Pediatric Cardiac Anesthesia Flashcards
Name the three branches of the aortic arch.
- Brachiocephalic (Innominate) Artery
- Left common carotid artery
- Left subclavian artery
What two arteries does the brachiocephalic artery split into?
- Right common carotid artery
- Right subclavian artery
What percentage of ventricular output will go to the lungs with a fetal heart?
5-10%
Limitation of blood flow to the lungs in a fetus is due to high __________.
PVR
How does blood flow bypass the lungs in a fetus?
- Foramen Ovale
- Ductus Arteriosus
What other organ has limited blood flow besides the lungs in a fetus?
Liver
How does blood flow bypass the liver in a fetus?
Ductus Venosus
Fetal Circulation Chart
Fetal Circulation Chart
What are three major changes in blood flow at birth?
- Marked decrease in PVR
- Increase blood flow through pulmonary veins
- Decrease placental blood flow
During birth, as blood flow to the lungs increases, what happens to Alveolar PCO2 and Alveolar PO2?
- Alveolar PCO2 Decreases
- Alveolar PO2 Increases
Usually occurs within minutes after birth
During birth, as blood flow increases through the pulmonary veins, ________ pressure becomes higher than ________ pressure.
During birth, as blood flow increases through the pulmonary veins, LEFT ATRIAL PRESSURE becomes higher than RIGHT ATRIAL PRESSURE.
During birth, as blood flow increases through the pulmonary veins, the atrial septum closes over the _____________.
Foramen Ovale
The foramen ovale is anatomically patent in _____% of children less than five years old.
50%
What happens to SVR as placental flow ceases during birth?
SVR increases
What happens to IVC flow and RA Pressure as placental flow ceases during birth?
- IVC flow decreases
- RAP decreases
What happens to the blood flow through the ductus arteriosus as placenta flow ceases during birth?
Blood flow through the ductus arteriosus reverses and fills with oxygenated blood.
What substances can be given to keep the ductus arteriosus open?
Prostaglandin
The ductus arteriosus is mostly closed by day ________ and usually completely closed by day _________.
- Mostly closed by day 2
- Completely closed by day 7
What communicates between the placenta, portal vein, and IVC?
Ductus Venosus
As the ductus venosus remains patent for several days after birth, how does this affect metabolism?
Delays Metabolism d/t reduce liver circulation
Fetal to Neonatal Circulation Chart
Fetal to Neonatal Circulation Chart
During transitional circulation, if hypoxia occurs, what will happen to PVR?
PVR increases
During transitional circulation, what will happen to the foramen ovale and ductus arteriosus if hypoxia occurs?
Foramen Ovale and Ductus Arteriosus may reopen → will cause a significant proportion of blood to bypass the lungs
List conditions that can prolong transitional circulation
- Prematurity
- Pulmonary Disease
- Hypothermia
- High Altitude
- Prolonged Stress
- Sepsis
- Acidosis
- Hypercarbia
- Congenital Heart Disease
What is unique about the RV wall of the neonatal heart?
RV wall thickness exceeds LV wall
What is the degree of axis of a neonatal heart?
180 degrees
30-90 degree axis for standard heart
Neonatal hearts have less contractile tissues, how does this affect SV and and CO?
- Limited SV d/t ↓ compliance
- CO will be rate-dependent
Why would a neonatal heart be more sensitive to CCB Drugs or Citrated Blood?
Immature myofibrils and sarcoplasmic reticulum will result in underdeveloped calcium handling mechanisms.
Due to neonatal hearts having immature myofibrils and sarcoplasmic reticulum, calcium exchange will be more dependent on the _____________-
Sarcolemma
Why does stress cause a compromised CO in a neonatal heart?
Immature Autonomic Innervation
What are the 4 types of congenital cardiac defects?
- Shunts
- Mixing Lesions
- Flow Obstructions
- Regurgitant Valves
What are the two categories of cardiac shunts?
- Intracardiac Connections (Opening between chambers)
- Extracardiac Connections (Opening between a systemic and pulmonary artery)
In Atrial Septal Defects (ASD) what is the direction and magnitude of blood flow related to?
- Ventricular Compliance
- AV Valve Function
In VSD and PDA what is the direction and magnitude of blood flow related to?
- Resistance of the Pulmonary System
- Resistance of the Systemic System
Is a Left-to-Right Shunt an Acyanotic or Cyanotic Heart Defect?
Acyanotic Heart Defect
Describe the PVR in a Left-to-Right Shunt.
Low PVR
Is a Right-to-Left Shunt an Acyanotic or Cyanotic Heart Defect?
Cyanotic Heart Defect
Pulmonary Blood Flow in Left-to-Right Shunt.
Pulmonary blood flow increases d/t low PVR → Volume overload for lungs
Effects on the LV from a Left-to-Right Shunt.
- Less blood flow to the LV
- Increase workload of LV to maintain adequate CO
Examples of Left-to-Right shunt
- ASD
- VSD
- PDA
- Coarctation of the Aorta