Postpartum Hemorrhage and Uterine Receptors

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What is the primary indication for administering tocolytics?

fetal head entrapment

postpartum hemorrhage

preterm labor (correct)

uterine tetany

What is the effect of magnesium on uterine muscle?

contraction

stimulation

tetany

relaxation (correct)

What is the mechanism of action of oxytocin on uterine muscle?

increases cAMP, causing relaxation

stimulates calcium channels, causing contraction (correct)

blocks prostaglandin synthesis, causing relaxation

decreases intracellular calcium, causing relaxation

What is the primary indication for administering uterotonics?

postpartum hemorrhage Signup and view all the answers

What is the effect of beta 2 agonists on uterine muscle?

relaxation Signup and view all the answers

What is the mechanism of action of alpha 1 agonists on uterine muscle?

stimulates calcium channels, causing contraction Signup and view all the answers

What is the half-life of oxytocin?

15 minutes Signup and view all the answers

What is the onset of action of oxytocin?

1-2 minutes Signup and view all the answers

What is the suggested dosage of oxytocin for women at low risk of postpartum hemorrhage during elective cesarean section?

20-40 IU in one liter of isotonic solution over four hours Signup and view all the answers

What is the recommended dosage of oxytocin by slow intravenous injection after delivery according to the British National Formulary?

5IU oxytocin Signup and view all the answers

What is the effect of continuous exposure of human myometrium cells to oxytocin?

It leads to a significant loss in their capacity to respond to oxytocin Signup and view all the answers

What is the ED90 of oxytocin for women who have labored compared to non-laboring women at term?

9x higher Signup and view all the answers

What is the recommended dosage of oxytocin for prevention of post-partum hemorrhage in the US?

10-40 IU/L Signup and view all the answers

What is the 'Rule of Threes' in oxytocin administration?

3 units of Pit in 3 mL over 3 minutes Signup and view all the answers

What is the effect of active labor on oxytocin receptor concentrations?

They are reduced Signup and view all the answers

What is the suggested dosage of oxytocin for laboring patients requiring cesarean section?

Slow 3IU bolus followed by an infusion of 510U Signup and view all the answers

What is a significant concern when combining methergine with other vasopressor agents?

Severe hypertension Signup and view all the answers

What is the primary mechanism by which prostaglandins cause uterine contraction?

Increase in calcium concentrations Signup and view all the answers

Which of the following is a contraindication for the use of methergine?

All of the above Signup and view all the answers

What is a potential side effect of Hemabate?

Bronchospasm Signup and view all the answers

What is the dose of Hemabate used for PPH?

250 mcg IM or intramyometrially Signup and view all the answers

Which of the following is a use of misoprostol?

All of the above Signup and view all the answers

What is a potential effect of PGE2 on the cardiovascular system?

Increased SVR and PVR Signup and view all the answers

What is a potential respiratory complication of PGE2?

Increased intrapulmonary shunting Signup and view all the answers

What is the effect of Nifedipine on the uterus?

Greater effect on uterus compared to other Calcium Channel Blockers Signup and view all the answers

What is the effect of Beta-mimetics on uterine muscle?

Relaxation of smooth muscle Signup and view all the answers

What is the mechanism of action of Ritodrine and Terbutaline?

Selective Beta 2 agonist producing increases in cAMP Signup and view all the answers

What is the effect of Calcium Channel Blockers on the fetus?

Decreased variability Signup and view all the answers

What is the combination of inhaled anesthetics and Calcium Channel Blockers associated with?

Uterine atony Signup and view all the answers

What is the cause of uterine hypertonicity in the postpartum period?

Unopposed oxytocin induced tetany as epinephrine levels decrease after labor Signup and view all the answers

How do Beta agonists compare to magnesium for tocolysis?

Beta agonists are superior to magnesium for tocolysis Signup and view all the answers

What is the formula for uterine perfusion?

Uterine arterial pressure - Uterine venous pressure/ uterine vascular resistance Signup and view all the answers

What is the primary mechanism of action of Ephedrine in terms of norepinephrine?

Inhibits norepinephrine reuptake Signup and view all the answers

What is the primary indication for using Phenylephrine?

Prophylactic treatment before spinal or cesarean section Signup and view all the answers

What is the primary effect of Hydralazine on the cardiovascular system?

Dilates arterioles Signup and view all the answers

What is the ratio of alpha to beta receptor activity for Labetalol?

1:3 Signup and view all the answers

What is the primary mechanism of action of Tranexamic Acid?

Reversibly inhibits plasminogen to plasmin conversion Signup and view all the answers

What is the primary indication for using Ephedrine in obstetric anesthesia?

Treatment of hypotension following neuraxial placement Signup and view all the answers

What is the duration of effect of Hydralazine when administered intravenously?

2-3 hours Signup and view all the answers

What is the primary benefit of using Tranexamic Acid in obstetric hemorrhage?

Reduced mortality from bleeding within three hours of delivery Signup and view all the answers