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138 Cards in this Set
- Front
- Back
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maternal O2 consumption changes in parturition at term
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increased by 20%
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alterations in lung volumes and capacities at pregnancy
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exp reserve vol, FRC, and residual vol down 20%
no change in vital capacity TLC down 0-5% |
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what happens to vital capacity in pregnancy
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no change
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what happens with FRC in preg
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decreased by 20%
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what happens with TLC in preg
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decreased by 0-5%
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what happens to CO in preg
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increases 10% by 10th week
increases 40-50% by 3rd trimester |
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why do we see increase in CO
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increased SV of 25-30% and Hr of 15-20%
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when does the largest increase in CO occur with preg
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immediatley after delivery
increased as much as 80% |
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when does CO return to normal
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by 2 weeks postpartum
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release of catecholamines during painful labor can result in
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tachycardia
systemic hypotension |
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what causes parturient anemia
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increase in intravascular fluid volume of 45%
increased RBC by 20% causes relative anemia |
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when do we see anemia with preg
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1st trimester
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blood loss with C section
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1000ml
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blood loss with vaginal
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500ml
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what happens with thyroid in preg
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T 3 and T 4 elevated
free T3, T4, TSH normal |
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what causes the changes in thyroid function
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secretion of HCG and elevated levels of estrogens which promote hypertrophy of the thyroid and increase thyroid binding sites
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general is technique of choice with
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acute fetal distress
maternal hypovol severe hypotension severe anemia coagulopathy septicemia acute neurologic deficit CV disorders in which sympathetic blockade would exacerbate |
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upper airway changes
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capillary engorgement of mucosal lining
1/2 size smaller ETT due to edema wt gain/big breast make difficult |
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what is supine hypotension syndrome
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decrease in BP due to aortocaval compression by gravid uterus when supine
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which artery compressed in aortocaval compression
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aorto-iliac artery
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vena cava compression leads to
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lower ext venous stasis--ankle edema and varices
diaphoresis, N/V, changes in cerebration |
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supine hypotension does what to CO and systmeic BP
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decreased
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gravid uterus can also compress the
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lower abdominal aorta leading to arterial hypotension in lower ext
mat s/s or decrease in BP in arms does not occur |
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compensatory mechanisms which prevent supine hypotension syndrome
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increased venous pressure below level of compression of inf vena cava(diverts bld to paravertebral venous plexus to azygos vein
reflex increase in PSNS activity |
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what is more common and profound during reg anesthesia when adm to preg women compared to non preg
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arterial hypotension
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risk of aortocaval compression
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decrease in urterine and placental bld flow
hypotension increased risk of epidural venous puncture anesthetic techniques that interfere with increased sym tone |
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treatment of supine hypotension
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lateral position
move gravid uterus to left and off IVC R hip elevation |
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what is bicitra
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used to maintain gastric ph >2.5 and decreases likelihood of severe aspiration pneumonitis
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who should be given bicitra and when
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pts at high risk for aspiration
45-60min prior |
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what is minimum fasting time for elective c section
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6 hours
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GI changes
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vulnerable to regurg
displacement of pylorus cephalad slows gastric emptying progesterone decreases GI motility--increased gastric vol even after fasting gastrin (secreted by placenta) stimulates gastic H ion secretion making ph even lower large uterus changes angle of gastroesophageal junction causing incompetent sphincter |
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what in medlesons
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perioperative aspiration of gastric contents
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what acid base in moms
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resp alkalosis
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what are fetal O2 stores estimated to be
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42ml
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at term, what is the average fetal O2 consumption
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21ml/min
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why does fetal hypoxia cause bradycardia
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d/t low storage to utilization ratio of O2
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uterine blood flow at term
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10% of CO (600-700mls/min)
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uterine blood flow is directly related to
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diff b/t uterine arterial and venous pressures
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uterine blood flow is inversely related to
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uterine vascular restistance
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uterine blood flow and autoregulation
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autoregulation is absent d/t max dilation of uterine vasculature but is sensitive to alpha adrenergic agonists
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uterine vasculature has what receptors
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a-adrenergic and possibly some b-adrenergic
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3 major factors that decrease uterine blood flow
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systemic hypotension
uterine vasoconstriction uterine contractions |
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extreme hypocapnia does what to uterine blood flow
