anesthesia for congenital heart disease

8/11/2019 Anesthesia for Congenital Heart Disease

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Anesthesia for Congenital HeartDisease

ANDIKA A. L. W.


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Introduction

Appropriate to distinguish between:

Congenital cardiac surgery

Non-cardiac surgery for patients with

congenital cardiac disease


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Congenital Cardiac Surgery

General Principles:

Pre-operative management

Intra-operative Management

Cardiopulmonary bypass

Deep hypothermic arrest


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Specific Considerations:

Simple procedures

Complex procedures

Closed procedures


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Selected Specific Conditions/Procedures:

Patent Ductus (PDA)

Coarctation of the Aorta

Tricuspid atresia (TA)

Tetralogy of Fallot/Pulmonary Atresia

Transposition of the great vessels (TGV)

Hypoplastic Left Heart Syndrome (HLHS)


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Preoperative Management

Preoperative evaluation

Wide spectrum of disease

Simple ASD to severe life-threatening HLHS

Remember psychological factors esp. family

Team oriented approach Laboratory data ranges from minimal to very

extensive


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Laboratory data

Cyanosis leads to polycythemia

May consider phlebotomy esp if no CPB

Leads to coagulation problems

Anemia may be relative and need transfusion

Newborn infant has immature systemsincluding renal/hepatic/coagulation

Hypoglycemia is much more common


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Laboratory data:

Cardiac catheterization

Anatomic diagnosis

Saturation datashunt analysis

Pressure datagradients/diastolic function

Angiographic datasystolic function/flow patterns Prior surgery delineatedline placement

Interventions in cath. Labe.g. septoplasty or trial

of 100% oxygen


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Premedication

Very varied practices

< 6 months 9 Atropine ( 0.01-0.02 mg/kg IM)

6-12 months

Pentobarbital (2-4mg/kg) po

Atropine and morphine (0.1-0.15 mg/kgIM)

> 12 months

Scopolamine (.015mg/kg IM up to .04mg max) or

morphine or midazolam (0.31.0 mg/kg), ketamine

(3mg/kg IM)

combinations are common


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Preoperative medication

D/C diuretics and digoxin unless heart failure is

poorly controlled or digoxin is being usedprimarily for rhythm

Continue inotropes

Continue prostaglandin infusions


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Intraoperative Management

Physiologic Monitoring

Again very varied depending on the case

ECG, SpO2 x 2, ETCO2, precordial stethoscope,

NIBP are standard

A-lines +/- CVP (Atrial line placed intraop often

more valuable)

TEE


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Intraoperative Management

Induction and Maintenance

Titrate to effect

Very dependent on age and cardiac reserve

Good cardiac reserveinhalational or IV

Neonatesopiate-relaxant technique Beware of PVR changes with inhalational induction

due to changes in PaO2, PaCO2, intrathoracic

pressure


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Cardiopulmonary Bypass

Differences from adult

Lower temperatures (15-20 degrees C) Lower perfusion pressure (20-30mmHg)

Very significant hemodilution (3-15 times greater)

Pump flows range from 200ml/kg/min to zero!

Different blood pH management (alpha-stat vs pH

stat)

Tendency to hypoglycemia

Cannula placement is much more critical


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Deep hypothermic circulatory arrest(DHCA)

Neonates and small infant usually < 10 kgOxygen consumption falls 2-2.5 times per 10

degree fall in temperature

Allows more controlled complex surgery in abloodless field

Often total CPB time is actually shortened bythis technique


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Weaning from CPB

Heart assessed by direct visualization and right

or left atrial filling pressure, central cannula orTEE

Pulse oximetry is also very helpful

Problems weaning are due to:

