agents used in obstetrical care chapter 37. the uterus 2 pear shaped organ highly muscular rich...
TRANSCRIPT
Agents Used in Obstetrical
Care
Chapter 37
The Uterus
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Pear shaped organHighly muscularRich blood supplySmooth muscle – very strong
During pregnancy uterus size increases tenfold
The UterusStrong rhythmic contractions can cause mild to strong discomfort or pain during labor
Many drugs stimulate smooth muscle of the uterus
Oxytocic agentsInitiate or increase uterine contractions
Used to control postpartum hemorrhage or to induce post first trimester abortion
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Agents Used in Obstetrical Care
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This presentation focuses on the following drug agents:Uterine stimulantsUterine relaxantsRhoGAM
Oxytocin
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Oxytocin is a hormone excreted by the posterior pituitary gland
Primarily stimulates smooth muscle of the uterus and mammary gland
Synthetic oxytocin (Pitocin)Increases frequency and force of contractions
Oxytocin
Dependent on estrogen’s presence
During last trimester uterus becomes more sensitive to oxytocin
Also released during intercourse to aid transport of sperm
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Oxytocin
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Muscle contraction in mammary glands results in milk letdown
Synthetic form is Pitocin - used IV when initiating or augmenting labor
Infusion should be maintained at the lowest level to permit labor
Oxytocin
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Also used for postpartum hemorrhage, uterine atony, or after caesarean delivery
Can be administered IV in IV fluids or as an IM injection
When Pitocin is used before the fetus is delivered, fetal heart rate and pattern must be carefully and constantly monitored.
Pitocin during labor can cause exhaustion of uterine muscles (atony), stress on the baby, edema in the mother and other severe complications
Nursing Considerations
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Nurse must frequently assess vital signs, contraction strength and frequency, and fetal status during administration of oxytocin
Use of a pump for delivery is required Able to precisely control dosage
Continuous fetal heart rate monitoring is required
Ergot Derivatives
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Complex mixtureDerived from fungusStimulates uterine smooth muscle
Ergonovine and methylergonovine
Causes powerful uterine contractions
Ergot Derivatives
Not for use in induction or augmentation of labor
Used for postpartum hemorrhage
Usually given orally or IM (IV only in emergencies)
Can cause elevation of blood pressure
Potent vasoconstrictive effect
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Nursing Considerations
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Monitor blood pressureMonitor for development of headache
Monitor postpartum bleeding
Monitor for signs of anemia
Prostaglandins
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Can stimulate uterine contractions at any stage of pregnancy
Used in terminating pregnancy between 12th and 20th week
Used to treat incomplete abortion and fetal death
Prostaglandins
Use of prostaglandins for induction or augmentation of labor has not been approved by the FDA
Scientific evidence confirmed usefulness
Are approved for second trimester abortions
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Prostaglandins
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Hemabate - administered IM - used for second trimester abortion and postpartum
hemorrhageDinoprostone - vaginal suppository or gel - promotion of cervical ripeningAdverse effects include nausea, vomiting, and diarrhea
Premature Labor
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Premature birth accounts for most neonatal deaths
Stopping preterm labor is desirable
Usually attempted when labor starts after 20 weeks gestation
Uterine Relaxants
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Prevent premature laborTerbutaline sulfate (Brethine)Stimulates beta2 receptorsRelaxes the uterus
Uterine Relaxants
Magnesium sulfateIV, must be titrated carefully
Deep tendon reflexes should be monitored
Calcium gluconate: antidote
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Nursing Considerations
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Assess for signs of advancing labor
Assess for rapid heart rate or palpitations
Bed rest and pelvic rest required
Report pulse rate greater than 120 before giving dose
Nursing ConsiderationsEducate patients terbutaline can cause anxiety and tremors
Assess for signs of anxiety and tremors
Consider obtaining order for antianxiety medication
Terbutaline may not be given for more than 48-72 hours at a time due to risk of cardiac problems
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RHoGAM
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Sterile concentrated solution of gamma globulin
Administered IM to nonsensitized Rh-negative mothers after delivery of an Rh-positive baby
Suppresses formation of antibodies
Protects against hemolytic disease
RhoGAM
Must be given with 72 hours of delivery
Never administer to an infantPatients may experience pain at injection site, mild fever, or mild headache
Anaphylaxis is rareStore in refrigerator; never freeze
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