OB: Maternal Physiology Flashcards
Increased ___ demands
[Maternal Physiology]
Metabolic
H______ changes
[Maternal Physiology]
Hormonal
A__ Changes
[Maternal Physiology]
Anatomic
Begin as early as the ___ week and extend into the postpartum period
[Maternal Physiology-VC]
4th___
_____ Left Ventricular Hypertrophy by 20 weeks, with a __% increase in mass at term
[Maternal Physiology-CV]
Eccentric
50%
___of parturients exhibit tricuspid and pulmonic regurgitation; ____ mitral regurg
[Maternal Physiology-CV]
94%, 27%
Heart Rate is increased________% at term
[Maternal Physiology-CV]
15-30
Tachyarrhythmias more common in ___ trimester
[Maternal Physiology-CV]
third
Cardiac Output increases approximately ___%
[Maternal Physiology-CV]
40
Initially due to increased ________
[Maternal Physiology-CV]
Heart rate
By the second trimester, increased ____more so than increased _______
[Maternal Physiology-CV]
stroke volume, heart rate
Increased stroke volume correlates with increasing ___ levels
[Maternal Physiology-CV]
estrogen
At term approximately ___% of CO perfuses the uterus
[Maternal Physiology-CV]
10-20
During labor uterine ____ autotransfuse volume to circulation
[Maternal Physiology-CV]
contractions
After delivery CO can increase up to ____% due to
____
____
[Maternal Physiology-CV]
80
Relief of aortocaval compressionn
Contracted uterus
CO gradually returns to normal at approximately 2 weeks postpartum as ___ and ___ normalize
[Maternal Physiology-CV]
HR and SV
Venous return _____ increases due to increased volume
[Maternal Physiology-CV]
Preload
Increased susceptibility to____ heart rate changes
[Maternal Physiology-CV]
baroreflex-mediated
Third heart sound can be heard in most women by 20 weeks due to early closure of the ____________ valve
[Maternal Physiology-CV]
Mitral
A ___ heart sound can be heard in 16% of pregnant women, but usually disappears at term.
[Maternal Physiology-CV]
Fourth
__________ murmurs are common, __________ murmurs are pathologic
[Maternal Physiology-CV]
Systolic, diastolic
Compression of the ___ ___ by the gravid uterus
More severe in polyhydramnios or multiple gestation pregnancies
Decreased venous return
Significantly decreased SV and ultimately ___________________
Then ___________________________________
May result in loss of consciousness
May be immediate or take up to 10 minutes to be symptomatic
Abdominal aorta may also be compressed
Upper body BP remains normal
Lower body (including uterus) BP decreases
[Aortocaval Compression]
vena cava
cardiac output
uterine/fetal oxygenation decrease
More severe in ____ or multiple gestation pregnancies
[Aortocaval Compression]
polyhydramnios
____ venous return
[Aortocaval Compression]
Decreased
Significantly decreased SV and ultimately ____
[Aortocaval Compression]
Cardiac output
Then decreases uterine ___ and fetal ____
[Aortocaval Compression]
perfusion and oxygenation
May result in loss of c_____
[Aortocaval Compression]
Consciousness
May be immediate or take up to ___ minutes to be symptomatic
[Aortocaval Compression]
10
A___ ___may also be compressed
[Aortocaval Compression]
abdominal aorta
Upper body___remains normal
[Aortocaval Compression]
BP
Lower body (including uterus) BP ___
[Aortocaval Compression]
decreases
Relieved by tilting to the ___ < laying on either side
[Aortocaval Compression]
left
Left uterine displacement increases intervillous blood flow an average of __% and increases fetal oxygenation __%
[Aortocaval Compression]
20, 40
Left uterine displacement can be achieved by tilting the operating table ___ degrees or by placing a ___ high wedge under the parturient’s right hip and back.
[Aortocaval Compression]
15, 15 cm
A small percentage of women may benefit from ___ uterine displacement more than___, but this is a small minority.
