OB Flashcards
anes for OB
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TERM PREGNANCY: Greater than how many weeks? PRE-TERM LABOR: Labor between what weeks of pregnancy?
37;
the 20th and 37th week
what type of meds are commonly used to treat pre-term labor? how do they work? name 3 examples.
TOCOLYTIC MEDICATIONS;
Relaxation of smooth muscle;
Magnesium sulfate, indomethacin, and Nifedipine
CV changes with pregnancy: Increased blood volume by about what% to meet increased fetal/ maternal demands (e.g. blood loss during delivery)
45%
CV changes with pregnancy: Increased cardiac output about 40% related to what 2 things?
increased SV and HR (Up to 20-50% increase for both)
CV changes with pregnancy: Systemic vascular resistance (SVR) decrease what% due to decrease in overall vascular tone
10 – 15%
CV changes with pregnancy: does the size of the heart change with all the hemodynamic changes? at what point in the pregnancy is this seen?
yes, hypertrophy;
1st and 2nd trimester
CV changes with pregnancy: why does cardiac output (CO) and blood volume (BV) increase?
to meet accelerated maternal and fetal metabolic demands
CV changes with pregnancy: what causes the dilutional anemia and reduces blood viscosity? how does hgb values change?
An increase in plasma volume in excess of an increase in red cell mass;
Hemoglobin (Hgb) concentration usually remains >11 g/dL.
CV changes with pregnancy: The reduction in Hgb concentration is offset by what?
the increase in CO and the rightward shift of the Hgb dissociation curve
CV changes with pregnancy: what hemodynamic parameter decreases in the 2nd trimester that decreases both diastolic and SBP.
A decrease in SVR by the 2nd trimester decreases both diastolic and SBP.
CV changes with pregnancy: At term, BV is increased by how much mL, allowing them to easily tolerate the blood loss associated with delivery? Total BV reaches how much mL/kg? when does BL return to normal?
1000-1500mL;
90 mL/kg00mL;
1-2 weeks after delivery
CV changes with pregnancy: *Greatest increases in CO are seen during what events? when does CO returns to normal?
during labor and immediately after delivery;
CO returns to normal 2 weeks after delivery
CV changes with pregnancy: all pregnancies are considered what ASA?
II
CV changes with pregnancy: Changes begins as early as what week of pregnancy.
4th
CV changes with pregnancy: HR increased by what% at term?
20-30%
CV changes with pregnancy: HR increase begins in what trimester and peaks at how many weeks of gestation.
1st trimester;
32 weeks
CV changes with pregnancy: At term, what% of CO perfuses the gravid uterus
10%
CV changes with pregnancy: When in labor, CO increases during uterine contractions due to what?
autotransfusion from the contracting uterus to the central circulation
CV changes with pregnancy: Immediately after delivery, CO increases as much as how much% above predator values? why?
80%;
due to increase in central volume from the contracted uterus and relief of aortocaval compression
CV changes with pregnancy: The diaphragm rises during pregnancy, shifting the heart in which direction, making the cardiac silhouette appear enlarged on x-ray
to the left
CV changes with pregnancy: The ventricular walls thicken and end-diastolic volume decr/incr?
incr
CV changes with pregnancy: is it usual to hear a grade 1 or 2 systolic murmur or a 3rd heart sound? when a systolic murmur is > than grade what or accompanied by chest pain or syncope, further evaluation is needed?
yes;
grade 3
CV changes with pregnancy: are Diastolic and cardiac enlargement are considered pathologic?
yes
CV changes with pregnancy: Total blood volume increases by what% throughout pregnancy
25-40%
CV changes with pregnancy: Plasma volume increases by what% whereas RBCs volume increase by only what%?
40-50%;
20%
CV changes with pregnancy: The incr in plasma volume is likely the result of greater circulating levels of what 2 hormones resulting in enhanced renin-angiotensin-aldosterone activity
progesterone and estrogen
CV changes with pregnancy: Average vaginal EBL is how much mL? and uncomplicated c-section EBL is how much mL.
