Haemodynamic Effects of Oxytocin (Syntocinon®) and Methyl Ergometrine (Methergin®) on the Systemic and Pulmonary Circulations of Pregnant Anaesthetized Women

Nj, Secher; Arnsbo, Per; Wallin, L

doi:10.3109/00016347809155884

Cited by 79 publications

(27 citation statements)

References 20 publications

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“…Indeed, decreased blood pressure may be observed in response to oxytocin given intracerebroventricularly (5), and the inhibition of brain OT synthesis by an antisense oligonucleotide increased blood pressure in rats (6). In primates or humans, the administration of oxytocin often is associated with a decrease in blood pressure (7,8). Peripherally injected OT decreases mean arterial pressure in rats by unknown mechanisms (5, 9).…”

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confidence: 99%

Rat heart: A site of oxytocin production and action

Jankowski

Hajjar

Kawas

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

172

133

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We report here that the rat heart is a site of oxytocin (OT) synthesis and release. Oxytocin was detected in all four chambers of the heart. The highest OT concentration was in the right atrium (2128 ؎ 114 pg͞mg protein), which was 19-fold higher than in rat uterus but 3.3-fold lower than in the hypothalamus. OT concentrations were significantly greater in the right and left atria than in the corresponding ventricles. Furthermore, OT was released into the eff luent of isolated, perfused rat heart (34.5 ؎ 4.7 pg͞min) and into the medium of cultured atrial myocytes. Reverse-phase HPLC purification of the heart extracts and heart perfusates revealed a main peak identical with the retention time of synthetic OT. Southern blots of reverse transcription-PCR products from rat heart revealed gene expression of specific OT mRNA. OT immunostaining likewise was found in atrial myocytes and fibroblasts, and the intensity of positive stains from OT receptors paralleled the atrial natriuretic peptide stores. Our findings suggest that heart OT is structurally identical, and therefore derived from, the same gene as the OT that is primarily found in the hypothalamus. Thus, the heart synthesizes and processes a biologically active form of OT. The presence of OT and OT receptor in all of the heart's chambers suggests an autocrine and͞or paracrine role for the peptide. Our finding of abundant OT receptor in atrial myocytes supports our hypothesis that OT, directly and͞or via atrial natriuretic peptide release, can regulate the force of cardiac contraction.Vasopressin and oxytocin (OT) are synthesized predominantly in the magnocellular neurons of the supraoptic nucleus and paraventricular nucleus as well as in the parvocellular neurons within the paraventricular nucleus as parts of larger precursor molecules (1). The precursors are modified posttranslationally and are transported to the posterior pituitary, where the final bioactive peptide products are stored until they are released into the blood stream. Despite being the first peptide hormone to be characterized and synthesized, the effects of oxytocin long were considered to be restricted to stimulation of uterine contractions during labor and milk ejection during lactation. However, OT is found in equivalent concentrations in the neurohypophysis and plasma of both sexes, which suggests that it also may have other physiological roles (2). Moreover, in the central nervous system, OT-containing axons terminate in several brain stem nuclei known to be involved in cardiovascular control, suggesting a potential role for OT in central cardiovascular regulation (3, 4). Indeed, decreased blood pressure may be observed in response to oxytocin given intracerebroventricularly (5), and the inhibition of brain OT synthesis by an antisense oligonucleotide increased blood pressure in rats (6). In primates or humans, the administration of oxytocin often is associated with a decrease in blood pressure (7,8). Peripherally injected OT decreases mean arterial pressure in rats by unknown mec...

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mentioning

confidence: 99%

Rat heart: A site of oxytocin production and action

Jankowski

Hajjar

Kawas

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

172

133

View full text Add to dashboard Cite

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“…5 Human studies have shown an oxytocin-mediated decrease in pulmonary vascular resistance of approximately 44% following intravenous bolus administration of 10 units in healthy parturients in their first trimester. 6 The vasodilatory effect of the V 1 agonist, vasopressin, is enhanced in chronically hypoxic rat models, and our case suggests this is also true for oxytocin and its effects on the vasculature of chronically hypoxic human lungs. 7 Oxytocin may act in a dose-dependent manner through the V 1 receptor to diminish the protective effects of hypoxic pulmonary vasoconstriction and produce clinically significant hypoxemic hypoxia.…”

Section: Discussionmentioning

confidence: 53%

Acute hypoxemia in a parturient with primary ciliary dyskinesia following the administration of intravenous oxytocin: a case report

