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Electronic Fetal Heart Rate Monitoring—Risks, Benefits, Future, and Strategies to Avoid Pitfalls
metabolic acidosis. If the metabolic acidosis is severe enough and lasts for
Figure 1: Model for Declining Fetal Respiratory Status and the
long enough, tissue damage will occur and the fetus will either become
Development of Hypoxia, Acidosis, and Death
damaged or die if an intervention to reverse the process by delivery and
resuscitation of the baby does not occur.
Normal oxygenation
Fortunately, the FHR of the baby can accurately depict the malfunctions
that can lead to fetal hypoxia. In a laboring mother, the fetus will always
experience decelerations that warn of the presence of hypoxia. Late Hypoxia
decelerations tell us that the placenta is not providing enough oxygen,
and variable decelerations can indicate hypoxia due to umbilical vascular
blockage. However, to diverge, although the primary reflex for umbilical
Acidosis
cord patterns, i.e. variable decelerations, is a baroreceptor reflex caused
by the blood pressure changes that occur with umbilical cord
obstruction, as these decelerations become deeper and last for longer
hypoxia becomes more likely. Sudden and profound hypoxia (due to
Tissue damage/death
either placental or cord problems) can also lead to prolonged
deceleration and bradycardia. Other changes in the FHR such as
tachycardia and loss of variability and loss of accelerations are not due to
Table 1: Common Problems with Electronic Fetal Heart
hypoxia per se, but to the consequences of hypoxia and developing
Rate Monitoring
acidosis. In a laboring patient with developing hypoxia and acidosis,
variable, late, or prolonged decelerations will come first, and as the Failure to adequately evaluate on admission
hypoxia becomes more severe tachycardia and/or a loss of accelerations Inadequate tracing
and loss of variability develop as the baby begins to become acidotic.
Failure to communicate severity of pattern
Thus, the FHR of the fetus will tell us when the baby is hypoxic and
Failure to recognize severity of pattern
acidotic, and at least where the problem is.
Failure to use common nomenclature
Failure of doctor to attend when nurse expresses concern
Delayed response time
Unfortunately, the problem with EFM is not that the hypoxic baby will not
Issues with oxytocin administration and hyperstimulation
be detected, but that many other things will affect the FHR besides
hypoxia. Fetal head compression during labor can cause early
decelerations, easily confused with late decelerations, and can also cause A review of extensive experience with lawsuits alleging substandard care
changes that mimic variable decelerations. Drugs or medications can with respect to EFM has led to a list of ‘key problem areas’
alter the FHR. Fetal diseases or anomalies can lead to confusing FHR (see Table 1). The following suggestions are made to assist care-givers
patterns. Previous neurological injury, not amenable to delivery and with improving care and outcome, and to decrease litigation related to
resuscitation, can cause profound FHR changes. Temperature alterations, problems with EFM.
both fever and hypothermia, will change the FHR. Thus, the major
problem of EFM is its lack of specificity. This means that while the FHR First, physicians, midwives, and nurses require ongoing education. This
will always be abnormal in the presence of significant hypoxia, when the can be accomplished in a number of ways, but recently both individual
FHR is abnormal this is more often due to causes other than hypoxia. Put hospitals and large hospital consortia have developed requirements
another way, a baby who is born hypoxic and acidotic will always have for staff stating that an annual course be taken and documented.
had an abnormal or non-reassuring FHR, but most babies with abnormal One such Internet-based educational program can be found at
or non-reassuring FHR patterns will be born well oxygenated and will be www.healthstream.com/hlc/hca-mdu
vigorous at birth.
3
Second, it is advised that all triage patients who are beyond 24 weeks
Another major problem with EFM is that it is based on pattern of gestation receive a monitoring strip prior to discharge, and that all
recognition, and care-givers and even experts cannot agree on abnormal non-reassuring or questionable strips be reviewed by a physician.
patterns. Care-givers given the same strip weeks apart will often differ
in interpretation from their original description. Even the computer Third, there must be a hospital policy put in place to determine which
interpretation of EFM has eluded us. patients require internal FHR and/or contraction monitoring. Not
all patients require internal monitoring, and this is true even of those
These are the bases of the many pitfalls of IP EFM. These pitfalls include with non-reassuring strips, but when an accurate FHR trace cannot be
an over-reaction to FHR patterns that are not associated with hypoxia. obtained—especially when there is any question regarding the
This leads to unnecessary interventions that increase anxiety for patients, reassuring status of the fetus—an internal electrode should be placed.
such as when the nurse uses oxygen on the mother or performs other
interventions, or unnecessary operative delivery takes place. Expectations Fourth, a nurse should initial the FHR strip every 15 minutes. Many
that EFM will lead to a perfect outcome lead to the blame and litigation hospital policies require that nurses perform extensive charting
that ensues when a baby is not perfectly normal. concerning every detail of the FHR in labor. Such policies are a waste of
US OBSTETRICS & GYNECOLOGY 61
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