M5: Amniotic Fluid (Part 4: Tests for Fetal Maturity) Flashcards
(5) parameters measured/detected for fetal maturity
Condition associated with fetal maturity?
Respiratory Distress Syndrome (RDS)
(5) parameters measured/detected for fetal maturity?
- Amount of Surfactant
- Lecithin-shingomyelin ratio
- Phosphatidyl glycerol
- Foam stavility index
- Lamellar bodies
(5) parameters measured/detected for fetal maturity
- aka Hyaline Membrane Disease
- Most frequent complication of preterm delivery
- Caused by an insufficiency of lung surfactant production and structural immaturity of the fetal lungs
Respiratory distress syndrome
(5) parameters measured/detected for fetal maturity
Normally appears in mature lungs and allows the
alveoli (air sacs of the lung) to remain open throughout the normal cycle of inhalation and exhalation.
Surfactant
(5) parameters measured/detected for fetal maturity
keeps the alveoli from collapsing by decreasing
surface tension and allows them to inflate with air more easily
Surfactant
(5) parameters measured/detected for fetal maturity
The amount of surfactant in fetal lungs can be estimated by?
measuring amount of surfactants in amniotic fluid
(5) parameters measured/detected for fetal maturity
Reference method to which tests of FLM are compared
Lecithin-sphingomyelin ratio
(5) parameters measured/detected for fetal maturity
is the primary component of the surfactants
(phospholipids, neutral lipids, and proteins) that make up the alveolar lining and account for alveolar stability
Lecithin
(5) parameters measured/detected for fetal maturity
is a lipid that is produced at a constant rate
after about 26 weeks’ gestation; therefore, it can serve as a control on which to base the rise in lecithin
Sphingomyelin
(5) parameters measured/detected for fetal maturity
T or F
sphingomyelin only appear in the amniotic fluid in amounts proportional to their concentrations in the fetus
Lecithin-sphingomyelin ratio
F (BOTH lecithin and shingomyelin)
(5) parameters measured/detected for fetal maturity
Before or After 35 weeks of gestation?
L/S ratio is usually less than 1.6 because large
amounts of lecithin are not being produced at
this time.
Lecithin-sphingomyelin ratio
Before 35 weeks’ gestation
(5) parameters measured/detected for fetal maturity
Before or After 35 weeks of gestation?
Lecithin concentration increases while the
sphingomyelin concentration remains constant
Lecithin-sphingomyelin ratio
After 35 weeks of gestation
(5) parameters measured/detected for fetal maturity
The L/S ratio will rise to 2.0 or higher as the lecithin
production increases to prevent alveolar collapse
Lecithin-sphingomyelin ratio
After 35 weeks of gestation
(5) parameters measured/detected for fetal maturity
when the L/S ratio reaches 2.0, a preterm
delivery is usually considered to be a relatively safe procedure
Lecithin-sphingomyelin ratio
After 35 weeks of gestation
(5) parameters measured/detected for fetal maturity
when the L/S ratio reaches 2.0, this is usually considered to be a relatively safe procedure
Lecithin-sphingomyelin ratio
preterm delivery
(5) parameters measured/detected for fetal maturity
when the L/S ratio reaches 2.0, aside from preterm delivery, what is the other indication?
Lecithin-sphingomyelin ratio
Indicates fetal maturity
(5) parameters measured/detected for fetal maturity
Results encountered in fluid contaminated with blood or meconium
Lecithin-sphingomyelin ratio
Falsely elevated results
both these substances contain lecithin and sphingomyelin
(5) parameters measured/detected for fetal maturity
Quantitative measurement of lecithin and sphingomyelin is performed using?
Lecithin-sphingomyelin ratio
thin-layer chromatography (TLC)
(5) parameters measured/detected for fetal maturity
SInce L/S ratio is labor intensive and subject to high CV, what did laboratories replace L/S ratio with?
(2)
- quantitative phosphatidyl glycerol immunoassays
- lamellar body density procedures
(5) parameters measured/detected for fetal maturity
- is also essential for adequate lung maturity
and can be detected after 35 weeks’ gestation - normally parallels that of lecithin, but its production is delayed in cases of maternal diabete
Phosphatidyl glycerol
(5) parameters measured/detected for fetal maturity
respiratory distress occurs in the
presence of an L/S ratio of?
2.0
(5) parameters measured/detected for fetal maturity
must include lecithin, sphingomyelin, and PG to provide an accurate measurement of FLM.
Phosphatidyl glycerol
thin-layer chromatography lung profile
(5) parameters measured/detected for fetal maturity
has provided a more rapid and easy to perform method for assessment of fetal maturity
Phosphatidyl glycerol
immunologic agglutination test for PG