OB anesthesia Flashcards
Deceleration
Early: head compression w/ Vagal stimulation
Late: fetal hypoxemia w/ Vagal stimulation or myocardial failure
Variable: umbilical cord compression w/ Vagal stimulation
Causes of fetal bradycardia
- Hypoxemia
- Acidosis
- Complete heart block
- Drugs: neostigmine+glycopyrrolate
Fetal tachycardia
Infection Fever Maternal smoking Fetal SVT Drugs: ritodrine, terbutaline, atropine
Cerebral palsy: etiology of CP occurs most frequently
Antepartum
Pregnancy diabetes
Type I: 1 of 700-1000
Gestational: 2-5% pregnancies
PDPH
Positional
Bilateral
N/v
Neckstiffness
Ocular (photophobia, diploma, difficulty in accommodation)
Auditory( hearing loss, hype racists, tinnitus)
Shivering in normal delivering
Epidural: sufentamol 50 mcg, fentanyl 100mcg, or meperidine 25 mg / LA
Warming iv fluids——can decrease rate
Normal values from umbilical cord blood
ph/ Pco2/ PO2/ bicar (mEq/L)
Arterial: 7.25/50/20/22
Venous: 7.35/40/30/20
Severely depressed 3 kg term newborn
Clearing airway, drying and stimulating. If apneic, positive pressure ventilation (40 to 60 bpm) x 30 s, if HR<60, CPR: 1:3 breath: compression x 30s, if not improving, epi: 0.1 to 0.3 ml/kg of 1:10,000 solution. (ETT: 0.3 to 1ml/kg).
If need volum: 10ml/kg over 5-10 min, can repeat. If anemia: o- pRBC. If narcotic-induced, naloxone 0.1 mg/kg iv or im. If severe metabolic acidosis, but adequate ventilation, bicar: 2 mEq/kg, slow
NO naloxone
Newborn if mom addicted to narc, or on methadone maintenance,
PIH (pregnancy-induced HTN)
High: <20yo, twins, DM I, polyhydramnios, hydatidiform mole, high BMI
Low: smoking
Aortocaval syndrome
Vena cava: Hypotention, n/v, pallor, changes in cerebration
Aorta: decrease UBF
Cocaine abusing pregnant pt
Urine + 24 to 72 hrs Life threatening: GA>RA Induction of GA: HTN MAC: increase in acute; decrease in chronic RA: risk of Hypotention Ephedrine: not effective d/t depletion
Infiltration anesthesia
Emergency c/s, contra to GA &RA
LA: 100ml, 0.5% lidocaine or ?% chloroprocaine (NOT Bupivacaine)
Hypotention post SA or EA in pregnant pt
- LUD (left uterine displacement)
- Fluid
- Vasopressors: phenylephrine > ephedrine
Threatened abortion
Uterine bleating w/o cervical dilation before 20 weeks gestation
Inevitable abortion
Cervical dilation &/or ROM
Incomplete abortion
Partial expulsion of tissue
Need D&E
Epidural narcotics is antagonized by prior or concomitant ?
Chloroprocaine
Marcaine = sensorcaine = ?
Bupivacaine
Chirocaine
Levobupivacaine
Naropin
Ropivacaine
TNS (transient neurologic syndrome)
SA w/ lidocaine ( xylocaine ) Back pain radiating to buttocks & legs Post block resolve No motor or sensory loss or EMG change Resolve w/i 1 to 4 day typically
Prilocaine = citanest
Methemoglobinemia
LMWH
Low dose: >12 hrs waiting for neuraxial techniques;
High fose: >24 hrs
If back pain + unexpecred neurologic paralysis–>work for hematoma.
Chloroprocaine
Nesacaine
Ester-hydrolyzed by pseudocholinesterase
T1/2: 21 sec in maternal, 43 sec in fetal blood
in homozygous atypical cholinesterase: t1/2 = 2 min
Horner’s syndrome post epidural Anesthesia
occasionally development even highest dermatome below T5
preeclampsia
SBP>140 or DPB>90 plus proteinuria >300 mg /24 hr.
Usually >24 wks, unless hydatidiform mole
5-9% of pregancies
Higher: hydatidiform mole, multiple gestations, obesity, polyhydramnios or DM
If 1st pregancy w/ –>33% in subsequent pregnancies
Before EA: check Plt
Mg
1.5-2 mEq/L: Normal level 4 to 8 mEq/L: Therapeutic range 10 mEq/L: loss deep tendon reflexes 15 mEq/L: respiratory paralysis >25 mEq/L: cardiac arrest Note: 1 mEq/L = 1.2 mg/dl. decrease release of Ach and sensitivity of motor endplate to ACh; Antagonist aplpha-adrenergic effect, antagonize NMDA receptor.
normal FHR
120-160
Leading direct cause of pregnancy related deaths in US
hypertensive disorders of pregancy
side-effects of methylergonovine and hemabate
methylergonovine: HTN, bronchospasm (rarely)
hemabate (carboprost): bronchospasm
P50 of Fetal hemoglobin at term
19-21 mmHg (note: in adult 27 mmHg)
Side effects of beta-agonists (ritodrine, terbutaline)
tachycardia, hypOtension, myocardial ischemia, pulmonary edema, hypoxemia (inhibitiion of hypoxic pulmonary vasoconstriction), hyperglycemia, metabolic (lactic) acidosis, hypokalemia, anxiety, nervousness.