Nandhakumar

Silverman

2013

Can J Anesth/J Can Anesth

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Purpose We present the case of a parturient diagnosed with primary ciliary dyskinesia with secondary bronchiectasis who developed significant hypoxemia following administration of intravenous oxytocin during Cesarean delivery under spinal anesthesia. This case suggests that oxytocin can affect pulmonary vascular tone and interfere with the protective effects of hypoxic vasoconstriction. Clinical features A 35-yr-old primigravida at 37 weeks gestation presented for a scheduled Cesarean delivery due to breech positioning and fetal abnormalities. The patient had a diagnosis of primary ciliary dyskinesia and had undergone a right middle lobectomy seven years earlier for resultant bronchiectasis. Pulmonary function testing in the month prior to delivery showed a 4% decline in her baseline FEV 1 to 1.06 L (32% of predicted value) but she was functionally well. The patient initially had an uneventful spinal anesthetic and maintained an oxygen saturation of 97% on room air in the supine position until delivery of her baby. An intravenous infusion of oxytocin for uterine contraction was started following removal of the placenta. The patient then became acutely hypoxemic with a drop in room air saturation to 84% but with no other accompanying hemodynamic instability. Maternal oxygen saturation did not improve with the addition of supplemental oxygen, and the patient had a significant arterial-alveolar oxygen gradient suggesting an intrapulmonary shunt. No supporting clinical, radiologic, or laboratory evidence of a thrombotic, air, or amniotic fluid embolism or mucous plug was detected. The patient remained hypoxemic during the postoperative period with gradual improvement back to baseline saturation in approximately 48 hr. Conclusion The vasodilatory effects of intravenous oxytocin on the pulmonary vasculature may worsen shunting and interfere with hypoxic pulmonary vasoconstriction, producing clinically significant hypoxemia in patients with comorbid lung disease. Oxytocin should be used with caution in patients with compromised lung function. RésuméObjectif Nous présentons le cas d'une parturiente ayant un diagnostic de dyskinésie ciliaire primitive avec bronchiectasie secondaire qui a développé une hypoxémie significative après l'administration intraveineuse d'ocytocine au cours d'un accouchement par césarienne sous rachianesthésie. Ce cas suggère que l'ocytocine peut affecter le tonus vasculaire pulmonaire et bloquer avec les effets protecteurs de la vasoconstriction hypoxique. Caractéristiques cliniques Une femme primigeste de 35 ans à 37 semaines de grossesse s'est présentée pour un

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“…1,2 The most consistent cardiovascular changes observed after oxytocin are a doserelated decrease in arterial pressure due to peripheral vasodilation with a compensatory increase in HR and cardiac output. 1,2,10,11 We found that an IV bolus of 2 u oxytocin at Caesarean section resulted in less haemodynamic change than a 5 u bolus. The increase in HR was significantly greater and more prolonged after 5 u than after 2 u.…”

Section: Discussionmentioning

confidence: 80%

Comparison of Two Doses of Oxytocin for the Prevention of Postpartum Uterine Atony in Parturients Undergoing Emergency Caesarean Delivery: A Randomized Double Blind Study

Munshi¹,

Yunus²,

Jan³

et al. 2016

jemds

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BACKGROUNDThe optimal dose of oxytocin at Caesarean section is unclear. Oxytocin may cause adverse cardiovascular effects including tachycardia and hypotension, whereas an inadequate dose can result in increased uterine bleeding. We compared the effects of two doses of oxytocin in a randomized double-blind trial. METHODS80 patients undergoing emergency Caesarean section received an IV bolus of either 2 or 5 units (u) of oxytocin after delivery, followed by an oxytocin infusion of 10 uh -1 . All patients received spinal anaesthesia with mean arterial pressure maintained by injection ephedrine. We compared changes in Heart Rate (HR), Mean Arterial Pressure (MAP), blood loss, uterine tone, the need for additional uterotonic drugs and antiemetics. RESULTSThere was a greater increase in mean (SD) HR in patients who received 5u of oxytocin [32 (17) beats min -1 ] than in those who received 2 u [24 (13) beats min -1 ] (P=0.015). There was a larger decrease in MAP in patients who received 5 u [13 (15) mmHg] than in those who received 2 u [6 (10) mmHg] (P=0.030). The frequency of nausea and antiemetic use was higher after 5 u (32.5%) than 2 u (5%) (P=0.003). There were no differences in blood loss, uterine tone or requests for additional uterotonic drugs (17.5% in both groups). CONCLUSIONSIn emergency Caesarean section, a 2 u bolus of oxytocin results in less haemodynamic change than 5 u with less nausea and no difference in the need for additional uterotonics.

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Haemodynamic Effects of Oxytocin (Syntocinon®) and Methyl Ergometrine (Methergin®) on the Systemic and Pulmonary Circulations of Pregnant Anaesthetized Women

Cited by 79 publications

References 20 publications

Rat heart: A site of oxytocin production and action

Rat heart: A site of oxytocin production and action

Acute hypoxemia in a parturient with primary ciliary dyskinesia following the administration of intravenous oxytocin: a case report

Comparison of Two Doses of Oxytocin for the Prevention of Postpartum Uterine Atony in Parturients Undergoing Emergency Caesarean Delivery: A Randomized Double Blind Study

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