Inadequate repair,

pulmonary hypertension

And/or left or right ventricular dysfunction


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Weaning from CPB

Problems weaning diagnosed by

Intraoperative cardiac catheterization

Echo-doppler

Leaving the operating room before correcting

the problem leads to a significant INCREASEin morbidity


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Anesthesia for simple open heart

procedures

Relatively straightforward repair

Uncomplicated hemodynamics

Uneventful post-op course anticipated

Examples: ASD, VSD and some case of Tetralogy of Fallot

Usually involve CPB, sometimes DHCA


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Anesthesia for simple procedures:

Inhalation induction usually well tolerated but

delayed if significant Right to Left shunt

Have agents available to maintain SVR

(phenylephrine) and reduce PVR (oxygen,

halothane and opioid)Beware increases in PVR if high RVOT

obstruction


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Anesthesia for simple procedures

Right atriotomy usually OK for most ASDs and

some membranous VSDsSome VSDs need a ventricular incision which

may lead to

AV node dysfunction

mechanical ventricular dysfunction

Simple Fallots involve VSD repair and somesurgery to RVOT/pulmonic valve


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Anesthesia for Complex Procedures:

Except for Left to Right shunt repairs and

uncomplicated Tetralogy, most procedures areconsidered complex

Multiple defects

Complicated hemodynamics

Inhalation induction after pre medication still usual

technique unless very compromised child

Nasotracheal intubation often preferred

Arterial line placed


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Anesthesia for closed heart operations,performed without CPB

Corrective

PDA ligation

aortic coarctation repair

Non-corrective

Pulmonary banding

Blalock-Taussig shunt

Balloon Atrial Septostomies (Rashkind procedure)

(perfomed in the catheterization lab)


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PATENT DUCTUS ARTERIOSUS

1/8000 live births, associated with prematurity

and female predominance of approx 3:1

Left to right shunt causes pulmonary edema

Occasionally right to left cause lower body

cyanosis

SpO2 probe on Right hand and lower limb Confirms correct vessel ligated

Vagal reflex is pronounced by lung traction

Antibiotics required to prevent endocarditis


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PATENT DUCTUS ARTERIOSUS

Usually left thoracotomy or thoracoscopy,sometimes procedure performed in the NICU,Lung retraction causes hypoxemia/hypercarbia

Air embolism, massive hemorrhage and

recurrent laryngeal nerve damage are possiblecomplications

LV overload can occur post-correction

Needs intercostal blocks or epidural for pain


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COARCTATION OF THE AORTA

1/12,000 Male:female 2-5:1

Associated mitral and aortic valve disease

When severe, systemic perfusion depends on

right to left shunt across the PDA

Upper body hypertension may be severePerioperative paraplegia in 0.5%


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COARCTATION OF THE AORTA

Left thoracotomy, may need DLT

Right radial a-line and lower NIBP or a-line

May need PGE1to keep open ductus arteriosus

Allow upper body hypertension on X-clamp

Nitroprusside may be necessary if pressure toohigh but beware distal hypoperfusion and cord

ischemia


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Tricuspid atresia

1/10,000 live births, third most common

cyanotic congenital heart disease

No connection between RA and RV

Maybe associated with transposition (TGA)

Obligatory flow through a PFO or ASDIf these are restricted then there is systemic

venous congestion


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Tricuspid atresia

Palliative and definitive procedures are

applicable to any patient with univentricularphysiology

The single ventricle always becomes thesystemic ventricle

Initial palliative procedures either increase ordecrease pulmonary flow depending on thelesions.


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Tricuspid atresia

More than 70% patients are severely cyanosed

due to inadequate pulmonary flow through thePDA

Need a systemic to pulmonary shunt

Variety used, most common Blalock-Taussig, this

RSC to RPA direct or via GortexWhere pulmonary flow is high the PA is

banded

Assessment of RV function is important here


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Tricuspid atresia

Definitive repair leads to a cavopulmonary

anastamosis (Fontan) and this is sometimes twostaged, i.e. Hemi-Fontan or Bidirectional Glenn

being the intermediary stage.

