Anesthesia for Congenital Heart Disease Glynne D. Stanley MB.ChB. FRCA.

Anesthesia for Congenital Heart Disease

Glynne D. Stanley MB.ChB. FRCA

Introduction

• Appropriate to distinguish between:

– Congenital cardiac surgery– Non-cardiac surgery for patients with

congenital cardiac disease

Congenital Cardiac Surgery

• General Principles:

– Pre-operative management– Intra-operative Management– Cardiopulmonary bypass– Deep hypothermic arrest


• Specific Considerations:

– Simple procedures– Complex procedures– Closed procedures


• 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)


• 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


• 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 systems

including renal/hepatic/coagulation– Hypoglycemia is much more common


• Laboratory data:– Cardiac catheterization

• Anatomic diagnosis

• Saturation data – shunt analysis

• Pressure data – gradients/diastolic function

• Angiographic data – systolic function/flow patterns

• Prior surgery delineated – line placement

• Interventions in cath. Lab – e.g. septoplasty or trial of 100% oxygen


• 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 (0.3 –1.0 mg/kg), ketamine (3mg/kg IM)

– combinations are common


• Preoperative medication– D/C diuretics and digoxin unless heart failure is

poorly controlled or digoxin is being used primarily for rhythm

– Continue inotropes– Continue prostaglandin infusions


• 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


• Intraoperative Management– Induction and Maintenance

• Titrate to effect

• Very dependent on age and cardiac reserve

• Good cardiac reserve – inhalational or IV

• Neonates – opiate-relaxant technique

• Beware of PVR changes with inhalational induction due to changes in PaO2, PaCO2, intrathoracic pressure


• 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


• Deep hypothermic circulatory arrest (DHCA)– Neonates and small infant usually < 10 kg– Oxygen consumption falls 2-2.5 times per 10

degree fall in temperature– Allows more controlled complex surgery in a

bloodless field– Often total CPB time is actually shortened by

this technique


• Weaning from CPB– Heart assessed by direct visualization and right

or left atrial filling pressure, central cannula or TEE

– Pulse oximetry is also very helpful– Problems weaning are due to:

• Inadequate repair, • pulmonary hypertension • And/or left or right ventricular dysfunction


• Weaning from CPB– Problems weaning diagnosed by

• Intraoperative cardiac catheterization

• Echo-doppler

– Leaving the operating room before correcting the problem leads to a significant INCREASE in morbidity


• 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


• 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


• Anesthesia for “simple” procedures– Right atriotomy usually OK for most ASDs and

some membranous VSDs– Some VSDs need a ventricular incision which

may lead to• AV node dysfunction • mechanical ventricular dysfunction

– Simple Fallot’s involve VSD repair and some surgery to RVOT/pulmonic valve


• Anesthesia for Complex Procedures:– Except for Left to Right shunt repairs and

uncomplicated Tetralogy, most procedures are considered complex

• Multiple defects

• Complicated hemodynamics

• Inhalation induction after pre medication still usual technique unless very compromised child

• Nasotracheal intubation often preferred

• Arterial line placed

Congenital Cardiac Surgery• 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)

Congenital Cardiac Surgery• 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


• 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 possible complications

– LV overload can occur post-correction – Needs intercostal blocks or epidural for pain


• 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 severe– Perioperative paraplegia in 0.5%


• COARCTATION OF THE AORTA– Left thoracotomy, may need DLT– Right radial a-line and lower NIBP or a-line

– May need PGE1 to keep open ductus arteriosus

– Allow upper body hypertension on X-clamp– Nitroprusside may be necessary if pressure too

high but beware distal hypoperfusion and cord ischemia


• 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 ASD– If these are restricted then there is systemic

venous congestion


• Tricuspid atresia– Palliative and definitive procedures are

applicable to any patient with univentricular physiology

– The single ventricle always becomes the systemic ventricle

– Initial palliative procedures either increase or decrease pulmonary flow depending on the lesions.


• Tricuspid atresia– More than 70% patients are severely cyanosed

due to inadequate pulmonary flow through the PDA

– Need a systemic to pulmonary shunt• Variety used, most common Blalock-Taussig, this

RSC to RPA direct or via Gortex

– Where pulmonary flow is high the PA is banded

• Assessment of RV function is important here


• Tricuspid atresia– Definitive repair leads to a cavopulmonary

anastamosis (Fontan) and this is sometimes two staged, i.e. Hemi-Fontan or Bidirectional Glenn being the intermediary stage.

