Purpose and Goal: CNEP # 2038

  • Understand the signs of congenital heart defects in the neonate.
  • Learn to recognize and detect heart defects in the neonate.

None of the planners, faculty or content specialists has any conflict of interest or will be presenting any off-label product use. This presentation has no commercial support or sponsorship, nor is it co-sponsored.

Requirements for successful completion:

  • Successfully complete the post-test
  • Complete the evaluation form

Date

  • April 2016 – April 2018

Learning Objectives

  • Describe the risk factors for congenital heart defects.
  • Describe the clinical features of suspected heart defects.
  • Identify 2 approaches for recognizing congenital heart defects.

Introduction

  • Congenital heart defects may be seen at birth
  • They are the most common congenital defect
  • They are the leading cause of neonatal death
  • Many neonates present with symptoms at birth
    • Some may present after discharge
  • Early recognition of CHD improves outcomes

Congenital Heart Defects

  • Congenital heart defects are also known as CHD
  • CHD occurs in 6-13/1000 live births
    • 15% occur as cyanotic defects
    • 25-33% occur as critical defects
  • Up to 58% of CHD may be diagnosed prenatally
    • Prenatal ECHO is highly variable
    • Its sensitivity depends on:
      • Operator expertise
      • Gestational age
      • Fetal position
      • Type of defect
  • CHD may be referred to as:
    • Cyanotic CHD
    • Ductal-dependent CHD
    • Critical CHD
  • When the diagnosis of CHD is delayed:
    • The risk of morbidity increases
    • The risk of mortality increases

Types of Congenital Heart Defects

  • CHD may be classified as:
    • Cyanotic CHD
    • Ductal-dependent CHD
    • Critical CHD
  • Cyanotic heart defects
    • Intra or extra cardiac shunting
    • Circulate deoxygenated blood
  • Ductal-Dependent heart defects
    • Dependent on a patent ductus arteriosis
    • To allow mixing of blood
      • Oxygenated
      • Deoxygenated
    • Many cyanotic defects are ductal dependent
  • Critical heart defects
    • Require intervention
      • Catheter intervention
      • Cardiac surgery

Risk Factors for Congenital Heart Defects

  • There are several risk factors for CHD
    • Family history
    • Multiple fetuses
    • Genetic syndromes
      • In 7-12% of CHD
      • Most common in:
        • Trisomy 21
        • Turner syndrome
        • DiGeorge Deletion 22q
    • Maternal factors
      • Obesity
      • Diabetes
      • Epilepsy
      • Hypertension
      • Preeclampsia
      • Thyroid disorders
      • Phenylketonuria
      • Mood disorders
      • Connective tissue disorders
      • Advanced age > 40
      • Alcohol or substance use
        • Amphetamines
      • First trimester tobacco use
      • Medications
        • NSAIDs
        • ACE inhibitors
        • Retinoic acid
        • Thalidomide
        • Phenytoin
        • Lithium
    • In utero infections
      • Rubella
      • Coxsackie virus
      • Cytomegalovirus
      • Ebstein-Barr virus
      • Toxoplasmosis
      • Parvo virus B19
      • Herpes simplex virus
      • Flu-like illness
    • Assisted reproductive technology
  • There are several risk factors for ↑ survival
    • Earlier diagnosis
    • Lower birth weight
    • Maternal age < 30

Clinical Features of Congenital Heart Defects

  • Some infants may present without symptoms
  • Some present with immediate onset of symptoms
    • Shock
    • Cyanosis
    • Tachypnea
    • Pulmonary edema
  • Shock may be seen in several types of CHD
    • Hypoplastic left heart syndrome
    • Critical aortic valve stenosis
    • Critical coarctation of the aorta
    • Interrupted aortic arch
  • When infants present with shock:
    • Septic shock must be ruled out
    • Cardiogenic shock is suggested when:
      • Cardiomegaly is present on x-ray
      • Volume resuscitation is unsuccessful
  • Cyanosis may be seen in several types of CHD
    • Pulmonary atresia
    • Ebstein’s anomaly
    • Truncus arteriosis
    • Tetralogy of Fallot
    • Ductal dependent lesions
    • Pulmonary valve atresia
    • Critical pulmonary valve stenosis
    • Hypoplastic left heart syndrome
    • Transposition of the great arteries
    • Total anomalous pulmonary venous return
  • When infants present with cyanosis:
    • Non-cardiac causes must be ruled out
      • Sepsis
      • Pulmonary
      • Hypoglycemia
      • Dehydration
      • Hypoadrenalism
      • Rare causes:
        • Methemoglobinemia
        • Metabolic disorders
    • Cyanosis is suggested when:
      • Pulse oximetry saturations are < 80s%
      • Pre and post-ductal saturations are different
        • A > 3% difference is abnormal
  • Tachypnea may be seen in several types of CHD
    • Truncus arteriosis
    • Patent ductus arteriosis
    • Large ventricular septal defects
    • Total anomalous pulmonary venous connection
  • When infant s present with respiratory distress:
    • Non-cardiac causes must be ruled out
      • Sepsis
      • Pulmonary
      • Hypoglycemia
      • Dehydration
      • Abnormal forms of hemoglobin

