Unit 11 - OB Part 2 Flashcards
1 major difference in prepping for surgery for a c section under general vs other surgeries
prep and drape prior to induction
induction drugs to use for C section under GA
- 2-2.5 mg/kg propofol
- 0.3 mg/kg etomidate
- 1 mg/kg ketamine
choose 1
induction drugs to use for C section under GA
- 2-2.5 mg/kg propofol
- 0.3 mg/kg etomidate
- 1 mg/kg ketamine
choose 1
should defasiculating dose be given with succs for OB patients
not needed – pregnancy reduces risk of myalgia
should defasiculating dose be given with succs for OB patients
not needed – pregnancy reduces risk of myalgia
ideal volatile concentration for c section under GA
low concentration of volatile (0.8 MAC) + 50% nitrous oxide
risk of neonatal acidosis increases when time between uterine incision and delivery is greater than:
3 minutes
normal amniotic fluid volume
~700 mL
fetal risks of nonobstetric surgery during pregnancy
- growth restriction
- low birth weight
- demise
- increased incidence of preterm labor
ideally, surgery is delayed for how long in pregnant patient?
delayed 2-6 weeks after delivery
nonobstetric surgeries during pregnancy assoc with highest fetal risks
intraabdominal and pelvic surgeries
if unable to delay until after delivery, when is the best time for pregnant pt to undergo surgery?
2nd trimester
avoids higher risk of teratogenicity in 1st trimester and increased risk of preterm labor in 3rd trimester
when is risk of teratogenicity highest
during organogenesis (day 13-60)
can pregnant patients undergoing nonobstetric surgery have preop anxiolytic
yes
Some evidence that links high-dose diazepam in first trimester to cleft palate but Barash says preop benzo is acceptable
can pregnant patients undergoing nonobstetric surgery have preop anxiolytic
yes
Some evidence that links high-dose diazepam in first trimester to cleft palate but Barash says preop benzo is acceptable
at what plasma level does magnesium diminish DTRs
5-7 mg/dL
is hypokalemia assoc with hyper or hypo-magnesemia
hypo
how should methergine be admin
always IM
IV assoc with severe HTN
3 benefits of GA over neuraxial for c section
- speed of onset
- secure airway
- greater hemodynamic stability
situations that warrant GA for c section
- Maternal hemorrhage
- Fetal distress
- Coagulopathy
- Patient refusal of regional anesthesia
- Contraindications to regional anesthesia
when are pregnant patients full stomachs
18-20 wga
aspiration ppx for nonobstetric surgery during pregnancy
- sodium citrate 15-30 mL within 15-30 min of induction
- ranitidine 1 hour before induction
- metoclopramide 1 hour before induction
at what point in pregnancy should you start LUD
2nd & 3rd trimester
meds that should be avoided in nonobstetric surgery during pregnancy
NSAIDs
potentially close ductus arteriosus
meds that should be avoided in nonobstetric surgery during pregnancy
NSAIDs
potentially close ductus arteriosus
why should hyperventilation be avoided in nonobstetric surgery during pregnancy
normal maternal PaCO2 is ~30 mmHg
hyperventilation reduces placental blood flow
pregnancy-induced HTN that occurs before 20 weeks gestation
chronic HTN
does not return to normal after delivery
when does gestational HTN develop
after 20 weeks
Only away to truly diagnose gestational HTN
after delivery (return to normotensive state rules out chronic HTN)
when does preeclampsia develop
after 20 weeks
BP in mild preeclampsia
> 140/90
BP in severe preeclampsia
> 160/110
common UA finding in pt with preeclampsia
proteinuria
s/s preeclampsia that may exist in the absence of proteinuria
- persistent RUQ or epigastric pain
- persistent CNS or visual symptoms (HA, hyperreflexia, hyperexcitability, coma)
- fetal growth restriction
- thrombocytopenia
- elevated serum liver enzymes
what is eclampsia
mother with preeclampsia develops seizures
most common critical pathology associated with the healthy parturient