– Patients present for BT shunt often on PGE1 – Meticulous airway management is key to

maintain flow balances


• 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


• 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


• 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 heart rate

– Intraoperative TEE


• 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 op– May need temporary pacing wire

• 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



• Transposition of the Great Vessels– Usual treatment is PGE1followed by a balloon

atrial septostomy (Rashkind) then either an arterial switch (Jatene) or (often older child) an atrial switch (Mustard)

– Older child will be polycythemic, CHF is frequently present

– CVA is possible due to poor perfusion, coagulopathy and hyperviscosity


• Transposition of the Great Vessels– Periop

• Maintain Cardiac output with adequate HR

• Continue PGE1

• Reduce PVR and maintain SVR

• Opioid/pancuronium technique

• Blood loss may be significant


• Transposition of the Great Vessels– 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


• 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


• Hypoplastic Left Heart Syndrome– 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)


• 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

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 anesthesiologists will encounter these cases coming for non-cardiac surgery


• Overview– Spectrum of disease– Management algorithms– Anatomy and implications of diseases– Cardiovascular factors– Antibiotics and anticoagulation– Specific problems……


• Specific problems:– The cyanosed neonate– Tetralogy of Fallot– Obstetrics and congenital heart disease– Patients with a single ventricle– Recipients of a heart transplant


• 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


• Questions to ask:– Should the patient be referred for specialist

cardiology 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?


• Specific lesions, anatomic/pathophysiologic considerations– VSD

• 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 • Endocarditis and arrhythmias post-correction


• PDA– Late problems rare once corrected

• Atrioventricular septal defect– Common in Down’s syndrome– Can cause heart failure and pulmonary HTN– Mitral regurgitation may persist after correction– Endocarditis and arrhythmias post-correction


• Hypoplastic Left Heart Syndrome– Before surgery pulmonary circulation needs a

patent duct– Three stage palliative surgery lead to single

ventricle and pulmonary flow through cavopulmonary connections

– Palliation may lead to heart failure and arrhythmias


• 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.


• Pulmonary atresia– Treatment and outcome depend on a VSD– Repeat palliations and residual cyanosis

possible


• Tetralogy of Fallot– Variable cyanosis with potential for

hypercyanotic spells– Corrected by VSD closure and relief of RVOT

obstruction– Damage to pulmonary valve may leads to RV

failure.– Residual arrhythmia and endocarditis risk


• 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


• Cardiovascular impairment– 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, Eisenmenger’s syndrome

• End-tidal CO2 will frequently underestimate PaCO2 due to reduced pulmonary flow and increased dead space


• Cardiovascular impairment– Cardiac failure

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

mandatory and usually IPPV should be helpful except where there are cavopulmonary shunts that cause passive blood flow to the lungs

– Arrhythmias• Common problems post correction• SVT, VT and complete heart block all seen


• Antibiotics and anticoagulation– Endocarditis risk has to be assumed in all but

the most simple congenital cardiac lesions especially if uncorrected

– Generally speaking anticoagulated patients should be switched from coumadin to heparin closer to the time of surgery and then d/c perioperatively

– Emergent surgery, on balance, should call for reversal of anticoagulation


• The Cyanosed Neonate– Ductus closes functionally within 6hrs of birth

so ductal-dependent lesions will present early– They will need to have the duct opened

pharmacologically with prostaglandin– The neonate will deteriorate rapidly and

ventilation and transfer to a specialist center is required


• Tetralogy of Fallot– VSD with RVOT obstruction– May live to adulthood, most corrected before– Principal sign is cyanosis

• Hypercyanotic episodes (Tet Spells) occur when child is distressed due to increased catecholamines causing RVOT spasm and increased Rt to Lt shunt

• Patient squatting or femoral pressure tend to alleviate

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


• Obstetric intervention in the presence of congenital heart disease– Maternal mortality is up to 30% if there is

pulmonary hypertension– If cyanotic lesions are present, 50% women

will suffer functional deterioration– Balancing SVR and PVR is key– GA for Cesarean section may be better option

for fixed cardiac output otherwise epidural


• Patient with single ventricle– HLHS or pulmonary atresia with intact septum– Shunts inevitably cause some degree of

cyanosis (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

risks

Anesthesia for Congenital Heart Disease Glynne D. Stanley MB.ChB. FRCA.

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Transcript of Anesthesia for Congenital Heart Disease Glynne D. Stanley MB.ChB. FRCA.