Exam 1: uterine blood flow, maternal phys, foundations, epidural, c section Flashcards
uterine blood supply pic
what are changes in the Lt and Rt uterine artery in pregnancy
increase in size and flow on the same side of placenta (so if placenta on L side, so L side increases)
where do uterine arteries branch from
internal iliac arteries
what branch of the uterine arteries suply the myometrium and radial arteries
arcuate arteries
what arteries branch to enter the endometrium to form the convoluted spiral arteries
radial
what space does oxygenated maternal blood enter
intervillous space
what invades the spiral arteries in a hypoxic state resulting in loss of smooth muscle tone
trophoblasts
where does the the exchange of O2, nutrients, and waste occur between fetus and mother
blood directed at chorionic plate bathes the villi
where does blood return fromfetus to mother
returns to basal plate and drains into multiple collecting veins
describe path of venous drainage of uterus
uterine veins-> internal iliac and utero-ovarian plexus-> inferior vena cava on right and renal vein on left
what does blood sample from intervillous space resemble
mixed venous
maternal fetal blood exchange picture
placental blood supply picture
what is uterine blood flow at term
700-900ml/min
uteroplacental blood makes up _________- perecent of maternal cardiac OP
12%
what is umbilical blood flow
110-120ml/min/kg
what are the three stages of changes in uterine blood flow
1- before and during implantation and early placentation
2- Growth and remodelingof uteroplacental vasculature
3-progressive uterine artery vasodilation
as flow to common iliac and uterine arteries increases blood flow to what artery decreases
external iliac
how does increased SVR effect placental blood flow??
decreased
how is SVR in uteroplacental circulation
low
uteroplacental circulation is _______ dependent
pressure
T/F uteroplacental circulation has well controlled autoregulation
false
if maternal BP is decreased, what happens to placental blood flow
decreased
uterine blood flow = __/_____
uterine perfusion pressure/uterine vascular resistance
what are some things that decrease uterine perfusion pressure FROM decreased uterine arterial pressure
supine position (aortocaval compression)
hemorrhage/hypovolemia
drug-induced hypotension
hypotension during sympathetic blockade
what are some things that decrease uterine perfusion pressure from increased uterine venous pressure
venal caval compression
uterine contractions
drug-induced uterine tachysystole (oxytocin, LAs)
skeletal muscle mypertonus (sezures, valsava, peep)
what are uterine effects of high doses of oxytocin
uterine tachysystole and decreased uterine blood flow
what are some causes of increased uterine vascular resistance FROM endogenous vasoconstrictors
catecholamines (stress)
vasopressin (in response to hypovolemia)
what are some causes of increased uterine vascular resistance FROM exogenous vasoconstrictors
epinephrine
vasopressors (phenylephrine>ephedrine)
LAs
does neuraxial anesthesia increase or decrease uteroplacental blood flow?
epidural CAN increase blood flow UNLESS you drop mother HR, BP, or put in supine position
which vasopressor is better at treating maternal hypotension
ephedrine (produces more uterine blood flow, but lower umbilical pH)
but Crouss says phenylephrine is safer
T/F commonly use induction drugs decrease uterine blood flow
false
T/F volatiles anesthetics decrease uterine blood flow
false
T/F hypoxia and hypercarbia decrease uterine blood flow
true
what are we minduful on during induction related to uterine blood flow
hypotension can decrease uterine blood flow
laryngoscopy can decrease uterine blood flow 2/2 NSS response
what effect does SNS response have on uterine blood flow
decreases
what can we do to furhter dilate placental artieries
nothing, they are already maximally dilated from trophoblasts
what is the effect of 5L of O2 on uterine blood flow
can causes vasoconstrictive affects-> decrease UBF
what is the average amount of weight gain in pregnancy
17% or 12 kg
what is the breakdown of weight gain in pregnancy
amniotic fluid 1 kg
fat 4kg
uterus 1 kg
fetus placenta 4kg
blood volume 1 kg
interstitial fluid 1kg
T/F in pregnancy your heart increases in size
true
what heart tone is often heard in pregnancy
4th tone
what causes the grade 2 systolic murmur at L sternal border
tricuspid and pulmonic regurge (benign)
when do pregnant patients develop LVH
12 weeks
how is HR affected by pregnancy
increases
what causes the increase in CO in the first trimester of pregnancy
HR
what causes the increase in CO in the 2nd trimester
SV
what hormone correlates with the increase in SV
estrogen
when does the increase in CO begin
5 weeks
