OB Flashcards

1
Q

Changes in respiratory in pregnancy (6)

A
  1. airway anatomy: edema and friable; difficult intubation
  2. MV and alveolar vent: increases 50% by term 2/2 increase TV (40%) RR 15% (progesterone increases sesitivity to Co2)
  3. FRC: 20% decrease by term (ERV and RV decrease 20%), rapid desat
  4. IC increases by 15%
  5. increased V02 20% prediposes to rapid desat also decrease time required for inhalation induction & pre-oxygenation (de-nitrogen)
  6. ABG: 7.44/30/103/22
  7. P50 27 to 30
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2
Q

CV changes in prenancy (3)

A
  1. elevated CO predisposes to CHF (40% 1st, 50% term; labor 40% 75% delivery, 30% post 1 hr, , normal 2 weeks (HR 25% SV increases 40%)
  2. aortocval compresson 18-20 weeks–>compromise venous return (hydration and LUD essential)
  3. SVR decreases: Decrease BP diastolic>systolic
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3
Q

Heme changes in pregnancy (4)

A
  1. anemia: plasma volume increases 50% RBC volume 25% ~hct 35 Hbg 11 (15% decrease)
  2. Leukocytosis
  3. hypercoagulable state: 7,8,9,10, 12 increase, fibrinogen increases (11, 13, AT3 decrease)
  4. plasma protein decrease: total protein, albumin, including plasma cholinesterase (decrease colloid oncoitc pressure. unclear if this increases free fraction of drugs or contibute to edema. increased vascular permeability
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4
Q

gastrointestinal changes in pregnancy (2)

A
  1. gastric emptying slows during labor, volume increase pH decreases during labor (not gestation)
  2. decrease LES tone 2/2 progesterone (Aspiration risk 18-20 weeks)
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5
Q

renal changes in pregnancy (1)

A

RBF and GRF increases (creatine 0.5-.6) BUN 8-9

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6
Q

endocrine changes in pregnancy(2)

A
  1. impaired glucose tolerance
  2. TBG causes increase in total T3 and T4 levels with no change in free levels
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7
Q

Anesthesia changes in pregnancy (3)

A
  1. MAC decreases by 40%
  2. increase sensitivity to local (cardiac toxicity esp to bupi enhanced)
  3. decreased epidural space and venous engorgaement increase risk of IV injection and dural puncture
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8
Q

How to assess fetal well being preoperatively

A
  1. H&P focusing on prenatal care, last medical assessment, any prenatal problems
  2. ask about fetal body movements
  3. obtain FHR tracing (detect 16 weeks), look for rate (120-160) and variability-25-27 weeks (6-10bpm beat to beat varibility): ensure optimal uteroplacental blood flow and O2 delivery to fetus. if bradycardia occurs could promp search for materal condition like maternal hypotension and anemia
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9
Q

ddx of fetal tachycardia and bradycardia

A

tachycardia:

hypoxemia (sympathetic stimulation),

maternal fever #1, maternal thyrotoxicosis, terbutaline, atropine, arrythmia

bradycardia:

severe hypoxia/uretoplacental issues, uterine hypertonus, head compression,

hypothermia, complete heart block (SLE antibodies), paracervical block

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10
Q

What is significance of early decels

A

normal finding from fetal head compression causing parasympathetically induced bradycardia

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11
Q

Cause of late decels?

what would you do?

A

false alarms common, but can suggest urteroplacental insufficiency

  1. determine severity. FHR <100 prompts tx, <60 prolonged may require emergency obstectric intervention. Loss of varibility makes prognosis worse
  2. check mom ABC: 100% O2, well oxgengated, LUD, optimize hemodynamics (fluid/pressors
  3. determine the circumstance surrounding the change. recieve LA, oxytocin, pt sx,
  4. make sure OB aware and discuss tx
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12
Q

significance of loss of short term varaibility

ddx?

