S.-H. Nong, Y.-M. Xie, X.-S. Huang, Y.-X. Zhang
Cerebral intracellular calcium concentrations in asphyxiated rat fetuses resuscitated with oxygen
Objective: To investigate the effects of resuscitation with
three different oxygen concentrations on cerebral intra- and
extra-cellular calcium, sodium and potassium
changes in asphyxiated rat fetuses.
Methods: Fifty-six fetal rats of gestational age of 20 days
were randomly assigned into five study groups: sham operation
group (control, n=11), room-air resuscitation
group (n=10), and 3 oxygen-resuscitated groups (n=14,
11, and 10 respectively). Different inhaled oxygen concentrations
and different timings of oxygen delivery
were assigned. Except for control all fetal rats were rendered
ischemic and hypoxic in utero by interrupting the
placental circulation. After re-circulation, intra- and extra-
cellular concentrations of calcium, sodium, and
potassium in the brains were measured for each individual
group.
Results: The mean intracellular free calcium concentration
of fetal rat brains was similar for the room-air resuscitation
group (552.1±93.5 nmol/L) and the group
resuscitated with 92.8% oxygen (520.6±79.1 nmol/L),
and both were significantly higher than in the control
(315.3±86.9 nmol/L) (P<0.001). After resuscitation
with 65% oxygen, be it instituted before or immediately
after hypoxia, their mean intracellular free calcium
concentrations in the brain cells (441.5±47.9 and
452.9±36.4 nmol/L respectively) were significantly lower
than those in the room-air resuscitation (P<0.01) and
92.8% oxygen group (P<0.05), though still higher than
in the control (P>0.05). There was no difference in the
total concentrations of calcium, sodium, or potassium
among all groups.
Conclusion: Resuscitation with 92.8% oxygen or room
air exerted a similar effect on the parameters measured,
indicating that resuscitation of asphyxiated neonates using
100% oxygen might not be superior to using room
air. Resuscitation with 65% oxygen resulted in lower
cerebral intracellular calcium concentrations and might
produce a better outcome than using 100% oxygen or
room air.
Journal of Perinatal Medicine, Walter de Gruyter
Print ISSN: 1619-3997
Volume: 30, 06/2002
Pages: 250 - 256
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