[Aortocaval Compression]
right, left
Needs a ___-degree or a ____ cm wedge under the right hip and back
[Left Uterine Displacement]
15, 15
Especially large uterus (___ or ___) may need more lift
[Left Uterine Displacement]
polyhydraminos or multiple
Degree of tilt is usually ___
[Left Uterine Displacement]
underestimated
Because MAP decreases slightly, the increase in uteroplacental blood flow is dependent on (1) a substantial decrease in ___ ___ ___, (2) increased c___ ___, and (3) increased i___ ___
[Vascular Changes and Regulation]
uterine vascular resistance, cardiac output, intravascular volume
Vascular remodeling of arteries in the uterus is believed to include increases in both vessel ___ > ___
(Dust off the cobwebs and think Physics laws!)
[Vascular Changes and Regulation]
diameter, length
Changes in vascular reactivity include vasodilatory response mediated at ___ and ___ smooth muscle levels
[Vascular Changes and Regulation]
endothelial and vascular
Growth of the placenta creates a [low/high] -resistance vascular pathway by eliminating ___ microcirculation and creating an ___ space
[Vascular Changes and Regulation]
low, intramyometrial, intervillous
SVR ___ as much as 21%
[Vasculature Changes]
decreases
Venous capacitance loses tone, allowing for pooling of the ___ ___
[Vascular Changes and Regulation]
blood volume
Aside from pathology, systolic blood pressure changes [little/more], diastolic blood pressure may decrease by up to ___ mmHg
[Vasculature Changes]
little, 15
Generalized reduction on response to ___ and ___ vasoconstrictors
[Decreased Response to Vasoconstrictors]
endogenous and exogenous
(lecture notes say exogenous and exogenous)
Angiotensin II, En___, Thromboxane, Epinephrine, Norepinephrine, Phenylephrine, S___, Thromboxane, and A___ ___
[Decreased Response to Vasoconstrictors]
Endothelin, Serotonin, Arginine Vasopressin
Concentrations of Angiotensin II increase __-___x more than non-pregnant
[Response to Catecholamines]
2-3
BUT the sensitivity to Angiotensin II is [decreased/increased]
[Response to Catecholamines]
decreased
The ___ circulation is even less responsive to Angiotensin II than the ___ circulation (contributes to the redistribution of cardiac output, increase of uterine blood flow
[Response to Catecholamines]
uterine, systemic
This ___ is decreased in patients with PIH
[Response to Catecholamines]
refractoriness
Sensitivity to Epinephrine, Norepinephrine, and Phenylephrine is also [increased/decreased] in pregnancy
[Response to Catecholamines]
decreased
BUT the uterine circulation is ___ sensitive to these than the systemic circulation
[Response to Catecholamines]
MORE
THEREFORE, during massive hemorrhage/trauma/stresses resulting in large ___ release, it is unlikely that ___perfusion will be preferentially preserved above essential ___perfusion
[Response to Catecholamines]
catecholamine, uteroplacental, maternal
Clearance of vasopressin at near/term is 3-4 times ___ than before pregnancy.
[Response to Catecholamines]
greater
Vasopressinase levels increase by a factor of ___between early and term pregnancy.
