Maternal A&P Flashcards
increased stroke volume correlates with increasing levels of what hormone?
estrogen
what happens to BP if abdominal aorta is compressed
- upper body BP normal
- lower body BP (including uterus) decreases
TSH in pregnancy
decreases during 1st trimester then returns to normal
EBL in vaginal delivery vs. uncomplicated C section
- vaginal: 500 mL
- C section: 800-1000 mL
(estimations are v inaccurate)
why can a pt have significant hypoxemia in between contractions?
*book
uncontrolled pain causes exaggerated hyperventilation during contractions
- minute ventilation can increase as much as 140%
- increased oxygen consumption during labor
- i guess decreased FRC would contribute to this too?
something i read said that they use more O2 than they can get on room air, so to give NC or facemaks supplemental?
why does pregnancy increase risk of gallbladder disease?
- biliary stasis
- greater bile secretion
- increased cholesterol
what musculoskeletal change of pregnancy might make neuraxial techniques more difficult?
*book
uterine growth = lumbar lordosis = narrowed distance between interspinous processes
2 factors that cause up to an 80% increase in CO after delivery
- relief of aortocaval compression
- contracted uterus
what GI changes make all parturients “full stomachs”?
- increased gastrin
- increased gastric volume
- decreased gastric pH
- stomach displacement may create outflow obstruction
- delayed gastric emptying (book says its only delayed during labor?)
- increased intragastric pressure
when might a parturient need a tilt > 15 degrees to relieve aortocaval compression
large uterus
(polyhydramnios or multiple lil bbys)
expected fibrinogen levels at term
what should you suspect if < 200-250 & what should you do about it?
*clinical pearl*
- normal: > 400 mg/dL
- 200-250: suspect severe hemorrhage, consider giving FFP/cryo
changes in venous capacitance
what does this cause
- loses tone
- allows blood volume to pool
why might increased progesterone cause increased LA sensitivity?
*book
causes changes in protein channels within neuronal membranes
uncomplicated elective C section patients can have clear liquids up to ___ hours prior
2
O2 consumption during rest vs. labor of parturient pt
- rest: increases up to 33%
- labor: increases 100% or more
serum cholinesterase activity in pregnant pts
- decreases by 30% or more in 1st/2nd trimesters
- slightly recovers by term
prolongation of cholinesterase-dependent drugs is not clinically significant
thyroid gland during pregnancy
enlarges 50-70%
preggos are more dependent on what system for BP maintenance
RAAS
one of the most effective ways to assess for effective L uterine displacement
*clinical pearl*
visualize displacement of uterus from perspective of pt’s HOB
effect of progesterone on vasculature
*book
vasodilation
blood volume during pregnancy - increased or decreased?
by how much?
increases 25-40%
(85-100 mL/kg)
what hormone may contribute to greater incidence of carpal tunnel during pregnacy?
relaxin
what causes the 3rd heart sound heard in pregnant women?
when is this usually heard by?
- early closure of mitral valve
- heard in most women by 20 weeks
sensitivity to epi, norepi, and phenylephrine during pregnancy
- decreased sensitivity
- uterine circulation is more sensitive than systemic circulation
SvO2 in a supine pregnant pt
*book
decreased d/t decreased CO
effect of progesterone on resp. drive
*book
sensitizes resp centers, increasing ventilatory response to CO2
why might a pregnant pt have a brachial plexus neuropathy
anterior neck flexion and slumping shoulders that usually accompany lordosis
why might a pregnant pt have sensory loss to the anterior thigh
~why do I care~
increased lumbar lordosis tends to stretch the femoral cutaneous nerve
when does CO normalize?
approx 2 weeks postpartum
increased uteroplacental blood flow depends on what 3 factors?
- substantial decrease in uterine vascular resistance
- increased CO
- increased intravascular volume
RBF, CrCl, and GFR during pregnancy
what explains this change?
*clinical pearl*
- all increased
- increased CO
- relaxin causes vasodilation
parturient dependence on SNS for maintenance of hemodynamic stability
increases, peaking at term and then returning to nonpregnant state within 36-48 hours postpartum
effects of vascular remodeling of arteries in uterus
increased vessel diameter and length (diameter > length)
what factors account for hyperventilation of pregnancy?
*book
changes in:
- wakefulness
- central chemoreflex drive for breathing
- acid-base balance
- metabolic rate
- CBF
blood glucose after carb load in pregnant vs. nonpregnant
levels will be higher in pregnant despite hyperinsulinemic response
contractility in parturients
*book
increased
- increased HR
- decreased SVR
what results in reduced interspinous gap in parturient pts
increased lumbar lordosis
BP changes in pregnancy
- little changes in SBP
- DBP may decrease up to 15mmHg
why should nasal intubation generally be avoided in pregnant pts
potentially significant epistaxis
plasma volume during pregnancy
increases 40-50%
according to the book and not MB, what should you expect if your parturient pt has a “normal” Cr of 0.8-1?
*clinical pearl*
“normal” or slightly increased indicates poor renal function
Cr decreased during pregnancy
normal H&H in pregnancy
12/35
(the book says hgb 9-10 is typical without iron supplements)
what part of the kidneys filter and almost completely reabsorb glucose?
proximal tubule
why are murmurs common during pregnancy?
what types is normal and what type is concerning
- hyperdynamic state
- systolic common
- diastolic pathologic
why do parturient pts have decreased neuraxial requirements
IVC compression causes engorged epidural veins and decreased volume of epidural & subarachnoid spaces
RSI with cricoid pressure should be used in parturient pts starting when?
> 12 weeks
airway mucosal changes in pregnancy
*book
increased mucosal friability and vascularity of upper airway
minute ventilation at term
increased by 50%
normal sodium bicarb level in parturient pt
why?
