Peds Test 4 Flashcards
Shunt Blood Flow Eq.
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)
Cardiac Separation Development Days
separation days 27-37
out flow tract day 29
only interior changes
Atrial Septum Anatomy (sides and holes)
Left side= septum primum= osmium secundum
Right Side= septum secundum= foramen ovale
Atrial Septal Defects 4 Types
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
ASD Pathophysiology
- 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
ASD Corrections
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
Ventricular Separation Anatomy
- muscular ridge- grows upward at inter ventricular foramen
- membranous, grows from top down
VSD Types
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
VSD Pathophysiology
L-R shunt= pulm= back to LV= circle
=LV overload, continue L to R
-bigger shunt compared to ASD (cuz bigger pressure difference)
VSD Corrections
1) Percutaneous (Amplatzer)
2) Surgical- primary vs. patch
CPB Considerations
-aortic and bicaval
-vent
-antegrade with 1 dose
-cool to 32 degrees, quick case
3 Names for AVSD
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
AVC Epidemiology
- 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
What formations are wrong in AVC
- 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
AVSD Classifications
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
Palliation for excessive pulmonary BF
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
Palliation for insufficient Pulmonary BF
- 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
2 Types of complete Repair
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
3 Stages of Uni-ventricular Repair
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
Bypass with AVC
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
