2a Respiratory Diseases (RDS) Yen

Question 1

What is the usual duration for a full term baby, and their normal weight?

Answer 1

38-40 weeks GA. 3.6kg (8 lbs)

Question 2

At what age is a baby considered premature?

Answer 2

< 38 weeks

Question 3

What is a “Low Birth Weight”?

Answer 3

< 1.5kg (3.3 lbs)

Question 4

What is “Very Low Birth Weight”?

Answer 4

< 1kg (2.2 lbs)

Question 5

What is an overview of Respiratory Distress Syndrome (RDS)?

Answer 5

Also called hyaline membrane disease. Respiratory distress common in newborns. RDS major cause of respiratory distress

Question 6

Which neonates are at higher risk of RDS?

Answer 6

White male infants. Infants born to mothers with diabetes. Infants born by means of cesarean delivery. Second born twins. Infants with a family history of RDS

Question 7

How does the incidence of RDS decrease?

Answer 7

Use of antenatal steroids. Pregnancy-induced or chronic HTN. Prolonged rupture of membranes. Maternal narcotic addiction

Question 8

Why does RDS often occur in premature infants?

Answer 8

RDS is the result of pulmonary surfactant deficiency. Lungs of premature infants lack pulmonary surfactant (inadequate production until 34 weeks GA). Full term infants can develop surfactant inactivation with sepsis, pneumonia, meconium, aspiration, asphyxia

Question 9

What are the clinical signs that result from abnormal pulmonary function in RDS?

Answer 9

Tachypnea. Nasal flaring. Grunting. Retractions. Cyanosis

Question 10

When do the clinical signs of RDS usually present?

Answer 10

Typically presents at birth. Will worsen over 48 hrs if untreated. If no improvements, death usually occurs in 2-7 days

Question 11

What is the Prevention for RDS?

Answer 11

Best intervention is to prevent premature birth. Cervical cerclage. Tocolytic agents. Treatment of maternal infections (ex. UTI). Smoke and alcohol cessation. Avoid unnecessary C-sections. Prenatal care

Question 12

What is Antenatal Corticosteroid Therapy (ACS) like for RDS?

Answer 12

Enhances maturational changes in the preterm lung. Results in improved lung function. Increases surfactant synthesis and release

Question 13

When is ACS recommended?

Answer 13

All women less than 34 weeks gestation. Optimal benefit begins 24 hrs after initial dose, effect lasts 7 days. ACS for less than 24 hrs still associated with reductions in RDS and infant mortality

Question 14

What are the ACS regimens to use?

Answer 14

Betamethasone 12mg IM Q24hrs x2 doses. Dexamethasone 6mg IM Q12hr x4 doses. Both of these are 48 hr regimens

Question 15

What is the theory behind surfactant use?

Answer 15

Widely used and is effective in reducing mortality and morbidity rate in RDS. Prevents development of RDS. Once RDS has been established, reduces severity of RDS

Question 16

What is Prophylactic Surfactant Therapy?

Answer 16

Administered at the time of delivery to those at risk of RDS (< 30 weeks GA)

Question 17

What is Early Surfactant Therapy?

Answer 17

Administered within 2 hrs of life. Prophylactic or Early therapy are superior to rescue therapy alone

Question 18

What is Rescue Surfactant Therapy?

Answer 18

Given once diagnosis of RDS is established

Question 19

What is a Surfactant?

Answer 19

A complex lipoprotein complex (phospholipoprotein) with 6 phospholipids and 4 apoproteins. Naturally found in Type II alveolar cells

Question 20

What are the 4 surfactant apoproteins identified?

Answer 20

Surfactant Protein A (SP-A), B, C, D

Question 21

What do Surfactant Proteins A (SP-A) and SP-D do?

Answer 21

Innate host defense. SP-A involved in negative feedback mechanism to control production of surfactant

Question 22

What do Surfactant Proteins B (SP-B) and SP-C do?

Answer 22

Required for proper biophysical lung function. Work in concert to facilitate rapid absorption and spreading of a thin monolayer

Question 23

What is the MOA of Surfactants?

Answer 23

Lung surfactant lines the alveolar surfaces and terminal airways. Reduces the surface tension of pulmonary fluids and stabilizes alveoli. Contributes to the elastic properties of pulmonary tissue (pulmonary compliance). Facilitates recruitment of collapsed airways

Question 24

What can surfactant deficiency lead to?

Answer 24

Atelectasis and impaired gas exchange. Hypoxemia. CO2 retention. Secondary lung injury

Question 25

What is Natural vs. Synthetic Surfactant?

Answer 25

Natural surfactants superior to synthetic surfactant without SBP (non-protein containing). Synthetic products that contain peptide analogs of SBP are superior to non-protein containing synthetic product. New synthetic product with peptide analogs of SBP are COMPARABLE to natural surfactant

Question 26

What is the synthetic surfactant currently used?

Answer 26

Lucinactant (Surfaxin)

Question 27

Which surfactant uses the lowest dose?

Answer 27

Poractant alfa (Curosurf)

Question 28

Which surfactant is porcine derived?

Answer 28

Poractant alfa (Curosurf)

Question 29

What are the side effects with surfactant therapy (many attributed to installation: intubation)?

Answer 29

Transient bradycardia, hypotension, endotracheal tube blockage, oxygen desaturation, pulmonary hemoorhage. Pulmonary hemorrhage may prevent further instillation

Question 30

What are postnatal steroids for RDS used for?

Answer 30

Improves pulmonary function and decreases incidence of CLD

Question 31

What are the short term complications with Postnatal steroids in RDS?

Answer 31

Intestinal perforations, HTN, hyperglycemia, increased risk of infections

Question 32

What are the long term complications with Postnatal steroids in RDS?

Answer 32

Abnormal neurodevelopmental outcomes, increased incidence of cerebral palsy

Question 33

What is the recommendation for postnatal steroids?

Answer 33

AAP does NOT recommend the use of postnatal steroids unless the infant is doing poorly on maximal support. Dexamethasone mostly used in low doses, short duration

Question 34

What is the management for RDS?

Answer 34

Used to correct atelectasis. Increases concentration of supplemental oxygen to avoid hypoxemia. Facilitates repeat administration of surfactant. Correct CO2 retention. Associated with volutrauma and barotrauma (along with oxygen toxicity leads to development of chronic lung disease). Avoid fluid overload (excess can lead to pulmonary edema)

Question 35

Which surfactant is produced by calf lung lavage?

Answer 35

Calfactant (Infasurf)