NEONATAL CARDIAC PROBLEMS

Fetal Cardiac Physiology

• Foramen Ovale• Ductus Arteriosus• Right heart is the dominant ventricle –

pumps 2/3 of cardiac output • Relative RVH in utero

Responses of Pulmonary artery (PA) and Ductus arteriosus to various stimuli

• PA responds to oxygen and acidosis in the opposite manner as the ductus arteriosus:

• 1. hypoxia & acidosis – relaxes the ductus and constricts the pulmonary arterioles

• 2. Oxygen relaxes the pulmonary arterioles but constricts the ductus

• 3. sympathetic stimulation and α-adrenergic stimulation constricts the PA; whle vagal stimulation & β adrenergic stimulation dilate the PA

Changes in circulation after birth…

• Primary change: shift of blood flow for gas exchange from placenta to the lungs

• 1. interruption of umbilical cord results in:– Increase SVR as a result of removal of very low

resistance placenta– Closure of ductus venosus as a result of lack of

blood return from the placenta

Changes in circulation after birth…• 2. Lung expansion results in:

– Decrease PVR, increase pulmonary blood flow and decrease pulmonary arterial pressure

– Functional closure FO occurs because of increase in LA pressure as a result of increased pulmonary venous return to LA; Ra pressure falls as a result of closure of ductus venosus

– Closure of ductus arteriosus as a result of increased arterial oxygen saturation

Changes after Birth

• Left heart now the dominant side• Process continues for up to 6-8 weeks

Nursery is the ideal time to diagnose congenital heart disease (if not prenatally diagnosed) in order to assure early appropriate care

Cyanosis in the newborn• Most are cyanotic at birth• Where to look? Lips, tongue, oral mucous

membrane, nailbeds , even the tips of the nose

• Usually recognized when arterial oxygen saturation is 80% or lower

• In the newborn, cyanosis may occur even at a high oxygen sat of 90% because Hgb is often high and peripheral circulation is sluggish

CYANOSIS

• Occurs when the amount of reduced hemoglobin reaches critical levels of 5gm/dl in the cutaneous veins

CENTRAL CYANOSIS• Maybe seen in:

– CNS depression– Pulmonary disease– Cyanotic cardiac disease– Hematologic – methemoglobinemia, severe blood

loss– endocrine disease

• Always significant

PERIPHERAL CYANOSIS

• Maybe seen in acrocyanosis ( hands &feet); exposure to cold (vasoconstriction), hypovolemia and circulatory shock

Approach to neonate with central cyanosis

• Take ABG to confirm type of cyanosis• Do hyperoxia test• Get CXR to assess heart size and shape; asses

pulmonary vascular markings• Get ECG to assess chamber enlargement• Request for 2D –echo with Doppler color

studies• If cyanotic and ductal dependent, start

prostaglandin E

PGE• RE-opens PDA and prevents it from closing• Allows partially desaturated systemic arterial

blood to enter the pulmonary artery and be oxygenated

• Initial dose 0.1mg/kg/min• Side effects- apnea, fever, hypotension

CONGENITAL HEART DISEASE• occurs in 8 per 1000 births• The spectrum of lesions ranges from

asymptomatic to fatal• Although most cases of congenital heart

disease are multifactorial, some lesions are associated with chromosomal disorders, single gene defects, teratogens, or maternal metabolic disease

Cardiac S/S:• Cyanosis - 1st sign to appear• Irregular rhythm• Variation in amplitude of heart sounds• Murmurs• Cardiac enlargement• Especially if any symptoms with

feeding (exercise for babies)

CHD can be divided into three pathophysiologic groups :

I. Left-to-right shunts (acyanotic)- Atrial septal defect- Ventricular septal defect- Patent ductus arteriosus

II. Right-to-left shunts (cyanotic)

- tetralogy of Fallot- transposition of

great arteries- tricuspid atresia- truncus arteriosus- TAPVR

III. Obstructive stenotic lesions

- coarctation of aorta

- valvular stenosis : aortic, pulmonarymitral

** although not all cyanosis is of cardiac originBUT cyanosis + murmur = cardiac problem

especially if with abnormal cardiac rate ad rhythm, (+) signs of heart failure

** However, absence of cyanosis during the newborn period DOES NOT exclude cardiac anomaly

Cardiac Evaluation• History

– Prematurity– Maternal pregnancy complications (DM, PIH,

infections, teratogen exposure)– Abnormal ultrasounds– Family history of congenital heart disease

• Exam:– Inspection– Palpation– Auscultation

Assessment - History• Maternal history

–Age• Advanced? risk of Down’s

w/associated endocardial cushion defect–Comorbidities

• Diabetes? Think ventricular septal hypertrophy

• Lupus? Risk of complete heart block

Assessment - History– Medications/Drugs

• Valproic Acid? Associated with CoA, HLHS, AS

–Illness• Rubella? Causes PDA

• Family history–Previously affected children?