A

etio: sym and para sym interaction is lost consistent with asphyxia

benzos, narotics, absoption of local

mag, atropine, steriod

ancephaly/neurological ab/hypxoxia/ prematrity/ fetal sleep

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13
Q

When would you want scalp pH

A

to determine significance of nonreassuring FHR

late decels good varaibility >7.25 good <7.2 bad

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14
Q

significance of variable decal: rule 60s

A

umbiical cord compression. serious if <60 bmp >60 sec, decrease >60bmp

look at varaibility between decels and consider scalp pH

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15
Q

hypertensive dx of pregnacy and dx

A
  1. chronic HTN <20 weeks
  2. preeclampsia: >20 weeks, HTN >140/90 (2 6 hours apart), and proteinuria >300mg/day (1+ dipstick)
  3. chronic HTN with superimposed preeclampsia
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16
Q

signs severe preeclampsia

A

One of the following:

BP>160/110

proteinuria >5g/day

signs end organ effects:

neuro: visual disturbances, H/A AMS, seizures
cardiac: HTN
pulm: pulm edema

GI: epigastric/RUQ (disstension of Glisson capsule), hepatic rupture, impaired liver fxn,

renal: proteinuria >5g/day 3+ dipstick, oliguria (<400mL/day)
heme: thrombocytopenia, HELLP
fetus: IUGR, oligohyrammnios

17
Q

goals with pt PIH

BP meds

A

preop: assess mom and baby
neuro: antiseziure ppx
cards: control BP (hydralazine and labteolol 1:7 most common), optimize fluid status
pulm: avoid overhydration, prone to pulm edema
renal: ensure adequate hydration and UOP(prone to hypovolemia),
heme: assess couagulation status

intraop: establish neuraxial for labor or c-section (try to avoid GA) try to avoid exaggerated BP response,

postop: monitor for pulm edema (more likely postpartum 2/2 increse in preload 2/2 decompression IVC), and seizures (30% post partum, continue mag 24 hr)

18
Q

BP meds during pregnancy

A

Labetalol decreases SVR w/o increasing maternal HR or decreasing CO/uterine blood flow; faster onset than hydralazine

Hydralazine: up to 20mg, reflex tachycardia (give labetalol 1st)

NTG: readily crosses placenta, most useful for short term treatment (intubation)

SNP: short term treatment, risk of CN toxicity w/ greater than 4mcg/kg/min x several hours

Nifedipine CCB, dilates arterial smooth muscle (SE: flushing, H/A reflex tachycardia), caution w/ concurrent Mg (risk of myocardial depression/PEd

19
Q

pathophys of PIH

A
  1. failure of trophoblasts to invade materal decidua and maternal ateries retain their adrenergic innvervation
  2. endothelium fails to produce prostacyclin (PGI2) and NO, excess thromboxane and endothelin
  3. platelets show increase aggregation increase TXA2/PGI2 ratio
20
Q

PIH head to toe effects

A

neuro: AMS, H/A, visual, cerebral edema, seziure, intracranial hemorrage #1 cause death
cardiac: elevated SVR, hypovolemia, low colloid oncotic pressure and increase vascular perm predipose to edema and hypovolemia,
pulm: airway edema, pulm edema (increase PCWP, decreased CO, excess fluid admin)

GI: distention, hemorrage, rupture, HELLP

renal: oliguria (decrease GFR), proteinuria from increase glomerular perm
heme: plt activation <100K, hypocoag, increased fibrinolysis
fetal: IUGR, decreased uteroplacnetal perfusion (placental infarcts), premature, abruption,

21
Q

Effects of magnesium

How to treat mag toxicity

A
  1. potentiation of muscular blockade (inhibits presynaptic Ach release and motor end plate depolarization)
  2. decreased uterine tone/atony; prolonged labor
  3. decreased FHR variability and neonatal depression
  4. toxicity

normal 2 meq/L

theraputic 4-8

10 loss DTR, prolong QRS, QT, PR, hypotension, AMS

15: resp arrest, conduction block

25 cardiac arrest

tx: calcium, diuresis, dialysis

relative contraindications: MG, impaired renal fxn, CCB (potentiates cardiotoxic effect)

22
Q

Why place an epidural for PIH

Pro con GA

A
  1. superior analgesia
  2. attenutate hypertensive response to pain
  3. reduce circulating catecholamines improving uteroplacental blood flow
  4. route to provide anesthesia for possible C/S

GA pro: faster?

