Module 4 - Fetal Assessment (Exam 2) 1 Flashcards
Indications for Fetal Asessment Testing
- To detect congenital anomalies
- To evaluate the condition of the fetus
Ultrasound
Frequently used diagnostic tool throughout pregnancy. Intermittent ultrasonic waves are transmitted by a transducer. Ultrasonic waves deflect off tissues, showing images of different densities.
Advantages of Ultrasound
- Non-invasive
- Painless
- No known side effects for fetus or patient
- Information obtained is abundant and accurate
Transabdominal Ultrasound
Placedon patient’s abdomen
Transvaginal Ultrasound
Inserted into vagina
Nursing Responsibilites regarding Ultrasound
- Educate:
- Full bladder for transabdominal ultrasound in early pregnancy
- Empty bladder for transabdominal ultrasound in late pregnancy
- Remain in one position for 20-30 minutes
- Abdominal or vaginal pressure
- Support the patient
What should you tell the patient regarding urination during an early pregnancy ultrasound?
Full bladder
What should you tell the patient regarding a late pregnancy ultrasound?
Empty the bladder
Indications for Ultrasound in Early Pregnancy
- Confirm Pregnancy
- Viability of fetus
- Location of pregnancy
- Determine gestational age
- Screening for potential fetal anomalies
- Identify multiple gestations
- Visualization for other procedures
Indications for Ultrasound in Mid Pregnancy (20 weeks)
- Evaluate fetal anatomy, organ structure, and function
- Identify gender
- Head and chest circumference and femur length (assess fetal growth)
- Less accurate in dating of pregnancy
Indications for Ultrasound in Late Pregnancy
- Check on fetal well-being (fetal oxygen status)
- Biophysical profile
- Amniotic fluid index
- Locate Placenta
- Estimate fetus size
- Visualization for other procedures
- Fetal presentation
- Portable ultrasound at bedside (triage/labor)
Multiple Marker Screening
Screens for chromosomal abnormalities and neural tube defects. It is an adequate first screening to determine need for more invasive testing. Evaluates substances found in maternal serum from fetal liver.
- Trisomy 21 and 18
- Spina bifida, meningocele, anencephaly
Which substances does the Multiple Marker Screening evaluate from the maternal serum?
Substances found in maternal serum from fetal liver:
- Alpha-fetoprotein (AFP)
- Human chorionic gondotropin (HCG)
- Unconjugated estriol
When is the Multiple Marker Screening performed?
- Completed between 15-20 weeks gestation
Multiple Marker Screening Results
- Maternal levels are compared to normal levels for the number of weeks gestation
- Abnormal Levels
- 60% accurate for chomosomal anomalies (trisomy 18 and 21)
- 80-90% accurate for neural tube defects
- False positive rate is most frequently due to inaccurate estimation of gestational age
Amniocentesis
To obtain amniotic fluid by use of a needle for a variety of tests
When is amniocentesis performed?
- Second trimester (15-20 weeks)
- After 35 weeks
Amniocentesis Second Trimester
- Screen for or confirm presence of choromosomal abnormalities
- Confirm a neural tube defect (follow up for a positive multiple marker screen)
Amniocentesis Third Trimester
- Assess fetal lung maturaity (after 35 weeks)
- Test for fetal hemolytic disease (bilirubin levels)
Amniocentesis Procedure
- Patient’s abdomen is scanned by ultrasound to identify an adequate pocket of amniotic fluid
- Abdomen is cleansed and local anesthetic given
- Sample is withdrawn using needle/syringe
Composition of Amniotic Fluid
- Fetal urine
- Fluid from maternal blood transported across amnion
- Epithelial cells (contain DNA)
- Fluid from fetal lungs
- May contain vernix or meconium
Advantage of amniocentesis
Accuracy of data
Disadvantages of Aminocentesis
- Labor
- Bleeding
- Premature rupture of membranes (PROM)
- Invasive
- Fetal injury
- Damage to umbilical cord vessels
- Placenta infection
- Rh sensitization for Rh negative parent
Nursing Responsibilites for Amniocentesis
- Instruct patient regarding what will occur
- Ensure that she empty her bladder
- Monitor VS and FHR baseline (if possible)
- Assist physician with procedure
- Monitor FHR (if possible) and contraction status for at least 20-30 minutes after procedure
-
After Procedure:
- Monior VS per protocol after procedure
- Monitor puncture site for bleeding, fluid
- Administer Rhogamif patient is Rh negative and unsensitized
- Instruct patient to call MD for fever, chills, vaginal bleeding, contractions, fluid leakage
Surfactant
Decreases surface tension of lungs, allowing them to remain slightly inflated all the time
- Lecithin
- Sphingomyelin
- Phosphatidylglycerol
How is lung materity assessed?
