Anaesthesia for Acyanotic Congenital Heart Disease

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Anaesthesia for Acyanotic Congenital Heart Disease

• Moderator Prof. Chandralekha
• Presenters Dr. Shalini
• Dr. Divya

• www.anaesthesia.co.in anaesthesia.co.in_at_gmail.c
  om

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Epidemiology

• Incidence of Congenital heart disease 8 per 1000
  live births
• Acyanotic congenital heart disease
• VSD 28
• ASD (Secondum) 10
• (Primum) 3
• PDA 10
• TAPVC 1
• 85 of these children survive to adulthood.
• 15 year survival rate 80 -- complex CHD
• 95 -- simple
  CHD
• 50 of patients with complex physiology are gt25
  years old
• Moreover this population is growing at a rate of
  5 each year.
• A diagnosis of congenital heart disease adds
  significant incremental risk of mortality in
  children
• requiring inpatient noncardiovascular surgery.
  This outcome difference is present for both minor
  and major
• surgical procedures, and regardless of whether
  mortality is measured at 1, 3, or 30 days. The
  incremental risk is greatest in neonates and
  infants where the presence of congenital heart
  disease is associated with a 2-fold increase in
  mortality from noncardiac surgery.
• (Pediatrics 2000105332335)

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Syndromes associated with ACHD

• Extracardiac malformation in 20-45
• Known chromosomal anomaly in 5 - 10
• ASD -- Trisomy 21,18,13,XXXY,Del
  4p,5p,CHARGE,Fetal Hydantoin Syndrome,Fetal
  alcohol syndrome,Holt Oram ,Treacher
  collins,Noonans
• VSD -- Trisomy 21,18,13,XXXY,Del
  4p,5p,CHARGE,Fetal Hydantoin Syndrome,Fetal
  alcohol syndrome, Del 10q, 13q, 18q, Fetal
  valproate syndrome, Elis van creveld syndrome,
  Apert

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Cardiac Embryology

• Embryogenesis from days 21 to 28. A, The cardiac
  loop is
• formed. The heart tube is folded into an S-shaped
  dextroventral
• convexity. B, The atria are partitioned. The
  septum primum
• (in brown) grows from the inferior part of the
  atria to the
• top, leaving a foramen called the ostium primum.
  The septum
• secundum (in orange) comes from the top. The
  ostium primum
• will be closed at the end of the fifth week by an
  expansion of
• tissue coming from the endocardial cushions (in
  yellow). C, The
• conus and the truncus are partitioned. The
  dextrodorsal and
• sinistroventral conus ridges, which are isolated
  in the first picture,
• partition the conus by a helical outgrowth into 2
  cavities
• the subpulmonary and the subaortic coni. The
  truncus is partitioned
• from the bottom upward from aorticopulmonary
  swellings,
• leading to the formation of the aorta and
  pulmonary
• arteries.
• 1
• Images in Cardiovascular Medicine
• Downloaded from circ.ahajournals.org by on
  September 30, 2007

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ATRIAL SEPTAL DEFECT

• Opening in the interatrial septum
• i 1 in 500 live births
• 6- 10 of CHD. 30 of CHD in adults
• Females gtmales
• Types
• Ostium secondum(75)
• Ostium primum(15)
• Sinus venosis(10)
• Patent foramen ovale(5)
• Coronary sinus(rare)

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• Pathophysiology
• L?R shunt is dependant on
• Size of defect
• Relative compliance of rt. lt. ventricle
• It induces dilatation of the RA, RV hypertrophy,?
  size of PA.
• The L?R flow is typical biphasic one peak flow
  occurs during late systole early diastole (v
  wave), other during late diastole (a wave)
• There may be R?L shunt component during
• sudden intrathoracic pressure drops as in
  spontaneous ventilation,relaxing phase of
  valsalva maneuver
• with ? in RV afterload (IPPV, PEEPgt15cm H2O)

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• Natural History
• Small ASDs lt3mm nearly 100 close
  spontaneously
• Medium 3 8 mm --80 close
  spontaneously
• Large gt8mm -- probably will not
  close
• Isolated ASDs usu asymptomatic in infancy
  childhood
• gt40years mortality of non operated patients
  ? by 6 /year
• gt60 years almost all symptomatic
• Failure to thrive
• CHF in 2nd or 3rd decade of life,Pul HTN in upto
  13 of unoperated children lt 10 years
• Recurrent respiratory tract infections
• Atrial arrhythmias
• Atrial Fibrillation more common gt40years
• Qp/Qs 2 ? 11
• 3 ? 38
• Eisenmangers syndrome
• Paradoxical emboli

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• Residual defects foll repair
• Residual ASD
• RV dilatation/dysfunction not in those
  repairedlt5 years of age
• LV dysfunction in those corrected in adulthood
• Supravntricular arrhythmias

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• Clinical features
• Hyperdynamic precordium
• Wide fixed split S2
• Functional ejection systolic murmur in left
  sternal border
• ECG
• Feartures of RA enlargement ,RVH, RAD
• Incomplete RBBB
• CXR
• RAE, RVH, Pulmonary Artery dilated, pulmonary
  plethora
• Echo
• Qp/Qs ratio
• Cardiac cath
• ? in saturation of atleast 10 between vena cava
  PA.

