CHILDREN WITH CONGENITAL HEART DISEASE

1
CHILDREN WITH CONGENITAL HEART DISEASE
ANESTHESIA FOR

• George Nicolaou, MD FRCPC
• Department of Anesthesia
• Perioperative Medicine
• University of Western Ontario

2
INTRODUCTION

• Number of children reaching adulthood with CHD
  has increased over the last 5 decades
• D/T advances in diagnosis, medical, critical and
  surgical care
• Therefore, not uncommon for adult patients with
  CHD to present for non-cardiac surgery

3
INCIDENCE

• 7 to 10 per 1000 live births
• Premature infants 2-3X higher incidence
• Most common form of congenital disease
• Accounts for 30 of total incidence of all
  congenital diseases
• 10 -15 have associated congenital anomalies of
  skeletal, RT, GUT or GIT
• Only 15 survive to adulthood without treatment

4
ETIOLOGY

• 10 associated with chromosomal abnormalities
• Two thirds of these occur with Trisomy 21
• One third occur with karyotypic abnormalities
  such as Trisomy 13, Trisomy 18 Turner Syndrome
• Remaining 90 are multifactorial in origin
• Interaction of several genes with or without
  external factors such as rubella, ethanol abuse,
  lithium and maternal diabetes mellitus

5
FETAL CIRCULATION

• There are 4 shunts in fetal circulation
  placenta, ductus venosus, foramen ovale, and
  ductus arteriosus
• In adult, gas exchange occurs in lungs. In fetus,
  the placenta provides the exchange of gases and
  nutrients

6
CARDIOPULMONARY CHANGES AT BIRTH

• Removal of placenta results in following
• ? SVR (because the placenta has lowest vascular
  resistance in the fetus)
• Cessation of blood flow in the umbilical vein
  resulting in closure of the ductus venosus

7
CARDIOPULMONARY CHANGES AT BIRTH

• Lung expansion ? reduction of the pulmonary
  vascular resistance (PVR), an increase in
  pulmonary blood flow, a fall in PA pressure

8
CARDIOPULMONARY CHANGES AT BIRTH

• LUNG EXPANSION
• Functional closure of the foramen ovale as a
  result ? LAP in excess RAP
• The LAP increases as a result of the ? PBF and ?
  pulmonary venous return to the LA
• RAP pressure falls as a result of closure of the
  ductus venosus
• PDA closure D/T ? arterial oxygen saturation

9
CARDIOPULMONARY CHANGES AT BIRTH

• PVR high as SVR near or at term
• High PVR maintained by ? amount of smooth muscle
  in walls of pulmonary arterioles alveolar
  hypoxia resulting from collapsed lungs
• Lung expansion ? ? alveolar oxygen tension ? ?
  PVR

10
CLASSIFICATION OF CHD

• L R SHUNTS
• Defects connecting arterial venous circulation
• SVR gt PVR ? ? PBF
• ? pulmonary blood flow ? pulmonary congestion ?
  CHF ? ? susceptibility to RTI
• Long standing L-R shunts ? PHT
• PVR gt SVR ? R-L shunt ? Eisenmengers syndrome

11
CLASSIFICATION OF CHD

• L - R SHUNTS INCLUDE
• ASD ?7.5 of CHD
• VSD ? COMMONEST CHD 25
• PDA ? 7.5 of CHD
• Common in premature infants
• ENDOCARDIAL CUSHION DEFECT - 3
• Often seen with trisomy 21
• AORTOPULMONARY WINDOW

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VENTRICULAR SEPTAL DEFECT
13
ATRIOVENTRICULAR CANAL DEFECT
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L R SHUNTS

• PERIOPERATIVE TREATMENT
• Indomethacin ? PDA closure
• Digoxin, diuretics, ACE inhibitors ? CHF
• Main PA band ? ? PVR ? ? L-R shunt
• Definitive open heart surgery
• POSTOPERATIVE PROBLEMS
• SVTs and conduction delays
• Valvular incompetence ? most common after canal
  defect repairs