Preeclampsia
preeclampsia is most common in:
mothers < 20 yrs and > 35 yrs
moms with highest risk of developing preeclampsia
Patients with chronic renal disease and those that are homozygous for the angiotensinogen T235 allele
roles of thromboxane in the pt with preeclampsia
- increased plt aggregation
- increased vasoconstriction
- increased uterine activity
- decreased uteroplacental blood flow
roles of prostacyclin in normal pregnancy
- ↓ platelet aggregation
- ↓ vasoconstriction
- ↓uterine activity
- ↑ uteroplacental blood flow
roles of thromboxane in normal pregnancy
- ↑ platelet aggregation,
- vasoconstriction
- ↑ uterine activity
- ↓ uteroplacental blood flow
prostacyclin and thromboxane production in pt with preeclampsia
produces up to 7x more thromboxane than prostacyclin
key maternal complications of preeclampsia
- heart failure
- pulmonary edema
- intracranial hemorrhage
- cerebral edema
- DIC
- proteinuria
BP threshold before treating HTN in preeclamptic patient
160/110
consequences of endothelial damage resulting from vasoactive substances
- glomerular leak
- activation of clotting cascade
- platelet aggregation
proteinuria in mild vs severe preeclampsia
mild: < 5 g/24 hr
< 3+ dipstick
severe 5+ g/24 hr
> 3+ dipstick
what causes proteinuria in preeclamptic patient
Glomerular capillary endothelial destruction
24-hr urine total in mild vs severe preeclampsia
mild: > 500 mL
severe: < 500 mL
what causes edema in preeclampsia
↓ oncotic pressure
↑ vascular permeability
what causes pulmonary edema in severe preeclampsia
Heart failure
↓ oncotic pressure
↑ vascular permeability
what causes headache in severe preeclampsia
Cerebral edema
what causes visual impairment in severe preeclampsia
Vasoconstriction of ocular arteries
what causes epigastric pain in severe preeclampsia
Liver subscapular hemorrhage
Hypoxic liver
plt count in mild vs severe preeclampsia
mild = > 100,000
severe = < 100,000
does preeclampsia affect fetal growth?
mild - no
severe - yes d/t uteroplacental hypoperfusion
primary reasons for medicating a pt with preeclampsia and HTN
to prevent a cerebrovascular accident, myocardial ischemia, and placenta abruption
medicate when > 160/110
primary reasons for medicating a pt with preeclampsia and HTN
to prevent a cerebrovascular accident, myocardial ischemia, and placenta abruption
medicate when > 160/110
treatment for acute HTN in preeclampsia
- Labetalol 20 mg IV followed by 40 - 80 mg q 10 min up to a max dose of 220 mg
- Hydralazine 5 mg IV q 20 min up to a max dose of 20 mg
- Nifedipine 10 mg PO q 20 min up to a max dose of 50 mg
- Nicardipine infusion started at 5 mg/hr and titrated by 2.5 mg/hr q 5 min up to a max dose of 15 mg/hr
dose of labetolol for HTN assoc with preeclampsia
20 mg IV followed by 40 - 80 mg q 10 min up to a max dose of 220 mg
dose of hydralazine for HTN assoc with preeclampsia
5 mg IV q 20 min up to a max dose of 20 mg
dosing nifedipine for preeclamptic pt with HTN
10 mg PO q 20 min up to a max dose of 50 mg
nicardipine infusion dosing for preeclamptic pt with BP > 160/110
infusion started at 5 mg/hr and titrated by 2.5 mg/hr q 5 min up to a max dose of 15 mg/hr
how long do risks of complications with preeclampsia continue
up to 4 weeks postpartum
when are the of pulmonary HTN and stroke highest in preeclamptic pt
in postpartum period
preeclamptic patients have an exaggerated response to what meds
sympathomimetics
methergine
Seizure prophylaxis with magnesium in pt with preeclampsia
4g loading dose over 10 min + infusion 1-2 g/hr
antidote for magnesium toxicity
10 mL 10% calcium gluconate IV
what is HELLP syndrome
Hemolysis, Elevated liver enzymes, Low Platelet count
incidence of HELLP syndrome
Develops in 5-10% of those with preeclampsia
definitive treatment of preeclampsia, eclampsia, & HELLP syndrome
delivery of the fetus and placenta
