The diverse effects of vasopressors on the fetoplacental circulation of the dual perfused human placenta.
BACKGROUND
We studied the effects of 5 vasopressors on fetal arterial perfusion pressure (FAP) in vitro using the dual perfused, single isolated cotyledon, human placental model.


METHODS
In 29 separate experiments, epinephrine (75 mg), norepinephrine (75 mg), ephedrine (50 mg), phenylephrine (2 mg), and methoxamine (40 mg) were introduced into the 250-mL reservoir serving the maternal perfusion circuit to determine the effect of each drug on FAP. The duration of drug exposure for each placental cotyledon was approximately 180 minutes.


RESULTS
After 180 minutes, FAP (mean +/- sd) increased significantly with ephedrine from 64 +/- 3 to 172 +/- 71 mm Hg (P < 0.001) and with phenylephrine from 81 +/- 4 to 132 +/- 11 mm Hg (P = 0.003). No changes in FAP were seen with epinephrine, norepinephrine, and methoxamine.


CONCLUSIONS
In the dual perfused, single isolated cotyledon, human placental model, exposure of the maternal circulation to ephedrine and phenylephrine caused an increase in FAP, whereas exposure to norepinephrine, epinephrine, and methoxamine did not. The pharmacodynamic mechanisms underlying these differences have yet to be explained. Thus, the clinical implications of the findings are as yet unclear.
Minzter
Beth H
BH
Division of Anesthesiology, Cleveland Clinic, Cleveland, Ohio, USA.
Johnson
Raymond F
RF
Paschall
Ray L
RL
Ramasubramanian
Ramiah
R
Ayers
Gregory D
GD
Downing
John W
JW
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D004809:Ephedrine / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D005865:Gestational Age; D006801:Humans; D066298:In Vitro Techniques; D008729:Methoxamine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D010477:Perfusion; D010656:Phenylephrine / Q000494:pharmacology; D010920:Placenta / Q000098:blood supply*; D021041:Placental Circulation / Q000187:drug effects*; D011247:Pregnancy; D013997:Time Factors; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D004809:Ephedrine; D008729:Methoxamine; D009638:Norepinephrine; D004837:Epinephrine