Obstetrics Flashcards
A patient requires an emergency cesarean section. Which of the following is the MOST likely cause for rapid arterial oxygen desaturation during intubation?
a. decreased expiratory reserve volume
b. increased inspiratory reserve capacity
c. increased residual volume
d. decreased vital capacity
a. decreased expiratory reserve volume
The parturient is at higher risk of these three things related to the airway:
difficult mask ventilation
difficult laryngoscopy
difficult intubation
Factors that make airway management more complicated in the parturient include
increased Mallampatti score
upper airway vascular engorgement
narrowing of the glottic opening
______ these factors hasten the onset of hypoxemia during apnea for the parturient.
increased oxygen consumption paired with a decreased FRC
__________ increases minute ventilation up to 50% leading to the mother developing a mild compensated respiratory alkalosis.
Progesterone
_______ falls below _________, which causes airway closure during tidal breathing.
Functional reserve capacity falls below closing capacity.
Upper airway swelling in the parturient is te result of
increased progesterone, estrogen, and relaxin causing vascular engorgement and hyperemia
& increased extracellular volume
Since the glottic opening is narrowed______ should be used.
a downsized endotracheal tube
Airway edema is worsened by
preeclampsia, tocolytics, and prolonged Trendelenburg position
What type of laryngoscope handle is recommended for large breasted women?
a short-handled laryngoscope (Datta handle)
Why should nasal intubation be avoided in full term mothers?
the tissue in the nasopharynx is particularly friable because of hormonal changes and local edema
Which hemodynamic variables increase during pregnancy?
a. heart rate
b. stroke volume
c. systemic vascular resistance
d. pulmonary artery occlusion pressure
A & B
SV is increased as a function of increased intravascular volume while heart rate is increased to satisfy higher metabolic demand
_________ increases throughout pregnancy to support the growing fetus.
Maternal oxygen consumption
What hemodynamic factors remain stable throughout pregnancy?
MAP & SBP
What hemodynamic variables decrease during pregnancy?
DBP, SVR, and PVR
Describe how dilutional anemia results in the pregnant patient.
plasma volume expansion outpaces new RBC production
Pregnancy produces a ___________ that predisposes mothers to DVT
hypercoagulable state
In the supine position, the gravid uterus compresses both the
vena cava and aorta leading to aortocaval compression
Aortocaval decompression (left displacement of the uterus) should be used in
2nd and 3rd trimesters
Describe how cardiac output is affected during the stages of labor.
1st stage: increases by 20%
2nd stage: increases by 50%
3rd stage: increases by 80%
Describe causes of thrombocytopenia during pregnancy.
gestational thrombocytopenia- most common
hypertensive disorders of pregnancy
idiopathic thrombocytopenia
Which factors are expected to increase during pregnancy?
a. creatinine clearance
b. lower esophageal sphincter tone
c. sensitivity to local anesthetics
d. MAC
e. Gastric pH
f. Urine glucose
creatinine clearance
sensitivity to local anesthetics
urine glucose
Pregnancy causes ______ to decrease by 30-40% beginning at 8-12 weeks and is caused by increased progesterone.
MAC
__________ remains unchanged before the onset of labor, but slows after labor begins.
Gastric emptying time
Describe how pregnancy affects ICP
No change
Describe what pregnancy does to epidural vein volume.
increases
Describe the GI effects that pregnancy has on gastric volume, gastric pH, LES sphincter tone, and gastric emptying.
volume- increased
pH- decreased
sphincter tone- decreased
gastric emptying- no change to decreased after labor begins
Describe how pregnancy affects GFR, creatinine clearance, glucose in the urine, and BUN and creatinine.
GFR- increased
creatinine clearance- increased
glucose in urine- increased
creatinine and BUN- decreased
Describe how pregnancy affects uterine blood flow, serum albumin, and pseudocholinesterase.
uterine blood flow- increased
serum albumin- decreased (higher free fraction of highly protein bound drugs)
pseudocholinesterase- no meaningful effect on succinylcholine metabolism
Uterine blood flow is:
a. 20% of cardiac output
b. 700 mL/min.
c. not autoregulated
d. reduced by phenylephrine
B & C
it’s 10% of the cardiac output
Uterine blood flow is not autoregulated. It is dependent on
maternal MAP, cardiac output, and uterine vascular resistance
Uterine blood flow increases up to _____ at term.
700-900 mL/min.
_____________ is as efficacious as ________ in maintaining placental perfusion and fetal pH in healthy mothers.
phenylephrine; ephedrine
Physiochemical drug characteristics that favor placental transfer include:
low molecular weight (<500 Daltons)
high lipid solubility
Non-ionized
Non-polar
Which drugs do NOT cross the placenta? (most do so it’s easier to learn which drugs do not cross)
heparin, neuromuscular blockers, glycopyrrolate, and insulin
Causes of reduced uterine blood flow include
decreased perfusion- maternal hypotension (sympathectomy, hemorrhage, aortocaval compression)
increased resistance- uterine contraction, hypertensive conditions that increase UVR
____________- can increase the concentration gradient, which leads to fetal ion trapping.
Fetal acidosis
Which stage of labor begins with the onset of perineal pain?
a. latent stage
b. active stage
c. first stage
d. second stage
second stage
________ begins with full cervical dilation and ends with the delivery of the newborn.
second stage
______ begins with the delivery of the newborn and ends with the delivery of the placenta.
third stage
_______ begins with cervical dilation with regular uterine contractions and ends with full cervical dilation (10 cm). It can be divided into the latent phase and active phase.
first stage
______ is always considered a full stomach!
A laboring mother
According to the ASA practice guidelines for obstetric analgesia, the laboring mother who is healthy may:
_____________ throughout labor
___________up to the point a neuraxial block is placed
drink a moderate amount of clear liquids throughout labor
eat solid food up to the point a neuraxial block is placed
An epidural does not prolong
the first stage of labor and it does not increase the need for a C-section
The latent phase of labor is
cervical dilation up to 2-3 cm
______ occurs when labor does not follow the expected pattern. ________ may be required to help the labor progress.
Dysfunctional labor
oxytocin
