Fetal cerebral energy metabolism and electrocardiogram during experimental umbilical cord occlusion and resuscitation.
OBJECTIVE
The purpose of this experimental study was to elucidate alterations in fetal energy metabolism in relation to ECG changes during extreme fetal asphyxia, postnatal resuscitation and the immediate post-resuscitatory phase.


METHODS
Five near-term fetal sheep were subjected to umbilical cord occlusion until cardiac arrest followed by delivery, resuscitation and postnatal pressure-controlled ventilation. Four sheep served as sham controls and were delivered immediately after ligation of the umbilical cord. Fetal ECG was analysed online for changes of the ST segment. Fetal metabolism was monitored by intracerebral and subcutaneous microdialysis catheters.


RESULTS
Fetal ECG reacted on cord occlusion with an increase in the T-wave height followed by changes in intracerebral levels of oxidative parameters. Cerebral lactate/pyruvate ratio and glutamate increased to median (range) of 240 (200-744) and 34.0 (22.6-60.5) mmol/l, respectively; both parameters returned to baseline after resuscitation. Cerebral glucose decreased to 0.1 (0.08-0.12) mmol/l after occlusion and increased above baseline upon resuscitation. In subcutaneous tissue as well as blood the increase in lactate occurred with a delay compared to cerebral levels.


CONCLUSIONS
The fetal ECG changes related to asphyxia preceded the increase in excitotoxicity as determined by increase in cerebral glutamate during asphyxia. Cerebral lactate increase was superior to subcutaneous lactate increase.
Amer-Wåhlin
Isis
I
Department of Clinical Sciences Lund, Lund University, Lund, Sweden. isis.amer-wahlin@ki.se
Nord
Anders
A
Bottalico
Barbara
B
Hansson
Stefan R
SR
Ley
David
D
Marsál
Karel
K
Ungerstedt
Urban
U
Nordström
Carl Henrik
CH
D000818:Animals; D001921:Brain / Q000098:blood supply / Q000196:embryology* / Q000378:metabolism; D001923:Brain Chemistry; D016887:Cardiopulmonary Resuscitation; D004195:Disease Models, Animal; D004562:Electrocardiography; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005311:Fetal Hypoxia / Q000209:etiology / Q000378:metabolism; D018698:Glutamic Acid / Q000032:analysis / Q000097:blood; D006323:Heart Arrest / Q000209:etiology / Q000378:metabolism*; D019344:Lactic Acid / Q000032:analysis / Q000097:blood; D011247:Pregnancy; D019289:Pyruvic Acid / Q000032:analysis / Q000097:blood; D012756:Sheep; D014470:Umbilical Cord / Q000502:physiology
D019344:Lactic Acid; D018698:Glutamic Acid; D019289:Pyruvic Acid