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Background
A. Definition: multiple biophysical parameters evaluated at a single setting
1. Dynamic
a. Fetal heart rate (Fhr): nonstress test (NST)
b. Fetal breathing movements (FBM) (1) Incidence (2) Rate c. Fetal body movements (FM): incidence d. Fetal blood flow: Doppler velocimetry
2. Static
a. Amniotic fluid volume (AFV)
(1) Pockets
(2) Quadrants
b. Neurologic tone: flexion-extension
c. Placental grade
B. Significance of biophysical parameters
1. FHR: interrelationship of autonomic nervous system (ANS), acid-base balance, oxygenation, conduction, contract
a. Clinical significance: standard tool assessing fetat-placental respiration, caloric reserves
b. Baseline data
(I) Rate
(2) Variability
(3) Response to stimuli
(4) Periodic changes
2. FBMs
a. Examples
(1) Central respiratory regulation (2) Acid-base balance
(3)Oxygenation
Neuromuscular integrity.
(5)Maturity
b. Clinical significance
(1) Episodic
(2) Related to time of day
(3) Electroconical state
(4) Maternal fed state
c. Baseline data
(1) Incidence (percent time spent breathing)
(2) Rate
(3) Varibility
3. Fetal body movements
a. Examples
(1) Neuromuscular integrity
(2) Oxygenat. ion
(3) Caloric reserves
b. Clinical signlilacs: rough measure of caloric homeostasis
c. Baseline data
(1) Incidence (percent time spent moving)
(2) Numeric counts
4. AFI
a. Examples
(1) Aggregate of fetal urination
(2) Gastrointestinal motility
(3) Tracheal flow
(4) Membrane exchange
b. Clinical significance
(1) Peaks at 34-36 weeks
(2) Reflects visceral shunting
(3) Anomalies
(4) Growth disturbances
c. Baseline data,: quantitative assessment
(2) Pockets
(3) Quadrants
5. Neurologic tone: reflex activity which may be elicited (sound) or spontaneous
a. Clinical significance
(1) Oxygenation
(2) Central nervous system integrity
(3) Motor function
b. Baseline data
(1) Flexion-extension
(2) Attitude
(3) Startle reflex
(4) Sucking
6. Placental grade
a. Morphologic description of placenta] maturity (senescence)
b. Clinical significance
(1) Crude estimate of placental aging
(2) May be more advanced in disease states
C. Concept of fetal states
1. Biophysical behavior is related at term to organized clusters called "states" a. State 1: quiet sleep
b. State 2: rapid eye movement sleep c. State 3: intermediate d. State 4: "wakefulness" (active)
State influences
a. Time of day: circadian rhythms
b. Maternal diem,'),' status, oxygenation
c. Maternal drugs
d. Gestational age
III. TECHNIQUE OF BIOPHYSICALING
A. Instrumentation
1. Electronic FHR monitor
a. Doppler
b. Air encephalogram (AECG)
2. Realtime ultrasound (US)
B. Test conditions
1. Standardized for a. Time of clay b. Maternal status
c. Length of observation
2. Concurrent acquisition of biophysical
A. "Standard" biophysical profile (Manning and Platt 1989):
Sequential NST and US
2. NST: two or more accelerations > 15 beats per minute (bpm) in 20
minutes
3. Realtime scan
a. FBM: > 30 seconds of continuous breathing
b. FM: > 3 movements
c. Fetal tone: > 1 flexion-extension episode
d. AFV: one pocket of 10 mm X 10 mm
e. Placement grade < 3
4. Overall test requires 25-70 minutes
5. Scoring system
a, Each parameter ranges from