Pressor, heart rate and plasma catecholamine responses to noradrenaline in pregnant and nonpregnant women

Autor: M. M. Ramsay, P. C. Rubin, F. Broughton Pipkin
Rok vydání: 1993
Předmět:
Zdroj: BJOG: An International Journal of Obstetrics and Gynaecology. 100:170-176
ISSN: 1471-0528
1470-0328
Popis: OBJECTIVE To study cardiovascular responses to noradrenaline during early pregnancy. DESIGN Administration of incremental intravenous infusions of noradrenaline under basal conditions. SETTING University Hospital, Nottingham. SUBJECTS Nineteen women admitted for termination of pregnancy in first or second trimester and 18 nonpregnant women as control subjects. INTERVENTIONS Recordings of blood pressure and heart rate responses during the infusion of noradrenaline. Blood samples taken before, during and after the infusion. MAIN OUTCOME MEASURES Evoked responses of systolic and diastolic blood pressure and heart rate at steady state during the noradrenaline infusion. Plasma catecholamine concentrations measured by high performance liquid chromatography. RESULTS There were no significant differences between the evoked pressor responses to noradrenaline in pregnancy compared to the nonpregnant state, but there was a lesser bradycardia in response to a standardised change in blood pressure. Neither basal plasma catecholamine concentrations nor those achieved during infusion of noradrenaline differed between pregnant and nonpregnant women. Thirty minutes after discontinuance of the infusion there was a persistent elevation of heart rate in all women, although plasma catecholamine concentrations had returned to basal levels. In pregnant women, systolic and diastolic blood pressures were also elevated at this time, compared to preinfusion levels. CONCLUSION Cardiovascular regulatory mechanisms are altered in pregnancy with a diminution in the bradycardic response to a pressor challenge evoked by noradrenaline and a delayed recovery from that challenge.
Databáze: OpenAIRE
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