Patients present for BT shunt often on PGE1Meticulous airway management is key to

maintain flow balances


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Tetralogy of Fallot

1/5000 live births, risks of Tet Spells

Mortality in repair approx. 6%Anatomy

RVOT Obstruction and RVH

Infundibular narrowing

Pulmonary stenosis and pulmonary hypoplasia

VSD (single or multiple)

Overriding aorta

LAD arises from RCA in 5% cases


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Tetralogy of Fallot

Perioperative concerns

Increase in PVR or decrease in SVR leading to

Right to Left shunt

Tet Spells pre induction (crying/anxiety)

Polycythemia and bleeding

Air embolus

RV failure


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Tetralogy of Fallot

Preoperative Preparation

Heavy premedication

Consider IM ketamine or inhalation induction

but get rapid control of airway.

Keep SVR up and PVR down, maintain heartrate

Intraoperative TEE


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Tetralogy of Fallot

Weaning from CPB, ratio RV:LV pressure

should be < 0.8

May need to keep PVR low with NTG,

milrinone, dobutamine phentolamine, PGE1

May need RV inotrope post opMay need temporary pacing wire


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Transposition of the Great Vessels

>5% congenital cardiac defects

Associated with VSD and LV outflow

obstruction

Without intervention, V. High mortality, 30%

1st

week, 45% 1st

mo. 90% 1st

year.Pre-op ductal patency may be life-sustaining



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Usual treatment is PGE1followed by a balloon

atrial septostomy (Rashkind) then either anarterial switch (Jatene) or (often older child) anatrial switch (Mustard)

Older child will be polycythemic, CHF is

frequently presentCVA is possible due to poor perfusion,

coagulopathy and hyperviscosity


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Periop

Maintain Cardiac output with adequate HR

Continue PGE1

Reduce PVR and maintain SVR

Opioid/pancuronium technique

Blood loss may be significant


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Problems and concerns:

Atrial switch

Venous obstruction with low CO or SVC syndrome

Wide specturm of dysrhymias

RV dysfunction if Right ventriculostomy

Arterial switch Ischemia due to kinking of reimplanted vessels or air

Inadequate LV function due to ischemia or low LV mass


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Hypoplastic Left Heart Syndrome

Anatomy

Aortic atresia and LV and mitral hypoplasia

Systemic blood flow occurs across a PDA

Pathophysiology

As ductus closes there is severe systemic

hypoperfusion and acidosis


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Two options:

Cardiac transplantation

2 or 3 stage procedure:

New aorta created from the pulmonary artery

Atrial defect is created to completely mix blood

Pulmonary flow improved by shunt e.g. BT

Later

Fontan (+/-preceded by a hemi Fontan)


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Hypoplastic Left Heart Syndrome (HLHS)

Anesthetic Management

Maintain HR, preload and PGE1

Balance SVR and PVR

Avoid too high PaO2

May need CO2

to avoid pulmonary over perfusion

and hence systemic hypo perfusion

Inotropic support may be necessary to support the

ventricular


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Anesthesia for Non-Cardiac Surgery in

Patients with Congenital Heart Disease

Congenital cardiac abnormalities are in 1%

live births Rapid growth in corrective and palliative

procedures

Increasingly likely that anesthesiologistswill encounter these cases coming for non-

cardiac surgery


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Overview

Spectrum of diseaseManagement algorithms

Anatomy and implications of diseases

Cardiovascular factorsAntibiotics and anticoagulation

Specific problems


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Specific problems:

The cyanosed neonate

Tetralogy of Fallot

Obstetrics and congenital heart disease

Patients with a single ventricle

Recipients of a heart transplant


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Spectrum of disease:

Congenital heart disease NOT YET treated

Surgically corrected and symptom-free

Surgically corrected but with residual problems

Surgically palliated but stable

Surgically palliated but still with severe

symptoms or new problems


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Questions to ask:

Should the patient be referred for specialistcardiology service before surgery?

Is entire procedure more suited to a specialist

center?If we decide to proceed or are forced by an

emergent event to proceed what do we need to

know?


