PAL – Distressed Newborn

Brittany Greene

Case Stem

A female infant is born in a community hospital by assisted breech delivery at 34 weeks to a 16 year old single primigravida. There had been no antenatal care. Her birth weight is 1.8 kg, and Apgar scores 51 95. 30 mins later, the baby’s breathing is laboured and there is apparent cyanosis.

Objectives

• Review the basic principles of newborn care and neonatal resuscitation and discuss use and significance of Apgar scores

• Understand the fetal circulation and the changes that occur at birth

• Review lung development in utero, the pathophysiology of respiratory distress syndrome and its management

• Explore the most common causes of distress in the newborn and its management

• Describe 3 commonly measured growth parameters and understand the concepts of low birth weight, prematurity, psychosocial issues, and their implications/significance

Fetal Circulation

• Ductus arteriosus• Foramen ovale• Ductus venosus

Changes at Birth• Alveolar fluid clearance• Lung expansion• Circulatory changes

Lung Development in Utero

1. Early Embryonic Phase(3-7 weeks)2. Pseudoglandular Phase (5-17 weeks)3. Canalicular Phase (16-26 weeks)4. Saccular Phase (24-36 weeks)5. Alveolar Phase (36 weeks to 8 years)

Surfactant

LaPlace’s Law:

P = 2T/RP is pressure necessary to

keep the sphere openT is surface tensionR is radius of the sphere

APGAR Score• Quick evaluation of newborn at 1 and 5 mins– 10 point score with > 7 being normal, 4-6 requiring

assistance, and < 4 requiring resuscitation

Apgar Sign 2 1 0Appearance (skin colour)

Normal colour all over (hands & feet pink)

Normal colour but hands & feet are bluish

Bluish-gray or pale

Pulse (HR) Normal (>100 bpm) < 100 bpm Absent pulse

Grimace (“reflex irritability”)

Pulls away, sneezes, coughs, or cries with stimulation

Facial movement only (grimaces with stimulation)

Absent (no response to stimulation)

Activity (muscle tone)

Active, spontaneous movement

Arms and legs flexed with little movement

No movement, floppy tone

Respiration (RR and effort)

Normal rate and effort, good cry

Slow or irregular breathing, weak cry

Absent (no breathing)

Basic Principles of Newborn Care• Rapid assessment: if “yes” to all 3 questions dry the baby, place

skin-to-skin with mother, covered with dry linen to maintain T– Term gestation?– Crying or breathing?– Good muscle tone?

• If “no” to any baby should receive one or more of the 4 categories of action (in sequence)1. Initial stabilization – provide warmth, clear airway if necessary, dry,

stimulate2. Ventilation3. Chest compressions4. Administration of epi and/or volume expansion

Newborn Resuscitation Algorithm

Case 1

• Male newborn baby weighing 2.62 kg born to 35 yo mother by c-section at 35+4 weeks GA because of oligohydramnios. APGAR scores at 51 and 95. The baby develops tachypnea soon after birth.

Transient Tachypnea of the NewbornPresentation Tachypnea within 2 hrs of birth, other signs of respiratory

distress. Often no hypoxia or cyanosis

Pathophys Residual pulmonary fluid in lung after delivery

Risk Factors Maternal asthma, male, macrosomia, maternal DM, c-section

CXR Findings “Wet silhouette” around heart, intralobar fluid accumulation, diffuse paranchymal infiltrates

Management Self-limited, symptoms last up to 2 days, provide supp O2 via hood or nasal cannula to maintain SpO2 > 90%, tube feeding, IV fluids if needed

Prognosis ExcellentIf doesn’t improve after 4-6 hrs or initial CBC abnormal, obtain blood culture, begin antibiotics (amp + gent)

Case 2

• A baby is born by spontaneous vaginal delivery at 30 weeks to a 25 yo primigravida. Her birth weight is 2.05 kg, and Apgar score is 81. RR 40 and poor air entry bilaterally, no adv. sounds. Within a few mins, she becomes cyanosed and cry is feeble. With suction and supp O2, RR becomes irregular and grunting is heard.

