Obstetrics I Flashcards
What pH changes are associated with pregnancy?
Respiratory Alkalosis
Compensated by increased bicarb excretion
So they have a low PaCO2 and a low bicarb
What happens to PaCO2 levels during labor?
They may fall to as low as 10-15, because Mv is increased by 200%
ART hormonal stimulation regimens are associated with what hemostatic changes?
Cause increased coagulation and decreased fibrinolysis
What is the most common complication of ART hormone therapy?
Ovarian Hyperstimulation Syndrome (OHSS)
What are the manifestations of OHSS?
Abdominal discomfort, bilateral ovarian enlargement, ascites → hemorrhage, pleural effusion, hemoconcentration, oliguria, thromboembolic events
Are women who undergo ART more or less likely to have an ectopic pregnancy?
More likely
What are the anesthetic considerations associated with OHSS?
- Retrieval of the oocyte may occur earlier
- Increased free drug concentrations
- Greater perioperative pain
- May need emergency Lap
- May need paracentesis and thoracentesis before induction
What fetal complications are associated with ART pregnancies?
Preterm
LBW
SGA
Appears to be due to infertility rather than the procedure itself BECAUSE women with infertility who conceive without ART have similar risks
What’s the difference between GIFT and ZIFT?
GIFT: Gamete, not fertilized - 1 procedure
ZIFT: Zygote, fertilized (also called PROST) - 2 procedures
How do intraoperative LAs effect pregnancy rates?
It doesn’t seem like they do
Which opioids do not interfere with fertilization or preimplantation?
All of them except morphine, which seems to increase multi-sperm fertilization
Does midazolam impair fertilization or embryo development?
No. It is not teratogenic.
Which anesthetics should not be used in ART surgeries?
Volatile halogenated agents and Nitrous
All of them reduce DNA synthesis and mitosis
Volatiles also increase prolactin, which is associated with diminished oocyte development and uterine receptivity
Which antiemetics may impact oocyte development?
Droperidol and metoclopramide, both of which increase prolactin levels. There is contrasting data on whether this hurts or helps
What is the window for maximal oocyte retrieval after hCG administration?
34-36 hours
What is the most commonly used technique for Transvaginal Oocyte Retrievals?
MAC
Is paracervical anesthesia sufficient for oocyte retrieval?
No. Additional analgesia is required
Discuss the anesthetic requirements for ET, GIFT, and ZIFT procedures
ET (transcervical) can be done awake or with minimal sedation
GIFT and ZIFT are usually laparoscopic procedures and require trendelenburg
How is induction usually performed for GIFT procedures?
TIVA: Prop, Fent, Lido, Succ
What respiratory changes occur by 12 WGA?
Mv increases by 15% from increased Vt, which exceeds the increase in VO2 → Respiratory alkalosis
PaO2 increases to 106-108
Decreased bicarb → compensated pH of 7.44
What lungs volume changes occur in the first half of pregnancy?
None
What mechanical ventilation changes should be made for women in early pregnancy?
They need an increased minute ventilation
In a typical pregnancy, when can aortocaval compression occur?
after 18-20 weeks
Does neuraxial have a higher or lower risk for aspiration than general anesthesia?
Lower
What are possible sequelae of ectopic pregnancy?
Death, infertility, and recurrent ectopic pregnancy
What is the leading cause of pregnancy-related maternal death in the first trimester?
hemorrhage from a ruptured ectopic pregnancy
What percentage of women who have an ectopic pregnancy subsequently suffer from ectopic pregnancy?
30%
What factors increase the risk of an ectopic pregnancy?
- Previous ectopic
- Infertility Treatments
- Prior PID or ruptured appendix
- Prior BTL
- AMA
Where do most ectopic pregnancies occur?
98% are tubal
The remaining 2% are in the cervix, vagina, ovary, or abdomen
What are clinical signs of impending rupture or ruptured tubal pregnancy?
- Abdominal or pelvic pain
- Delayed menses
- Vaginal Bleeding
Patients with hemorrhagic/ruptured ectopic cysts may experience:
- Dizziness or syncope from hypovolemia
- Urge to defecate
- Shoulder pain from diaphragmatic irritation from intra-abdominal blood
What physical findings may be seen with an ectopic pregnancy?
Abdominal tenderness with OR without rebound
Small uterus for gestational age
Tender adnexal mass
Ectopic pregnancy should be excluded in any patient who has ______ and _______
pelvic pain and a positive pregnancy test
What determines how “active” an ectopic pregnancy is?
