Chapter 14 Flashcards
Surfactant Replacement Therapy
- Surfactant agents
Surface-active agents that lower surface tension
- Surface tension is the force caused by attraction between like molecules that occurs at liquid-gas interfaces and that hold the liquid surface intact (measured in dynes per centimeter)
- Two types of surface tension in the lung
- Surface tension of pulmonary edema, you want to decrease the tension to break the bubble
- Force in the alveoli that pulls them in, you want to decrease the tension of the alveoli to prevent collapse
- Exogenous Surfactants Surfactant is
Produced by type II alveoli cells
90-95% is reabsorbed by the type II cells and recycled
Regulates the surface tension forces of the liquid alveolar lining Lowers surface tension as it is compressed during expiration, thus,
reducing the amount of pressure and inspiratory effort needed to re-expand
the alveoli during inspiration Composed of lipids and proteins
90% Lipids
90% of lipids are phospholipids.
About 50% of phospholipids are DPPC, aka lecithin,
primary component responsible for reducing tension
10% proteins
serum proteins
surfactant specific proteins (SP-A, SP-B, SP-C, SP-D)
- What is surfactant produced outside the body?
Exogenous means surfactant produced outside the body
Places surfactant in the lungs of premature babies born before the type II alveoli cells are able to produce their own.
Once the surfactant is in the alveoli it will be reabsorbed by the type II alveoli cells and they will start producing their own.
- What are Types of surfactant?
Types of surfactant
Natural/Modified: from natural sources (human or animal) with addition or
removal of substances. Advantage of being natural and having the needed lipids, disadvantage risk of contamination (i.e. passing on a virus)
Synthetic: prepared by mixing in vitro synthesized substances which may or may not be in natural surfactant. Advantage of not causing contamination but does not have as many of the needed lipids.
- What are Indications of surfacant?
Prophylactic in infants less than 1250 g birth weight (29 weeks) Prophylactic in infants more than 1250 g birth weight but have signs of
pulmonary immaturity or RDS (over 29 weeks)
Rescue in infants that have developed RDS less than 72 hour from onset
On the horizon, studies show pt needs less oxygen and better outcomes
- Meconium aspiration
- Viral Bronchiolitis
- ECMO
- Diaphragmatic hernia
- Pneumonia and sepsis
- What are the Brands of Sarfacant?
Survanta (beractant)
Modified natural, made from bovine lungs, has proteins and DPPC added Dose, 100 mg/kg, repeat no sooner than 6 hours if needed
Direct tracheal instillation via ETTube
-Administer via 5 fr catheter placed in ETT
-Split into 4 doses, bag pt after each dose for at least 30 seconds
- Infasurf (calfactant)
Modified natural, from bovine lungs, lipids and proteins Dose, 3 ml/kg up to 3 doses 6-12 hours apart
Direct instillation via ETT
-Side port, slowly instill half dose with pt on right side, repeat on left side
-Catheter, give 4 doses one each-supine, prone, right, and left, place on MV in between
Curosurf (portactant)
Natural from porcine lungs, lipids and proteins
Dose, 2.5 ml/kg, 1.25 ml/kg second and third dose 12 hours later if needed Direct instillation via ETT
-Two doses through catheter one with pt on each side
-Bag or MV in between
Exosurf(colfosceril)
Synthetic surfactant
- Hazards and complications Surfacant.
Airway occlusion from liquid leading to desaturation and bradycardia As drug works and lungs improve the infant may become over ventilated
- Increased PaO2
- Increased volumes and barotrauma
Apnea
Pulmonary hemorrhage in infants less than 700 g (cerebral hemorrhage)
Assessment of pt, monitor (Surfacant)
cardiac, pulse and rhythm
Signs of airway occlusion: desaturation, bradycardia, (manual ventilate and sx) Color and activity
Ventilation: chest rise, peak pressures, tidal volumes, compliance, PaCO2 Saturation and PaO2: P ox, Transcutaneous monitors, ABG
