|
Physiologic
Basis of Fetal Heart Monitoring
The
swimmer's analogy holds true when thinking about the potential
reversible causes of uteroplacental insufficiency. Many of the causes
that are uterine or maternal in origin can be easily reversed, such as
uterine hyperstimulation or maternal hypotension, just like it would be
easy to have the swimmer stay under water for a shorter duration of
time or have him breathe cleaner air when not submerged. But
placental causes, such as infarction or abruption are likely to not be
ameliorated by normal resuscitative measures.
|
Placental causes
(unhealthy swimmer)
Abruption
Infarction
Increased placental resistance
|
Uterine causes
(submerged too long)
Hyperstimulation
Tetanic contraction
|
Maternal causes
(smoky atmosphere)
Hypotension
Hypoxia
|
Another
cause of decreased fetal oxygenation is decreased umbilical cord
patency (cord compression). In the analogy above (although
not
anatomically analogous), imagine the swimmer having to breathe through
a snorkel each time he comes out of the water. If
the lumen
of the snorkel were compressed, the swimmer would have difficulty
recovering when he is out of the water. Similarly, any event
that
causes umbilical cord compression will decrease oxygen
delivery to
the fetus.
<<
Back | Next >>
|