[Response to Catecholamines]
50
Vasopressinase is made by the ___
[Response to Catecholamines]
placenta
More dependent on ___-___ ___ for maintenance of blood pressure than non-pregnant
[Renin]
renin-angiotensin system
Plasma levels of ___ and ___ are increased during pregnancy (**despite increased ____ volume)
[Renin]
renin and angiotensin II, blood
Baseline renin in the third trimester is ___ times greater than non-pregnant
[Renin]
12
Sensitivity to Angiotensin II is [reduced/increased] during the third trimester, but varies throughout the ___ in a daily pattern
[Renin]
reduced, day
Sensitivity to norepinephrine is ___
[Renin]
unchanged
*** Since the Renin Angiotensin System provides support for ____, the loss of sympathetic controlled vaso___ in the presence of epidural anesthesia → maternal hypotension
[Renin]
MAP, vasoconstriction
Blood Volume increases ___-___% in part to prepare for the normal blood loss of delivery
[Hematologic Changes]
25-40
Blood volume increases to _______mL/kg
[Hematologic Changes]
85-100
Plasma volume increases ___-___%
-Beginning as early as ___ weeks gestation
-Approx 50% net increase by ___ weeks
[Hematologic Changes]
40-50
6
34
RBC volume increases ___%
[Hematologic Changes]
20
The result is ___ ___ “physiologic anemia of pregnancy”
-Normal pregnant H/H are about ___/___
Reduced viscosity
[Hematologic Changes]
dilutional anemia
12/35
Blood Loss
-Vaginal delivery – ___cc
-Uncomplicated Cesarean Section – ___-____cc
Estimations are wildly ____
[Hematologic Changes]
500
800-1000
inaccurate
In general parturients are ___coagulable
[Hematologic Changes]
hyper
Factors VII, VIII, IX, X, XII, and fibrinogen are [increased/decreased]
[Hematologic Changes]
increased
___ ___ are one of the leading causes of maternal mortality
[Hematologic Changes]
Thromboembolic events
Platelet count remains___ or slightly ___
-Several pathologic conditions of pregnancy are associated with [decreased/increased] platelets, fibrinogen, or both
[Hematologic Changes]
stable, decreased
Decreased
Maternal thrombocytopenia (<___) in ___% but its not associated with increased morbidity or mortality
[Hematologic Changes]
150, 11.6
White Blood Count increases – mean of 10.5 but may be as much as ___-___ in labor.
[Hematologic Changes]
20-30
Diaphragm is displaced ___ by the growing uterus
[Respiratory Anatomic Changes ]
cephalad
The thorax undergoes both ___ and ___ changes during pregnancy.
[Respiratory Anatomic Changes ]
anatomic and hormonal
Relaxin (the hormone responsible for relaxation of the ___ ligaments) causes relaxation of the ___ attachments to the lower ribs.
[Respiratory Anatomic Changes ]
pelvic, ligamentous
The subcostal angle progressively widens from ___ to ___degrees.
[Respiratory Anatomic Changes ]
68.5 to 103.5
The___ and ___diameters of the chest wall each increase by 2 cm, resulting in an increase of 5 to 7 cm in the circumference of the lower rib cage.
[Respiratory Anatomic Changes ]
anteroposterior and transverse
These changes peak at ___weeks’ gestation.
[Respiratory Anatomic Changes ]
37
The ___ angle remains about 20% wider than the baseline value after delivery.
[Respiratory Anatomic Changes ]
subcostal
The vertical measurement of the chest cavity decreases by as much as ___ cm as a result of the [elevated/lowered] position of the diaphragm.
[Respiratory Anatomic Changes ]
4, elevated
Capillary engorgement → narrowed ___ opening, ___ in nasal and oropharynx
[Respiratory Changes]
glottic, edema
Airway tissues are friable and more susceptible to ___/___
[Respiratory Changes]
damage/bleeding
Generally nasal intubation should be [first choice/avoided]
___-___ ETT is recommended, oral
[Respiratory Changes]
Avoided
6.5-7.0
___/___ handled laryngoscope is beneficial
[Respiratory Changes]
Stubby/Short
At term O2 consumption increases up to ___% at rest and ___% or more during labor
[Respiratory Changes]
33, 100
Minute ventilation at term is increased by ___%
[Respiratory Changes]
50
Tidal volume increases by ___%
[Respiratory Changes]
40
Respiratory rate remains the same or slightly [increases/decreases]
[Respiratory Changes]
Increases
By ___ weeks the partial pressure of CO2 decreases to ___-___ mmHg
[Respiratory Changes]
12, 30-32
Serum bicarbonate [decreases/increases] to compensate
[Respiratory Changes]
decreases
Normal partial pressure of oxygen is normally greater than ___mmHg
[Respiratory Changes]
100
Functional residual capacity , expiratory reserve, and residual volume all decrease due to the upward pressure of the diaphragm which is similar to _____ lung disease
[Respiratory Changes]
restrictive
CO2 production [increases/decreases] (metabolic) but [increased/decreased] alveolar ventilation [increases/decreases] PaCO2
[Blood Gas Changes in Pregnancy]
increases, increased, decreases
PaO2 increased as a result of increased ___ ___
[Blood Gas Changes in Pregnancy]
alveolar ventilation
Metabolic compensation for the respiratory alkalosis of pregnancy reduces serum bicarbonate concentration to approximately ___mEq/L, the base excess by ___ to ___ mEq/L, and the total buffer base by approximately ___ mEq/L.
