6. Surfactant Replacement Therapy in Neonates

Question 1

What is the action of surfactant, specifically related to surface tension?

Answer 1

reduces surface tension

Question 2

Decreased surfactant can lead to what syndrome?

Answer 2

RDS

Question 3

How does Leplace’s Law apply to the alveoli?

Answer 3

P = 2(ST)/R

the smaller the alveoli, the more pressure required to inflate it

Question 4

Surface tension causes alveoli to _____ and requires _____ pressure to ventilate.

Answer 4

collapse, high

Question 5

Surfactant coats the inside of the ____, ____ surface tension, and prevent alveoli from ______.

Answer 5

alveoli, lowers, collapse

Question 6

List some function of surfactant. (Hint: there are 7)

Answer 6

prevents collapse of alveoli during expiration, decreased WOB and O2, optimizes surface area for gas exchange (improves V/Q mismatch), improves lung compliance, protects lung epithelium and facilitates clearance of foreign materials, prevents capillary leakage of fluid into alveoli, defends against infection

Question 7

List some benefits of surfactant therapy. (Hint: there are 6)

Answer 7

improves oxygenation/ventilation, reduces rates of pneumo/PIE, faster weaning/quicker extubation, reduced rates of BPD, less severe BPD, reduced mortality

Question 8

What type of compound on surfactant? Where is it formed?

Answer 8

lipid/protein compound

formed in type II cells

Question 9

T or F: surfactant phospholipids form a bilayer of the alveolar air-liquid interface.

Answer 9

F: monolayer

Question 10

What is the composition of surfactant?

Answer 10

lipids = 90% (phospholipids/DPPC - 90%, neutral lipids - 10%, cholesterol - minimal)
proteins = 10% (serum proteins - 80%, surfactant specific proteins - 20%)

Question 11

What are the 4 serum specific proteins? What is their % composition of surfactant?

Answer 11

SP-A, SP-B, SP-D, SP-D, 20%

Question 12

List some characteristics of SP-A and SP-D.

Answer 12

collagen like, most abundant, hydrophillic, immune function, not found in commercial surfactant extracts

Question 13

List some characteristics of SP-B and SP-C.

Answer 13

important in reabsorption, facilitate DPPC spread/stabilization, hydrophobic, found in commercial surfactant preparations

Question 14

A deficiency in which serum specific protein leads to death in the infancy?

Answer 14

SP-B

Question 15

Survanta (Beractant): source? composition? dose?

Answer 15

bovine lung mince
DPPC, neutral lipids SP-B/SP-C
4 ml/kg (100mg/kg)
re-treatment may be given as early as 2hr after initial dose

Question 16

Bles (Neosurf): source? composition? dose?

Answer 16

bovine lung lavage
DPPC, neutral lipids SP-B /SP-C
5ml/kg (135mg/kg)
repeat up to 3 times within the first 5 postnatal days if oxygenation difficulties persists

Question 17

Curosurf (Poractant alfa): source? composition? dose?

Answer 17

porcine
DPPC, neutral lipids SP-B/SP-C
2.5ml/kg (200mg/kg)
2 repeat doses 1.25ml/kg 12 hrs apart, max 5ml/kg total

Question 18

Describe the surfactant treatment for RDS in neonates < 24-26 weeks.

Answer 18

intubate and administer surfactant at birth, patient will remain intubated

Question 19

Describe the surfactant treatment for RDS in neonates > 24-26 weeks.

Answer 19

administer surfactant if pt requires intubation at birth
NIV with FiO2 > 30-40% then intubate and administer surfactant
extubate ASAP

Question 20

When should surfactant doses be repeated in relation to FiO2?

Answer 20

FiO2 increase > 30-40%

Question 21

What are some examples of non RDS use of surfactant?

Answer 21

meconium aspiration syndrome, congenital pneumonia, pulmonary hemorrhage, bronchopulmonary dysplasia, congenital diaphragmatic hernia, bronchiolitis, ARDS

Question 22

What are some hazards/complications related to surfactant therapy?

Answer 22

desat, brady, tachy, reflux into ETT, apnea, plugging of ETT, pulmonary hemorrhage, may open DA

Question 23

What are some special considerations for surfactant administration?

Answer 23

emergency airway equipment ready, optimize lung volume before surfactant admin (PEEP), administration through in-line catheter, lung volumes/ventilation should be maintained during admin to help disperse surfactant homogeneously

Question 24

What type infusion should be used to deliver surfactant? Dose? Position?

Answer 24

bolus (better distribution/improvement in oxygenation), single dose, supine position

Question 25

Describe the method of administration.

Answer 25

1) ensure ETT is appropriately positioned
2) sxn if needed
3) defrost/warm surfactant to room temp (DO NOT SHAKE, draw into syringe)
4) instill surfactant intra-tracheally through surfactant catheter (do not pass catheter past end of ETT, allows ventilation to continue)
5) assess adequacy of ventilation (observe chest expansion/monitor tidal volume, transcutaneous CO2, SpO2, HR

Question 26

Surfactant can be administered using the:

Answer 26

Neopuff, Flow inflating bag, HFOV, conventional

Question 27

It is important to maintain ____ and ______ _____ during administration

Answer 27

FRC, lung volumes

Question 28

List some adjustments/monitoring to ventilation/oxygenation that may be required post surfactant admin?

Answer 28

bag more gently (improvement in compliance), watch VT/chest rise and wean ventilating pressures to avoid hyperinflation and hyperventilation, decrease FiO2 to maintain SpO2, avoid suctioning for 6 hours unless there is a need

Question 29

What should you expect to see post surfactant therapy? What should you monitor for?

Answer 29

reduction in FiO2, reduced WOB, improved CXR, improved pulmonary mechanics (compliance), able to wean ventilator settings
repeated surfactant doses

Question 30

What are some indications that pt can be immediately extubated following surfactant therapy? What are some indications that pt requires delayed extubation?

Answer 30

very rapid response with natural surfactant, patient has good respiratory drive (*ongoing ventilation increases risk of barotrauma)
smaller Prem’s, poor respiratory drive, very sick

Question 31

How can an RT adminsiter surfactant therapies using minimally invasive surfactant therapy (MIST)?

Answer 31

LMA, thin ET catheter/feeding tube, aerosolized/nebulized in spontaneously breathing pts

Question 32

What is LISA? When is it indicated?

Answer 32

surfactant admin using thin catheter to a spontaneously breathing pt while they are supported on NIV, indicated when intubation/PPV may cause ALI in preterm infants