Respiratory Distress Syndrome

Max Angelo G. Terrenal

Veterans Memorial Medical Center Post-Graduate Intern

Respiratory Distress Syndromeor

Hyaline Membrane Disease

a c u t e l u n g d i s e a s e

n e w b o r n

P u l m o n a r y S u r f a c t a n t D e f i c i e n c y

Incidence

• Premature Infants

• Inversely related to gestational age and birth weight

• 60-80% of <28 weeks

• 15-30% of 32-36 weeks

• Rarely >37 weeks

Who are at risk?

• Maternal diabetes

• Multiple births

• Cesarean delivery

• Precipitous delivery

• Asphyxia

• Cold stress

• Maternal history of previously affected infants

• Highest in preterm male or white infants

Who are less likely to have RDS?

• Chronic or pregnancy-associated hypertension

• Maternal heroin use

• Prolonged rupture of membranes

• Antenatal corticosteroid prophylaxis

Etiology

• Surfactant deficiency

• (decreased production and secretion)

Surfactant

Pathophysiology

Assessment of Fetal Lung Maturity

• Lecithin:sphingomyelin ratio in amniotic fluid: • >2 means mature lungs

• <1.5 means HMD

Clinical Manifestation

• Early onset

• Rapid and shallow respirations

• Tachypnea > 60 breaths/min

• Prominent grunting

• Intercostal and subcostal retractions

• Nasal flaring

• Cyanosis

• Breath sounds may be normal or diminished• With harsh tubular quality on deep insipiration

• Fine rales may be heard

Natural Course

• Severity peaks at 24-48 hours, resolution by 72-96 hours (without surfactant therapy)

• If not treated, BP may fall

• Fatigue, cyanosis, and pallor increase, and grunting disappears as the condition worsens

• Apnea and irregular respirations : immediate intervention

• Mixed respiratory-metabolic acidosis

• Respiratory failure

Outcome

• Improvement• Spontaneous Diuresis

• Improved Blood Gas at lower inspired oxygen

• Death• Severe impairment of gas exchange

• Alveolar air leaks

• Pulmonary hemorrhage

• IVH

Diagnosis

Differential Diagnosis

• Early-onset sepsis – Maternal Group B Streptococcus

• Pneumonia

• Cyanotic heart disease – TAPVR

• Persistent Pulmonary Hypertension

• Transient tachypnea of newborn

• Spontaneous pneumothorax

• Pleural effusion

• Diaphragmatic hernia

• Lobar emphysema

Prevention

• Avoidance of unnecessary or poorly timed cesarean section,

• appropriate management of high-risk pregnancy and labor, and

• prediction of pulmonary immaturity with possible in utero acceleration of maturation

Treatment

• Avoid hypothermia

• IV Calories and fluids

• Warm humidified oxygen

• CPAP : prevents collapse of surfactant-deficient alveoli

• Assisted ventilation

• High-frequency ventilation (HFV )

• Surfactant replacement therapy• is initiated as soon as possible in the hours after birth. Repeated dosing

is given via the endotracheal tube every 6-12 hr for a total of 2 to 4 doses, depending on the preparation.