Symptoms and hCG levels
What defines a “very less active” ectopic pregnancy and what is the appropriate treatment?
No symptoms, hCG < 1500 and plateaued
Expectant management
What defines a “less active” ectopic pregnancy and what is the appropriate treatment?
hCG < 5000 and no fetal cardiac activity, no symptoms, hemodynamically stable
Methotrexate “medical management”
What is Methotrexate’s MOA?
It’s a folate antagonist. It interrupts DNA synthesis and inhibits the growth of trophoblastic cells
What is a heterotopic pregnancy?
An ectopic and an intrauterine pregnancy at the same time (usually from ART surgery)
Maternal death from abortion is usually the result of:
sepsis, hemorrhage, or embolism
What gestational age does fetal demise usually occur?
The symptoms of early pregnancy loss are usually around 8-14 weeks, but the actual demise is usually before 8 weeks
What causes most early pregnancy losses?
chromosomal abnormalities
What is a threatened EPL?
uterine bleeding WITHOUT cervical dilation before 20 WGA
What is inevitable pregnancy loss?
cervical dilation or ROM without expulsion of the fetus
What is an incomplete EPL?
when only partial expulsion of uterine contents occurs
In patients with significant blood loss after a D&C or D&E, how long should they be observed after lithotomy is discontinued?
At least 5 minutes before leaving the OR table
MAC is appropriate for what kind of dilation procedure?
when the cervix is dilated and gestational age is first trimester
When should volatile gases be avoided?
When there is significant bleeding or uterine atony
What level of neuraxial anesthesia is required for a D&C or D&E?
T10 to S4
What level of neuraxial anesthesia is required for surgical ectopic pregnancy?
T4
For a D&E, anesthesia maintenance is usually:
IV (propofol and fentanyl)
Avoid above 0.5 MAC gas
Why is oxytocin less effective in D&E or D&C patients?
oxytocin receptor expression increases with gestation. At early gestation, they may not have sufficient receptors to cause a big contraction of the uterus
What are symptoms of cervical insufficiency?
Altered vaginal discharge
Lower ab or back pain
vaginal fullness
urinary frequency
For women with two or more second trimester losses due to cervical insufficiency, when may a cerclage be placed?
12-14 weeks
In which women does cerclage tend to worsen outcomes, regardless of cervical length?
Multiple gestations
What are contraindications to cerclage placement?
preterm labor
vaginal bleeding
fetal anomalies
fetal death
ROM
Abruption
Infection
What is the greatest risk during a cerclage?
ROM
What anesthetic may be optimal for a cerclage?
Anesthetic gases. Uterine relaxation is imperative.
Can also use nitroglycerin and/or trendelenburg positioning
When might general anesthesia be recommended for cerclage placement?
If the cervix is dilated and uterine relaxation is needed
In a patient whose cervix is not dilated, what is the usual anesthesia choice?
Usually epidural or spinal
Why is a smooth induction and emergence an imperative with cerclage placement?
Any coughing/bucking/vomiting significantly increases intrauterine pressure and may rupture the cerclage
When are cerclages removed?
37-38 WGA
What anesthesia is optimal for cerclage removal?
Usually anesthesia isn’t required for a McDonald
Paracervical block may be needed for Shirodkar
What is gestational trophoblastic disease (GTD)?
when trophoblastic tissue proliferates after the pregnancy is concluded
Includes hydatiform moles, choriocarcinomas, and placental site trophoblastic tumor
What is the most malignant form of GTD?
gestational choriocarcinoma
What is the least malignant form of GTD?
partial hydatidiform mole
What specific complications should be assessed for in patients with molar pregnancy?
Hyperemesis gravidarium
gHTN
Pre-E
Anemia
Thyrotoxicosis
What are the main anesthetic considerations in molar pregnancy removals?
potential for rapid blood loss
risk for cardiopulmonary distress during evacuation of the uterus
What is the preferred anesthesia type for molar pregnancy removal?
General, because there’s such a high risk of complications
Serious complications of hyperemesis may include:
Wernicke encephalopathy
ATN
Esophageal rupture
Splenic avulsion
When do corpus luteum cysts usually occur?
during early pregnancy
What is the treatment for corpus luteum cysts?
usually self resolve over several weeks, but sometimes an oopherectomy is required
What is the fetal prognosis if a corpus luteum cyst arises?
Usually fine as long as supplemental progesterone is administered until 10-12 WGA