When to Be Suspicious of a Heart Defect

  • CHD should be suspected with:
    • Family history of CHD
    • Abnormal fetal ECHO
    • Failed CCHD screens
  • CHD should also be suspected with:
    • Heart murmur
    • Central cyanosis
    • Comfortable tachypnea
    • Comfortable desaturations
    • Increased CRT > 3 seconds
    • Associated anomalies
      • Trisomy 21
      • Skeletal anomalies
        • Hand and arm
      • CHARGE syndrome
      • Ear anomalies
      • Renal anomalies

Initial Diagnosis of Congenital Heart Defects

  • Initial diagnosis is based on:
    • History
    • Physical findings
    • Chest x-rays
    • Hyperoxia test
    • Echocardiogram
  • History
    • Risk factors
    • Poor feeding
    • Color changes
    • Excessive irritability
    • Excessive sweating
    • Poor weight gain
    • Excessive sleeping
  • Physical findings include:
    • Abnormal heart rate
    • Comfortable tachypnea
    • Abnormal heart sounds
    • Abnormal precordial activity
    • Abnormal oxygen saturation
      • < 90% in any extremity
    • Oxygen saturation gradient
      • > 3% difference in extremities
    • Blood pressure gradient
      • > 10 mmHg higher in arms
      • > 10 mmHg lower in legs
    • Abnormal femoral pulses
      • Weakened pulses
      • Absent pulses
    • Hepatomegaly
  • Chest x-rays
    • Heart size and shape
      • Dextrocardia
      • Enlarged heart size
        • > 60% of the chest
      • Boot shaped heart
      • Egg shaped heart
      • Snowman shaped heart
    • Pulmonary vascular markings
      • Decreased markings
        • ↓ pulmonary blood flow
      • Asymmetric markings
      • Pulmonary congestion
        • ↑ pulmonary blood flow
    • Site of the aortic arch
      • Left sided arch is normal
      • Right sided arch abnormal
  • Hyperoxia test
    • Useful in ruling out pulmonary causes
      • Obtain an ABG in room air
        • Right radial artery
      • Provide 100% oxygen for 10 minutes
      • Obtain an ABG in oxygen
        • Right radial artery
        • An ↑ O2 should be seen
        • pO2 should be > 150
      • No significant ↑ in O2 is abnormal
  • Electrocardiograms
    • A large right ventricle is normal
      • Right ventricular hypertrophy
    • Other presentations suggest CHD
      • A small right ventricle is abnormal
      • A large left ventricle is abnormal
        • Left ventricular hypertrophy

Classification of Abnormal Heart Sounds

  • Murmurs may or may or be associated with CHD
  • Murmurs associated with CHD include:
    • ≥ grade 3 intensity
    • Holosystolic timing
    • Maximum intensity
      • At upper left sternal border
      • With upright positioning
    • Diastolic murmur
    • Harsh or blowing quality
  • Grading of murmurs:
    • Grade 1 murmur
      • Faint sound detected
      • Often only audible to cardiologists
    • Grade 2 murmur
      • Soft murmur
      • Readily detected
    • Grade 3 murmur
      • Louder than grade 2
      • Not associated with palpable thrill
    • Grade 4 murmur
      • Easily detected murmur
      • Associated with palpable thrill
    • Grade 5 murmur
      • Very loud murmur
      • Easily audible with stethoscope
    • Grade 6 murmur
      • Extremely loud murmur
      • Easily audible with stethoscope off chest

Specific Congenital Heart Defect Care

  • Specific care is indicated for infants who are:
    • Cyanotic
    • Fail a hyperoxia test
    • Do not have PPHN
    • Do not have lung disease on x-ray
  • In most cases, these infants have:
    • Cyanotic heart disease
    • A ductal dependent heart defect
    • An increased risk of significant morbidity
    • An increased risk of death
  • The ductus arteriosis must be kept open
    • To ensure mixing of oxygenated blood
    • To ensure mixing of deoxygenated blood
  • Prostaglandin should be started prior to an ECHO
    • The initial dose should be 0.01 mcg/kg/min
    • Dosing may be ↑ to 0.05 mcg/kg as needed
    • A Cardiology consult should be obtained
  • An ECHO is not needed to treat these infants
  • Transfer to a referral center should be immediate

Echocardiogram Examination

  • Echocardiogram imaging is definitive
  • It provides information on cardiac:
    • Anatomy
    • Function
  • It can also evaluate for pulmonary causes
  • The ECHO should include:
    • Cardiac imaging
    • Pulsed Doppler flow
    • Color Doppler flow
  • ECHOs should be done in consultation with a cardiologist
  • All ECHOs should be interpreted by a pediatric cardiologist

Summary

  • CHDs are the most common defect in the neonate
  • They are a leading cause of morbidity and mortality
  • Early recognition and identification is critical
  • Several clinical signs are suspicious for CHD
  • Alert neonatal nurses can identify infants at risk

References

  1. Altman, C.A. 2015. Identifying Newborns with Critical Congenital Heart Disease. Up-To-Date.
  2. Geggel. R.L. 2014. Diagnosis and Initial Management of Cyanotic Heart Disease in the Newborn. Up-To-Date.
  3. Geggel, R. L. 2014. Cardiac Causes of Cyanosis in the Newborn. Up-To-Date.
  4. Federspiel, M.C. 2010. Cardiac Assessment in the Neonatal Population. Neonatal Network, 29 (3), p. 135-142.
  5. Westmoreland, D. 1999. Critical Congenital Cardiac Defects in the Newborn. The Journal of Perinatal and Neonatal Nursing, 12 (4), p. 67-87.

Evaluation

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