Syndromes

• Turner: aortic disease• Downs: VSD• Rubella: PDA

ACYANOTIC HEART DISEASES (LEFT TO RIGHT SHUNTS)

VENTRICULAR SEPTAL DEFECT• A congenital abnormality

in which blood flows from high pressure LV low pressure RV through a hole

• the most common congenital heart defect, accounts for 25% of all congenital heart disease

VENTRICULAR SEPTAL DEFECT

• Perimembranous VSDs are the most common of all VSDs (67%)

• PANSYSTOLIC/ HOLOSYSTOLIC murmur

• Typically loudest left lower sternal border

• Large VSDs are not symptomatic at birth because the pulmonary vascular resistance is normally elevated at this time.

• As the pulmonary vascular resistance decreases over the first 4 to 6 weeks of life the amount of shunt increases, and symptoms may develop.

VENTRICULAR SEPTAL DEFECT

Patent Ductus Arteriosus

• Persistent functioning connection between the pulmonary artery and the beginning of descending aorta

• CONTINUOUS, MACHINE-LIKE murmur

• Heard best under the clavicle (left)

• The physical examination findings depend on the size of the shunt.

• A widened pulse pressure is often present as a result of the runoff of blood into the pulmonary circulation during diastole.

Patent Ductus Arteriosus

ATRIAL SEPTAL DEFECT• Most common

congenital heart disease encountered in adults

• The ECG may show right axis deviation and right ventricular enlargement

CYANOTIC HEART DISEASES (RIGHT TO LEFT SHUNTS)

Five T’s

• Tetralogy of Fallot• Transposition of Great arteries• Tricuspid valve atresia• Truncus arteriosus• Total anomalous pulmonary venous return

Tetralogy of Fallot

• Most common of the cyanotic cardiac diseases

• 10% of CHDs

Tetraology of Fallot

1. VSD2. RVOT Obstruction ( PA stenosis)3. RVH4. Overriding aorta

Tetralogy of Fallot

Pulmonary Artery Stenosis -determinant factor related to severity

Clinical Presentation of Cyanotic TOF• Cyanosis, clubbing, dyspnea on exertion,

squatting, hypoxic spells. • Loud systolic ejection murmur, systolic thrill

at middle LSB

Tetralogy of Fallot

“Boot shaped heart” on x-ray

• “couer en sabot”• Uplifted apex, with

concave MPA segment and decreased PVM

Hypoxic Spell (“TET Spell”)

• Peak incidence of 2-4 months• Characterized by:

– Hyperapnea (Rapid and deep respirations)– Irritability and prolonged crying– Increased cyanosis– Decreased heart murmur

• Lower SVR or inc resistance of RVOT can increase the R-L shunt

• Stimulates the respiratory center to produce hyperpnea– Results in an increase

SVR– In turn, increases R-L

shunt through VSD

Pathophysiology – TET spells

TET Spell Treatment1. Hold infant in knee-chest position2. Morphine 3. Sodium bicarbonate to treat acidosis-

decreases resp stimulating effect of acidosis4. Vasoconstrictor (phenylephrine)5. Propranolol6. Surgical: Blalock Taussig shunt

Complete Transposition of the Great Arteries

• 5% of all CHD• Boys 3:1• Most common cyanotic condition that

requires hospitalization in the first two weeks of life

Complete Transposition of the Great Arteries

• Aorta arises from RV and Pulmonary Arteries from LV.

• Without an abnormality, life would not be possible.– ASD– VSD (30-40%)– PDA

Transposition of the Great Arteries

• Cyanosis always present at birth• CHF develop during NB period• Often no murmur• (+) family history of diabetes• LAB:

– CXR: cardiomegaly with “egg shaped” cardiac silhouette

Complete Transposition of the Great Arteries

• “Egg on side” on x-ray

Tricuspid Atresia

• Absence or imperforation of tricuspid valve

• RV hypoplastic• HUGE heart on x-ray

(mainly right atrium)

Tricuspid Atresia

• Presents with cyanosis and heart failure in the first few weeks, as pulmonary vascular resistance falls

• CXR- boot shaped heart

Tricuspid Atresia

Total Anomalous Pulmonary Venous Return

• All four pulmonary veins drain to the right side.

