Intrapartum Fetal Surveillance
Chapter 18
Intermittent auscultation and palpation
Using a fetoscope or Doppler, the nurse intermittently auscultates
FHR and palpates the abdomen. Mobility is the advantage.
Disadvantages include lack of printed record and only periodic data on
fetal response to UC. This also is more “staff-intensive.”
Electronic Fetal Monitoring
Heavily used in this area and most common in US. This allows a 1:2
nurse/patient ratio during stage 1 of uncomplicated labors. Supplies a
constant “paper trail” of activity both for fetal heart rate and UC. Also
allows the nurse to see subtle trends develop during labor. The biggest
limitation is that the mother lacks mobility while laboring. While it’s
possible to use remote tracing equipment, most electronic monitoring
equipment requires the mother to stay in bed and the belts must be
readjusted often with movement.
Central monitoring
The strips of laboring patients are displayed at a central place,
usually in the nursing station, so that the nurse doesn’t have to stay in
the room constantly. Also, when in another patient’s room, the nurse
can sometimes monitor her “other” patient periodically if she needs to.
FHT monitoring
External vs. internal
External
As described above, a belt is used to secure the Doppler to the
abdomen. This type is most commonly used and is non-invasive. A
limitation is that increased abdominal fat in the mother makes tracing
the FHT difficult.
Internal
A small spiral electrode (called fetal scalp electrode or FSE) is
placed on the fetal scalp which detects signals from the fetal heart.
Advantages include more precise monitoring that is not diminished by
fetal or maternal movement. Disadvantages include invasiveness and
need for minimum cervical dilation of 2-3cm along with ROM. This also
cannot be used in cases of some maternal infections and some blood
disorders.
UC monitoring
External vs. internal
External
A belt is used to secure the tocotransducer to the abdomen. This
is useful for monitoring frequency and duration of UC but not intensity.
Internal
This catheter (called an intrauterine pressure catheter or IUPC) is
inserted into the uterus between the wall and the presenting part. This
accurately measures intensity as well as frequency and duration. It may
also have a lumen for infusing fluid into the uterus. Invasive and
requires the same dilation, etc, that the FSE does.
Assessing FHT
Baseline
This is where the FHR stays when there are no UC or other
stimulations, etc. In a normal fetus, this is between 110-160 bpm.
Variability
This is the fluctuation in baseline FHR. Moderate variability
is 6-25 bpm and is called “reassuring” because it is associated with
adequate fetal oxygenation and a healthy autonomic nervous system. See
figure 18-7 to compare minimal vs. moderate variability.
Accelerations
This is a recurrent increase in FHR that is associated with
UC. By definition the accel needs to be at least 15 bpm above baseline
and last at least 15 seconds. This is usually a reassuring sign.
Decelerations
Classified into three types.
Early
Fetal head compression slows FHR. See figure
18-9…they mirror contractions.
Late
Uteroplacental insufficiency causes decreases in
FHR that begin after the contraction has started and don’t recover until
the contraction is over. See figure 18-10. This pattern must be
addressed.
Variable
Abrupt falls in FHR during UC, these usually
indicate cord compression. See figure 18-11. These are more pronounced
closer to delivery.
Reassuring vs. Nonreassuring patterns
Reassuring
Accels and moderate variability are associated with fetal wellbeing.
Nonreassuring
Things like decels and minimal variability are more significant if
they occur together. There may be a transient reason for some FHR
patterns, i.e. variability declines when the mother is medicated for pain
with narcotics. Things like fetal scalp stimulation can be done to further
assess the fetus and clarify data. There are several nursing interventions
plus things covered by standing orders that the nurse can do.
ID the cause
Check VS
do SVE
Increase placental perfusion
Turn to left side
Bolus IV fluids
Discontinue Pitocin
O2 via facemask
amnioinfusion