CO
1st trimester: increase to 30 to 40% At term: 50% Latent phase: another 10 to 15% Active phase: 25 to 30% Expulsive stage: 40 to 45% Immediately after delivery: greatest increase (autotransfusion and increased venous return d/t uterine involution). 2 wks: back to nonpregnant value.
GA induction in Emergent C/S
RSI: sevo not good for induction, versed too slow for induction, for mild asthma: ketamine, thiopental or propofol, but thiopental not for severe asthma (d/t release histamine). Ketamine not good for HTN.
asthma for GETA
adequate GA before ETT
UBF at term pregancy
700 to 900ml/min (i.e., >1 U blood /min)
50 to 100 ml/min before pregnancy
HIV infected parturient
- EA, SA, CSE or blood patch: safe
- vertical transmission: untreated–>15 to 40%; treat + C/S–>2%
- Needlestick–>develop HIV 0.3% (HBV 30%, HCV 2 to 4 %).
- protease inhibitor—>(-)cytochrome P-450 –> prolong benzodiazepines and narcotics.
At term
- No change: CVP, PCWP, PADP, LVESV
- Increase: LVEDV, SV, EF, HR, CO
- Decrease: SVR
AFE (amniotic fluid embolism)
- acute hypoxemia: pulmonary edema, cyanosis
- hemodynamic collapse: severe hypotension, cardiopulmonary arrest
- coagulopathy
Fetus: most susceptible to teratogenic agents
15 th to 56 th days (3 to 8 wks) of gestation <—organogenesis
New born respiratory depression from chronic narcotic mother
controlled ventilation, but NOT naloxone <—acute withdrawal
Respiratory in pregnancy
- Increase: MV, Vt, PaO2 (d/t fall in PaCO2), O2 consumption
- decrease: serum bicarb.
Uterine
- Bartiturates: dose-dependent reduction in contraction
- Diazepam & N2O: no effect
- Ketamine: oxytocic during 2nd trimester, but NO at term
- LA: IV increase in tone, at high level—>tetanic
Normal term fetus
- approx. 3 kg
- O2 consumption: 7 ml/kg/min–>21 ml/min
- O2 store: 42ml–>but d/t compensatory–>survive 10 min
Parturient–>GA for no-obstetric surgery
- maternal safety
- avoid teratogenic: current anesthetic drugs OK
- avoid fetal asphyxia
- prevent induction of preterm labor: abd surgery
MG (masthenia gravis)
- IgG vs ACh-R: only on skeletal muscle
2. Newborns: 10 to 20% affected maternal IgG metabolized.
DIC
placental abruption: MCC dead fetus syndrome AFE G- sepsis severe pregnancy-induced hypertension Note: not placenta previa<--bleeding not induce coagulopathy.
Eisenmenger’s syndrome–>epi in SA?
- Avoid increase PVR: hypercabia, acidosis, hypoxia
- Avoid decrease SVR:
- Narcotic-based analgesic: spinal or epidural
- CVP, A-line, evaluate shunt
- Caution with central LA: decrease pre and after load
- Avoid epi in EA or SA: decrease SVR or increase PVR.
h/o c/s + current placenta previa
increase risk of placenta accrete—>emergency cesarean hysterectomy
Neonatal brain damage
MC injury in ASA-closed claim project regarding OB anesthesia claims
epidural morphine
slow onset (30 to 60 mim @7.5 mg); pruritus, N/V, drowsiness—>not routinely for labor epidural
meconium-stained amniotic fluid
if vigorous (i.e., strong respiratory efforts, good muscle tone, HR>100)—->not treatment.
Difficult airway + hypovolemic—>emergent C/S
infiltration local anesthetic
Epinephrine in local anesthetics
- check for IV placement of epidural cath
- decrease vascular uptake of LA
- increase intensity and duration of block
Note: more lipid-soluble the LA, more less effect
LA + narcotic effets
meperidine
diazepam
Not used in 1st trimester d/t unproven side effect on fetus
I.t. opiates (morphine, fentanyl or sufentanil)
- very effective in relieving visceral pain in 1st stage
2. inadequate for 2nd stage.
