TEST 2 Flashcards
During fetal circulation: PVR is _____________ (the lungs are bypassed) and SVR is ___________
PVR is HIGH
SVR is low
During fetal circulation _____ is high and _____ is low causing a _______ to _______ shunt
PVR
SVR
R to L shunt
During fetal circulation; Foramen ovale; blood shunts from ___ to _____?
RA to LA
Connection between PA and Aorta?
Ductus Arteriosus
- Characteristics of Hypoplastic Left Heart Syndrome?
- Very small LV
- Mitral and aortic valve stenosis/atresia
- Hypoplastic aortic arch
- Pulmonary blood flow (BF) from LA via ASD to RA/RV
- Single ventricle (RV)
- Systemic BF from RV to PA to aorta via PDA
Hypoplastic Left Heart Syndrome (HLHS) have patent ________ and _______ and have _______ LV
Patent ductus Arteriosus
Patent foramen ovale
Hypoplastic left ventricle
If mitral valve is completely stenosed what is it called?
Atresia
What kind of defect do you need with HLHS?
ASD; have to have atrial septal defect because road block in the LA.
How often is HLHS diagnosed?
2/10,000 live births
When is HLHS usually diagnosed?
At birth usually diagnosed prenatal
What do HLHS patient present with? (4 S\S)
Tachypnea
Tachycardia
Systolic murmur
Cyanosis
What side of the heart is underdeveloped in HLHS?
The L side of the heart is underdeveloped
What are the 3 procedures that can convert the HLHS into a single- ventricle type circulation? And when are they performed?
- Norwood: neo- aorta and BT shunt (within days after birth)
- Bidirectional Gleen: passive pulmonary BF from SVC (within 6 mo of age)
- Fontan: passive pulmonary BF from SVC and IVC (within 1.5-3 years of age)
Norwood stage operation is the creation of _______ and placement of ____ shunt for passive/active pulmonary blood flow.
Neo- aorta
BT
Passive
Norwood is the reconstruction of ________ in neonatal period
Neo- aorta
What arteries are disconnected from the pulmonary trunk in the HLHS- Norwood?
The pulmonary arteries are disconnected from the pulmonary trunk
In the Norwood HLHS the only blood supply to the lungs is provided from either a shunt from __________ artery (Blalock- Taussig shunt) or from the R/L ventricle (Sano modification)
Are these shunts considered passive or active and what are they dependent on?
Subclavian artery
Right ventricle
Passive blood from what and dependent on pressures
After the HLHS Norwood are patients still cyanotic?
Yes SpO2 70’s- 80’s
What is the general anesthetic technique for Norwood anesthesia considerations?
High dose opioid techniques
Where is venous access typically for the Norwood anesthesia?
Venous access often via femoral vein; avoid internal Jugular vein for future Glenn Shunt
What is common after Norwood procedure?
Post op myocardial dysfunction
After Norwood procedure it is hard to balance SVR and PVR after CPB usually require 3 medications?
Milrinone
Epinephrine
Dopamine
How long does the sternum stay open after a Norwood procedure?
Several days post op
When does the Glenn operation take place?
6 months of age
What happens during the Glenn operation?
The BT shunt is taken down and a new connection is created from the SVC to the PA
What is a result of the Glenn shunt?
Pulmonary blood supply that is provided by systemic venous blood from the SVC.
After the Glenn shunt is flow passive or active and what does it depend on?
Flow is passive and depends on pulmonary arterial pressures
The infant remains cyanotic after the Glenn shunt with arterial saturations in the mid _______ because desaturated/saturated blood from the IVC continues to flow into the heart and ______ circulation
80’s
Desaturated
Systemic
What does the Fontan surgery involve?
Connecting the IVC to the PA via extracardiac or intracardiac conduit to create a single ventricle circulation (Fontan)
After the Fontan where does the RV pump blood?
The single RV pumps blood to the systemic circulation
After the Fontan procedure where and how is the pulmonary blood supplied?
Provided by passive flow from SVC and IVC
In the Fontan procedure it is common for a small hole to be created between the _________ conduit and the ______ so that if PVR/SVR rises, blood will be directed to the RA/LA and allow cardiac output to be maintained.
