HLHS and SV
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Transcript of HLHS and SV
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Hypoplastic Left HeartSyndrome (and stuff regarding
single ventricle physiology)
Enrique Oliver Aregullin Eligio, MD
Miami Childrens Hospital
February 2013
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GOALS
Appreciation of history of Hypoplastic Left HeartSyndrome.
Basic anatomy & physiology.
Understand the LOGIC behind the management ofHLHS (& single ventricle lesions in general).
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Hypoplastic Left Heart Syndrome
Spectrum of underdevelopment of the left ventricularcavity.
Have underdeveloped aortic & mitral valves (stenosis or
atresia). Left ventricle is unable to support systemic circulation
(and, therefore, right ventricle is used as the singleventricle).
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History of HLHS
First described by Maurice Lev in 1952.
Term used by Noonan & Nadas in 1958.
Options offered:
Comfort care
Staged palliative repair, i.e. Norwood procedure
First successful 3-stage completion in 1983 (after multiplesurgeries from 1979).
Cardiac transplant
First successful cardiac transplant: Bailey, Nov. 1985
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Xenotransplantation, Baby Fae
Dr. Leonard Bailey, Loma Linda University MedicalCenter, November 1984.
http://www.babyfae.com
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Anatomy
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HLHS Epidemiology
Low incidence of 1.6 to 3.6 per 10,000 live births, BUT causes23% or cardiac deaths during 1st week of life and 15% duringthe 1st month of life.
Makes up about 2-4% of congenital heart disease.
More commonly males (55% to 67%). With ONE affected child, recurrence risk is about 0.5% to 2%.
12% prevalence of left-sided obstructive lesions in 1st degreerelatives.
15-30% incidence of genetic syndromes and extracardiac
anomalies in patients w/HLHS. Genetic markers: dHAND, HRT1, HRT2, NOTCH.
Moss & Adams, 2008.
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PATHOPHYSIOLOGY
Cardiac development: Flow begets growth.
Altered flow through the left side of the heart:
Reduced/altered flow across the foramen ovale.
Aortic or mitral obstruction.
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Typical Clinical Presentation
Known Congenital Heart Defect
Prenatal Diagnosis
Unknown Congenital Heart Defect Normal pregnancy, labor and delivery
Clinically doing okay until the PDA closes **
Cyanosis that does not improve withoxygen
Many have no other obvious anomalies
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DUCTAL-DEPENDENT LESION
PDA needed to:
Provide systemic perfusion
HLHS **
Critical aortic stenosis
Provide pulmonary blood flow
Tricuspid atresia
Pulmonary atresia
Provide mixing of oxygenated & deoxygenated blood
Transposition of the Great Vessels
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Hyperoxitest
ABG is measured on room air.
Patient is placed on 100% oxygen (intubated) for 10-15minutes, then ABG is repeated.
If problem is respiratory (i.e. hypoventilation), thenPaO2 improves (usually above 200mmHg).
If problem is cardiac (i.e. right-to-left intracardiacshunt), there is little improvement of PaO2.
Primary pulmonary hypertension may also result inlittle improvement of PaO2.
(Oxygen may hasten closure of PDA!)
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Positive Hyperoxitest
Seriously consider initiation of prostaglandin (PGE) ata low dose (0.03 mcg/kg/min) until diagnosis isconfirmed.
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Initial Assessment
ALWAYS
A - Airway B - breathing
C circulation
CXR and ECG usually not very helpful in Dx.
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Physical Findings
Comfortable or in distress?
Cyanosis w/out respiratory distress is cardiac untilproven otherwise
Active or lethargic? Cyanosis?
Degree - saturation usually
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Respiratory Status
Tachypnea but with minimal distresscardiacuntil proven otherwise.