[Blood Gas Changes in Pregnancy]
20, 2 to 3, 5
Sleep disturbances in pregnancy are [common/uncommon]
[Nervous System Changes]
common
Cerebral blood flow [increased/decreased] in pregnancy
[Nervous System Changes]
increased
[Increase/Decrease] in Cerebral Vascular Resistance
[Nervous System Changes]
Decrease
[Increase/Decrease] in Internal Carotid diameter
[Nervous System Changes]
Increase
Transient restless leg syndrome
-___% in first trimester, ___% in third trimester
[Nervous System Changes]
15, 22
[Decreased/Increased] permeability of the blood-brain barrier
[Nervous System Changes]
Increased
Beginning in the first trimester [increased/decreased] sensitivity to local and general anesthetics
[Nervous System Changes]
increased
[Increased/Decreased] intraabdominal pressure _ engorgement of epidural veins _ decreased volume epidural space & subarachnoid space volume (and CSF volume)
[Nervous System Changes]
Increased
Dependence on the Sympathetic Nervous System for maintenance of hemodynamic stability [decreases/increases], [declining/peaking] at term then returning to nonpregnant state within 36-48 hours postpartum
[Nervous System Changes]
increases, peaking
Increased lumbar lordosis during pregnancy may [reduce/augment] the ___ gap.
[Technical Considerations]
reduce, interspinous
Widening of the pelvis results in a head-[up/down] tilt in the lateral position.
So?
[Technical Considerations]
down
Head down tilt can result in a higher spread than intended.
The flow of CSF from a spinal needle is [unchanged/changed] in pregnancy
Except?
[Technical Considerations]
unchanged
During a contraction, CSF is expelled
Consider all parturients ___ stomachs –[Increased/Decreased] gastrin → [Increased/Decreased] gastric volume → [higher/lower] pH
[Gastrointestinal Changes]
full, increased, increased, lower
Displacement of the ___ may create an outflow obstruction → ___ gastric emptying → ___intragastric pressure
[Gastrointestinal Changes]
stomach, delayed, increased
[Decreased/Increased] progesterone → [Decreased/Increased] gastric motility and [Decreased/Increased] lower esophageal sphincter tone → heartburn
- ___% first trimester, ___% in the second, ___% in the third
[Gastrointestinal Changes]
Increased, decreased, decreased
10, 40, 55
Labor pain further [slows/increases] gastric emptying
-Ultrasound has demonstrated solid food in the stomach of ___/___ of women in whom LEA has been initiated.
-Solid food has been shown in the stomach of more than ___% of laboring women who had not eaten in ___-___ hours
[Gastrointestinal Changes]
slows, 2/3, 40, 12-24
Uncomplicated, elective c-section patients can have clear liquids up to ___ hours prior
[Full Stomach Anesthetic Implications]
2
Nonparticulate antacids (___) , H2 antagonists (___), and ___ may be beneficial
[Full Stomach Anesthetic Implications]
bicitra, Pepcid, metoclopramide
If ___ ___ becomes necessary, these are even more important
[Full Stomach Anesthetic Implications]
general anesthesia
Induction of parturients greater than ___ weeks gestation through the post partum period should be ___ with ___ pressure
[Full Stomach Anesthetic Implications]
12
RSI with cricoid
___% of pregnant women will experience nausea and vomiting during pregnancy
[Nausea and Vomiting]
80
Typically begin at ___-___ weeks gestation and persist until ___-___ weeks gestation
[Nausea and Vomiting]
4-9
12-16
___% will develop symptoms that persist throughout the pregnancy known as ___ ___
[Nausea and Vomiting]
1-5, hyperemesis gravidarum
Liver is displaced slightly [downwards/upwards] and to the [left/right]; size morphology, and blood flow [do/do not change]
[The Liver and Gall Bladder Changes]
upwards, right, do not change
Serum bilirubin, ALT, AST, and lactate [decrease/increase] to the [lower/upper] limits of normal. Serum albumin [decrease/increase] somewhat.
