|
Electronic
fetal monitoring (EFM) during labor remains a
controversial
procedure because it continues the "medicalization"
of
the normal birth process (McRae, 1999). The
purpose of EFM
is
to detect complications during labor, particularly hypoxia,
metabolic
acidosis in order to prevent brain damage (cerebral
palsy)
or fetal death (Garite, 2001).
At
the time EFM was introduced in the 1950s, physicians felt
that
its use would also reduce the cesarean birth rate because
hypoxia
could be more accurately diagnosed. However, there has
been
no significant reduction in cerebral palsy since EFM was
introduced
(Garite, 2001) and the cesarean rate in the U.S.
has
steadily risen (Merck Manual Online, 2002).
On
the plus side, the number of stillbirths during labor has
been
reduced to almost zero (Schifrin, 1999). Additionally,
EFM
is a convenient and accurate means to determine the status
of
a fetus. Paradoxically, though
criticized as being more
highlt
technical than necessary for a normal labor and delivery,
EFM
is an accurate means to determine whether the fetus
remains
healthy and "normal."
Forms
of EFM include
- Doppler
auscultation through the mother's abdomen
- External
or internal electrical fetal heart rate (FHR)
monitoring. Be aware that
* Internal
electrical FHR monitoring is contraindicated
for fetuses with face or unknown presentation, when
placenta previa
occurs, or in others who are IV
positive or have genital herpes (British Columbia
Reproductive Care Program, 1997).
* Abnormal rhythms and artifacts are not unusual
during normal labor,
so the FHR itself does not give
an indication of fetal oxygenation.
* EFM yields a strip that shows both the rate and
pattern of heart beats.
* Along with the uterine contraction monitor, electrical
FHR monitoring gives some indication about how the
fetus is handling contractions (FDA, 2000).
-
Fetal scalp sampling of the blood pH, an invasive
procedure
* The normal fetal blood pH is >7.25.
A pH of
<7.0 indicates an urgent emergency.
* The procedure is not done if there is a history of
hemophilia in the family or if the mother is HIV
positive or has genital herpes (British Columbia
Reproductive Care Program, 1997).
-
Fetal oxygen saturation monitoring, to measure fetal
oxygenation continuously during labor, another invasive
procedure
* This device is used when the FHR is compromised, to
determine whether the change in the FHR is affecting
the fetus.
* The sensor is inserted into the uterus and rests
on the fetus's cheek or temple.
* Fetal oxygen saturation monitoring can only be done
with a single fetus at least 36 weeks old, a normal
vertex position (head down, face to the posterior),
and a broken amniotic membrane.
Indications
for EFM include
-
Vaginal birth after cesarean (VBAC) patients, to more
accurately determine when a cesarean is necessary
(Johnson, 2000).
-
Any high risk pregnancy, such as a diabetic or hyper-
tensive mother, or high risk situation such as
oligohydrammios, premature labor, post-term pregnancy.
-
Any complication, such as an inaudible pulse, meconium
stained amniotic fluid, hemorrhage, premature rupture
of membranes, or difficult labor.
EFM
has become routine in hospital settings, promoted
by
nurses as well as obstetricians. The
question remains
whether
it is appropriate or desirable for all cases.
Nurse
midwifery
education emphasizes avoiding medical
intervention
unless complications ensue. Yet
labor nurses
eagerly
embrace the objective data EFM provides (Hoerst
& Fairman, 2000). As with any high technology intervention,
hands-on
assessment remains an important part of the
overall
picture patients present.
Bibliography:
Garite,
T.J. (2001). Evaluating fetal
hypoxia with pulse
oximetry.
Contemporary OB/GYN, July, 2001.
Hoerst,
B.J. & Fairman, J. (2000). Social
and professional
influences
of the technology of electronic fetal monitoring
on
obstetrical nursing. Western
Journal of Nursing Research,
22,
475-491.
Johnson,
K. (2000). Fetal pulse oximetry
raises VBAC success
rate.
Family Practice News, May 15, 2000.
McRae,
M.J. (1999). Fetal surveillance and
monitoring legal
issues
revisited. Journal of Obstetric,
Gynecologic, and
Neonatal
Nursing, 28, 410-419.
Merck
Manual Online (2002). Management of
normal labor.
Retrieved
June 29, 2002.
http://www.merck.com/pubs/mmanual/section18/chapter249/249e.htm.
Nesbitt,
B. (1999). The pitfalls of fetal
monitoring,
Interview
with Barry Schifrin, MD, American Institute of
Ultrasound
in Medicine, San Antonio, Texas, March, 1999.
Retrieved
June 29, 2002.
http://www.obgyn.net/avtranscripts/nesbitt_schifrin_aium.htm.
|
