1. Acyanotic congenital heart defects like ventricular septal defects (VSD), atrial septal defects (ASD), and atrioventricular septal defects involve left-to-right shunting that can cause pulmonary overcirculation and congestion over time. 2. During anesthesia for repairs of these defects, careful attention must be paid to balancing systemic and pulmonary vascular resistances to avoid increasing or decreasing the shunt. Inhalational induction is relatively contraindicated due to risk of shunt reversal and cyanosis. 3. Intravenous induction with ketamine or etomidate is preferred for acyanotic left-to-right shunt defects to gradually control hemodynamics

1. PEDIATRIC
ANESTHESIA AND
CARDIAC PROBLEMS
BY SHRIDEVI SHAH MD

3. Fetal Circulation
• The key features of fetal circulation are shown in Figure and listed
below:
• 1. Low systemic vascular resistance (SVR) secondary to the low-
resistance placenta
• 2. High PVR secondary to fluid-filled lungs and a hypoxic
environment
• 3. Minimal pulmonary blood flow and low left atrial pressure
4. High pulmonary artery pressure
•
5. The most oxygenated blood from the umbilical vein perfuses the
brain and heart, bypassing the liver via the ductus venosus and
bypassing the right ventricle via the foramen ovale.
•
6. High PVR forces most right ventricular output across the ductus
arteriosus into the descending aorta, allowing deoxygenated blood to
return to the placenta.

4. Transitional Circulation-Changes at
Birth
• Cord clamping initiates breathing and causes
inflation of lungs with air which in turn causes
changes in resistances within the system. Cord
clamping also removes the low resistance
placenta from the circulation and so increase
SVR.
• Increased oxygen tension in lungs causes PVR
to decrease
• On cord clamping flow through ductus venosus
ceases. Permanent closure of ductus arteriosus
takes weeks

5. Fetal Circulation
– Not in series as in
adults
– Right heart dominant
(65% CO from RV;
35% from LV)
– Lung flow 8%, Brain
20%, Coronaries 3%
– Fetal heart pumps
55% BV through the
placenta and acts as
fetal lung

7. Normal Values of Intracardiac Cardiac and Vascular
Pressures (in mm Hg)
Location
Term Newborns Infants and Children
Right atrium m = 0-4
a = 5-10
v = 4-8
m = 2-6
Right ventricle 35-50/1-5 15-25/2-5
Pulmonary artery
35-80/20-50
m = 25-60
15-25/8-12
10-6
Pulmonary wedge m = 3-6
a = 6-12
v = 8-15
m = 5-10
Left atrium m = 3-6
a = 6-12
v = 8-15
m = 5-10
Left ventricle 80-130/5-10
Systemic artery
65-80/45-60
m = 60-65
90-130/60-80
m = 70-95

8. Congenital Heart Diseases
• #1 cause of common congenital diseases (30%)
• Diagnosed by fetal US or echo if suspected after
birth (50% diagnosed during 1st week of life, the
rest before age 5)
• S/s: dyspnea, slow physical development (FTT),
cardiac murmur
• Chromosomal abnormalities- 10% congenital
(trisomy 21)
• 90% are genetic with or without external factors
(rubella, ETOH abuse, lithium, maternal DM)

10. Classification of Congenital Heart
Diseases
Acyanotic Defects (L to R
shunts)
• VSD
• ASD
• PDA
• Pul stenosis
• Aortic Stenosis
• CoA
• Atrioventricular septal
defect
Cyanotic Defects (R to L
shunts): 5 T’s
• TOF
• Transposition of Great
Vessels
• Truncus Arteriosus
• Tricuspid Atresia
• Total Anomalous
Pulmonary Venous
Return
• HLHS