what causes the decrease in SVR in pregnancy
low resistance in pregnancy
how is EF in pregnancy
increased
how is LVESV in pregnancy
same
how is LVEDV in pregnancy
increased
where is perfusion increased in pregnancy
uterus
skin
kidneys
extremities
what does increased skin perfusion lead to
flushing, heat loss
uterine blood flow increases from 50 ml/m to __________ ml/m by term
700-900
what percent of cardiac output goes to uterus in second half of pregnancy
12% (5% pre pregnancy)
what position do you put pregnant patient in to prevent aortocaval compression
left lateral about 30*
when can aortocaval compression begin
13 weeks
what does supine position affect pregnancy patient
10-20% decline in SV and CO, decreased RA filling pressure
how dose supine position affect uterine blood flow
decrease by 20%
how does supine position affect lower extremity blood flow
50%
what are s/s supine hypotension syndrome
light headedness
n/v
chest heaviness
how does sitting up effect BP
can be 10% decrease do to low SVR state
how can we combat decrease in BP when placing spinal/epidural
lateral position OR bend legs up
what happens to CO right after delivery
up to 150% increase above prepregnant baseline
how much does CO increase in early first stage labor
10%
how much does CO increase in late first stage labor
25%
how much does CO increase in second stage labor
40%
how much does CO increase immediate postpartum
75%
how is CO 24 hours post partum
24 hours postpartum decreases to just below prelabor levels
when dose CO return to baseline
12-24 weeks
what causes the rapid increase in CO after delivery
no AV compression
decreased low resistance placenta
how does uterine contraction effect blood
displaces 300-500 ml
when does HR return to baseline
2 weeks
what hormone relaxes ligament and cartilage in pregnancy
relaxin
what happens to the subcostal angle in pregnancy
widens (69-104*)
what happens to the vertical measurement of chest cavity
decreases (4cm)
what happens to the AP and traverse diameters in pregnancy
increase (2 cm by 37 2weeks)
what happens to capillaries of larynx and nasal/oropharyngeal mucosa
capillary engorgement
T/F use nasal trumpets/nasal intubation in preggers
false
what happens to airway in preggers
friable, bleeds
how is nasal breathing
difficult
how is pulmonary resistance in pregnancy
decrease 50%
how is chest wall excursion in pregnancy
decreased
how is diaphragm excursion in pregnancy
increased
how is FEV1 in pregnancy
unchanged
resp changes
how is flow volume loop in resp
no change
how is Total lung capacity in pregnancy
slightly reduced
how is TV in pregnancy
increased by 45%
how is expiratory reserve in pregnancy
decreased by 25%
how is residual volume in pregnancy
decreased by 15%
how is MV in pregnancy
45% increased
how is VC in pregnancy
maintained
how is RR in pregnancy
increased slightly
what are the pulmonary volumes that are decreased in pregnancy
expiratory
residual
(TLC slightly)
how is closing capacity in preggers
no change
T/F dyspnea affects up to 75% of women during pregnancy
true
what ph state are pregnancy in
resp alkalosis
how is PaO2 in pregnancy
increased
how is PaCO2 in pregnancy
decreased
how is pH in pregnancy
increased
how is bicarb in pregnancy
decreased
what causes the increase in PaO2 in pregnancy
increased alveolar ventilation
how is stomach affected by pregnancy
stomach displaced up and to the left, axis is rotated 45*
decreased lower esophageal sphincter tone
at how many weeks does a pregnant patient become aspiration risk
any week, RSI
GI changes chart
when do preggers have delayed gastric emptying
labor
T/F pregnant patients have increased gastric acid secretion
false
what is an important drug to give preop for preggers
antiemetic/zofran (80% have N/V)
fix the N/V before
what is a potential issue with zofran
leads to birth defects
how is liver affected by preggers
liver displaced upward
increased bilirubin,alanine aminitransferease, aspartate aminiotransferease, and lactate dhydrogenase
how does preggers effect gallbladder
gastric smooth muscle relaxes leading to billiary stasis and increased gallstones
increased rates of lap Chole
how long after birth do women still have aspiration risk
7 days
how is renal blood flow affeted by pregnancy
increases by 75%
how is GFR affected by preggers
increased by 50%
how is creatinine clearance in preggers
150-200 ml/min
T/F protenuria is only possible with preeclampsia
false
how is urine glucose in preggers
increased
T/F twin pregnancy has higher proteinuria
true
T/F later term has higher proteinuria
true
what causes the physiologic anemia in preggers
increased plasma volume
not as much increased RBC
when do RBCs decrease in preggers
8 weeks
when do RBCs return to baseline in preggers
16 weeks