Extracardiac
RA
PVR
RA
What does the fenestration between the extracardiac conduit and the RA prevent?
A state of low CO
Even after the Fontan procedure what do these kids need for long term?
Heart transplant because the RV (the only ventricle that fails) over time
Post op Fontan what must remain very balanced?
PVR must remain very balance post operatively
Post op Fontan, in order to maintain PVR, we must minimized?
To minimize atelectasis
What is occasionally required after Fontan procedure to maintain PVR?
Nitric oxide
If an inotropy is required what is a good choice d/t its beneficial effects on PVR post op fontan?
Milrinone
What is beneficial in terms of hemodynamic post op fontan?
Early extubation
What are 2 anesthetic considerations with HLHS?
- Essential to maintain the balance of PVR and SVR
2. Oxygen is a drug and should be used cautiously in congenital heart disease patients
3 ways FiO2 influences PVR?
- Hypoxia causes pulmonary vasoconstriction but causes systemic vasodilation
- Hypoxia and acidosis are potent stimuli for increase in PVR
- Reversely, high FiO2 will cause a significant decrease in PVR and potentially increased blood flow toward the lungs and away from systemic circulation
In some HLHS children (who present for a Norwood procedure) excessive blood flow to the lungs resulting from a significantly high/low PVR and a relatively high/low SVR steals blood from systemic circulation, leading to hypotension/hypertension, myocardial ischemia and progressive acidosis.
Low PVR
High SVR
Hypotension
Why is it dangerous to administer high FiO2 to an HLHS patient?
Because it can decrease PVR
If the PVR is greater than SVR what happens to the patient?
The child develops progressive desaturation
It can be difficult to manipulate SVR and PVR predictably -> PVR is well understood and vasoactive drugs work on both circulations. T/F?
False PVR is not well understood
Potent volatiles reduce ______ more than _______.
SVR
PVR
PVR is decreased in in children by increasing/decreasing FiO2 (100%) and during hyperventilation
Increasing
Low ETCO2 causes a increase of PVR. T/F
False; causes a decrease
PVR is increased with what 4 things?
- PEEP
- Acidosis
- Hypothermia
- Low FiO2 (30% or less)
Phenylephrine increases SVR/PVR more than SVR/PVR?
What shunt will it reduce and what shunt will it increase?
Increases SVR more than PVR
Reduces R->L shunt
Increases L-> R shunt
7 factors that increase PVR?
- Hypoxemia
- Hypercapnia (increase ETCO2 causes increase in PVR)
- Academia
- Hypothermia
- Atelectasis
- Transmitted positive airway pressure
- Stress response/ stimulation/ light anesthesia
2 anesthesia considerations with HLHS?
- Keep neonate spontaneously breathing with FiO2 of 21 % and prostaglandin E1 infusion to maintain ducal patent (to keep PDA open)
- Keep normal/high PaCO2
What are prostaglandins?
Naturally occurring hormone- like substance (it circulates in the fetus’ bloodstream and keeps the ductus Arteriosus DA open)
What happens to prostaglandins after birth?
They decrease plus increased oxygen tension will close the ductus Arteriosus
What can you give to maintain patent PDA?
Prostaglandins
What can you give if PDA is undesired?
Give Indomethacin or PDA ligation
What prostaglandin maintains patency of ductus Arteriosus?
E1
When does prostaglandin E1 maintain patency of ductus arteriosus?
When the body is supplied by R -> L ducts flow such as:
Cases of interrupted aortic arch
Critical aortic stenosis
HLHS
The PDA can supply pulmonary blood flow from the aorta to the lungs in lesions such as what? (3 things)
- Pulmonary atresia
- Tricuspid atresia
- Severe tetrology of Fallot
Subacute bacterial endocarditis antibiotic prophylaxis is suggested for children that are?
High risk
Subacute bacterial endocarditis prophylaxis: Amoxicillin PO
50 mg/kg
Subacute bacterial endocarditis ampicillin IM/IV dose?
