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52 Cards in this Set

  • Front
  • Back
What is the most common non-hemorrhagic emergency in OB?
Fetal distress
What is the normal fetal heart rate?
<120bpm = fetal bradycardia
>160bpm = fetal tachycardia
What is the nomral PaCO2 & PaO2 in the normal fetus?
PaCO2 = 48torr (at maternal PaCO2 of 40-45)

PaO2 = 30 torr as leaves placenta
What are two signs of fetal hypoxia?
Fetal bradycardia
Late decelerations
When does fetal acidosis occur?
When fetal pH <7.20, 7.20-7.24 is considered pre-acidotic
What causes fetal acidosis?
fetal hypoxia & the resulting anaerobic metabolism
Which local anesthetic crosses the placenta the least?
Chloroprocaine b/c it is rapidly hydrolyzed; the amide least likely is bupivacaine d/t it's 95% protein binding
What are the advantages of chloroprocaine in OB anesthesia?
Low potency, low cardiotoxicity, rapidly metabolized by plasma cholinesterase,
Which anesthetic agen is best for an epidural in a parturient with an acidotic fetus?
Which amide local anesthetic most extensively crosses the placenta?
Most-to-least: Mepivacaine, Etidocaine, Lidocaine, Ropivacaine, Bupivacaine
Discuss Ion trapping:
non-ionized form of LA crosses placenta & once in fetal circulation which is more acidotic in nature (pH 7.03-7.23) becomes "trapped"
Will maternal alkalosis faciltiate diffusion of the LA accross the placenta?
Yes, alkalosis shifts a greater proportion of the LA to its non-ionized form which can cross the placenta easier; maternal alkalosis from hyperventilation
Will fetal acidosis facilitate ion trapping?
Yes, leads to increased ionized fraction of the LA & won't be easily passed back to maternal circulation
What are 5 complications associated with placement of a fetal scalp electrode?
Ecchymoses, lacerations, leakage of CSF, sepsis, scalp abscess-most common
What is normal FHR beat to beat variability?
3-6bpm variability implies intact oxygenated CNS; atropine causes loss of FHR variability as well as fetal hypoxia & maternal meds
What are early decelerations?
Early/Type I decelerations are decreases in FHR of 10-40bpm that coincide with uterine contractions; these are benign, start at onset of contraction & are greatest @ height of contraction
What are late decelerations?
Late/Type II are decreases in FHR that start at peak of contraction and greatest after peak; the decrease may only be 5bpm; these are thought to be d/t fetal compromise/poor placental blood flow
What is the significance of late decels with normal beat to beat variability?
Pattern is associated with acute insults (i.e. maternal hypotension), with treatment this pattern can be reversed
What is the significance of late decels with diminished beat to beat variability?
Associated with prolonged fetal asphyxia, needs further testing
What is the significance of late decels without beat to beat variability?
Signifies SEVERE fetal decompensation, immediate delivery is indicated
What are variable decelerations?
Type III can occur any time during contraction, onset is abrupt, decel can last for prolonged time & can exceed 30bpm, thought to be d/t uterine induced umbilical cord compression; *Fetal asphyxia assoc with decels that last >60sec or decrease FHR by 70bpm and lasts >30 min = immediate delivery
Urgent delivery is indicated by what FHR pattern?
Prolonged decelerations without beat to beat variability, or FHR <70bpm
What is measured by the fetal scalp monitor?
Takes blood specimens to evaluate fetal acidosis; more direct measure of fetal status than FHR, pH<7.2 is abnormal
How is the GI tract changed by pregnancy?
Increased intragastric pressure, LES tone is decreased, barrier pressure is decreased; Full stomach after 12 weeks gestation=RSI
How is the maternal airway changed by pregnancy?
Capillary engormgement of resp. tract=edema of nasal & oral pharynx; **Failed intubation is leading cause of maternal death
