Wed3November0919PM 11

Rapid intravenous administration of 10 units of oxytocin produces:

True / False

A decrease in cardiac output Correct

Cutaneous vasodilation Correct

A decrease in total peripheral resistance Correct

Reflex tachycardia Correct

A decrease in systolic and diastolic blood pressure Correct

Explanation

Oxytocin is a naturally occurring peptide, secreted from post pituitary; syntocinon is a synthetic analogue. They are agonists for oxytocin receptors on myometrial cells and stimulate uterine contraction.

It is used for the initiation, maintenance and augmentation of labour and used routinely at caesarean section delivery.

Oxytocin is also used for the control of postpartum haemorrhage due to uterine hypotonia. It is given by intravenous infusion or a "slow" bolus, the latter a dose of 5 IU. A dose of 10 IU increases the risk of cardiovascular complications.

Oxytocin is inactivated in the liver and kidneys and by circulating oxytocinase. The T1/2 is approximately 5-minutes.

Complications include:

Transient fall in systemic vascular resistance, blood pressure and a reflex tachycardia.

Increase in stroke volume and therefore cardiac output

Skin flushing from cutaneous vasodilatation

Autotransfusion from uterine contraction

Reduced uteroplacental blood flow, and

Water intoxication in mother and foetus if large doses are used.

Answer Statistics

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Average score: 72.83%

Times answered: 240