Obstetric Patient Part 1 Flashcards
Changes during pregnancy include
CV hematologic respiratory nervous GI hepatic Renal
Describe the main changes to the CV system of the pregnant woman.
Increased HR Increased CO Ventricular walls thicken Dilutional anemia Decrease in SVR
HR will increase by
20-30% by term for the parturient (peaks at 32 weeks)
Cardiac output will increase by _______
40% over non-pregnant values
- stroke volume contributes to a great extent
- 10% perfuses the uterus
- increase by 80% immediately following delivery
- returns to baseline in 14 days
When ventricular walls thicken,
systolic murmurs not uncommon
diastolic murmurs and cardiac enlargement pathologic
Describe dilutional anemia
there is a large increase in plasma volume more than RBC volume
Normal blood loss for a vaginal delivery is
500 mL
Normal blood loss for Cesarean section is
800-1000 mL
A decrease in SVR results in
venous pooling
decrease in diastolic blood pressure
Aortocaval compression results from
compression of aorta and vena cava by gravid uterus leading to supine hypotension
Aortocaval compression is more severe in
polydraminos and multiple gestation
With aortocaval compression, hypotension can occur
immediately
-usually 10 minutes to develop
Aortocaval compression is relieved by
left uterine displacement
-optimal angle is 15 degrees
Hematologic changes to the mother include
“hypercoagulable”
increased risk for thromboembolic events
platelet count decreases slightly
WBC count rises
Describe what makes the parturient hypercoagulable.
clotting factors VII-IX increased
fibrinogen increased
One of the leading causes of maternal mortality is
thromboembolic events
Describe respiratory changes for the pregnant woman.
airway swelling during labor
increase in O2 consumption
minute ventilation increases
upward pressure of diaphragm
Airway swelling during labor results from
capillary engorgement resulting in
- narrowed glottic opening
- oral & nasal pharynx edema
- laryngeal edema
Describe airway considerations for the parturient.
avoid nasal intubation
short handle on laryngoscope
intubation with a smaller tube 6.5 mm cuffed endotracheal tube
Describe the increase in oxygen consumption.
33% at rest
100% during labor
Describe the rise in minute ventilation.
increase in TV>RR
PaCO2 decreases slightly- compensatory decrease in HCO3
Upward pressure of the diaphragm results in
decrease in FRC, less residual volume
In the apneic mother,
there is RAPID DESATURATION
Describe changes to the nervous system.
Increased sensitivity to anesthetic gases & LAs
increased block height
Describe why there is increased block height for the parturient.
engorged epidural veins
increased intra-abdominal pressure- decrease in epidural & SAH spaces
Describe the gastrointestinal changes to the parturient.
increased risk for regurgitation and aspiration
- increased levels of gastrin
- upward displacement- mechanical obstruction
- Labor further reduces gastric emptying
Prior to cesarean section for GI reasons, give the mother
nonparticulate antacid
H2 receptor blocker
prokinetic
Describe the hepatic changes to the parturient.
decrease in serum albumin
-increase in free-fraction of highly protein bound drugs
Describe the renal changes for the parturient.
-Increased GFR BUN & creatinine decrease -glucose excreted in urine high GFR reduced renal absorption -protein excretion elevated
At term, uterine blood flow increases to a maximum of
800 mL/min.
- 10% of CO
- 150 mL/min supplies nutrients to the myometrium
- 100 mL/min flow to the decidua basalis (maternal part of placenta)
Uterine blood flow allows for exchanges of
nutrients, respiratory gases, and waster
- oxygen & CO2 are “perfusion limited”
- fetal transfer dependent on perfusion, not gases rate of diffusion
The fetus sends oxygen-poor blood to
the placenta
- two umbilical arteries
- perfuse capillary networks of the placental villi
Most _____ are transferred via diffusion
drugs
Placental transfer of drugs is dependent upon
concentration gradient molecular weight (<500 daltons cross easily) lipid solubility state of ionization protein binding
Fetal effects of placental drug transfer are minimized by
dilution with intervillous blood
redistributed once in the fetus
umbilical blood passes through liver (first pass effect)
increase in maternal hepatic enzymes decrease serum drug levels
_______ may affect drug accumulation for the fetus
acid-base status
-“ion-trapping”
One-fifth of fetal cardiac output returns
directly back to placenta
-shunt flow from foramen ovale & ductus arteriosus
Labor is a progressive
dilation of the cervix in response to uterine contractions
Describe the stages of labor.
stage 1: effacement & dilation of the cervix
Stage II: cervix 10 cm dilation to delivery of the fetus (active pushing)
Stage III: delivery of the placenta
Describe the latent versus active stage of stage I labor
latent: onset of labor to point of rapid cervix dilation
active: cervix dilation 2 cm to full dilation (10 cm)
Describe pain in the first stage of labor.
non-localized aching or cramping
T10-12 & L1
Describe pain in the second stage of labor.
cervical dilation complete and presenting part descends into the pelvis
S2-S4
Pain during labor is accentuated by
fear of the unknown
Pain is highly _____ and varies
individualized and varies widely among patients
Four factors critical to a woman’s childbirth experience include
personal expectations
amount of support from caregivers
quality of patient-caregiver relationship
-patient’s involvement in decision making
Fetal heart rate monitoring is
not a specific predictor
most readily available method to determine fetal condition
allows you to relate FHR to uterine activity
Describe the two methods for fetal evaluation.
external- doppler placed on maternal abdomen
internal- electrode placed in fetal scalp
The two channel format of fetal heart rate monitoring monitors
FHR
uterine contractions
Normal FHR is
110-160 BPM***
When examining changes in fetal heart rate, we are looking at
variability
accelerations
Describe accelerations
results from fetal movement & adequate oxygenation
The single best indicator of fetal well-being is
variability
- indicates fetal oxygen reserve
- -hypoxia (CNS depression) decreases it
- interaction in autonomic nervous sytem
Describe the types of decelerations.
early
variable
late
Early decelerations occur in
concert with uterine contractions
consistent with each
decrease in FHR approximately 20 bpm
Variable decelerations are an
abrupt decrease in FHR irrespective of contractions
Baroreflex-mediated response to umbilical cord compression
Describe late decelerations.
non-reassuring!
- lowest point of deceleration occurs after peak contraction
- represents uteroplacental insufficiency
Categories for FHR evaluation include
Category I (normal) Category 2 (continue to observe) Category 3 (intervene)
Describe category one for FHR evaluation.
normal baseline HR & moderate variability with NO variable or late decels
Describe category II for FHR evaluation.
all tracings not included in I or III
do not indicate acid-base imbalance
-warrant continued observations
Describe category III.
fetal bradycardia and absent variability with variable or late decels
warrants prompt intervention