11. Classification of Congenital Heart Lesions and Associated Repairs
Lesion Type Repair
Shunt Lesions
Left-to-Right
• Atrial septal defects Complete repair
• Ventricular septal defects Complete repair
• Atrioventricular canal defects Complete repair
• Patent ductus arteriosus Complete repair
• Aortopulmonary window Complete repair
Right-to-Left
• Tetralogy of Fallot Complete repair
• Ebstein's anomaly Complete repair
• Pulmonary stenosis in conjunction with atrial
or ventricular septal defects Complete repair
• Eisenmenger's syndrome No repair
Transposition Physiology
• Dextro-transposition of the great arteries Complete repair
Single-Ventricle Physiology
One-Ventricle Lesions
• Hypoplastic left heart syndrome Staging to Fontan
• Tricuspid atresia Staging to Fontan
• Double inlet left ventricle Staging to Fontan
Two-Ventricle Lesions
• Truncus arteriosus Complete repair
• Tetralogy of Fallot with pulmonary atresia Complete repair
• Severe neonatal aortic stenosis Complete repair

12. LeftVentricularObstructive Lesions
Mitral Stenosis
• Valvular Completerepair
• Cortriatriatum Completerepair
Aortic Stenosis
• Valvular Completerepair
• Subvalvular(subaortic membrane) Completerepair
• Supravalvular(Williams-BeurenSyndrome) Completerepair
Coarctation
• Shone's syndrome (mitral stenosis, aortic stenosis, Repair withlikely
coarctation) residual lesions
Mixing ofSystemicand PulmonaryVenousBlood with SeriesCirculation
• Partial anomalous pulmonary venous return (PAPVR) Completerepair
• Total anomalous pulmonary venous return(TAPVR) Completerepair

13. Factors Influencing Outcome and
Anesthetic Risk
• Defect and type of repair
• Shunting
• Ventricular dysfunction
• Ventricular outflow obstruction
• Hypoxemia and cyanosis
•
Rhythm and conduction abnormalities
• Pulmonary hypertension and Eisenmenger's syndrome
• Myocardial ischemia
• Infective endocarditis
• End-organ dysfunction and injury
• Extracardiac anomalies
• Heart transplant recipients

14. Defect and Type of Repair
• Anatomic repair – morphologic left ventricle is
connected to the aorta, and morphologic right
ventricle is connected to the pulmonary artery,
the circulation is in series, cyanosis is corrected
• Physiologic repair- the heart is either
univentricular or biventricular with the
morphologic right ventricle being systemic
ventricle and morphologic left ventricle being
pulmonary ventricle, circulation is in series and
cyanosis is relieved

15. Anesthetic Considerations
• Simple anatomic repair- near normal
hemodynamics with structurally normal heart
• Complex anatomic repair- pose more
anesthetic risk
• Physiologic repair- always palliative, associated
with progressive ventricular dysfunction

16. Shunting
• Physiology-oxygenated blood to lungs with L to
R shunt and deoxygenated blood to systemic
circulation with R to L shunt
• Factors influencing degree and direction of
shunting- size of shunt orifice, pressure
gradient between chambers, relative
compliance of ventricles, ratio of PVR
/SVR,blood viscosity

17. Anesthetic Considerations
• Avoidance of air bubbles to prevent
systemic embolization
• Attention to pulmonary vascular tone and
its influence on PVR/SVR.

18. Ventricular dysfunction
• Most common cause of disability and
death in patients with CHD
• Ventricular volume overload secondary to
L to R shunt,valvular regurgitation and
single ventricle lesions
• Ventricular pressure overload secondary
to ventricular outflow obstruction
,increased PVR

19. Anesthetic considerations
• Carefully integrate historical, physical and
diagnostic test to judge the degree of ventricular
dysfunction
• Consider prophylactic inotrope perioperatively
• Appropriate fluid administration
• Suitable anesthetic techniques to maintain
contractility and hemodynamics
• Positive pressure ventilation improves function
of dysfunctional systemic ventricle by decreasing
afterload