Respiratory Distress Syndrome (Hyaline Membrane Disease)

Presentation Immediately after birth, tachypnea, grunting, retractions, hypoxia, cyanosis

Pathophys Immature type II alveolar cells less surfactant, increased alveolar surface tension, decreased compliance pulmonary vascular constriction, hypoperfusion, lung tissue ischemia formation of hyaline membranes bronchopulmonary dysplasia

Risk Factors Prematurity (1/3 of infants born at 28-34 wks), male, maternal DM

CXR Findings Homogenous opaque infiltrates, diffuse atelectasis, air bronchograms

Management Prevention – give antenatal corticosteroids to pregnant women at <34 wks if high risk of preterm delivery within 7 days.Nasal CPAP. If respiratory failure, intubate. Indicated if persistent resp. acidosis on CPAP, hypoxemia on CPAP, severe apnea.Surfactant therapy via ETT– exogenous surfactant replacement most effective if given within first 30-60 mins of life. Supportive care – prophylactic abx, maintain temperature, tube feeds

Prognosis Acute complications – alveolar rupture, infection, IVH, PDA, pulmonary hemorrhage, NEC, GI perforation, apnea of prematurityChronic – BPD, retinopathy of prematurity, neurologic impairment

Case 3

• A female baby is delivered at 42+6 wks GA by emergency c-section because of fetal distress and thick MSAF. Birth weight is 3 kg. Apgar is 3 at 1 min. The baby is grunting with moderate retractions.

Meconium Aspiration SyndromePresentation Respiratory distress immediately after delivery, with hypoxia.

Baby born through meconium stained amniotic fluid, or evidence of meconium staining on exam.

Pathophys Fetal passage of meconium in utero aspiration of mec irritation, obstruction, medium for bacterial culture

Risk Factors Post-term neonates, small for GA, fetal hypoxia

CXR Findings Patchy atelectasis or consolidation, hyperinflation

Management if MSAF – use minimal stimulation and keep baby head down to prevent breathing in meconioumNo evidence for routine amnioinfusion or suctioning (if HR>100, spont. respitation, reasonable tone). Supportive care, supp. O2. Prophylactic abx until cultures neg.

Prognosis Pulmonary sequelae – reactive airway disease commonNeurodevelopmental impairment – possibly due to underlying intrauterine hypoxia and chronic infection

Less Common Causes

• Infection– Presents as respiratory distress, temperature instability hours to

days after birth– RFs: prolonged rupture of membranes, prematurity, maternal

fever– Bilateral infiltrates on CXR ± pleural effusions, serial blood cultures

• Pneumothorax– Can occur spontaneously, or secondary to infection, MAS, lung

deformity• Persistent pulmonary hypertension of the newborn

– Pulmonary vascular resistance fails to decrease after birth– Can occur spontaneously, or secondary to MAS, infection, TTN

Differential Diagnosis of Respiratory Distress in the Newborn

• Most common (in order of incidence)– Transient tachypnea of the newborn (TTN)– Respiratory distress syndrome (RDS), aka hyaline membrane disease– Meconium aspiration syndrome

• Less common, but significant– Delayed transition– Infection (pneumonia, sepsis)– Persistent pulmonary hypertension of the newborn (PPHN)– Pneumothorax– Non-pulmonary causes, e.g. anemia, congenital heart disease,

congenital malformation, medications, neurologic or metabolic abnormalities, polycythemia, upper airway obstruction

ADDITIONAL INFORMATION

Growth Parameters

• Growth is a reflection of overall health and nutritional status– Pattern of growth, not just absolute number

• Height• Weight– Normal birth weight is 2.5 – 4.5 kg (5.5 to 10 lbs)

• Head circumference

Prematurity

• Definitions: any birth occurring before 27 weeks GA– Late preterm = GA 34-37 weeks– Very preterm = GA < 32 weeks– Extremely preterm = GA < 28 weeks

• Associated with 1/3 of all infant deaths, 50% mortality rate if born at or before 25 weeks– Short term complications – respiratory distress, retinopathy,

PDA, bronchopulmonary dysplasia, late-onset sepsis, necrotizing enterocolitis, IVH

– Long term complications – neurodevelopmental disabilities, e.g. CP, respiratory disorders, gastrointestinal problems, vision and hearing impairment

Low Birth Weight

• Premature infants can be classified by birth weight– Low BW if < 2500 g– Very Low BW if < 1500 g– Extremely BW if < 1000 g

• Assess birth weight by percentile for GA• Both low birth weight premature infants and

small for gestation age (at term) infants have increased mortality and morbidity