AMNIOTIC FLUID Flashcards
Amniotic fluid is found
AMNION
Ultimate source of AF water and solutes
Placenta
During 1ST TRIMESTER AMNIOTIC FLUID IS DERIVED FROM
MOTHER (35 mL
DURING 2ND TRIMESTER AMNIOTIC FLUID IS DERIVED FROM
FETAL URINE
DURING 3RD TRIMESTER THE AMNIOTIC FLUID IS DERIVED FROM
Fetus releasess lung fluid
Amniotic fluid is regulated through
FETAL SWALLOWING
INTRAMEMBRANOUS FLOW
Function of Amniotic fluid
- cushion for fetus
- development
- movement
- stabilizes temperature
NORMAL VALUE
800-1200 mL
- INCREASES throughout pregnancy
- DECREASES before delivery
Increased AF
>1200 mL
POLYHYDRAMNIOS
Increased AF is due to
- Decrease fetal swallowing
- neural tube defect
Decreased AF
>800mL
OLIGOHYDRAMNIOS
Oligohydramnios is due to
- Increased fetal swallowing
- Membrane leakage
- Urinary tract deformities of fetus
METHOD OF COLLECTION OF AF
AMNIOCENTESIS
Maximum volume collected
30 mL
Volume discarded to avoid maternal blood, tissue fluid, cell contamination
2-3 mL
Amniocentesis is safe to perform around
14th WEEK OF GESTATION (early 2nd trimester)
2nd Trimester Amniocentesis is subjected to
CHROMOSOMAL STUDIES
(Genetic anomalies, Trisomy 21/Down syndrome)
Used for assessment of FETAL LUNG MATURITY and HEMOLYTIC DISEASE OF A NEWBORN
3RD TRIMESTER
Amniotic fluid subjected to assessment of FETAL LUNG MATURITY IS TRANSFERRED USING
ICE
TEST CANNOT BE DONE ASAP THEN REFRIFERATE
TEST FOR CYTOGENETICS/MICROBIOLOGY
Kept at ROOM TEMPERATURE OR BODY TEMPERATURE
TEST FOR HEMOLYTIC DISEASE OF THE NEWBORN
- detects BILIRUBIN
Materials use to protect Bilirubin
- Amber-colored bottle
- Foil-wrapped bottle
- Black plastic cover
FERN TEST DETECTS
Ruptured Amniotic Membrane (RAM)
FERN-LIKE CRYSTALS ARE COMPOSED OF
PROTEIN AND NACI
Other term for HDN
Erythroblastosis Fetalis
Destruction of RBC releases RBC degradation product such as
BILIRUBIN
Test used for HDN
OD 450
Normal absorbance of AF
Increased @365 nm
Decreased @550 nm
HDN absorbance
Increased @ 450nm
Maximum bilirubin absorbance
450 nm
Absorbance result are plotted using
LILEY GRAPH
Reporting of Liley Graph
Zone I - non affected/mildly affected
Zone II - Moderately affected fetus (monitoring)
Zone III - Severely affected (intervention)
Interferences in OD 450
CHOCOLATE MADE HEAVENLY DENSER
Cells
Meconium
Hemoglobin (peak absorbance @450)
Debris
PATHOGENICITY RELATED TO NEURAL TUBE DEFECTS
- SPINA BIFIDA (incomplete closing of backbone)
- ANENCEPHALY (absence of major portion of brain and scalp)
MAJOR PROTEIN PRODUCED BY FETAL LIVER
ALPHA-FETOPROTEIN (AFP)
Production of AFP starts
EARLY 18TH WEEK GESTATION
AFP is increased or decreased in both AF AND MATERNAL SERUM
INCREASED
If the skin fails to close neural tissues, there will be a continuous production of AFP
TRUE OR FALSE
TRUE
SCREENING TEST RESULT FOR NEURAL TUBE DEFECT
Increased AFP: Spina Bifida, Anencephaly
Decreased AFP: Down syndrome
CONFIRMATORY TEST USES
ACETYLCHOLINESTERASE (AChe)
Acetylcholinesterase should not be performed when
THERE IS A BLOODY SPECIMEN
- may cause false elevation
TEST FOR FETAL LUNG MATURITY
Reference Method
L/S RATIO
Lecithin/Sphingomyelin Ratio
Characteristics of Lecithin
- Primary component of lung surfactant
- Before and During 35th WEEK: LOW PROD
- After 35th WEEK: HIGH PROD
SPHINGOMYELIN CHARACTERISTICS
- Produced at a constant rate
<35 weeks: Decreased L - Increased S
>35 weeks: Increased L - Decreased S
REPORTING OF RESULTS (L/S RATIO)
<1.6 L/S = <35 weeks (immature)
>2.0 L/S = MATURE (preterm delivery is safe)
IMMUNOLOGIC TEST FOR PHOSPHATIDYL GLYCEROL
AMNIOSTAT-FLM
Production of PHOSPHATIDYL GLYCEROL IS PARALLEL TO THE PRODUCTION OF ___
LECITHIN
ADVANTAGE AND DISADVANTE OF PHOSPHATIDYL GLYCEROL
ADVANTAGE: not affected by blood and meconium
DISADVANTAGE: Phosphatidyl glycerol is DECREASED AMONG DIABETIC MOTHER
FOAM TEST / SHAKE TEST (MECHANICAL) PROCEDURE
Amniotic Fluid + 95% ethanol
Shake for 15 secs
Stand for 15 minutes
MATURE LUNG = (+) FOAM/BUBBLES
FOAM STABILITY INDEX PROCEDURE
- 0.5 mL AF + Inc. amt 95% Ethanol (0.42-0.55)
- Shake 15 secs
- stand for 15 minutes
POSITIVE RESULT FOR FOAM STABILITY INDEX
MATURE LUNG = FOAM FORMATION @>0.47 tUBE
Test that measures friction when particle is diffused
MICROVISCOSITY
Microviscosity is measured through
Fluorescence Polarization
What is being measured in Micro viscosity test
Surfactant/Albumin ratio
Increased surfactant has INCREASED OR DECREASED FRICTION
DECREASED
(Surfact is inversely proportional to friction)
PRODUCES LUNG SURFACTANT STORED IN THE FORM OF LAMELLAR BODIES
TYPE II PNEUMOCYTES
LAMELLAR BODY COUNT METHOD
Impedance and Optical scatter
Has same diameter to platelets
LAMELLAR BODIES
ADEQUATE FETAL LUNG MATURITY IN LAMELLAR BODY COUNT
> 32,000/uL Lamellar body
OD 650 nm
Increased Lamellar = Increased OD
(> 0.150) in OD 650 nm is equivalent to
L/S Ratio of >2.0
Presence of Phosphatidyl glycerol
Most FREQUENT COMPLICATION OF EARLY DELIVERY
RESPIRATORY DISTRESS SYNDROME
Respiratory distress syndrome is caused by
INSUFFICIENT LUNG SURFACTANT
Function of lung surfactant
Allow alveoli to open and close in respiration
TEST FOR FETAL AGE DETECTS
AF CREATININE
REFERENCE FOR FETAL AGE (CREATININE)
<36 WEEKS = 1.5-2.0 mg/dL
36 WEEKS = >2.0 mg/dL