What are the most common causes of maternal mortality r/t pregnancy?
Most-to-least: Hemorrhage, embolism, PIH, infection, cardiomyopathy, aneshtesia
What is the greatest danger to the neonate delivered at 30 weeks gestation?
immature lungs; extrauterine life possible @25 weeks; production surfactant @30 weeks-level sufficient by 34 weeks
What is a tocolytic?
Tocolytics suppress uterine contractility, Include: Beta2 agonist: ritodrine, terbutaline, Smooth muscle relaxant: magnesium sulfate
List 4 side effects of beta agonist tocolytics:
Possible Pulmonary edema
Should atropine be given to patinets on beta agonist tocolytics?
No, increased tachycardia can lead to increased risk of pulmonary edema
What is the indication for an emergency c-section?
Fetal distress as r/o: maternal hypotension, prolapsed fetal part, compromised fetal circulation, fetal trauma
How much time do you have to start a c-section?
ACOG says 30min
Techniques for intrauterine resuscitation:
relieve caval compression, maternal O2, maintain B/P, D/C oxytocin, IV terbutaline for tocolysis, saline amnioinfusion
Anesthetic techniques for specific circumstances:
Hemorrhage: GA
Uterine tetany: GA
Uterine rupture: GA or CLE
Fetal distress: SAB, CLE, GA
Prolapsed cord: GA, CLE
How does chloroprocaine interact with opioids?
Competes with opioids at the mu-receptor sites decreasing efficacy of the opioids
What are 5 disadvantages of redosing an epidrual catheter with chloroprocaine?
>20-25ml assoc with backache
Opioids efficacy decreased
Short acting-35-55min
Tachyphylaxis can develop
What dose of ketamine produces excellent analgesia w/o depressing the neonate?
0.2-0.5mg/kg IV
How does one do a GA for c-section?
Bicitra to raise gastric pH, position SLUD, pre-O2, RSI with CP, STP 3-5mg/kg, Anectine 1-1.5mg/kg or Zemuron; 50% N20, 0.5 MAC volatile agent (If patient on Magnesium Sulfate @ increased risk resp. depression so don't give priming dose)
Why do parturients desaturate so rapidly during apnea?
decreased FRC, increased O2 consumption
Why would you use Ketamine instead of STP?
Ketamine 1mg/kg induction if patient hypovolemic; >1mg/kg can compromise uterine tone = fetal distress; AVOID Ketamine in HTN/pre-eclamptic
Why would a low dose of volatile agent be used during a c-section?
ensures amnesia without excessively relaxing uterus; also pregnancy increases sensitivity to volatile agents
What are the advantages of low doses volatile agents for the patient undergoing c-section?
Decreases awareness, permits higher FIO2, may improve uterine blood flow; DOES NOT increase uterine bleeding or depress neonate
How does pregnancy effect MAC?
MAC is decreased 40%, increased sensitivity d/t increased progesterone & beta endorphin levels
If the surgeon asks for a relaxed uterus what would you do?
Increase volatile agent to 1.5-2MAC, NTG SL or IV
Intubation fails, but you can ventilate & the fetus is NOT in distress, what do you do?
Awaken pt, attempt awake intubation or regional
Intubation fails, but you can ventilate, but the fetus is in DISTRESS, what would you do?
Mask ventilate with cricoid pressure--NO LMA
Intubation fails, the fetus is in distress, you can NOT ventilate-what would you do?
Cricothyroidotomy or trach, deliver baby
What does the Apgar Score evaluate?
Resp effort
Muscle tone
Reflex irritability

Apgar @ 1min reflection of survival, @ 5min neuro status
What is the appropriate drug for a neonate with an Apgar of 3 after 5 minutes?
Sodium Bicarb, if resuscitation prolonged >5min and no ABG available
What should be done for meconium aspiration?
Mouth-bulb syringe
Below cords-intuabate & suction if baby NOT vigorous
Who is responsible for resuscitation of the neonate?
ASA states someone other than anesthetist that is attending to mother
Neonatal resuscitation:
consider gestational age, open airway, warm patient; evaluate resp, HR-give PPV is apneic or HR <100; HR<60 chest compressions, consider epinephrine or narcan