- approx 20 mEq/L
- metabolic compensation for respiratory alkalosis of pregnancy (kidneys respond by increasing bicarb excretion)
functions of relaxin
- relaxation of pelvic ligaments
- renal vasodilation (book)
what happens to the subcostal angle during pregnancy
progressively widens from 68.5 to 103.5 degrees
EF in parturients
*book
increased LVEDV + LVESV unchanged
= increased EF
effects of increased alveolar ventilation in preggos
- decreased PaCO2
- increased PaO2
what happens to CO during pregnancy?
what contributes to this?
- increases approx 40%
- initially d/t increased HR
- by 2nd trimester, SV increased > HR
why do parturient pts have decreased afterload?
*book
dilutional anemia of pregnancy = decreased blood viscosity = decreased afterload
(also vasodilation r/t prostacyclin and progesterone)
why do pregnant patients have decreased chest wall excursion?
*book
elevated diaphragm and increased anterior-posterior diameter of thoracic cage
when does blood volume return to normal after pregnancy?
*book
~6 weeks postpartum
what should you expect if your parturient pt’s hgb is > 13
*book
may be a sign of preeclampsia
does neuraxial anesthesia typically impact gastric emptying during labor?
*book
not unless opioid boluses are used to supplement
FRC in pregnancy & why
decreased d/t upward pressure of diaphragm
what causes total T3 & T4 to increase during the first trimester?
estrogen-induced increase in thyroid binding globulin
why are pregnant women insulin resistant
placental lactogen
BUN & Cr during pregnancy
*book
both decreased
parturient plasma levels of renin and angiotensin II
increased
(baseline renin in 3rd trimester is 12x greater)
dysrhythmias common in 3rd trimester
tachyarrhythmias (ex. SVT)
- book: most common in pregnancy are PACs, PVCs, and sinus tach
effect of prostacyclin on vasculature
*book
vasodilation
platelet count during pregnancy
remains stable or slightly decreased
type of LVH seen by 20 weeks gestation
eccentric
what causes aortocaval compression?
at what point in pregnancy is this seen?
IVC compression against vertebral column as uterus enlarges (16-20 wks)
preload in partriurients
increased d/t increased volume
response to vasoconstrictors during pregnancy
generalized reduced response to exogenous and endogenous vasoconstrictors
cerebral blood flow and cerebral vascular resistance in pregnancy
- CBF = increased
- resistance = decreased
consequences of aortocaval compression
*clinical pearl*
- decreased venous return
- significantly decreased SV and ultimately decreased CO (can have severe hypotension)
- decreased uterine perfusion & fetal oxygenation
parturient vasopressin clearance
clearance at term/near term increased 3-4x
liver changes in parturient
displaced slightly upward and to the right
- blood flow doesn’t change
coagulation factors increased during pregnancy
factors VII, VIII, IX, X, XII
fibrinogen
serum albumin in parturients
*book
decreased by up to 60%
according to MB it “decreases somewhat”
ETT recommendation for parturients
generally smaller than would normally use (6-6.5)
what causes pregnancy-induced increased minute ventilation
*book
Vt & RR both increase (but RR increase is negligible- 1-2 breaths/min)
what causes physiologic anemia of pregnancy
dilution r/t plasma volume increasing > RBC volume
when does LES tone return to normal?
*book
~4 weeks postpartum
how early in pregnancy can CV changes begin
4th week
unclear what changes this includes
MAC in pregnant pts
why?
*clinical pearl*
decreased as much as 30%
- increased plasma endorphins
- increased progesterone (CNS depressant)
mechanisms of hypoxia in parturients
*clinical pearl*
- increased O2 consumption
- reduced apnea tolerance (decreased FRC)
when is widening of pubic symphisis evident
30 wks
this seems irrelevant
positioning to relieve aortocaval compression
relieved by tilting to the left 15 degrees or by placing a 15cm wedge under right hip
when do parturient changes in respiratory anatomy peak (increased subcostal angle, increased circumference of lower rib cage, etc)
37 weeks gestation
most common valve problems in partriurients
94% have tricuspid and pulmonic regurg
(27% have mitral regurg)
Vd in parturients
increased
% of CO that perfuses the uterus at term
10-20%
how does placental growth create a low-resistance vascular pathway
eliminates intramyometrial microcirculation and creates an intervillous space
why might a pregnant mom have decreased glucose levels in the 3rd trimester
baby and placenta have higher glucose demands
what point in pregnancy is renal plasma flow 75% greater vs. nonpregnant
16 wks
consequence of loss of sympathetic-controlled vasoconstriction with epidural anesthesia
maternal hypotension
what causes vertical measurement of the chest cavity to decrease?
elevated position of diaphragm
what effect does progesterone have on GI tract
- decreased motility and LES tone (= heartburn)
- gallbladder hypomotility
accounts for partial compensation of aortocaval compression
*book
Azygous system (lateral flow)
when does CO return to normal after pregnancy?
*book
~2 weeks postpartum
changes in angiotensin II during pregnancy
- concentrations increase 2-3x
- decreased sensitivity to AT II
- uterine circulation even less responsive to AT II
what organ makes vasopressinase
placenta
(is this considered an organ or just like a weird blob in there? unsure)
when does GFR return to normal?
3 months postpartum
when can the fetal thyroid gland produce enough thyroid hormone to not solely rely on mom’s?
why is T4 important to the bébé?
end of 1st trimester
T4 is important to organ development
EKG changes in parturient
*book
- changes from LAD (d/t elevated diaphragm)
- QRS shift
- small Q-T inversions in lead III
- transient ST-T wave changes