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CLASSIFICATION OF CHD

• R L SHUNTS
• Defect between R and L heart
• Resistance to pulmonary blood flow ? ? PBF ?
  hypoxemia and cyanosis
• INCLUDE
• TOF 10 of CHD, commonest R-L shunt
• PULMONARY ATRESIA
• TRICUSPID ATRESIA
• EBSTEINS ANOMALY

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R L SHUNTS

• GOAL ? ? PBF to improve oxygenation
• Neonatal PGE1 (0.03 0.10mcg/kg/min) maintains
  PDA ? ? PBF
• PGE1 complications ? vasodilatation,
  hypotension, bradycardia, arrhythmias, apnea or
  hypoventilation, seizures, hyperthermia
• Palliative shunts ? ? PBF, improve hypoxemia and
  stimulate growth in PA ? aids technical
  feasibility of future repair

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GLENN SHUNT
18
MODIFIED BLALOCK-TAUSSIG SHUNT
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TETRALOGY OF FALLOT

• 10 of all CHD
• Most common R L shunt
• 4 anomalies
• RVOT obstruction ( infundibular, pulmonic or
  supravalvular stenosis )
• Subaortic VSD
• Overriding aorta
• RVH

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TETRALOGY OF FALLOT
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TETRALOGY OF FALLOT

• Hypercyanotic ( tet ) spells occur D/T
  infundibular spasm, low pH or low PaO2
• In awake patient manifests as acute cyanosis
  hyperventilation
• May occur with feeding, crying, defecation or
  stress
• During anesthesia D/T acute dynamic infundibular
  spasm

22
TETRALOGY OF FALLOT

• Treatment of Hypercyanotic Spells
• High FiO2 ? pulmonary vasodilator ? ? PVR
• Hydration (fluid bolus) ? opens RVOT
• Morphine (0.1mg/kg/dose) ? sedation,? PVR
• Ketamine ? ? SVR, sedation, analgesia ? ? PBF
• Phenylephrine (1mcg/kg/dose) ? ? SVR
• ß-blockers (Esmolol 100-200mcg/kg/min)
• ? ?HR,-ve inotropy ? improves flow across
  obstructed valve ? infundibular spasm

23
TETRALOGY OF FALLOT

• Halothane ? ? HR -ve inotropy
• Rapidly tuned on and off
• Careful in severe RVF
• Thiopental ? -ve inotropy
• Squatting, abdominal compression?? SVR

24
EBSTEINS ANOMALY
25
CLASSIFICATION OF CHD

• COMPLEX SHUNTS (MIXING LESIONS)
• Continuous mixing of venous and arterial blood
  blood saturation 70 - 80
• May or may not be obstruction to flow
• Produce both cyanosis and CHF
• Overzealous improvement in PBF steals circulation
  from aorta ? systemic hypotension ? coronary
  ischemia

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CLASSIFICATION OF CHD

• COMPLEX SHUNTS INCLUDE
• TRUNCUS ARTERIOSUS
• TRANSPOSITION OF GREAT VESSELS 5
• Arterial switch procedure gt 95 survival
• TOTAL ANOMALOUS PV RETURN
• DOUBLE OUTLET RIGHT VENTRICLE
• HYPOPLASTIC LEFT HEART SYNDROME
• Most common CHD presenting 1st week of life
• Most common cause of death in 1st month of life

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TOTAL ANOMALOUS PULMONARY VENOUS RETURN
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TOTAL ANOMALOUS PULMONARY VENOUS RETURN
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HYPOPLASTIC LEFT HEART SYNDROME
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TRANSPOSITION OF GREAT VESSELS
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TRUNCUS ARTERIOSUS
32
DOUBLE OUTLET RIGHT VENTRICLE
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FONTAN PROCEDURE
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NORWOOD PROCEDURE
35
JATENE PROCEDURE
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CLASSIFICATION OF CHD