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VSD

• Most common CHD(20)
• i 2.6 5.7 per 1000 live births
• 10 of adult CHD
• Types
• Subpulmonary (5 7 ) , ass. With aortic valve
  insufficiency
• Perimembranous (80 ) , ass with tricuspid valve
  abnormality
• AV canal (5 8 )
• Muscular (5 20)
• Restrictive, Non restrictive
• Small, medium, large

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Anatomy
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• Pathophysiology
• L?R shunt predominantly during systole. The
  septal defect is anatomically close to the RVOT
  such that the shunted blood bypasseshe RV cavity.
  Hence RV hypertrophies sec to pul. HTN only.
• Adaptive mechanisms include ?Stroke
  volume,contractility,Heart rate myocardial mass

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Features of VSD based on size
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• Natural History
• Spontaneous closure of defects lt5mm before 5
  years of age
• Natural course depends on
• Size of defect
• changes in PVR
• Changes in the above with age
• Large defects CHF in infancy(2- 6 weeks of life),
  when PVR falls
• Failure to thrive
• Recurrent Resp tract infection
• Eisenmangers syndrome

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• Abnormalities in repaired adult patient
• lt2 years of life residual defect unlikely
• Late closure, or non restrictive , or moderately
  restrictive VSD closure are necessariy
  accompanied by varying degrees of pre op PAH
  PVOD
• Residual VSD
• LV dysfunction ?LVEDV, ?LV wall mass ? LVEF,
  abnormal response to exercise
• Arrhythmias inc BBB or complete AV block, may
  have a PPI

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• Clinical features
• Cardiomegaly
• Restrictive VSD Pansystolic murmur Left sternal
  border radiating across the sternum
• Non restrictive VSDDecrescendo murmur or absent
  murmur
• ECG LVH
• Echo LV enlarged , PA dilated
• RVH proportionate to degree of PHT

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VSD with PHT
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Preop evaluation of CHD patient

• Review underlying anatomy physiology of cardiac
  lesion
• Previous cardiac surgeries palliative vs.
  reparative
• Evaluate existing residua or sequelae
• Assess other pre existing or congenital anomalies
• Review information from last cardiological
  examination
• Recent cardiac cath, echo
• Functional status
• Assess risk factors
• Pulmonary HTN
• Cyanosis
• Reoperation
• Arrhythmias
• Vent dysfunction
• Review changes since last cardiac examination
• History physical examination
• Lab data
• Current medication

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• 6. Review proposed surgical procedure
• Elective vs. emergent
• Expected length invasiveness
• 7. Plan treatment of potential complications
• Dysrhythmias
• Pulmonary hypertension
• Ventricular dysfunction
• 8. Plan post op care
• Monitoring
• Pain management
• Cardiology follow up
• 9. Discuss anaesthetic plan risk with
  patient/parent

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• Is the patients cardiac disease
• The primary condition in his perioperative care?
• One of several considerations?
• A relatively minor consideration?

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• History
• 1. Congestive heart failure
• Infants
• Cyanosis
• Respiratory difficulty
• Seizures
• Failure to thrive
• Children
• Chronic cough
• Cyanosis
• ? activity during exercise
• Excessive perspiration
• Failure to thrive
• Fatigue
• Poor feeding
• Syncope

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• 2. Cyanotic spells
• 3. Recent illness esp., Resp tract infection
• 4. Coexisting illness GERD, Reactive airway
  disease, seizure disorder

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• Examination
• Airway
• Cardiac
• Respiratory
• Investigation
• Hemogram,Electrolytes
• ECG, CXR,
• Echo

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• Fasting Guidelines
• Avoid dehydration/hypovolemia
• Premedication
• Benefits
• Anxiolysis
• ?cooperation
• ?separation anxiety
• ?cardiovascular liability
• Detrimental effects
• Hypoventilation
• Hypotension
• Pain on administration