HELLP syndrome increases what 2 risks
DIC
intraabdominal bleeding (from liver)
s/s HELLP syndrome
epigastric pain
upper abd tenderness
how does cocaine use affect MAC
- Acute intoxication increases MAC
- Chronic use decreases MAC
reasonable choice of antihypertensive for cocaine user
labetolol
reasonable choice of antihypertensive for cocaine user
labetolol
hematologic consequence of chronic cocaine use
thrombocytopenia
best option to treat hypotension in chronic cocaine user
neo
Hypotension may not respond to ephedrine (d/t catecholamine depletion)
best option to treat hypotension in chronic cocaine user
neo
Hypotension may not respond to ephedrine (d/t catecholamine depletion)
placenta accreta
placenta attaches to surface of myometrium
placenta increta
placenta invades myometrium
placenta percreta
placenta extends beyond uterus
placenta previa
placenta partially or completely covers cervical os
where does the placenta normally implant
into decidua of endometrium
preferred anesthesia method in pts with abnormal placental implantation
Although neuraxial is safe, GA is preferred
abnormal placental implantation is closely assoc with what 2 conditions
placenta previa & previous c sections
sign of placenta previa
painless vaginal bleeding
risk factors for placenta previa
- previous c-sections
- history of multiple births
placental abruption
Partial or complete separation of the placenta from the uterine wall before delivery
6 risk factors for placental abruption
- PIH
- preeclampsia
- chronic HTN
- cocaine use
- smoking
- excessive alcohol use
placental disorder assoc with inc risk amniotic fluid embolism
placental abruption
s/s placental abruption
- maternal pain
- vaginal hemorrhage
- fetal hypoxia
most significant concerns regarding abnormal placental implantation
- impaired uterine contractility
- potential for tremendous blood loss during labor & delivery
most common cause of postpartum hemorrhage
uterine atony
4 risk factors for uterine atony
- Multiparity
- Multiple gestations
- Polyhydramnios
- Prolonged oxytocin infusion before surgery
other causes of OB bleeding
besides uterine atony
- Retained placenta/placenta fragments
- Laceration to the cervix or vaginal wall
- Uterine inversion
- Coagulopathy
- Placenta previa
- Placental abruption
- Abnormal placental implanation (acreta, increta, percreta)
med used to provide uterine relaxation for extraction of retained placenta
IV nitro
method to tamponade postpartum hemorrhage when other methods are ineffective
intrauterine balloon
methods to stop postpartum hemorrhage
- uterine massage
- oxytocin
- ergot alkaloids
- manual massage
- intrauterine balloon
OB conditions assoc with DIC
- AFE
- placental abruption
- intrauterine fetal demise
when is APGAR score assessed
1 and 5 min after delivery
Apgar score at 1 min correlates with:
fetal acid-base balance
Apgar score at 5 min may be predictive of:
neurologic outcome
normal apgar score
8-10
apgar score assoc with moderate distress
4-7
apgar score assoc with impending demise
0-3
5 aspects of apgar score
- heart rate
- resp effort
- muscle tone
- reflex irritability
- color
Apgar scoring - heart rate
- absent = 0
- 1 = < 100
- 2 = > 100
Apgar scoring - resp effort
absent = 0
slow, irregular = 1
normal, crying = 2
Apgar scoring - muscle tone
limp = 0
some flexion of extremities = 1
active motion = 2
Apgar scoring - reflex irritability
absent = 0
grimace = 1
cough, sneeze, or cry = 2
Apgar scoring - color
pale, blue = 0
body pink, extremities blue = 1
completely pink = 2
normal neonatal HR
120-160
normal neonatal RR
30-60
when does neonatal breathing begin
30 seconds after delivery
normal pattern is established at 90 seconds
when does neonatal breathing begin
30 seconds after delivery
normal pattern is established at 90 seconds
neonatal SpO2 after delivery
Immediately after delivery, normal SpO2 is 60%.