• ASD is present to sustain life

Total Anomalous Pulmonary Venous Return

• Infant presents in first days with cyanosis, circulatory and respiratory failure and collapse.

• If obstructed, is the only pediatric cardiac surgical EMERGENCY

Total Anomalous Pulmonary Venous Return (TAPVR)

• CXR is “snowman” “figure of 8”

appearance

Truncus Arteriosus

• A single trunk leaves the heart – Gives rise to pulm,

systemic, and coronary circulations

– Large VSD is always present

Clinical Signs• Cyanosis immediately after birth• Early signs of CHF• 2-4/6 systolic murmur at LSB suggestive of

VSD

OBSTRUCTIVE / STENOTIC LESIONS

• Localized narrowing of aorta

• Systolic ejection murmur best LUSB and over back

• Decreased femoral pulses

COARCTATION OF AORTA

• Diagnosed by a difference in blood pressure between lower extremities and upper ones.

• Pressure in upper extremities > lower

COARCTATION OF AORTA

Coarctation of the Aorta

• Pre-Ductal– Less common but more serious– Associated with VSD, PDA, Transposition

• Post-Ductal– More common– Often associated with collateral circulation

beyond coarctation, which minimizes effect.

Coarctation of the Aorta

• CXR:–Rib notching may also be seen in older

children (>8 years of age) with large collaterals.

Key Points

• A normal neonatal examination does not guarantee that the baby is normal and certainly does not exclude life threatening cardiovascular malformation

• The absence of a murmur does not exclude serious heart disease

Key Points• Most murmurs are benign, but if its loud,

harsh, diastolic, or the infant has symptoms, be concerned

• A persistent murmur or any other sign of congenital heart disease should warrant prompt pediatric cardiac evaluation

• Genetic syndromes have commonly associated heart defects

GASTROINTESTINAL ANOMALIES

Common congenital GI anomalies in the newborn

- Anomalies of the mouth cleft lip & cleft palate

- Anomalies of the esophagus esophageal atresia chalasia of the esophagus

• Anomalies of the stomach and duodenum:

- pyloric stenosis - duodenal obstruction - hiatus hernia

• Anomalies of the intestine: - Imperforate anus. - Omphalocele. - Intestinal atresia. - Diaphragmatic hernia. - Hirschsprung’s disease (congenital

aganglionic megacolon) - Intussusception

FETUS : Gastrointestinal Function• 12th week: swallowing

• 16th week: Meconium present Digestive enzymes are all active EXCEPT

amylase

• 20th week: gut in final position, non nutritive sucking present

• 32nd -34th week: nutritive sucking

Things to remember: the baby at birth

• Stomach holds 15-30ml

• Gastric emptying time 2-3 hours

• Presence of mucus in the stomach delays emptying further

• Enzymes are less effective than an adults

• Initiation of feeding stimulates growth of the intestinal mucosa

GASTROINTESTINAL S/S

VOMITING

• 1st few hrs after birth - mucus, occasionally blood streaked

• Should disappear after first few feedings

• If protracted → do gastric lavage

• If persistent → pathologic

VOMITING

• If with early onset and persistent:

• Intestinal obstruction

• Metabolic• CNS -

increased ICP

• If with maternal polyhydramnios

• Upper gastrointestinal (esophageal, duodenal, ileal) atresia

VOMITUS

• If bile stained:• Intestinal obstruction

beyond the duodenum

• If blood stained: ? Maternal or infant Perform APT’S TEST

- mix vomitus with equal amounts of water → centrifuge → to 5 parts of supernatant , add 1 part of 0.25% NaOH

• if it turns YELLOW within 2 minutes - maternal bloodno change - infant’s blood

REGURGITATION• Effortless movement of stomach contents into

the esophagus and mouth• Not associated with distress• Result of gastroesophageal reflux through an

incompetent LES• mainly due to stomach distention because of

overfeeding or excessive swallowed air in the rapid act of sucking

• Resolves with maturity

CONSTIPATION• 99% of healthy full-term infants pass their first

stool or meconium within 24 hours of birth and all healthy term neonates should do so by 48 hours.

• With preterm infants, the length of time can extend up to 9 days.