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reduces and causes fetal hypoxia
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normal fetus has how many accels
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15-40/hour
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define accels
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increase of 15 beats/min or lasting >15 secs
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preiodic accels relfect
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normal oxygenation
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accels usually d/t
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fetal movements and responses to uterine pressure
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accels due to
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increase in catecholamine secretion with decrease in vagal tone
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what decreases accels
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fetal sleep
drugs --opoids. Mg, atropine fetal hypoxia |
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early type I decels
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10-40 beats/min
vagal response to compression of fetal head/stretching of neck |
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what FHR forms a smooth mirror image of the contractions
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early type I decel
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which FHR are not associated with fetal distress
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early type I decel
accels |
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which FHR are associated with fetal compromise
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late type 2 decel
variable type 3 |
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which is characterized by a decrease in HR at or after the peak of uterine contraction
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late type 2 decel
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which FHR may be as few as 5 beats/min
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late type II decel
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what is thought to cause late type II decels
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decrease in arterial oxygen tenxion on chemoreceptors or the SA node
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late decels with normal variablity are
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usually reversible with treatment
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late decels with decreased variability
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prolonged asphyxia
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ph < 7.20
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depressed neonate
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ph > 7.20
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vigourous neonate
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complete abolition of variability
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ominous sign of severe decompensation and need for immediate delivery
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most common decel
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varaiable type 3
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variable type 3
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variable in onset, duration, magnitude (>30 beats)
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which FHR usually abrupt in onset
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variable type 3
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cause of variable type 3
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umbilical cord compression and acute intermittent decrease in uterine blood flow
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variable type 3 usually associated with fetal asphyxia when they are
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> 60 beats/min
lasts > 60 secs occur in pattern for > 30 min |
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NST should not exceed
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80 min
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normal score on NST
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2 reactive
at least 2 episodes of FHR accel >15 beats or secs fetal movement > 30 min |
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how does placental exchanges of substances occur
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diffusion
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diff depends on
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mat to fet conc gradient
mat prot binding molecular wt LS degree of ionization |
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what is the most important method of limiting amout of drug that reaches fetus
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minimizing maternal blood conc
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do NDMB cross placenta
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no
high molecular wt low LS |
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does sux cross placenta
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no
low molecular wt high ionized |
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is the fetus paralyzed with sux in GA
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no
does not cross |
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which drugs has low molecular wts and crosses the placenta
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barbs
opoids LA's |
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transfer of drugs across the placenta is reflected by the ratio
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of fetal umbilical vein to maternal venous conc
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uptake by fetal tissues is reflected by
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ratio of fetal umbilical artery to umbilical vein conc
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fetal effects of drugs depends on
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route of administration
dose timing of administration (to delivery and cont) maturity of fetal organs |
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inhalation agents and fetal depression
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little if MAC < 1 and delivery wihtin 10 mins of induction
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what specific drugs readily crosses BBB
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thiopental
ketamine propofol benzo |
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what drugs cross BBB
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ephedrine
BB vasodilators phenothiazines antihistamines metoclopramide atropine scopolamine |
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does glycopyrrolate cross placenta
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no
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what anesthetic with emergency c section
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ketamine
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lower limit of platlets with reg
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< 100,000
70,000 maybe acceptable |
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most common cause of pp hemorrhage
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uterine atony
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what meds to relax uterus
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terbutaline, ritodrine--B2 agonists
mag NTG and NO for retained placenta |
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what meds for uterine constriction
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oxytocin
methylergonovine carboprost |
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why should methergine be used with caution
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it can percipitate HTN crisis in pre-eclamptic women
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s/s of HELLP
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hemolysis
elevated liver enzymes low platlets |
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what is the hallmark of HELLP
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hemolysis, the presence of microangiopathic hemolytic anemia
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what drugs cross BBB
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ephedrine