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Respiratory Status
Respiratory distress
Inability of the respiratory system tocompensate for the metabolic acidosis
Concurrent respiratory disease
Unrelenting metabolic acidosis - decreasedcardiac function
Exhaustion
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AssistedVentilation
Intubate if:
Impending respiratory failure
Potentially not necessary to intubate just forPGE therapy if ground transport
Intubate for air transport in PGE dependentbabies
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Assisted Ventilation
Ventilation strategy
Volume ventilation if possible to maintainconsistent minute ventilation in the face of
changing lung compliance
Bigger tidal volumes compared to prematurenewborns (10 cc/kg); lower rates
No need to over-ventilate
40/40/40 club
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Arterial Blood Gases
In congenital heart disease typically:
Compensated or partially compensatedmetabolic acidosis
Arterial PO2 usually low
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Blood Gases
PH accurate accurate lower
PO2 accurate invariable lower
PCO2 accurate accurate higherHCO3(calculated) accurate accurate accurate
Arterial Capillary Venous
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Oxygen
Oxygen is a drug - use it with respect
Oxygen is a pulmonary vasodilator
May worsen pulmonary congestion
Oxygen is a stimulus for the PDA to close
May worsen ductal dependent lesions byspeeding up closure of the PDA
Oxygen is not bad
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Saturation Monitoring
Oxygen saturation reflects tissueoxygenation and usually does not correlatewith PO2.
With pulmonary hypertension will seedifferential cyanosis - shunts right to leftacross the PDA.
The number is not as important as thepatient.
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Prostaglandin Infusion
Purpose is to open the PDA if a ductaldependent lesion is suspected
Can be initiated before a definitive diagnosis
is established
Need a secure IV (PIV, PIC, or UVC-central orin the liver)
Start at low dose 0.03 mcg/kg/min
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Prostaglandins continued
Side effects -
Apnea - be prepared to intubate
Fever
Hypotension - have volume and inotropesavailable
Flushing
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Access
Umbilical is preferred in a newborn
UVC even if in suboptimal position
UAC PIC line
PIV
AVOID groin line if possible
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Fluid Resuscitation
Needed if poorly perfused
5% albumin bolus (5-10 cc/kg)
Watch for and treat hypoglycemia - stresscauses epinephrine release whichincreases utilization of glucose.
PRBC to treat anemia - optimize oxygencarrying capacity.
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Hypotension
Check ionized calcium
Treat with 50-100mg/kg calcium gluconate or10 mg/kg calcium chloride via central access
Dopamine
Epinephrine
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Metabolic Acidosis
Treat metabolic acidosis aggressively(base deficit < -3)
1 meq/kg Na bicarbonate
Repeat blood gas
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Other Systems
Renal function
Urine output
BUN/Cr
Renal ultrasound
Head ultrasound
Liver function tests
Coagulopathy
Thrombocytopenia
R/O sepsis
Genetics
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Fetal Diagnosis
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Fetal Studies
Hornberger, 1995: 21 fetuses with prenatal echos thatshow left-sided obstruction (small mitral valve &ascending aorta) developed HLHS.
Critical aortic stenosis
decreased blood flowthrough left heart LV dilation & dysfunctionendocardial fibroelastosis (EFE) backwards flowacross PFO LV stops growing & eventually shrinks
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HLHS
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NORMAL FETAL 4-CHAMBER
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Case Presentation
Term infant born via SVD
Uncomplicated labor and delivery
APGARs of 8 at 1min., 9 at 5min. Tachypnea noted at 12hrs of life.
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Case Presentation
Airway-Breathing-Circulation
Respiratory rate (60-90 bpm)
Work of breathing (no retractions)
Saturations (80%)
Warm extremities; good cap refill
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Case Presentation
No obvious dysmorphic features.
More Cardiac Exam Findings: No murmur.
Single second heart sound (S2).
Hyperdynamic precordium.
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Case Presentation
Urgent Cardiology Consult
Cardiac History & Physical
Echocardiogram
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Echocardiogram HLHS
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echo
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Hypoplastic Left Heart Syndrome
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Case Presentation
BUT:
No beds available immediately
Need to manage infant for 24 hoursbefore transport
NOW what do we do?
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Case Presentation
Intravenous access
UVC (double lumen)
UAC
PIV
PIC
Remember: AVOID groin lines
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Case Presentation
Prostaglandins
0.03 mcg/kg/min
Side effectsApnea
Options ?