GA COn: aspiration, airway, awareness

23
Q

How will you treat seizure

A
  1. airway/breathing: bag/mask ventilate pt w crioid pressure. assess adequancy of oxygenation and ventilation. hypervent lowers seizure threshold, hypoxia, hypercarbia and acidosis exacerbate LAST

may need to intubate to control ventilation and prevent aspiration (call for difficult airway cart)

  1. Circulation management: control BP w fluids, pressors. (AFE)
  2. seizure control: assume eclampsia-tx mag 4-6g over 20 min, midaz for acute manageemnt, Intralipid for LAST
24
Q

causes of antepartum bleeding, RF, pathophys,

A

placenta previa

pathophys: implantation placenta in LUS. bleeding from tearing of placenta, LUS contracts poorly unable to compress spiral arteries,

painless vaginal bleeding, confirm w ultrasound

RF: advanced age, prior section or uterine surgery, multiparity

complications: C/S/ through anterior placenta, failure LUS to contract, placenta accreta

delay delivery with tocolysis, blood transfusions, allow for fetal lung maturation at 37 weeks than elective c/s

placenta abruption

pathophys: premature seperation of placenta from decidua basalis, ruupture of spiral artery can lead to retroplacenta hematoma with blood that dissects decidua basalis causing futher seperation of placenta, placenta insufficiency, ineffective contractions (atony), consumption of clotting factors, increase in intrauterine pressure

RF: HTN, cocaine, smoking, stress

trauma (forceps, blunt abdominal trama), physical work,

advanced age, multiparity, low lying placenta, placenta previa, fibroids, prior abruption

signs: abdominal pain/uterine tenderness, coagulopathy (DIC), fetal distress, signs of hemorrhage may be concealed, change in uterine tone or contraction pattern
complications: hypotension, DIC, atony, sheehan syndrome (pit necrosis), RF, fetal demise

Uterine rupture

pathophys: fetal distress from hypotension or interrupton of placenta flow, 2/2 dehise of uterine scar (less pain and hemodynamic collase), forceful contraction (significant pain and collapse), trauma

RF: prior uterine surgery (VBAC), trauma, excess oxytocin (forceful contraction), multiparity, fetal macroscomia, malposition, uterine anomalies/tumors, percreata

signs: vaginal bleeding, abdominal pain(despite working epidural), hypotension, fetal distress

vaso previa

pathophys: umbilical vessels present agead of the fetus and place at risk of bleeding and tearing, and fetal hemorrhage

25
Q

anesthetic concerns w antepartum bleeding

A

preop: assess maternal and fetal stability, and cause of bleeding
intraop: avoid Ra if hypotension, hypovolemia, and likely to experience significant bleeding

post op concerns: hemorragic shock (RF, sheehan), massive transfusion, DIC (abruption

neonatal resus

26
Q

hypotension in a laboring pt ddx

How does delivery of baby within 5 min of cardiac arrest help?

