most common congenital cardiac defect in adults?
Bicuspid aortic valve.
What are some early signs of an ASD?
What are some later signs of an ASD?
Early: exercise intolerance
Late: afib, aflutter, CHF
What is VSD associated with? (Congenital dx)
Trisomy 13, 18, 21
VACTERL
CHARGE
Where is the best place to measure BP in a patient with coarctation of the aorta?
Right upper extremity
What is coarctation if the aorta?
Narrowing of the thoracic aortic lumen ~ usually occurs before or after after ductus arteriosus, BUT occasionally it comes proximal to the subclavian 😳
When does preductal coarctation usually present?
Less common ~ present in the neonate!
When does postductal coarctarion usually present?
More common ~usually present in the adult!
What syndrome is strongly associated with coarctation?
Turner Syndrome
Due to the obstruction of blood flow at the level of the coarctation….?
LV afterload is increased!
SBP is elevated in upper extremities
SBP reduced in the lower extremities
What might be visible on CXR for a patient with Coarctation of the aorta?
Rib notching (this is due to increased vessel diameter)
What is epstein’s anomaly?
Downward (apical) displacement of the tricuspid valve ~ RV becomes part of the right atrium (atrialization)
**usually an ASD or PFO
What is transposition of the great arteries?
Each great vessel arises from wrong ventricles. This produces circulation in parallel instead of series
What are some traits about Epstein’s anomaly?
Most common defect of tricuspid valve
Tricuspid regurge can be intense
IV drug onset is prolonged (d/t pooling)
Risk of CHF
SVT is common
RV failure is common in postop
In transposition of the great arteries, what does the RV give rise to?
The aorta (poorly oxygenated circuit)
**systemic venous blood > RV > aorta > repeat
Does not circulate to the pulmonary system
In transposition of the great arteries, what does the LV give rise to?
Pulmonary artery (well-oxygenated circuit)
LV > lungs > repeat
Does not circulate to systemic
What type of emergency is transposition of the great arteries?
Medical!! Without fetal communication (I.e. pda or ASD) death is eminent.
May need prostaglandin to keep PDA open.
What is the definitely treatment for transposition of the great arteries?
Intra atrial baffle and arterial switch procedures
What is hypoplastic left heart syndrome?
Hypoplastic LV
Hypoplastic aortic arch
Mitral and Aortic stenosis or atresia
Ductal-dependent circulation
What is the surgical goal for hypoplastic left heart?
Separating the pulmonary and systemic circulations.
What are the 3 stages of surgical correction for hypoplastic Left heart?
Norwood stage 1
Norwood stage 2
Norwood stage 3 (Fontan procedure)
What is the Norwood stage 1?
Occurs in neonatal period
> aortic reconstruction ~ aortic arch rises from pulmonary trunk. Pulmonary arteries are disconnected from pulmonary trunk and are used to create a shunt from subclavian artery to RV
What is the Norwood stage 2? (Glenwood)
3-6 months of age
Shunt from first stage is taken down and a new connection is made between the SVC and pulmonary arteries
What is the Norwood 3 (fontan procedure)?
The IVC is connected to the pulmonary artery with a conduit
How is the circulation system after Fontan completion?
Patient has single ventricle that pumps blood into systemic circ while pulmonary blood flow occurs passively from SVC/IVC to the pulmonary artery
How does PVR affect blood flow in the hypoplastic heart?
Increased PVR is detrimental to pulmonary flow
> Spontaneous breathing is best!
positive-pressure vent is bad (avoided)
patients are PRELOAD dependent
What is truncus arteriosus?
Characterized by a single artery that gives rise to the pulmonary, systemic, AND coronary circulations.