• Failure to pass meconium → consider intestinal obstruction

• Seldom in breast fed infants

CONGENITAL GIT ANOMALIES

ESOPHAGEAL ATRESIA– Resistance is encountered during an attempt to

pass a catheter into the stomach• Should be diagnosed early• s/s : Unusual drooling from the mouth

copious saliva Vomiting occurs with the 1st feeding choking, coughing

cyanosis on food intake• Complication: aspiration pneumonia

ESOPHAGEAL ATRESIA

CHALASIA• Continuous relaxation of

esophageal-gastric sphincter

• Presents with regurgitation of feedings

• Management: – keep the infant in semi-

upright position– Thicken the feedings– Administer prokinetic

drugs

Anomalies of the stomach and duodenum:

• hypertrophy of the pylorus, with elongation and thickening of tissue that progresses to near-complete obstruction of the gastric outlet.

• most cases arising at 3-6 weeks, but it can present even in the first few months.

Pyloric Stenosis

Rate of 3 in 1,000 live births, more commonly in males (4-6:1).

Anomalies of the stomach and duodenum:

• congenital absence or complete closure of a portion of the lumen of the duodenum

• The diagnosis confirmed by radiography.

• An X-ray of the abdomen shows two large air filled spaces, the so-called "double bubble" sign.

DUODENAL ATRESIA

DUODENAL ATRESIA

• Approximately 20–40% of all infants with duodenal atresia have Down syndrome. Approximately 8% all infants with Down syndrome have duodenal atresia.

• It is also associated with polyhydramnios, which is increased amniotic fluid in the uterus.

• Anomalies of the intestine: - Imperforate anus - Abdominal wall defects:

1. Omphalocele2. gastroschisis – more common

- Intestinal malrotation/volvulus - Diaphragmatic hernia - Hirschsprung’s disease (congenital

aganglionic megacolon) - Meconium ileus

IMPERFORATE ANUS• signs & symptoms

• absence of anal opening • misplaced anal opening • no passage of first stool

within 24 to 48 hours after birth

• stool passed by way of vagina or urethra

• Abdominal distention

OMPHALOCELE• an abdominal wall

defect at the base of the umbilical cord (umbilicus); the infant is born with sac protruding through the defect which contains small intestine, liver, and large intestine.

GASTROSCHISIS• an abdominal wall

defect to the side of the umbilical cord

• is rarely associated with other birth defects.

• a life-threatening event requiring immediate intervention.

DIAPHRAGMATIC HERNIA• two types of diaphragmatic

hernia:

1. Bochdalek hernia - usually involves an opening on the left side (85%) of the diaphragm.

2.Morgagni hernia - involves an opening on the right side of the diaphragm.

MECONIUM ILEUS

Incidence Almost always associated with cystic fibrosis Reported to be the presenting symptom in 15-

20% of cases

MECONIUM ILEUS

• Plain radiographsVarying sized loops

of distended bowel

Absence of air fluid levels

Soap bubble appearance particularly in the right lower quadrant

MECONIUM PLUG SYNDROME• most common form of functional bowel

obstruction in the newborn, with an incidence of 1/500.

• Lower colonic or anorectal plugs with a lower normal water content causing intestinal obstruction

• Treatment: glycerin suppository rectal irrigation with

isotonic saline

MECONIUM PLUG SYNDROME

• Supine frontal view of the abdomen in a newborn with meconium plug syndrome demonstrates multiple dilated loops of bowel but no rectal gas.

NECROTIZING ENTEROCOLITIS (NEC)

• Characterized by mucosal or transmural necrosis

• Life threatening• ? Cause - UNCLEAR• May be multifactorial• Incidence: 1-5%

NECROTIZING ENTEROCOLITIS (NEC)

• Occurrence:– 20% premature births– Males = Females– common in LBW who had perinatal distress

• most frequently involved: distal part of ileum and proximal

segment of colon

NECROTIZING ENTEROCOLITIS (NEC)

• Clinical triad:– intestinal ischemia– early formula feeding– bacterial colonization

• Greatest risk factor: prematurity

NECROTIZING ENTEROCOLITIS

S/S: nonspecific lethargy

temp instability

abdominal distention

bloody stools (25%)

NECROTIZING ENTEROCOLITIS • Diagnosis: high index of

suspicion

• Abdo Xray: pneumatosis intestinalis (air in the bowel wall)

portal venous gas indicates severity seen on ultrasound

pneumoperitoneum (perforation)