A

neuro: seizure, cerebral hemorrhage

Cardiac: MI CHF

pulm: PE, amnotic fluid embolism

Anesthesia: LAST, anaphlaxis,

Pregnancy: aortocaval compression, bleeding (abruption, rupture, previa), rupture subcapuslar hematoma

Drugs: magnesium, Local sympathectomy

arrest

  1. relieve aortocaval compression
  2. decrease metabolic demands
  3. allows for more effective compressions
27
Q

causes of uterine atony

A

overdistention: multiparity, polyhydramnios, prolonged or oxytocin induced labor

chorio (resistance to oxytocin and methergeine)

mechancial factors: retained placenta, retained clot, fibroids, uterine anomolies

placenta previa w non contractile LUS

volatiles, mag

28
Q

management of atony

SE uterotonics

A
  1. bimanual massage
  2. uterine tonic: cause smooth muscle contraction by increasing intracellular calcium
    - oxytocin: hypotension/tachycardia, SIADH (fluid retention, pulm edema)
    - Methergine: vasoconstriction, HTN, pulm cerebal edema, coronary vasospasm MI (give nitro)
    - carboprost PGF2- broncoconstriction, altered VQ matching, shunt, hypoxemia
    misoprostol: hyperthermia
  3. intrauterine balloon, compression sutures

surgical embolization/liation (uterine, ovarian, hypogastric), hystectomy

29
Q

how to provide uterine relaxation for retained placenta or inverted uterus

A
  • NTG
  • B2 agonist terbutaline
  • inhalational agent
  • Mag
  • uterotonic once fixed 2/2 atony
30
Q

concerns for surgery during pregnancy

A

Maternal

Neuro: decreased MAC and increased sensitivity to LA

cards: aortocaval compression predisposing to hypotension
pulm: difficult airway, low FRC predisposing to desaturation

GI: aspiration risk

Fetal: teratogencity (postnatal changes function or form, weeks 1-6), spontaneous abortion, premature labor, fetal mortality

31
Q

how does one classify teratogenicty

agents shown to be teratogens

A

A- no risk

B-no evidence of risk in humans

C: risk cannot be ruled out

Dpositive evidence of risk

X: contraindicated

No human studies have conclusively shown that any anesthetic agent increases congenital abnomalities

32
Q

drugs to consider avoiding in pregnant pt

A

N20: renders methionine synthease nonfunctional (regulates step in folate metabolism important in DNA sythesis –>spontaneous abortion

benzos: clift lift palate evidence limited
ketamine: >1mg/kg uterine hypertonus

rapid bolus anticholinesterase–>uterine hypertonus

33
Q

what are steriods for fetal lung maturity indicated? What do they reduce?

When would you admin mag for fetal neuroprotection

A

risk of preterm delivery between 24-34 weeks (betamethason 34-37 weeks)

reduce RDS, IVH, and neonatal death before 30 weeks

<32 weeks for mag, decreased CP (also decreases SVR and increases uteroplacental perfusion

34
Q

How would you monitor removing epidural in pt with low plt

A

wait until coagulation status normalized (placement and removal at highest risk for bleeding

wait for motor/sensory block to resolve so staff can better monitor for decline in fxn

1hr neuro checks q24h

make pt aware of signs and sx of epidural hematoma: backache, bowel/bladder dysfxn, radiculopathy, tenderness over spinous process, fever)

35
Q

other blocks for labor pain

A

T10-L1 first stage: paracervical–>bradycardia Uteroplacetal insufficiency

S2-4 second stage: pundendal block

36
Q

signs of AFE

A

phase 1: pulm HTN (pulm vasospasm), hypotension (RHF), hypoxia (VQ mismatch), seizure, cardiac arrest

phase 2: pulm edema, LVH, coagulopthy (circulating trophoblast)

37
Q

Downside to C section

A

increased EBL

higher infection risk

delayed ambulation/clot

increased post op pain

38
Q

ddx of seziure in pregnant female

A
  1. AFE after delivery
  2. LAST
  3. preeclampsia
39
Q

how does Rhogam work

A

anti rh antobdies that destroy fetal rehesus D erythrocytes in maternal circ before maternal immune response can make an immune response. admin at 28 weeksand within 72 hrs of delivery (unless dad is know RH-)