Intubate vs nasal cannula air
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Case Presentation
Labs
Arterial (or venous) blood gas
Electrolytes (normalize)
CBC
LFT
Genetics
Lactic acid
Head and Renal ultrasound
ECHO/EKG
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Case Presentation
R/O Sepsis
If no clinical suspicion or maternalindicators no need to start antibiotics
Follow ABG frequently (Q 4 hrs)
Monitor urine output
Monitor for acidosis Watch for hypotension
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Blood Pressure
Blood pressure - systolic and diastolicblood pressures are equally importantnotjust mean!!
Coronary flow to heart dependant ondiastolic BP
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Case Presentation
Saturations 95%
pO2 50
Decreased urine output
Metabolic acidosis
Rising lactic acid
Whats going on?!?
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Chest X-Ray
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Case Presentation
Pulmonary Over Circulation with systemiccompromise
Intubate/hypoventilate
CO2
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Hypoplastic Left Heart Syndrome
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Case Presentation
Y- tube Physiology:
Pulmonary Resistance
Lowered by:
- Oxygen
- Prostaglandin
- Resp alkalosis
Raised by:
- PPV
- Hypoxia
- Resp acidosis
Systemic Resistance
Raised by:
- Dopamine
- Epinephrine
To BodyTo Lungs
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Monitoring Innovations
Lactic Acid
Mixed venous oxygen saturation Near infrared spectroscopy
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Pulmonary Atresia
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Hypoplastic RIGHT Heart
Flow begets
growth
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Same Y-tube Physiology
To BodyTo Lungs
But now not
enough blood flow
to lungs
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Ideal Saturation for PDA-dependant
For balanced amount of blood flow to both thelungs and the body in a single ventricle (i.e. Y-tube physiology infant) is:
75% to 85% oxygen saturation
(in upper extremity)
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Options for HLHS in 2013
Comfort Care
Transplant
3-Stage Palliative Repair
Fetal Intervention
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Cardiac Transplant
Fairly good quality of life as transplant recipient(have structurally normal heart).
Obstacles:
Availability of donor heart (approximately 25-30% dieawaiting transplant).
Life-long immunosuppression & risk of infection/CA.
Usual cause of death/organ death: coronary
vasculopathy. Survival: 84% at 1 yr, 76% at 5 yrs., 70% at 7 yrs.
Organ survival MUCH reduced w/subsequenttransplants.
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HLHS Palliative Repair
A. HLHS (sats 80s)B. Norwood repair in 2wks
- Provide systemic BF
- Balance pulmonary BF
C. Glenn repair (SVC to PA)- More pulmonary BF
D. Fontan repair (IVC to PA)
- Relieve volume load to RV- Venous blood totally
bypasses heart (sats
100%)
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Norwood (Stage I)
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HLHS Survival
Standard Risk (i.e. no genetic or extracardiac issues)
1 month85%
1 year80%
5 year73%
Higher Risk
1 month61%
1 year20%
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Fetal Intervention
VERY small balloon catheter is inserted via mothersabdomen, across uterus, through fetal heart acrossaortic valve. Fetal aortic valvuloplasty is performed.
Marginal success with select patients
Must have diagnosis in early 2nd trimester
Absence of genetic or extracardiac anomalies
Early stage of critical aortic stenosis (LV is dilated with
some preserved function, but not yet involuted) Favorable maternal habitus
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Why Fontans Fail
As we age, the ventricular EDP rises.
In Fontan patients, the CVP must
exceed the EDP. Eventually, the EDP
will rise to an intolerable level.
C f C /
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Comfort Care/Hospice
Why is it a viable option in 2010?
The Fontan is doomed to fail. Dr. Reddington, ACC2003
Fontan patients will develop protein-losing enteropathy,ventricular dysfunction, hypoxemia, thromboembolism,arrhythmias and liver failure.
S
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Summary
HLHS is universally lethal w/out treatment.
A patent foramen ovale & ductus arteriosus are necessary forsurvival.
Echocardiogram is modality of choice for diagnosis.
Management of the neonate w/HLHS is complicated: PGE isnecessary as well as ventilation/support to permit sats 75% to85% and no acidosis.
Transplant and staged repair are not w/out their complications(survival for both about 70% in 5 yrs).
Comfort care & fetal interventions are options to be considered.
Decision-making is a TEAM effort by pt. family & medical team.