500 mL;
800-1000 mL
CV changes with pregnancy: In labor each contraction moves how much mL of blood from the contracting uterus to the central circulation
300-500ml
CV changes with pregnancy: In the presence of adequate what and little sympathetic stimulation, there’s often a corresponding decr in maternal HR during uterine contractions due to what?
neuraxial analgesia;
transiently incr preload
CV changes with pregnancy: what CV change by end of term pregnancy, owe to a large decr resistance in the uteroplacental, pulmonary, renal, and cutaneous vascular beds
SVR decr as much as 21% by end of term pregnancy
CV changes with pregnancy: The decr in SVR effect the SBP during normal pregnancy?
no, despite the incr blood volume
CV changes with pregnancy: A decr in DBP of up to how much mm Hg may occur, resulting in a decr in what pressure?
15 mm Hg;
mean pressure
CV changes with pregnancy: The gravid uterine blood flow is how many X above nonpregnant level, accounting for 20% of maternal CO at term
20-40x
CV changes with pregnancy: what causes the aortocaval compression or the “maternal supine hypotensive syndrome.”
The enlarged uterus produces mechanical compression of surrounding vascular structures
CV changes with pregnancy: In the supine position, compression of the inferior vena cava decreases venous return, resulting in what 3 CV effects? Compression of the aorta further decreases uterine perfusion and may result in what?
decreased SV/CO and hypotension;
fetal distress
CV changes with pregnancy: Normal maternal compensatory responses to aortocaval compression consist of what 2?
tachycardia and lower-extremity vasoconstriction
Resp changes: Changes evident after how many weeks gestation
12
Resp changes: The expanding uterus produces cephalad displacement of the diaphragm resulting in a decr in what 2 resp parameters? which plays a major role in preserving O2 saturation during hypoventilation or apnea
FRC, expiratory reserve (ER), and residual volume (RV);
FRC
Resp changes: The decr FRC combined with the increase in what commonly results in rapid arterial desaturation in the apneic pregnant patient. Morbid obesity, labor and sepsis exaggerate this effect.
O2 consumption
Resp changes: how do Total lung capacity (TLC), vital capacity (VC), and Inspiratory capacity (IC) change?
= unchanged due to compensatory subcostal widening and enlarging of the thoracic anteroposterior diameter.
Resp changes: Term pregnancy = incr 02 consumption up to what% at rest? and what% during the 2nd stage of labor due to increase in alveolar ventilation at term?
33%;
100%
Resp changes: Elevation of the diaphragm seen in what trimester? Results in about a what% decrease in FRC that mimics what type of lung disease?
third;
20% decrease in FRC;
mimics restrictive lung disease
Resp changes: Increased oxygen demand coupled with decreased reserve results in…. ?
rapid desaturation
Resp changes: what causes maternal arterial pressure of CO2 to drop below 15 mmHg
During labor, increases of minute ventilation of up to 300% can occur in response to pain
Resp changes, airway: Generalized airway edema from what?
capillary engorgement
Resp changes, airway: Overall narrowing of glottic opening can result from what? The possibility of technically difficult intubation requiring what should be kept in mind when caring for these patients
edema;
small-diameter ETT (7 or 6.5)
Resp changes, airway: Nasal intubation of the parturient should generally be avoided?
true
Metabolic change: incidence of gestational DM? what are the 2 complications to the fetus due to this?
3%;
decr placental perfusion and impaired O2 transport
Metabolic change: what are the 2 diagnostic tests for gestational DM?
glycosuria and glucose challenge/tolerance test
Metabolic change: when is a glucose challenge/tolerance test typically performed (at what week) if no h/o of it? when if there is a h/o gest. DM?
24-28 weeks;
13 weeks
Metabolic change: gestational DM increases the change of what procedure?
c-section due to high birth wts
Metabolic change: gestational DM can decrease uteroplacental circulation by what %
35 – 45%
Metabolic change, gestational DM: what causes the infant hypoclymia? Must check what lab at delivery of infant?
Increase glucose in mother;
infant’s blood sugar is checked.
Metabolic change: Altered carbohydrate, fat, and protein metabolism favors fetal what? These changes resembles starvation why?
growth and development;
because blood glucose and amino acids levels are low, whereas free fatty acids, ketones, and triglyceride levels are high
Metabolic change: Pregnancy is a diabetogenic state why? Insulin levels steadily rise during pregnancy. Secretion of what by the placenta is probably responsible for the relative insulin resistance associated with pregnancy.