It should rise to 90% after 10 minutes
after delivery, the baby’s HR < ____ is assoc with significantly decreased CO
100
considerations for assisted ventilation of neonate
- Supplemental O2 increases risk of inflammatory response
- if assisted ventilation is required, use room air instead of 100% FiO2
- If bradycardia or inadequate oxygenation persists, use of supplemental O2 must be balanced against this risk
best indicator of adequate ventilation in neonate
resolution of bradycardia
3 possible routes emergency drugs can be given in newborn without IV access
- umbilical vein
- ETT
- IO
during which stage of labor are patients with valve stenosis and pHTN at greatest risk
stage 3 (immediate postpartum)
CO increases 80%
during which stage of labor are patients with valve stenosis and pHTN at greatest risk
stage 3 (immediate postpartum)
CO increases 80%
LA least likely to undergo fetal ion trapping
chloroprocaine
LA least likely to undergo fetal ion trapping
chloroprocaine
hallmark of placenta previa
painless vaginal bleeding ~32 weeks gestation
when should uterine rupture be considered in laboring pt with epidural
new onset abdominal pain
how does uterine rupture present
- severe abdominal pain
- may have referred shoulder pain from diaphragm irritation 2/2 intraabdominal blood
primary contributor to placental drug transfer
maternal concentration of free drug
most likely indicator of intravascular volume depletion in preclamptic patient
high Hct
priorities in patients with eclampsia
- airway management/aspiration prevention (#1)
- control HTN
- anti-seizure meds
why do pregnant pts require increased neo dose to treat hypotension
down-regulation of alpha receptors
what explains pregnant pt’s reduced sensitivity to sympathomimetics
beta receptor down regulation
minimum FHR monitoring for nonobstetric surgery during pregnancy
< 23 wga: minimum pre and postop
> 23 wga: pre and postop FHR + pre and postop assessment of contractions
initial treatment for retained products of conseption
- uterine exam - nitro provides relaxation
- curettage to extract retained products
advantages of epidural volume extension technique for CSE
uses smaller dose of LA
more stable hemodynamic profile
faster recovery
following IV drug delivery to parturient, drug enters fetus via:
umbilical vein
most of this travels to fetal liver and is subjected to 1st pass metabolism
first priority in treating a term parturient with eclampsia
prevent aspiration/airway management
is eclampsia an indication for emergency c section
no
seizure typically < 10 min long and not recurrent
minimum fetal assessment required during anesthesia for non-obstetric abdominal surgery with a fetus < 23 weeks
document FHR pre and post op
minimum fetal assessment required during anesthesia for non-obstetric abdominal surgery with a fetus > 23 weeks
document FHR pre and post op along with pre and postop assessment of uterine contractions
primary contributor to placental drug transfer
maternal concentration of free drug
how does molecular charge affect placental drug transfer
non-ionized = greater transfer
how does plasma protein binding affect placental drug transfer
less binding = greater transfer
a high concentration gradient (driving force) between the mother and the fetus is the most important contributor of placental drug transfer.
most common first sign of uterine rupture
fetal bradycardia
“classic” triad of s/s with uterine rupture
abdominal pain
vaginal bleeding
abnormal FHR pattern
only in ~9%
s/s uterine rupture
severe abdominal pain
fetal bradycardia
vaginal bleeding
undetectable uterine contractions
breakthrough pain with epidural that was previously working
surgical treatment options for uterine rupture
uterine repair
arterial ligation
hysterectomy
The mother may require a c-section
surgical treatment options for uterine rupture
uterine repair
arterial ligation
hysterectomy
The mother may require a c-section
what should be ruled out if parturient is passing dark blood clots
placental abruption
best pain management option for term parturient with severe aortic stenosis
opioid only neuraxial
could do opioid only CSE
if pt requires c-section, GA is the gold standard