BB vasodilators phenothiazines antihistamines metoclopramide atropine scopolamine |
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does glycopyrrolate cross placenta
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no
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what anesthetic with emergency c section
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ketamine
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lower limit of platlets with reg
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< 100,000
70,000 maybe acceptable |
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most common cause of pp hemorrhage
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uterine atony
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what meds to relax uterus
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terbutaline, ritodrine--B2 agonists
mag NTG and NO for retained placenta |
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what meds for uterine constriction
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oxytocin
methylergonovine carboprost |
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why should methergine be used with caution
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it can percipitate HTN crisis in pre-eclamptic women
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s/s of HELLP
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hemolysis
elevated liver enzymes low platlets |
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what is the hallmark of HELLP
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hemolysis, the presence of microangiopathic hemolytic anemia
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normal gluc tolerance
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2hPG <140
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GD risk factors
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advanced maternal age
obesity family hx prior stillbirth, fetal death or malformation |
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tx of GD
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diet,exercise
insulin no oral hypoglycemics--cross placenta |
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what is used for induction with PIH and emergency c section
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thiopental or propofol
then sux |
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what is avoided in pre-eclamptic pts due to sympathetic nervous system stimulation may exacerbate HTN
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ketamine
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what can be used in PIH C section to attenutate BP response
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NTG
fentanyl lidocaine esmolol remifentanyl vol anesthetic |
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what could lower our dose of NMB
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mag
could potentiate effects |
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what decreases uterine tone and increases risk for bleeding after delivery
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mag
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what is the 1st choice for most pts with PIH in labor
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cont epidural if no coagulopathies
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why choose epidurals with PIH
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no risk with intubation
decreases catecholamine secretion and improves uteroplacental perfusion avoids hypotension |
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what is virchow's tirad
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alterations in normal blood flow-stasis
injuries to vascular endothelium alterations in constitution of blood-hypercoagulopathy |
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avoid what with preg women using marijuana
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ketamine--causes tachycardia
atropine pancuronium LA's with epi |
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treat tachycardia due to marijuana use with
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BB
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marijuana with volatile halogenated agents
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may have additive effect and CV depression
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cocaine abuse leads to
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placental abruption
premature ROM meconimum stained amniotic fld low birth wt cogenital abnormalitites |
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cocaine causes
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maternal vasoconstriction
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what is placenta previa
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abnormally low implantation of placenta on uterus
painless vag bleeding at 32 weeks associated with older age and multiparity |
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what med for emergency situation with hemorrhage
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GA with ketamine
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neonates after hemorrhagic shock are
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acidotic
hypovolemic |
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placental abruption
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seperation of placenta > 20 weeks
painful vag bleeding with uterine contractions |
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most common cause of fetal death
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abruption
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what is accreta
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implantation onto myometrium
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what is increta
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implantation into myometrium
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what is percreta
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implantation thourgh full thickness of myometrium
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avg blood loss with previa and accreta combined
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2000-5000ml
30 units PRBC |
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20% accreta pts develop
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coagulopathies
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pre-eclpamsia
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> 20weeks and resolves within 48 hrs of delivery
HTN, edema, proteinuria |
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eclampsia
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seizure with pre-eclampsia s/s
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when do we see eclampsia
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> 20 weeks
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fetal hgb does what to oxyhgb curve
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right shift in mom
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pitocin used to
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induce or augment uterine contractions or maintain uterine tone postpartum
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complications of pit
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fetal distress d/t overstimulation
uterine tetany maternal water intoxication hypotension reflex tachy |
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ion trapping
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lower fetal ph means that weakly basic drugs ( LA, opiods) that cross the placenta in non-ionized form will become ionized in fetal circ and be unable to cross placenta back to mom---accumulates
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2nd stage pain
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visceral
well localized sharp |
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which stage of pain due to descent of fetus into pelvis
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2
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which stage dull aching
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1
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stage 1 pain
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visceral pain due to uterine contraction and cervical dilation
poorly localized |
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which pain is poorly localized
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stage 1
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