50 mg/kg
Subacute bacterial endocarditis cefazolin IM/IV dose?
50 mg/kg
Subacute bacterial endocarditis for ceftriaxone IM/IV dose?
50 mg/kg
What is an appropriate abx if pt is allergic to PCN/Ampicillin?
Clindamycin IV 20 mg/kg
When are air bubbles very dangerous in children?
In children with R -> L shunts
Air bubbles are very dangerous in children with R -> L shunts because it is shunted directly into ___________ circulation.
Systemic
Patients with L-> R shunts can transiently reverse their shunts during _______ or __________ when the normal trasarterial pressure gradient is reversed.
Coughing
Valsalva
What is the induction agent of choice in pediatric anesthesia?
SEVO
At what MAC can Sevo SLO’s the HR and cause respiratory depression?
> 1.5 MAC
What is the “Hole” in the atrial septum =connecting with RA with LA -> because PVR is HIGH, blood shunts from _______to ________ (bypassing the lungs)
Foramen ovale
Right to Left
What is the connection between Pulmonary artery and aorta = blood flows from RA -> tricuspid valve into the RV - PA -> bypasses the lungs again to take a shortcut to the ________________ (systemic circulation)?
Ductus arteriosus
Aorta
After birth, the neonate takes its first breaths, the lungs inflate and PVR _______ while the placenta is disconnected and blood is not drained back to mom ___________ SVR.
Reduces PVR
Increasing SVR
With decreasing PVR, increasing SVR, blood flow becomes EASIER/DIFFICULT into the _________ and becomes oxygenated.
EASIER
Lungs
The increased pressure in the LA (compared with RA) pushes the flap of the _______ _________ shut.
Foramen ovale
The increased pressure in the aorta allows some “back flow” of blood via __________ __________ back into the pulmonary artery (PA) which causes additional _______ of the blood.
Ductus arteriosus
Oxygenation
After birth: eventually the __________ changes within the two circulation and reduced levels of __________ causes the closure of ductus arteriosus and foramen ovale within days after birth.
Pressure changes
Prostaglandins
Prostaglandins are naturally produced by the _____ and available for the fetus during _____. Some congenital heart disease where it is absolutely imperative to keep the DA open. Having _______ keeps the DA and FO patent.
Mother
Pregnancy
Prostaglandin
What is a “hole” within the atrial septum between RA and LA?
Atrial Septal Defect (ASD)
What is the “hole” within the ventricular septum = between RV-LV?
VSD = ventricular septal defect
What kind of shunt is due to higher pressure in the left heart, blood flows back to the right hear via ASD/VSD, causing increased blood flow in the lungs = pulmonary congestion which can lead to ________?
Left to right shunt
Pulmonary HTN
What kind of shunt is occurring when the blood bypasses the lungs because of obstruction to the lungs (ie pulmonary stenosis) -> blood flows through ASD/VSD or both systemic side =________?
Right to Left shunt
Cyanosis
What occurs in “simple” left to right shunt? And List the 4 congenital heart disease
Increased pulmonary blood flow
ASD (Atrial Septal Defect)
VSD (Ventricular Septal Defect)
AVSD (Atrioventricular Septal Defect)
AP window (aortapulmonary window)
What occurs in “simple” right to left shunt? List the 4 congenital heart disease.
Decreased pulmonary blood flow -> CYANOSIS
TOF (Tetrology of Fallot)
Pulmonary atresia
Tricuspid atresia
Ebstein anomaly (congenital malformation of tricuspid valve)
What occurs in complex shunts? List the 4 Congenital Heart Disease.
Mixing of pulmonary and systemic blood flow with CYANOSIS
TGA (Transposition of great arteries)
Truncus arteriosus
DORV (Double outlet RV)
HLHS (Hypoplastic Left heart Syndrome)
List 4 obstructive lesions.
Pulmonary stenosis
Aortic Stenosis
Mitral stenosis
Coarctation of Aorta
__________ ASD is causing a left to right shift through the defect.
Secundum
What defect is common heart defect in children (10% of CHD)?
Secundum ASD