20. Ventricular outflow obstruction
• May be subvalvar,valvar or supravalvar
• Results in a stiff ventricle(diastolic
dysfunction) and ultimately systolic
ventricular dysfunction
• LV obstruction-AS,Coarctation,variants of
HLHS
• RV obstruction-PS,TOF,Secondary to RV
to PA conduits,Rastelli procedure

21. Anesthetic considerations
• Pressure overload increases risk of
ischemia
• Maintaining sinus rhythm and preload is
vital to maintain CO
• Careful choice of induction and
maintenance agents i.e. inhaled agents vs.
narcotics

22. Hypoxemia and Cyanosis
• ETIOLOGY-Cyanotic lesions include
tricuspid atresia,TOF,TGA,Truncus
arteriosus,low cardiac output states
,increased a-v oxygen difference and
respiratory disease
• Chronic hypoxemia-polycythemia-
increased blood viscosity-increase PVR
and SVR,thrombocytopenia
• Increased risk of stroke

23. Anesthetic Considerations
• Maintain adequate preoperative hydration
• Consider measures to reduce red cell
mass if Hgb more than 20g/dl
• Expect coagulopathic states

24. Rhythm and conduction
abnormalities
• May be secondary to injury to SA node,AV node,
conduction system,atrial or ventricular
scarring,chamber dilation or hypertrophy and
ischemia
• Anesthetic considerations
• Careful workup on new onset of palpitations or
syncope for elective surgery
• Careful preop check on pacemakers and AICDs
• Consider temporary pacing for significant
bradycardias

25. Pulmonary Hypertension
• Mean PAP greater than 25 mm of Hg
• Increase in PVR-increased RV afterload and decreased
RV stroke volume-RV dilation-left shift of interventricular
septum –impaired filling of LV and finally decreased CO
and leading to ischemia
• Anesthetic considerations
• Consider adequate preop sedation, high inspired
oxygen,hyperventilation,maintain normal to increased
preload, early use of inotrope and careful choice of
anesthetics to maintain contractility
• Endotracheal intubation a potential trigger to pulmonary
vasoreactivity,avoid PEEP, use NO, consider continuing
pulmonary vasodilatiors

26. Acyanotic Defects (L to R):
VSD
• Intracardiac left to
right shunt
• Increased pulmonary
blood flow
• CHF secondary to
systemic and
pulmonary vascular
congestion
• Usually no cyanosis

27. Acyanotic Defects (L to R):
VSD
• Compare
inhalation and
intravenous
induction
methods for left
to right shunt

28. Acyanotic Defects (L to R):
ASD
• May occur anywhere
in the atrial septum,
most as spont genetic
mutations
• May be assoc with
MVP or MR
• Direction and
magnitude of the
shunt are determined
by the size of the
defect

29. Acyanotic Defects (L to R):
AV Septal Defect
• ASD, VSD, A-V
valvular insufficiency
• L to R shunting at the
atrial and vent levels
• Pul and Syst HTN
• Some infants have
palliative PA banding
• Most have total
correction

30. Acyanotic Defects (L to R):
ASD
Anesth considerations:
• Careful attention to
SVR, PVR during
induction and
maintenance
• Prophylactic
antibiotics
• Avoid air in IVs

31. Acyanotic Defects (L to R):
VSD
• Most common
congenital anomaly
• Most spontaneously
close by 2 years (30-
40%)
• S/s: asymptomatic,
feeding difficulty,
deceased exercise
tolerance, fatigue,
frequent URIs, CHF,
Pul HTN

32. Acyanotic Defects (L to R):
VSD
Anesth considerations:
• Avoid increases in SVR and decreases in PVR.
Why? How would 100% oxygen affect the
balance?
• IV induction is preferred (ketamine/etomidate
+fentanyl) or very slow low concentrations of
inh agents
• LVH and limited cardiac reserve- potential for
myocardial depression with inh agents
• Potential for shunt reversal with induction;
cyanosis on induction is confirmation