Insulin levels steadily rise during pregnancy;
Secretion of human placental lactogen, also called human chorionic somatomammotropin
Metabolic changes: Pancreatic beta cell hyperplasia occurs in response to an increased demand for what?
insulin secretion
Metabolic changes: Secretion of human chorionic gonadotropin and elevated levels of estrogens promote hypertrophy of what gland? resulting in increase what hormone?
thyroid gland;
thyroid-binding globulin.
Metabolic changes: how are T3 and T4 and free T3 and T4 and thyrotropin effected?
T3 and T4 are elevated but free T3 and T4 and thyrotropin are normal
Renal changes: Kidneys increase in size and weight during pregnancy and return to normal size when?
6 months post partum
Renal changes: when do renal pelvis and ureters begin to dilate? what causes this?
Begins during 1st trimester;
Related to progesterone production during atony of calyces and ureters
Renal changes: Ureters hold how many times their normal volume (300 mL) of urine
25x
Renal changes: bladder tone decr/incr?
decr
Renal changes: Increased GFR by what %? Peaks around which weeks of gestation, falls as term approaches
50%;
at 9-16 weeks
Renal changes: GFR changes with changes in what CV parameter?
cardiac output
Renal changes: is Proteinuria and glycosuria pathologic in parturient?
no
Renal changes: GFR returns to normal within how many weeks postpartum
3 weeks
Liver and gallbladder changes: there is a Mild decrease serum albumin level due to what?
expanded plasma volume
Liver and gallbladder changes: what% decrease in serum pseudocholineserase activity present at term? does it produce prolongation of sux action? Pseudocholinesterase returns to normal how many weeks postpartum
25 – 30%;
rarely;
2-6 weeks
Liver and gallbladder changes: what inhibits the release of cholecystokinin resulting in poor emptying of the gall bladder? Pregnancy predisposes to what gallbladder issue?
High progesterone levels;
gallstone formation
Heme changes: Pregnancy is associated with hypercoagulable state. How is this beneficial?
limiting blood loss during delivery;
Heme changes: Increase in what 4 factors and blood product? what factor may decr?
Increased fibrinogen (Factor 1), factor VII, factor X, factor XII, and platelets; XI
Heme changes: The coagulation profile returns to normal how many weeks postpartum
2 weeks
Heme changes: hypercoagulability places Parturients at higher risk for what?
embolus
Heme changes: Increased clotting levels coupled with venous pooling puts patient at risk for what?
DVT
Heme changes: can Thrombocytopenia be seen in a normal pregnancy
yes
Heme changes: what event remains one of the leading causes of maternal mortality
Thromboembolic events
Heme changes: In the nonpregnant state, fibrinogen levels average from 200-400 mg/dl. In late pregnancy, levels are normally at least what mg/dL? and may be as high as what mg/dL?
400 mg/dL;
650 mg/dL
Heme changes: The platelet count remains stable (this contradicts an earlier slide) or is decreased slightly in what trimester?
3rd trimester
Heme changes: The WBC count decr/incr in pregnancy. In 3rd trimester, the mean is 10.5K, and in labor the WBC may increase to what?
incr;
20-30K
GI changes: Increased incidence of what 2 complications?
GERD and aspiration
GI changes: Upward displacement of stomach results in what 2 findings/
possible decreased emptying and decreased sphincter tone
GI changes: Increased levels of what substance excreted by the placenta causes increased acid secretion
gastrin
GI changes: ALL PREGNANT PATIENTS ARE A FULL STOMACH at what point in pregnancy?
from 8 weeks of pregnancy until 6 weeks postpartum
GI changes: what is Mendelson’s syndrome? Most parturients have a stomach pH what mL.
Chemical pneumonitis caused by aspiration during general anesthesia, especially during pregnancy;
pH 25 mL.
GI changes, aspiration: preventative tx includes what to neutralize stomach acidity? what is given to increase lower esophageal sphincter tone and increase gastric emptying?
bicitra or H2 blockers;
PPIs (reglan)
MS changes: what hormone increases resulting in pain
Relaxin
MS changes: what increase in flexibility (consider this in regional technique)
Joints and ligaments
MS changes: Increased incidence of what type of spinal curvature?
lumbar lordosis
Uterine changes: A non pregnant uterus typically receives about 50 ml/ min of blood flow compared to what ml/min in the pregnant uterus? that is what % of CO?
