Antihypertensive mechanism of ketanserin in postoperative hypertension after cardiopulmonary bypass.
The effect of ketanserin (0.15 mg/kg followed by an infusion at 6 mg/hr) was studied in 13 patients who developed hypertension (blood pressure greater than 150/90 mm Hg) after cardiopulmonary bypass (CPB) for coronary artery bypass grafting. Eleven patients responded to ketanserin with a decrease of arterial pressure from 159 +/- 15/83 +/- 10 mm Hg to 131 +/- 9/70 +/- 12 mm Hg (P less than 0.01), which was sustained during the subsequent infusion of ketanserin. Mean plasma ketanserin concentrations were maintained at 187 micrograms/L (range 118-525). No significant changes in plasma levels of 5-hydroxyindoles or in platelet 5-hydroxytryptamine content were observed during or after CPB, or after administration of ketanserin. Plasma epinephrine (398 +/- 124 pg/ml) and norepinephrine (1161 +/- 673 pg/ml) concentrations were markedly increased during the hypertensive period after CPB. Plasma epinephrine concentrations decreased (P less than 0.01) during ketanserin infusion to 213 +/- 101 pg/ml, whereas plasma norepinephrine concentrations did not change. The pressor response to three graded doses of phenylephrine was decreased during CPB (P less than 0.01), and a further decrease (P less than 0.05) occurred during infusion of ketanserin. The hypotensive effect of ketanserin after CPB may be attributable to alpha 1-adrenoceptor blockade rather than to its antiserotoninergic effect. Serotonin does not appear to be involved in the short-term disturbances of arterial pressure during or after CPB.
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Sir Humphry Davy Department of Anaesthesia, University of Bristol, Bristol Royal Infirmary, United Kingdom.
Carter
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Prys-Roberts
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D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D002315:Cardiopulmonary Bypass; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000097:blood; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007262:Infusions, Intravenous; D007650:Ketanserin / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology* / Q000627:therapeutic use; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D010656:Phenylephrine / Q000008:administration & dosage / Q000494:pharmacology; D011183:Postoperative Complications / Q000188:drug therapy*; D012701:Serotonin / Q000097:blood
D010656:Phenylephrine; D012701:Serotonin; D007650:Ketanserin; D009638:Norepinephrine; D004837:Epinephrine