33. Acyanotic Defects (L to R):
PDA
• Continous flow of oxy
rich blood to the PA
• Detected during PE
• Most are
asymptomatic
• Uncorrected lesions
lead to CHF, Pul HTN
• 70% preterm infants
will require surgical
ligation

34. Acyanotic Defects (L to R):
PDA
• Ligation can be
performed in NICU
with a small left
thoracotomy incision
without CPB
• Risks: ICH, blood
loss, ligation of wrong
vessels, infections,
RLN damage

35. Acyanotic Defects (L to R):
PDA
Medical management:
• Cox inhibitors (indomethacin, ibuprofen)
inhibit prostaglandin synthesis

36. Acyanotic Defects (L to R):
CoA
• Narrowing of the aortic
lumen distal to the left SV
artery
• In older kids-post ductal
• In infants- pre ductal
• May occur with other
anomalies: bicuspid AV,
PDA, VSD, Turner
syndrome, MS or MR,
aneurysms of the circle of
Willis

37. Acyanotic Defects (L to R):
CoA
• Systemic circulation depends on shunting
• Medical management: PGE1 infused at
0.1mcg/kg/min to reopen the DA until the
severity of the CoA is assessed with echo
or cardiac MRI
• Surgical management: resection of the
CoA; balloon dilatation

38. Acyanotic Defects (L to R):
CoA
Anesth considerations:
• Maintain adequate
perfusion to the LE during
cross-clamping of the
aorta
• Aline in the right radial
artery (WHY?) and
femoral aline (where?)
• Gradient can be >40
mmHg

39. SINGLE VENTRICLE
PHYSIOLOGY
• Definition: presence of two atrioventricular valves with
one ventricular chamber
• Pathophysiology-Complex mixing of systemic and
pulmonary venous blood at atrial or ventricular level
• Correction involves three phases
I) Optimization of oxygen delivery and perfusion pressure
II) Reducing volume load on ventricle (glenn procedure)
III) Achieving series circulation with fully saturated
systemic arterial blood(fontan procedure)

40. Cyanotic Defects (R to L):
Teratology of Fallot
• What are the 4
components?

41. Cyanotic Defects (R to L):
Teratology of Fallot

42. Cyanotic Defects (R to L):
Teratology of Fallot
• “Tet” spells:
hypercyanosis period
associated with
hyperventilation and
syncope due to exertion
and drop in SVR
• Tet spell treatment:
prone, knee-chest
position, squatting,
supplemental O2,
morphine, propranolol,
phenylephrine

43. Cyanotic Defects (R to L):
Teratology of Fallot: Pre-op
• Hydrate prior to OR arrival
• Crying can precipitate hypercyanotic
attack
• Continue B-blockers

44. Cyanotic Defects (R to L):
Hypoplastic Left Heart Syndrome
• Uniformly lethal cardiac abnormality if not
surgically corrected
• Norwood procedure (stage I), the hemi-
Fontan or bidirectional Glenn procedure
(stage II), and the Fontan procedure
(stage III).

45. Cyanotic Defects (R to L):
Hypoplastic Left Heart Syndrome
• Norwood procedure (stage I)
first weeks of life
(1) creating an anastomosis
between the main pulmonary
artery and the aorta to provide
systemic blood flow
(2) placing an aorta–to–
pulmonary artery shunt (BTS) to
provide pulmonary circulation
(3) performing an atrial
septectomy to provide
unrestricted blood flow across the
atrial septum
.

46. Cyanotic Defects (R to L):
Hypoplastic Left Heart Syndrome
• Hemi-Fontan procedure (stage II) 6
months
(1) creating an anastomosis between
the superior vena cava and the right
pulmonary artery, so that venous
return from the upper body can flow
directly into both lungs.
(2) The aorta–to–pulmonary artery
shunt that was placed at stage I is
ligated.
(3) The superior vena cava–right
atrial junction is closed with a patch
that is removed during the next stage.
Blood from the inferior vena cava
continues to drain into the right atrium.