700 ml/min;
10% of CO
Uterine changes: Fetal gas exchange is completely dependent upon what perfusion pressure?
maternal uterine perfusion pressure
Uteroplacental circulation: what causes intrauterine growth retardation and can result in fetal demise
Uteroplacental insufficiency
Uteroplacental circulation: what are the Two key components
uterine BF and placental function
Uterine BF: T/F Uterine vasculature is maximally dilated under normal conditions and has a lot capacity to further dilate.
False, no autoregulation
Uterine BF: uterine blood flow is determined by what equation?
Uterine arterial pressure – Uterine venous pressure/ uterine vascular resistance
Uterine BF: what can reduce uterine blood flow and cause fetal hypoxia and acidosis
Extreme hypocapnia (PaCO2
Uterine BF: what are the three events that primarily determine (decrease) uterine blood flow and their causes?
Hypotension: most commonly d/t aortocaval compression, hypovolemia, and sympathetic blockade
Uterine vasoconstriction: caused by stress-induced release of endogenous catecholamines during labor and any drug with alpha-adrenergic activity (phenylephrine)
Contractions: decreases blood flow by elevating uterine venous pressure. Hypertonic contractions during Pitocin infusions can critically compromise uterine blood flow
Uterine BF: Aortocaval compression occurs after what week when the patient is in supine position
the 28th week
Placental exchange: what is the placental function (3)?
the fetus depends on the placenta for respiratory gas exchange, nutrition, and waste elimination
Placental exchange: what is Placental composition? what lies within the villi that are able to exchange substances with the maternal blood that bathe them in this arrangements?
Fetal tissue (villi) that lies in the maternal vascular space (intravillous spaces); Fetal capillaries
Placental exchange: what sends oxygen poor blood to the placenta/ mom to be oxygenated
umbilical arteries (2)
Placental exchange: Water moves across by this method. Movement occurs related to hydrostatic or osmotic gradient
a. diffusion
b. bulk flow
c. active transport
d. pinocytosis
e. breaks in placental membrane
b
Placental exchange: Large molecules (immunoglobulins) move across by this method. There is a binding of a specific receptor on a cell surface and it is then enclosed on the plasma membrane
a. diffusion
b. bulk flow
c. active transport
d. pinocytosis
e. breaks in placental membrane
d
Placental exchange: Respiratory gasses and small ions are transported by diffusion. Most anesthetic drugs have molecular weights well under 1000 Dalton and consequently diffuse across the placenta. No energy is needed for this process
a. diffusion
b. bulk flow
c. active transport
d. pinocytosis
e. breaks in placental membrane
a
Placental exchange: Amino acids, vitamins, and some ions (Calcium and iron) utilize this method
a. diffusion
b. bulk flow
c. active transport
d. pinocytosis
e. breaks in placental membrane
c
Placental exchange: mixing of maternal and fetal blood are probably responsible for Rh sensitization
a. diffusion
b. bulk flow
c. active transport
d. pinocytosis
e. breaks in placental membrane
e
stages of labor: from 10cm dilated until the delivery of the baby is complete (pushing stage)
a. first
b. first, latent
c. first, active
d. second
e. third
d
stages of labor: more frequent contractions (3-5 minutes) and progressive cervical dilation up to 10 cm.
a. first
b. first, latent
c. first, active
d. second
e. third
c
stages of labor: Progressive cervical effacement and minor dilation (2-3 cm) “soft and thin”
a. first
b. first, latent
c. first, active
d. second
e. third
b
stages of labor: Delivery of baby until placenta is delivered
a. first
b. first, latent
c. first, active
d. second
e. third
e
stages of labor: regular contractions until fully dilated (10 cm)
a. first
b. first, latent
c. first, active
d. second
e. third
a
stages of labor & pain pathways: Nociceptor stimulation is mediated by C fibers (Small, unmyelinated nerves).
a. first
b. second
a
stages of labor & pain pathways: Pain travels via the pudendeal nerves, they enter the spinal cord at S2 – S4
a. first
b. second
b
stages of labor & pain pathways: Pain travels via visceral afferents accompanying sympathetic nerves as they enter the spinal cord at T10 – L1
a. first
b. second
a
stages of labor & pain pathways: This pain is caused by distention of lower vagina, vulva, and perineum epidural may not cover this
a. first
b. second
b
stages of labor & pain pathways: Cervical dilation and effacement and possibly uterine muscle ischemia during contraction causes this pain.
a. first
b. second
a
Labor anes pearls: which anes techniques are by far preferred over general anesthesia/ parenteral narcotics
Regional
Labor anes pearls: location of analgesia for First stage of labor? second stage location?