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Specific lesions, anatomic/pathophysiologic

considerationsVSD

L-R shunts and pulmonary overload pre-correction

Endocarditis and arrhythmias post-correction

ASD L-R shunts and pulmonary overload pre-correction

Potential for paradoxical air embolus



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PDA

Late problems rare once corrected

Atrioventricular septal defect

Common in Downs syndrome

Can cause heart failure and pulmonary HTNMitral regurgitation may persist after correction



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Before surgery pulmonary circulation needs apatent duct

Three stage palliative surgery lead to single

ventricle and pulmonary flow throughcavopulmonary connections

Palliation may lead to heart failure and

arrhythmias


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Transposition of Great Vessels

Balloon septoplasty in first few hours of life

Arterial/atrial switch performed depending age

Residual risks of endocarditis, arrhythmias and

right ventricular (systemic) failure.


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Pulmonary atresia

Treatment and outcome depend on a VSD

Repeat palliations and residual cyanosis

possible


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Tetralogy of Fallot

Variable cyanosis with potential for

hypercyanotic spellsCorrected by VSD closure and relief of RVOT

obstruction

Damage to pulmonary valve may leads to RVfailure.

Residual arrhythmia and endocarditis risk


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Cardiovascular impairment

Cyanosis

Indicates persistent abnormality

Associated with polycythemia altered hemostasis

Ensure hydration, maintain SVR and reduce PVR

Use high FiO2

Avoid sudden increase in oxygen requirement

Meticulous removal of air


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Pulmonary disease

Associated pulmonary lesions, vascular rings,compression form shunts, phrenic or RLN damage

Rising PVR can eventual lead to a Rt to Lt shunt

through an ASD or VSD, Eisenmengers syndrome

End-tidal CO2will frequently underestimate PaCO2due to reduced pulmonary flow and increased dead

space


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Cardiac failure

Elective surgery should be postponed In emergent situation, invasive monitoring is

mandatory and usually IPPV should be helpfulexcept where there are cavopulmonary shunts thatcause passive blood flow to the lungs

Arrhythmias

Common problems post correction

SVT, VT and complete heart block all seen


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Antibiotics and anticoagulation

Endocarditis risk has to be assumed in all butthe most simple congenital cardiac lesionsespecially if uncorrected

Generally speaking anticoagulated patientsshould be switched from coumadin to heparin

closer to the time of surgery and then d/cperioperatively

Emergent surgery, on balance, should call forreversal of anticoagulation


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The Cyanosed Neonate

Ductus closes functionally within 6hrs of birth

so ductal-dependent lesions will present earlyThey will need to have the duct opened

pharmacologically with prostaglandin

The neonate will deteriorate rapidly andventilation and transfer to a specialist center is

required


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Tetralogy of Fallot

VSD with RVOT obstruction

May live to adulthood, most corrected beforePrincipal sign is cyanosis

Hypercyanotic episodes (Tet Spells) occur whenchild is distressed due to increased catecholamines

causing RVOT spasm and increased Rt to Lt shunt Patient squatting or femoral pressure tend toalleviate

Other therapy includes increasing SVR, fluid bolus,morphine and Beta-blockers


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Obstetric intervention in the presence ofcongenital heart disease

Maternal mortality is up to 30% if there ispulmonary hypertension

If cyanotic lesions are present, 50% womenwill suffer functional deterioration

Balancing SVR and PVR is keyGA for Cesarean section may be better option

for fixed cardiac output otherwise epidural


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Patient with single ventricle

HLHS or pulmonary atresia with intact septum

Shunts inevitably cause some degree ofcyanosis (eg BT shunt)

As child grows pulmonary flow inadequate and

cavopulmonary shunts are needed (Fontan)

Spontaneous (negative pressure) ventilation

Morphology of ventricle determines outcome

Arrhythmias and ventricular failure are real

anesthesia for congenital heart disease

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