Maternal and fetal cardiorespiratory responses to adenosine in sheep.
OBJECTIVE
We determined the cardiorespiratory effects of maternal adenosine administration on the ewe and fetus.


METHODS
Adenosine was infused intravenously to five pregnant ewes as graded (25 to 400 micrograms/min per kilogram) and constant (200 micrograms/min per kilogram) infusions and as a single injection (200 micrograms/kg). Heart rate, arterial pressure, and arterial blood gases and pH were monitored in the ewe and fetus; the data were analyzed with two-way analysis of variance with Duncan's test.


RESULTS
Graded adenosine infusion produced a dose-dependent rise in maternal heart rate and hemoglobin concentration and a fall in diastolic and mean arterial pressures, effects that were maintained during 1 hour of constant infusion. Single injections transiently lowered diastolic pressure and induced a biphasic change in heart rate consisting of a bradycardia followed by a tachycardia with a return to control values. Adenosine administration to the ewe did not affect maternal arterial blood gases and systolic pressure nor alter fetal heart rate, arterial pressure, or arterial blood gases.


CONCLUSIONS
Although adenosine causes cardiovascular changes in pregnant ewes, the effects are well tolerated and do not significantly affect the cardiorespiratory status of the fetus.
Nicholas S. Assali Perinatal Research Laboratory, Department of Obstetrics and Gynecology, University of California, Los Angeles School of Medicine 90024.
B A
BA
Mason
D
D
Ogunyemi
O
O
Punla
B J
BJ
Koos
D000241:Adenosine / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects*; D005260:Female; D005333:Fetus / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood / Q000187:drug effects*; D012756:Sheep
D000241:Adenosine