Aminocentesis - sufactant
Lecithin/Sphyngomyelin
- Present in fetal amniotic fluid at about 35 weeks gestation in a ration of 2 to 1
- L/S ratio of 2 to 1 indicated fetal lung maturity
Phosphatidylglycerol
- Present in fetal amniotic fluid at about 35 weeks gestation
- PG present indicates fetal lung maturity
Summary of assessment of lung maturity (amniocentesis)
L/S ration 2 to 1 with PG present in amniotic fluid = fetal lung maturity
Third Trimester Fetal Oxygenation Assessment
- Fetal Movement
- Kick counts
- Fetus will conserve energy if oxygen levels are low
- This is detected by mother as decreased movement
- Kick counts
Nursing Responsibilities for Third Trimester: Kick Counts
- Instruct the patient to lie on her side
- Count the number of fetal movements for a time specified by her provider
- Complete procedure daily at same time
- Increase fluids if fetus is moving less than the number specified
- Call the provider if movements continue less than the number specified
Non-Stress Test
Assessment of fetal oxygenation status using the external fetal monitor (EFM)
Evaluation of Non-Stress Test
- After 30 weeks gestation
- Normal fetal baseline heart rate of 110-160 BPM
- Moderate baseline variability (6-25 BPM) around the baseline heart rate
- Accelerations with fetal movement
Physiologic basis behind non-stress test
- Fetus who is well oxygenated should move in utero
- Fetus who is well oxygenated should have a heart rate which has a normal baseline, moderate variablitiy, and shows acceleration when moving
- A fetus who is hypoxic will not have enough oxygen to meet these criteria
- First screening test used to determine fetal oxygen status
Full Term Infant - Reactive (Non-stress test)
- 2 accelerations of 15 beats above the baseline heart rate lasting 15 seconds
- Normal baseline heart rate lasting 15 seconds
- Normal baseline heart rate
- Moderate variability (6-25 BPM)
Full Term Infant - Non-Reactive (Non-stress test)
Criteria of reactive were not met
Full Term Infant- Unsatisfactory (Non-stress test)
- Inability to obtain consistent tracing
Nursing Responsibilities for Non-stress test
- Apply external monitor to patient’s abdomen
- Record fetal heart rate for a minimum of 20 minutes
- Instruct patient to indicate fetal movement by pushing a recording button
Advantages of the Non-Stress Test
- Non-invasive
- Accurate
- No known side effects or risks
Disadvantages of the Non-Stress Test
- May be difficult to obtain accurate tracing
- Patient may be required to stay in one position for up to 40 minutes if unable to ovtain accurate tracing
Why is the Non-Stress Test indicated after 30 weeks?
The fetus is mature enough to show nromal heart beat charcteristics
Biophysical Profile
- High Risk mothers
- Combination of data from:
- Non-Stress Test
- Amniotic fluid level (index) *Ultrasound*
- Fetal Movement *Ultrasound*
- Fetal “Breathing” *Ultrasound)
- Fetal Tone *Ultrasound*
Amniotic Fluid Index (AFI)
- Estimation of the amount of amniotic fluid present when fetus is close to term
- Ultrasound is used to detect pockets of fluid in the amniotic sac
- Pockets of fluid are measured to determine the index
Why is the amniotic fluid index (AFI) important?
- Amniotic fluid consists primarily of fetal urine when fetus is close to term
- A well-oxygenated fetus will have adequate blood flow to the kidneys
- If kidneys are well perfused with blood, will produce adequate urine
- A poorly oxygenated fetus will have little blood flow to the kidneys
Biophysical Profile Interpretation
- Score of 8-10 considered reassuring if amniotic fluid volume is =2
- Fetus is well-perfused with oxygen
- As the amniotic fluid level drops, fetal perfusion is considered to be worsening