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Infective Endocarditis

• Congenital heart disease (CHD)
• Unrepaired cyanotic CHD, including palliative
  shunts and conduits
• Completely repaired congenital heart defect with
  prosthetic material or device, whether placed by
  surgery or by catheter intervention, during the
  first 6 months after the procedure
• Repaired CHD with residual defects at the site or
  adjacent to the site of a prosthetic patch or
  prosthetic device (which inhibit
  endothelialization)

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• OT Preparation
• Equipment
• Anaesthesia machine check
• Prepare for invasive monitoring
• Set alarm limits appropriate for age patient
• Emergency drugs
• Infusions infusion pump
• Monitoring
• Pulse Oximetry
• NIBP
• ECG
• Capnography
• Urine Output, Temperature
• CVP
• IBP
• TEE

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• Anaesthetic Goals
• Bubble avoidance
• Optimizing O2 delivery ventilatory function
• Avoid hypovolemia
• ? L?R shunt

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• Paradoxical Emboli
• PFO
• incidence 5 in 2D Echo
• 27 Direct intraop visualization
• Paradoxical emboli i 1-2per year/patient
• Preferential shearing of IVC blood towards
  secondum ASD
• Paradoxical emboli can occur during
• Valsalva
• PEEP,IPPV
• Deep sea diving
• Lap procedures
• Sudden R?L shunt
• sudden intrathoracic pressure drops as in
  spontaneous ventilation, ,relaxing phase of
  valsalva maneuver.

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• Bubble Avoidance
• Remove all bubbles from iv tubing
• Connect iv tubing to the venous cannula while
  there is free flow of iv fluid and blood
• Eject small amount of solution from syringe to
  clear air from needle to hub before injection
• Aspirate injection port of 3 way before injection
  to clear air
• Hold the syringe upright to keep bubbles at the
  plunger end
• Do not inject the last ml from the syringe
• Do not leave a central line open to air

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• Induction
• In L?R shunts with ? pulmonary blood flow, speed
  of inhalation induction is unchanged.
• We found more episodes of severe hypotension an
  increased incidence of bradycardia and emergent
  drug use in the patients that received halothane
  than in patients who received sevoflurane
• (Anesth Analg 20019211528)
• Intravenous
• Time to appear in systemic circulation is
  unchanged though peak plasma conc. Are lower
  effect is prolonged
• Thiopentone? SVR, well tolerated in
  normovolemic, stable CHD
• Propofol Significant ? in SVR MAP
• Ketamine ? SVR, ? L?R shunt
• Etomidate minimal cardiovascula effect

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Hemodynamic Goals

• Reduction of L?R shunt
• Slight increase in preload as hypovolemia is
  poorly tolerated

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• Hypovolemia is poorly tolerated in these
  patients.
• The low resistance pulmonary circulation tends to
  steal volume from the high resistance systemic
  circulation. This is further increased by the
  systemic arterial vasoconstriction of hypovolemia

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Pathophysiologic classification of shunts
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Cardiac Grid - ASD
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Cardiac Grid - VSD
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• ? PVR
• PEEP
• High airway pressures
• Atelectasis
• Hypoxia
• Hypercarbia
• Acidosis
• ? HCT
• Drugs

• ? SVR
• Anaes agents
• Vasodilators

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• Controlled ventilation is optimal as
• Many patients with CHD cannot tolerate the high
  conc. Of inhalation agents required during SV
• Appropriate ventilation helps prevent atelectasis
  hypercarbia
• Ventilation is a compromise between active
  hyperventilation preservation of mean
  intrathoracic pressure
• Ideal tidal volume corresponds to FRC to obtain
  PaCO2 lowest mean intrathoracic pressure

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• At low Tidal volume hypercarbia atelectasis ?
  PVR
• At high tidal volume large extra alveolar vesels
  are much compressed ? PVR

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Central Neuraxial Blockade

• Merit
• ? SVR
• Demerits
• Incremental IPPV represents a weak ? compared
  with already elevated pulmonary pressure RV
  well adapted to ? afterload
• IPPV allows hypervent ? PVR
• Vasodil due to sudden profound fall in SVR can
  reverse shunt

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Pregnancy L?R shunts

• Modest L?R shunts are well tolerated during
  pregnancy
• Anaesthetic management should pay attention to
• Care to avoid bubble infusion
• LOR to saline rather than air during epidural
  catheterization
• Early administration of labor analgesia as pain ?
  SVR catecholamine release worsening L?R shunt
• Slow onset of epidural anaesthesia is preferred
• Monitoring of SpO2 provision of supplementary
  O2

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• Thank You

www.anaesthesia.co.in anaesthesia.co.in_at_gmail.c
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