• OBSTRUCTIVE LESIONS
• Either valvular stenosis or vascular bands
• ? perfusion pressure overload of corresponding
  ventricle
• CHF common
• Right sided obstructions ? ? PBF ? hypoxemia and
  cyanosis
• Left sided obstructions ? ? systemic blood flow ?
  tissue hypoperfusion, metabolic acidosis and
  shock

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CLASSIFICATION OF CHD

• OBSTRUCTIVE LESIONS INCLUDE
• AORTIC STENOSIS
• MITRAL STENOSIS
• PULMONIC STENOSIS
• COARCTATION OF AORTA 8 of CHD
• 80 have bicuspid aortic valve
• COR TRIATRIATUM
• INTERRUPTED AORTIC ARCH

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COARCTATION OF AORTA
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COARCTATION OF AORTA
40
INTERUPTION OF AORTIC ARCH
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COR TRIATIATUM
42
CLASSIFICATION OF CHD
43
CLASSIFICATION OF CHD
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ANESTHETIC MANAGEMENT

• Perioperative management requires a team approach
• Most important consideration is necessity for
  individualized care
• CHD is polymorphic and may clinically manifest
  across a broad clinical spectrum

45
ANESTHETIC MANAGEMENT
Anesthesiologists will encounter children with
CHD for elective non-cardiac surgery at one of
three stages

• Unpalliated
• Partially palliated
• Completely palliated
• ASD and PDA only congenital lesions that can be
  truly corrected

46
ANESTHETIC MANAGEMENT

• 50 Dx by 1st week of life rest by 5 years
• Childs diagnosis current medical condition
  will determine preoperative evaluation
• Understand the anatomic and hemodynamic function
  of childs heart
• Discuss case with pediatrician and cardiologist
• Review diagnostic therapeutic interventions
• Above will estimate disease severity and help
  formulate anesthetic plan

47
HISTORY PHYSICAL

• Assess functional status daily activities
  exercise tolerance
• Infants - ? cardiac reserve ? cyanosis,
  diaphoresis respiratory distress during feeding
• Palpitations, syncope, chest pain
• Heart murmur (s)
• Congestive heart failure
• Hypertension

48
HISTORY PHYSICAL

• Tachypnea, dyspnea, cyanosis
• Squatting
• Clubbing of digits
• FTT d/t limited cardiac output and increased
  oxygen consumption
• Medications diuretics, afterload reduction
  agents, antiplatelet, anticoagulants
• Immunosuppressants heart transplant

49
LABORATORY EVALUATION

• BLOODWORK
• Electrolyte disturbances 2 to chronic diuretic
  therapy or renal dysfunction
• Hemoglobin level best indicator of R-L shunting
  magnitude chronicity
• Hematocrit to evaluate severity of polycythemia
  or iron deficiency anemia
• Screening coagulation tests
• Baseline ABG pulse oximetry
• Calcium glucose - newborns, critically ill
  children

50
LABORATORY EVALUATION

• 12 LEAD EKG
• Chamber enlargement/hypertrophy
• Axis deviation
• Conduction defects
• Arrhythmias
• Myocardial ischemia

51
LABORATORY EVALUATION

• CHEST X - RAY
• Heart size and shape
• Prominence of pulmonary vascularity
• Lateral film if previous cardiac surgery for
  position of major vessels in relation to sternum

52
LABORATORY EVALUATION

• ECHOCARDIOGRAPHY
• Anatomic defects/shunts
• Ventricular function
• Valve function
• Doppler color flow imaging ? direction of flow
  through defect/valves, velocities and pressure
  gradients

53
LABORATORY EVALUATION

• CARDIAC CATHERIZATION
• Size location of defects
• Degree of stenosis shunt
• Pressure gradients O2 saturation in each
  chamber and great vessel
• Mixed venous O2 saturation obtained in SVC or
  proximal to area where shunt occurs
• Low saturations in LA and LV R L shunt
• High saturations in RA RV L R shunt