~ T10 – L1;
~ T10 – S4
Labor anes pearls: which regional anes techniques are preferred over other regional techniques
Continuous epidural analgesia (CEA) infusions
Labor anes pearls: does CEA in dilute doses have much of an effect on progress of labor
no, has little effect
Labor anes pearls: why is the Incidence of inadvertent intravenous injection high? tx?
bc all vessels are engorged;
Tx: lipid emulsion for LA tox
Labor anes pearls: Hypotension is common and must be treated aggressively with what?
fluid & ephedrine
Indications for a c-section: Immediate or emergent delivery necessary in what 5 conditions/scenarios?
fetal distress, Umbilical cord prolapse, Maternal hemorrhage, Amnionitis, Genital herpes with ruptured membranes Impending maternal death
Pregnancy HTN: Pregnancy induced hypertension (PIH) is defined as a SBP >what mmHg, DBP >what mmHg
SBP >140 mmHg, DBP >90 mmHg
PIH: PIH more accurately describes one of what three syndromes?
preeclampsia, eclampsia, and the HELLP syndrome
PIH: hypertension, proteinuria, peripheral edema, plus Hemolysis, Elevated Liver Enzymes, and a Low Platelet Count
a. preeclampsia
b. eclampsia
c. HELLP syndrome
c
PIH: Triad of hypertension, proteinuria, and peripheral edema
a. preeclampsia
b. eclampsia
c. HELLP syndrome
a
PIH: hypertension, proteinuria, peripheral edema, and seizures
a. preeclampsia
b. eclampsia
c. HELLP syndrome
b
PIH: Patient c/o epigastric pain, malaise, N&V
a. preeclampsia
b. eclampsia
c. HELLP syndrome
c
PIH: Definitive treatment is delivery of fetus
a. preeclampsia
b. eclampsia
c. HELLP syndrome
b
PIH: 20% have decrease in clotting factors
a. preeclampsia
b. eclampsia
c. HELLP syndrome
a
PIH: Leading cause of maternal mortality
a. preeclampsia
b. eclampsia
c. HELLP syndrome
b
PIH: Usually occurs after 24 weeks gestation
a. preeclampsia
b. eclampsia
c. HELLP syndrome
a
PIH: Usually occurs after 36 weeks
a. preeclampsia
b. eclampsia
c. HELLP syndrome
c
PIH: Hepatic rupture possible
a. preeclampsia
b. eclampsia
c. HELLP syndrome
c
PIH: Higher incidence in: African-American women, extremes of age, multiple gestation, DM
a. preeclampsia
b. eclampsia
c. HELLP syndrome
a
PIH: tx is Immediate delivery regardless of fetal gestation
a. preeclampsia
b. eclampsia
c. HELLP syndrome
c
PIH: Can start as mild and rapidly progress including DIC
a. preeclampsia
b. eclampsia
c. HELLP syndrome
c
PIH: Management involves: Magnesium sulfate gtt to increase seizure threshold, Anti-hypertensives (hydralazine), BB
a. preeclampsia
b. eclampsia
c. HELLP syndrome
b
PIH: tx Thiopental, benzodiazepines, magnesium to stop seizure
a. preeclampsia
b. eclampsia
c. HELLP syndrome
b
PIH preeclampsia: mild form SBP what range, DBP what range. +? edema, trace proteinura
SBP 140-160, DBP 90-110. +1 edema, trace proteinura
PIH preeclampsia: severe form is SBP >what, DBP >what, > +?edema, > how much gm proteinura in 24 hours
SBP >160, DBP >110, > +2 edema, > 5gm proteinura in 24 hours
Preeclampsia anes mgmt: is regional is appropriate?
yes, once clotting factors are checked
Preeclampsia anes mgmt: how avoid HOTN when administering regional?
After test dose of epi, administer bolus in divided doses and infuse fluids to avoid HOTN