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Effects of oxytocin and anaesthesia on vascular tone in pregnant women : a randomised double-blind placebo-controlled study using non-invasive pulse wave analysis

Rabow, Sofus LU ; Hjorth, Ull; Schönbeck, Sofia and Olofsson, Per LU (2018) In BMC Pregnancy and Childbirth 18(1).
Abstract

BACKGROUND: Oxytocin is an uterotonic drug with profound cardiovascular effects, which in compromised patients could lead to serious events. The objective was to investigate whether oxytocin affects cardiac function and vascular tone in large and small arteries. We hypothesized that oxytocin decreases arterial vascular tone and elevates cardiac output. METHODS: 51 pregnant women were randomised to treatment with 8.3 μg (5 U) oxytocin or placebo injection during first trimester surgical evacuation of the gravid uterus under general anaesthesia. Oxytocin or placebo was administered once either early or late in the procedure, in a double-blind fashion. Digital photoplethysmography pulse wave analysis variables, heart rate, mean arterial... (More)

BACKGROUND: Oxytocin is an uterotonic drug with profound cardiovascular effects, which in compromised patients could lead to serious events. The objective was to investigate whether oxytocin affects cardiac function and vascular tone in large and small arteries. We hypothesized that oxytocin decreases arterial vascular tone and elevates cardiac output. METHODS: 51 pregnant women were randomised to treatment with 8.3 μg (5 U) oxytocin or placebo injection during first trimester surgical evacuation of the gravid uterus under general anaesthesia. Oxytocin or placebo was administered once either early or late in the procedure, in a double-blind fashion. Digital photoplethysmography pulse wave analysis variables, heart rate, mean arterial blood pressure and electrocardiographic ST index were recorded before and after anaesthesia and after each injection. Non-parametric statistics were used with a two-sided P value < 0.05 considered significant. RESULTS: Anaesthesia induced a significant fall in blood pressure, heart rate and vascular tone in small and peripheral arteries. Oxytocin had a vasodilatory effect on small and peripheral arteries and increased the left cardiac ventricular ejection time. The ST index decreased. CONCLUSIONS: Pulse wave analysis indicated peripheral vasodilation and increased cardiac output after oxytocin, implying increased myocardial oxygen demand. These effects might have been enhanced by the vasodilating effects of anaesthesia. Previous studies have demonstrated myocardial ischaemia after oxytocin, as reflected by a decrease in ST index in the present study. TRIAL REGISTRATION: Trial registration number ISRCTN17860978 , 2018/03/14, Retrospectively registered.

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author
organization
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type
Contribution to journal
publication status
published
subject
keywords
Anaesthesia, Arterial stiffness, Oxytocin, Photoplethysmography, Placebo, Pregnancy, Pulse wave analysis, RCT, Vascular tone
in
BMC Pregnancy and Childbirth
volume
18
issue
1
publisher
BioMed Central
external identifiers
  • scopus:85057101055
ISSN
1471-2393
DOI
10.1186/s12884-018-2029-1
language
English
LU publication?
yes
id
fd835dd0-32c7-4d14-84bb-b77636582370
date added to LUP
2018-12-03 14:38:19
date last changed
2019-10-15 06:51:59
@article{fd835dd0-32c7-4d14-84bb-b77636582370,
  abstract     = {<p>BACKGROUND: Oxytocin is an uterotonic drug with profound cardiovascular effects, which in compromised patients could lead to serious events. The objective was to investigate whether oxytocin affects cardiac function and vascular tone in large and small arteries. We hypothesized that oxytocin decreases arterial vascular tone and elevates cardiac output. METHODS: 51 pregnant women were randomised to treatment with 8.3 μg (5 U) oxytocin or placebo injection during first trimester surgical evacuation of the gravid uterus under general anaesthesia. Oxytocin or placebo was administered once either early or late in the procedure, in a double-blind fashion. Digital photoplethysmography pulse wave analysis variables, heart rate, mean arterial blood pressure and electrocardiographic ST index were recorded before and after anaesthesia and after each injection. Non-parametric statistics were used with a two-sided P value &lt; 0.05 considered significant. RESULTS: Anaesthesia induced a significant fall in blood pressure, heart rate and vascular tone in small and peripheral arteries. Oxytocin had a vasodilatory effect on small and peripheral arteries and increased the left cardiac ventricular ejection time. The ST index decreased. CONCLUSIONS: Pulse wave analysis indicated peripheral vasodilation and increased cardiac output after oxytocin, implying increased myocardial oxygen demand. These effects might have been enhanced by the vasodilating effects of anaesthesia. Previous studies have demonstrated myocardial ischaemia after oxytocin, as reflected by a decrease in ST index in the present study. TRIAL REGISTRATION: Trial registration number ISRCTN17860978 , 2018/03/14, Retrospectively registered.</p>},
  articleno    = {453},
  author       = {Rabow, Sofus and Hjorth, Ull and Schönbeck, Sofia and Olofsson, Per},
  issn         = {1471-2393},
  keyword      = {Anaesthesia,Arterial stiffness,Oxytocin,Photoplethysmography,Placebo,Pregnancy,Pulse wave analysis,RCT,Vascular tone},
  language     = {eng},
  month        = {11},
  number       = {1},
  publisher    = {BioMed Central},
  series       = {BMC Pregnancy and Childbirth},
  title        = {Effects of oxytocin and anaesthesia on vascular tone in pregnant women : a randomised double-blind placebo-controlled study using non-invasive pulse wave analysis},
  url          = {http://dx.doi.org/10.1186/s12884-018-2029-1},
  volume       = {18},
  year         = {2018},
}