[The Liver and Gall Bladder Changes]
increases, upper, decreases
Biliary stasis and greater bile secretion with cholesterol increase the risk of ___ ___ disease in pregnancy.
[The Liver and Gall Bladder Changes]
gall bladder
Progesterone inhibits ____ of gastrointestinal smooth muscle leading to gall bladder ___
[The Liver and Gall Bladder Changes]
contractility, hypomotility
Incidence of ___ ___ is 5-12% in pregnant women
[The Liver and Gall Bladder Changes]
gall stones
One in 1,600 to 10,000 women will undergo ___ during pregnancy
[The Liver and Gall Bladder Changes]
cholecystectomy
Serum cholinesterase activity decreases by ___% or more during the ___ and ___ trimesters, and slightly recovers by term
[The Liver and Gall Bladder Changes]
30, 1st and 2nd
Prolongation of cholinesterase dependent drugs is ___clinically significant
[The Liver and Gall Bladder Changes]
not
Due to increased intravascular volume, both renal _______ and ___________ volumes increase.
-Enlarged kidneys by as much as ___%
[Renal]
Vascular and interstitial
30
Vasodilation of the kidneys contributes to overall ___ SVR
[Renal]
decreased
The collecting system (___, ___, and ___) dilates.
[Renal]
calyces, pelvis, and ureters
Hydronephrosis may occur in up to ___% of pregnant women by mid-pregnancy
[Renal]
80
[Increased/decreased] cardiac output → [Increased/decreased] renal plasma flow → [Increased/decreased] GFR and reduced renal absorption
Renal plasma flow is 75% greater by 16 weeks gestation than nonpregnant
[Renal]
Increased, increased, increased
Renal plasma flow is ___% greater by ___weeks gestation than nonpregnant
[Renal]
75, 16
At the end of the first trimester the GFR is ___% greater than baseline and does not return to normal values until ___ ___ postpartum
[Renal]
50, 3 months
Creatinine clearance increases to ___-___mL/min
[Renal]
140-160
Total protein excretion and urinary albumin excretion are higher than non-pregnant at around ___ mg and ___ mg in 24-hour clearance
[Renal]
200, 12
___ (>300 mg/24 hr) has been described without the diagnosis of preeclampsia BUT, women with isolated proteinuria are more likely to progress to preeclampsia than women with___hypertension
Glucose is filtered and almost completely reabsorbed in the _________ tubule. Pregnancy reduces the glucose resorptive capacity of the proximal tubules, so all pregnant women exhibit an elevation of glucose excretion.
Kidneys respond to the increased alveolar ventilation with ___________ bicarb excretion -> ____________ bicarbonate levels
[Renal]
Proteinuria
isolated
proximal
increased
decreased
___ (>300 mg/24 hr) has been described without the diagnosis of preeclampsia BUT, women with isolated proteinuria are more likely to progress to preeclampsia than women with___hypertension
[Renal]
Proteinuria, isolated
Glucose is filtered and almost completely reabsorbed in the _________ tubule. Pregnancy reduces the glucose resorptive capacity of the proximal tubules, so all pregnant women exhibit an elevation of glucose___.
[Renal]
Proximal, excretion
Kidneys respond to the increased alveolar ventilation with ___________ bicarb excretion -> ____________ bicarbonate levels
[Renal]
Increased, decreased
Thyroid
Thyroid gland enlarges ___-___%
[Endocrine Changes]
50-70
Thyroid
Estrogen-induced increase in thyroid binding globulin results in ___% increase in total T3 and T4 during the ___ trimester
[Endocrine Changes]
50, first
Thyroid
Concentrations of ___ and ___ do not change, TSH [decreases/increases] during the first trimester then returns to normal shortly thereafter
[Endocrine Changes]
T3 and T4, decreases