54
LABORATORY EVALUATION

• CARDIAC CATHERIZATION
• Determine shunt direction ratio of pulmonary to
  systemic blood flow Qp / Qs
• Qp / Qs ratio lt 1 R L shunt
• Qp / Qs ratio gt 1 L R shunt

55
PREMEDICATION

• Omit for infants lt six months of age
• Administer under direct supervision of
  Anesthesiologist in preoperative facility
• Oxygen, ventilation bag, mask and pulse oximetry
  immediately available
• Oral Premedication
• Midazolam 0.25 -1.0 mg/kg
• Ketamine 2 - 4 mg/kg
• Atropine 0.02 mg/kg

56
PREMEDICATION

• IV Premedication
• Midazolam 0.02 - 0.05 mg/kg titrated in small
  increments
• IM Premedication
• Uncooperative or unable to take orally
• Ketamine 1-2 mg/kg
• Midazolam 0.2 mg/kg
• Glycopyrrolate or Atropine 0.02 mg/kg

57
MONITORING

• Routine CAS monitoring
• Precordial or esophageal stethoscope
• Continuous airway manometry
• Multiple - site temperature measurement
• Volumetric urine collection
• Pulse oximetry on two different limbs
• TEE

58
MONITORING

• PDA
• Pulse oximetry right hand to measure pre-ductal
  oxygenation
• 2nd probe on toe to measure post-ductal
  oxygenation
• COARCTATION OF AORTA
• Pulse oximeter on right upper limb
• Pre and post - coarctation blood pressure cuffs
  should be placed

59
ANESTHETIC AGENTS

• INHALATIONAL AGENTS
• Safe in children with minor cardiac defects
• Most common agents used are halothane and
  sevoflurane in oxygen
• Monitor EKG for changes in P wave ? retrograde P
  wave or junctional rhythm may indicate too deep
  anesthesia

60
INHALATIONAL ANESTHETICS

• HALOTHANE
• Depresses myocardial function, alters sinus node
  function, sensitizes myocardium to catecholamines
• ? MAP ? HR
• ? CI ? EF
• Relax infundibular spasm in TOF
• Agent of choice for HCOM

61
INHALATIONAL ANESTHETICS

• SEVOFLURANE
• No ? HR
• Less myocardial depression than Halothane
• Mild ? SVR ? improves systemic flow in L-R shunts
• Can produce diastolic dysfunction

62
INHALATIONAL ANESTHETICS

• ISOFLURANE
• Pungent ? not good for induction
• Incidence of laryngospasm gt 20
• Less myocardial depression than Halothane
• Vasodilatation leads to ? SVR ? ? MAP
• ? HR which can lead to ? CI

63
INHALATIONAL ANESTHETICS

• DESFLURANE
• Pungent ? not good for induction highest
  incidence of laryngospasm
• SNS activation ? ? with fentanyl
• ? HR ? SVR
• Less myocardial depression than Halothane

64
INHALATIONAL ANESTHETICS

• NITROUS OXIDE
• Enlarge intravascular air emboli
• May cause microbubbles and macrobubbles to expand
  ? ? obstruction to blood flow in arteries and
  capillaries
• In shunts, potential for bubbles to be shunted
  into systemic circulation

65
INHALATIONAL ANESTHETICS

• NITROUS OXIDE
• At 50 concentration does not affect PVR and PAP
  in children
• Mildly ? CO at 50 concentration
• Avoid in children with limited pulmonary blood
  flow, PHT or ? myocardial function

66
IM IV ANESTHETICS

• KETAMINE
• No change in PVR in children when airway
  maintained ventilation supported
• Sympathomimetic effects help maintain HR, SVR,
  MAP and contractility
• Greater hemodynamic stability in hypovolemic
  patients
• Copious secretions ? laryngospasm ? atropine or
  glycopyrrolate

67
IM IV ANESTHETICS

• KETAMINE
• Relative contraindications may be coronary
  insufficiency caused by
• anomalous coronary artery
• severe critical AS
• hypoplastic left heart syndrome with aortic
  atresia
• hypoplasia of the ascending aorta
• Above patients prone to VF d/t coronary
  insufficiency d/t catecholamine release from
  ketamine