47. Cyanotic Defects (R to L):
Hypoplastic Left Heart Syndrome
• Fontan procedure (stage III) 12
months
(1) Atrial patch is removed
(2) A wall (baffle) is built in the
right upper chamber. The baffle
guides the blue blood to the
pulmonary arteries
(3) Small holes (fenestration) are
made in the baffle. This allows a
small amount of blue blood to go
across the baffle into the atria.
This hole works like a pop-off
valve in case the pressure in the
lungs gets too high.

48. Symptoms of significant CHF in
Infants
• Respiratory-
Tachypnea,Grunting,Flaring,Retractions,P
ulmonary congestion on chest x’ray
• Growth and Nutrition-
Poor feeding,Poor growth,Failure to thrive
• Cardiovascular-
Tachcardia,Diminished pulses,Decreased
peripheral perfusion,hepatomegaly

49. •ANESTHETIC
IMPLICATIONS OF
SPECIFIC PROBLEMS
FOR NONCARDIAC
SURGERY

50. ASD
Physiology – L to R shunt
Unrepaired- small to moderate defects well tolerated,A fib, Risk
of paradoxical emboli, large defects lead to arrhythmias, poor
exercise tolerance and rarely PHT
*Anesthetic consideration: De air IV line
VSD
Physiology
Unrepaired-large defects lead to PHT,Small to moderate defects
risk of endocarditis,sub-pulmonic or sub-aortic obstruction,
aortic regurgitation, right ventricular failure
*Anesthetic consideration: manage L to R shunt, or R to L shunt
Repaired-complete heart block,persitent PHT,dysrhythmia
*Anesthetic consideration: Manage pacemaker

51. • COARCTATION OF AORTA
Physiology-LV pressure overload and
hypertrophy,Aortic branch collaterals,
Association with biscuspid aortic valve(50-
80%),Endothelial dysfunction
Problems: Blood pressure gradient between
upper and lower limbs, Systemic hypertension,
Aneurysms of ascending and descending aorta,
Premature CAD, Intracranial aneurysms
*Anesthetic consideration: Inaccurate blood
pressure with previous subclavian
angiolplasty,post op hypertension, Avoid
tachycardia and hypotension

52. • TETRALOGY OF FALLOT
Unrepaired-R to L shunt, Cyanosis,
Anesthetic consideration: Avoid
tachycardia,hypovolemia ,increased contractility
Palliated-Blalock-Taussig shunt-chronic LV
overload,+/- cyanosis, Pulmonary HTN
Anesthetic consideration: Maintain pulmonary
blood flow, maintain systemic blood pressure
Repaired-Sinus and A-V node dysfunction,
PHT,Residual VSD,LV RV dysfunction
Anesthetic consideration: Detect and manage
dysrhythmias,manage pacemaker

53. SINGLE VENTRICLE PHYSIOLOGY
Unrepaired- Bidirectional shunt,
cyanosis,CHF,Dysrhythmias
*Anesthetic consideration: manage
dysrhythmias ,maintain pulmonary blood flow
Repaired-Blalock taussig,Glenn or Fontan—
dysrhythmias, heart
failure,thromboemboli,hepatic
dysfunction,restrictive lung disease
*Anesthetic consideration: Maintain low PVR,
Manage dysrhythmias,maintain adequate
preload, replace coagulation factors

54. Transplanted Heart
• Autonomically mediated responses are absent
i.e.vagal slowing,baroreceptor induced blood
pressure changes
• Cardiac output is dependent on venous return &
circulating catecholamines
• Changes in HR as index of light anesthesia or
hypovolemia are unreliable
• Cardiac drugs exert direct effects only-
epinephrine,norepinephrine,dopamine and
isoproterenol
• Hypovolemia is poorly tolerated