how does blood volume change in pregnancy
increased 45%
how does plasma volume change in pregnancy
increased 55%
how does RBC volume change in pregnancy
increased 30%
what is a typical hgb concentration g/dL
chart says 11.6
crouss said aroun 9
typical hct in pregnancy
chart says 35.5%
how is cholinesterase affected in preggers
25% decrease (drops during first trimester)
how much blood is lost in normal vaginal delivery
600ccs
when is the greatest decrease in psuedocholinesterase activity
3rd day postpartum
when do you use succs during preggers
emergency c section
no need to redose paralytics
T/F the psuedocholinesterase deficiency affects succs metabolism
false
what factors are increased in preggers
1,7,9,10,12
what factors are unchanged in preggers
2,5
what factors are decreased in preggers
11, 13
what bleeding/clotting state is preggers
hypercoag
how are platelets in preggers
greater production and consumption
8% have platelet count <150,000
what is normal blood loss in c section
1000ccs
what makes c section blood hard to estimate
amniotic fluid
irrigation
how are clotting factors post partum
rapid decrease in
platelets,
fibrinogen,
factor 8 and
plasminogen
when does coags return to normal postpartum
2 weeks postpartum
how is immune system in preggers
immunocompromised
how are leukocytes in preggers
increased to 9-11,000 up to 15000
how are autoimmune disorders in preggers
improved
what kind of T cells are in successful preggers
th2
what kind of T cells are in miscarriage
Th1
how is thyroid in preggers
enlarges 50-70%
which Thyroid hormones are increased
estrogen increased T3 T4
how is TSH in preggers
same
how many preggers have gestational hypothyroid
15%
how is insulin affected
insulin resistance
how are cortisol levels
2.5x higher at end of 3rd trimester
how is calcium in preggers
insufficient 2/2 fetal demand
T/F post partum back pain is from epidural
false, relaxin
how does preggers effect sleep
disturbed REM cycle
how is cerebral blood flow in preggers
increased 2/2 decreased cerebral vascular resistance
how is BBB
more permeable
how is epidural space in preggers
epidural fat and venous plexus enlarge
how is CSF volume in preggers
decreased
how is CSF pressure in preggers
same
during preggers dependence on the SNS is (increased/decreased)
decreased
why is it important to stay midline in epidural
enlarged venous plexus
what is best position to avoid AV compression in preggers
L lateral 15%
how do we position after spinal
raise head up (10*)
what do we watch for high spinal
pinky numb/tingle C8
how many class 4 mallampati
increased by 34%
what makes preggers higher to iNtubate
DECREASED FRC
swollen tissue
tissue demands of fetus
class 4 airways
in preggers PaO2 decreases _______ x faster
2
how long do you have till hypoxia in preggers
2-3 min
what kind of airway equip should you have in preggers
videoscope
how is MAC in preggers
40% lower
does not affect anesthesia requirements in practice
T/F use lots of narcs in preggers
false
risk of fetal bradycardia
how are Beta adrenergic receptors in preggers
down regulated
so need higher doses of vasoactives if using
what makes neuraxial anesthetics more difficult in preggers
lordosis
increased weight
increased bleeding
what is a complication for neuraxial
hypotension
difficulty breathing
what are risks for ectopic preggers
previous ectopic
intertility tx
prior pelvic infection
tubal sx
advanced maternal age
where do most ectopic implantation occur
tubal
what are s/s ectopic
pelvic pain
delayed menses
vaginal bleeding
abd pain with or without tenderness
signs of shock
what is the leading cause of maternal death in the US
ruptured ectopic
what is ectopic called before it is diagnosed officially
pregnancy of unknown location
what is the gold standard of diagnosising ectopic
transvaginal ultrasound
how does ectopic appear on ultrasound
adnexal mass with free fluid
how do seerial HCGs diagnose ectopic
serial for 48rs, if it does not increase by 53% then possible PUL
what does a decrease in HCG by 10% tell us
failed pregnancy
what labs do you do for PUL
HCG
progesterone
pregnancy test
what is your induction med for ectopic
etomidate
how do you prepare for ectopic case
2 ivs
fluid
blood
etomidate induction
type and scree/cross
aspiration prophylaxis
urinary catheter
RSI
vasopressors ready
a-line if unstable
Ng tube
warming device
pitocin
when does aspiration risk begin in preggers
1st week
sever features vs without sever features preeclampsia
preeclampsia tests
HELLP chart
hypertensice disorders of pregnancy
contraindications to epidural
epidural vs CSE
managing bad epidural chart
esters vs amines
opioid receptor types
emergent vs urgent vs scheduled c section
spinal med doses
epidural anesthesia doses
risk factors for NV chart