68
IM IV ANESTHETICS

• IM Induction with Ketamine
• Ketamine 5 mg/kg
• Succinylcholine 5 mg/kg or Rocuronium 1.5 2.0
  mg/kg
• Atropine or Glycopyrrolate 0.02 mg/kg
• IV Induction with Ketamine
• Ketamine 1-2 mg/kg
• Succinylcholine 1-2 mg/kg or Rocuronium 0.6-1.2
  mg/kg
• Atropine or Glycopyrrolate 0.01 mg/kg

69
IM IV ANESTHETICS

• OPIOIDS
• Excellent induction agents in very sick children
• No cardiodepressant effects if bradycardia
  avoided
• If used with N2O - negative inotropic effects of
  N2O may appear
• Fentanyl 25-100 µg/kg IV
• Sufentanil 5-20 µg/kg IV
• Pancuronium 0.05 - 0.1 mg/kg IV ? offset
  vagotonic effects of high dose opioids

70
IM IV ANESTHETICS

• ETOMIDATE
• CV stability
• 0.3 mg/kg IV
• THIOPENTAL PROPOFOL
• Not recommended in patients with severe cardiac
  defects
• In moderate cardiac defects
• Thiopental 1-2 mg/kg IV or Propofol 1-1.5 mg/kg
  IV
• Patient euvolemic

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ANESTHETIC MANAGEMENT

• GENERAL PRINCIPLES
• Where
• Q Blood flow (CO)
• P Pressure within a chamber or vessel
• R Vascular resistance of pulmonary or
  systemic vasculature
• Ability to alter above relationship is the basic
  tenet of anesthetic management in children with
  CHD

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ANESTHETIC MANAGEMENT

• P ? manipulate with positive or negative
  inotropic agents
• Q ? hydration ?preload and inotropes
• However, the anesthesiologists principal focus
  is an attempt to manipulate resistance, by
  dilators and constrictors

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ANESTHETIC MANAGEMENT

• GENERAL CONSIDERATIONS
• De-air intravenous lines air bubble in a R-L
  shunt can cross into systemic circulation and
  cause a stroke
• L-R shunt air bubbles pass into lungs and are
  absorbed
• Endocarditis prophylaxis
• Tracheal narrowing d/t subglottic stenosis or
  associated vascular malformations

74
ANESTHETIC MANAGEMENT

• Tracheal shortening or stenosis esp. in children
  with trisomy 21
• Strokes from embolic phenomena in R-L shunts and
  polycythemia
• Chronic hypoxemia compensated by polycythemia ? ?
  O2 carrying capacity
• HCT 65 ? ? blood viscosity ? tissue hypoxia
  ? SVR PVR ? venous thrombosis ? strokes
  cardiac ischemia

75
ANESTHETIC MANAGEMENT

• Normal or low HCT D/T iron deficiency ? less
  deformable RBCs ? ? blood viscosity
• Therefore adequate hydration decrease RBC mass
  if HCT gt 65
• Diuretics ? hypochloremic, hypokalemic metabolic
  alkalosis

76
ANESTHETIC MANAGEMENT

• ANESTHESIA INDUCTION
• Myocardial function preserved ? IV or
  inhalational techniques suitable
• Severe cardiac defects ? IV induction
• Modify dosages in patients with severe failure

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ANESTHESIC MANAGEMENT

• ANESTHESIA MAINTENANCE
• Depends on preoperative status
• Response to induction tolerance of individual
  patient
• Midazolam 0.15-0.2 mg/IV for amnesia

78
ANESTHETIC MANAGEMENT

• L - R SHUNTS
• Continuous dilution in pulmonary circulation may
  ? onset time of IV agents
• Speed of induction with inhalation agents not
  affected unless CO is significantly reduced
• Degree of RV overload and/or failure
  underappreciated careful induction

