Peds Test 4

Question 1

Shunt Blood Flow Eq.

Answer 1

Qp/Qs= (SaO2-SvO2)/(Sat PV - Sat PA)
>1 = L to R (pulm hypertension/failure), shunt >1.8 needs surgery 
<1 = R to L (cyanotic)

Question 2

Cardiac Separation Development Days

Answer 2

separation days 27-37
out flow tract day 29
only interior changes

Question 3

Atrial Septum Anatomy (sides and holes)

Answer 3

Left side= septum primum= osmium secundum

Right Side= septum secundum= foramen ovale

Question 4

Atrial Septal Defects 4 Types

Answer 4

1) Ostium Secundum (most common)- failed growth of septum secundum OR reabsorbed of septum premium = L to R, dilates right heart
2) Patent Foramen Ovale (PFO)- foramen ovale doesn’t close, little hemodynamic consequences
3) Ostium Primum- failed fusion of cushions, located low on septum, often seen with cleft in mitral anterior leaflet
4) Sinus Venosus- hole where SVC/IVC meets RA, normally with partial anomalous venous return (PAPVR)- pulm veins return to RA instead of LA

Question 5

ASD Pathophysiology

Answer 5

• large ASD >9 mm= significant L to R shunt causing volume overload in RA and RV= pulm congestion and hypertension
• anything that increases LV pressure worsens L to R shunt (like systemic hypertension)
• Pulm Hypertension increases PVR after load and RV preload = could lead to right heart failure
• if pressure in RA gets to great, can reverse to a R to L shunt (Eisenmenger’s Syndrome!) causing cyanosis

Question 6

ASD Corrections

Answer 6

1) percutaneous closure (Amplatzer)- thru vein to RA
2) Surgical closure (primary vs patch)
CPB Considerations
-cannulate aorta and bicaval
-vent
-antegrade 1 dose, 10-15 min pump run

Question 7

Ventricular Separation Anatomy

Answer 7

• muscular ridge- grows upward at inter ventricular foramen

- membranous, grows from top down

Question 8

VSD Types

Answer 8

membranous- 75%- close to AV node near valves- can close any time
muscular- 20%- 4 locations; anterior, midventricular (most common), post, apical- normally close by 2 yo
supracristal (outflow)- 5% = VSD below out flow tract valves
—crista supraventricularis= infudibular/conus ventricular septum= separates tricuspid/pulm valves, more superior placement of pulm valve to aortic valve, provides muslcar support for aortic valve (right coronary cusp)
also at inlet- near mitral valve

Question 9

VSD Pathophysiology

Answer 9

L-R shunt= pulm= back to LV= circle
=LV overload, continue L to R
-bigger shunt compared to ASD (cuz bigger pressure difference)

Question 10

VSD Corrections

Answer 10

1) Percutaneous (Amplatzer)
2) Surgical- primary vs. patch
CPB Considerations
-aortic and bicaval
-vent
-antegrade with 1 dose
-cool to 32 degrees, quick case

Question 11

3 Names for AVSD

Answer 11

AVSD= atrio-ventricular septal defect
ECD= endocardial cushion defect
AVC= atrio-ventriuclar canal defect
-failure for cushions to form, fibroblasts don’t migrate to form AVC (day 34-36)= septum and valves abnormal
-cushions normally form = septum primum, valves, inlet to ventricular septum
==ASD, VSD (L to R), common valve
===high pulm flow and pulm vascular obstruction disease

Question 12

AVC Epidemiology

Answer 12

• AVSD #5 most common occurring CHD (5% or .4/1000 births) –total CHD 8/1000
• 40-50% with down syndrome (other TOF, DORV, SAS)
• patients with heterodoxy (organs on opp sides)= 60% have AVSD
• if repaired at 4-6 months >80% survival (may survive longer if high PVR= lower L-R shunt= high LVEF

Question 13

What formations are wrong in AVC

Answer 13

• deficient atrial primum septum, ventricular septum, septal leaflet of tricuspid, anterior leaflet of mitral
• AV valves can be not is correct position
• anterior leaflet expands across septum
• the valve can open to a preferred side= hypoplasia

Question 14

AVSD Classifications

Answer 14

1) Complete (CAVSD)- ASD, VSD, common valve
2) Transitional (TAVSD)- ASD, VSD, 2 valves
3) Partial (PAVSD)- ASD, no VSD, 2 valves
- 2 valves= cleft mitral valve= regurg, AV node, coronary sinus shift and PDA, persistent left SVC

Question 15

Palliation for excessive pulmonary BF

Answer 15

PA Banding= increases PVR=lowers pulm BF/overscirculation = lowers pulm damage

• complications- movement of band, erosion into lumen, distorting valve, sub annular ventricular hypertrophy
• used mostly with balanced

Question 16

Palliation for insufficient Pulmonary BF

Answer 16

• can be caused by TOF, AVC, left unbalanced (small right)
• make arterial to pulmonary artery shunt
  1) Blalock-Tausig Shunt= right subclavian artery to pulm artery (not artificial); modified= any systemic artery to pulm artery (or with artificial graft)
  2) Central Shunt= aortic root/ascending aorta to pulmonary artery

Question 17

2 Types of complete Repair

Answer 17

1) Bi-ventricular Repair= for balanced RV and LV normal function
- close ASD with pericardial patch
- close VSD with synthetic or bovine patch
- suture/cut cleft of mitral valve
2) Uni-ventricular Repair= single ventricle or left unbalanced (small right)
- goal= separate pulm/venous outflow tracts and ensure venous blood goes through pulm system

Question 18

3 Stages of Uni-ventricular Repair

Answer 18

1) Blalock-Taussig Shunt- first few days of birth
-subclavian (or brachiocephalic) artery to pulm artery
=establishing flow to lungs to get oxygenated
2) Bi-Directional Glenn Procedure- within 4-6 months
-remove BT shunt/PA band
-connect SVC to right PA (1/3 of venous return straight to pulm)
-cut pulm trunk and SVC
3) Fontan Completion- 2-3 years old
-connect IVC to right PA (via tunnel within RA, lateral tunnel fontan/atrial baffle OR outside RA, extra cardiac fontan)
-NEED BYPASS for Fontan

Question 19

Bypass with AVC

Answer 19

Palliation
- PA band, PT shunt= stand by
- Central= on or off
Biventricular
-cannulate aorta/bicaval, vent thru pulm veins into LV, multiple antegrade doses
Fontan- single atrial and aortic