79
ANESTHETIC MANAGEMENT

• L-R SHUNTS
• GOAL ? SVR and ? PVR ? ? L-R shunt
• PPV PEEP increases PVR
• Ketamine increases SVR
• Inhalation agents decrease SVR

80
ANESTHETIC MANAGEMENT

• R-L SHUNTS
• GOAL ? PBF by ? SVR and ? PVR
• ? PVR ? SVR ? ? PBF
• Hypoxemia/atelectasis/PEEP
• Acidosis/hypercapnia
• ? HCT
• Sympathetic stimulation surgical stimulation
• Vasodilators inhalation agents ? ? SVR

81
ANESTHETIC MANAGEMENT

• ? PVR ? SVR ? ? PBF
• Hyperoxia/Normal FRC
• Alkalosis/hypocapnia
• Low HCT
• Low mean airway pressure
• Blunted stress response
• Nitric oxide/ pulmonary vasodilators
• Vasoconstrictors direct manipulation?? SVR

82
ANESTHETIC MANAGEMENT

• R L SHUNTS
• Continue PE1 infusions
• Adequate hydration esp. if HCT gt 50
• Inhalation induction prolonged by limited
  pulmonary blood flow
• IV induction times are more rapid d/t bypassing
  pulmonary circulation dilution
• PEEP and PPV increase PVR

83
ANESTHETIC MANAGEMENT

• COMPLEX SHUNTS
• Manipulating PVR or SVR to ? PBF will
• Not improve oxygenation
• Worsen biventricular failure
• Steal circulation from aorta and cause coronary
  ischemia

• Maintain status quo with high dose opioids that
  do not significantly affect heart rate,
  contractibility, or resistance is recommended

84
ANESTHETIC MANAGEMENT

• COMPLEX SHUNTS
• Short procedures slow gradual induction with low
  dose Halothane least effect on ve chronotropy
  SVR
• Nitrous Oxide limits FiO2 helps prevent
  coronary steal ? Halothane requirements

85
ANESTHETIC MANAGEMENT

• OBSTRUCTIVE LESIONS
• Lesions with gt 50 mmHg pressure gradient CHF ?
  opioid technique
• Optimize preload ? improves flow beyond lesion
• Avoid tachycardia ? ? myocardial demand ? flow
  beyond obstruction
• Inhalation agents ? -ve inotropy decrease SVR?
  worsens gradient flow past obstruction

86
REGIONAL ANESTHESIA ANALGESIA

• CONSIDERATIONS
• Coarctation of aorta ? dilated tortuous
  intercostal collateral arteries ? ? risk for
  arterial puncture and ? absorption of local
  anesthetic during intercostal blockade
• Lungs may absorb up to 80 of local anesthetic on
  first passage. Therefore ? risk of local
  anesthetic toxicity in R-L shunts

87
REGIONAL ANESTHESIA ANALGESIA

• Central axis blockade may cause vasodilation
  which can
• Be hazardous in patients with significant AS or
  left-sided obstructive lesions
• Cause ? oxyhemoglobin saturation in R-L shunts
• Improve microcirculation flow and ? venous
  thrombosis in patients with polycythemia

• Children with chronic cyanosis are at risk for
  coagulation abnormalities

88
POSTOPERATIVE MANAGEMENT

• Children with CHD are very susceptible to
• Deleterious effects of hypoventilation
• Mild decreases in oxyhemoglobin saturation
• Therefore, give supplemental O2 and maintain
  patent airway
• In patients with single ventricle titrate SaO2 to
  85. Higher oxygen saturations can ? PVR ?? PBF
  ? ? systemic blood flow

89
POSTOPERATIVE MANAGEMENT

• Pain ? ? catecholamines which can affect vascular
  resistance and shunt direction
• Anticipate conduction disturbances in septal
  defects
• Pain ? infundibular spasm in TOF ? RVOT
  obstruction ? cyanosis, hypoxia, syncope,
  seizures, acidosis and death