5. Anesthesia in the OB Unit Flashcards
antepartum
before birth
dystocia
difficult labor
intrapartum
during the act of birth
multiple gestation
twins, triplets, etc
multiparous
has had multiple gestations
normal labor happens at what point in gestation
38-40wk
Nulliparous
never completed a pregnancy beyond 20 wks
parturient
pregnant patient
postpartum
after birth
preterm labor
<37wks
primapara (primip)
first pregnancy
age of viability
~24 wks
when would you consider immediate intubation after birth?
<28 wks
G (gravida)
total number of pregnancies regardless of how they ended
P (parity)
number of live births at any gestation OR
the number of completed pregnancies including stillbirths that lasted more than >20wks
does the number of fetuses delivered determine the parity?
no
twins = P1
oxytocic (uterotonic)
drugs promote uterine contraction
what does promoting uterine contraction do? 2
decrease uterine bleeding after delivery
induce labor in pregnant patients
what are 4 uterotonic drugs?
pitocin
hemabate
methergine
cytotec
2 effects of pitocin
stimulates uterine contraction
induces labor
when is pitocin dosed?
after the baby and placenta are delivered
what is the most common side effect of rapid administration of pitocin?
hypotension
should pitocin be dosed slowly or quickly?
slowly and intravenously
other side effects of pitocin?
N/V chest pain ECG changes chortness of breath myocardial ischemia pulmonary edema death
tradiational Pit dosing?
20-40 units in IV bag after delivery of placenta
20 units in each bag after
what is the ED50 of Pit for c-sections?
0.35 units non laboring
3 units laboring
Newer pitocin dosing “rule of threes”
- give 3 units over 30sec (repeat twice if needed)
- if no response after 3 doses move to another uterotonic
- 3 units/hr for maintenance
Carboprost (hemabate) dose
1mL (250mcg) intramuscular
when is hemabate contraindicated?
asthma
methylergonovine (methergine) dose
1mL (200mcg) intramuscular
when is methergine contraindicated?
hypertensive patients
preeclampsia
when is misoprostol (cytotec) considered?
if there is still uterine bleeding despite pitocin, methergine, and hemabate admin
given rectally
tocolytic drug
promote uterine relaxation and can help prevent labor (also can promote uterine bleeding after birth)
tocolytic drugs 5
1 magnesium 2 beta 2 agonists 3 calcium channel blockers 4 volatile agents 5 nitroglycerin
what are the two calcium channel blockers we would use?
nicardipine (cardene)
nifedipine
what is nitroglycerine normally given for?
treat HTN or relieve angina in pts with CAD
low doses can cause drops in BP
why does NTG have less of an effect on blood pressure in pregnant patients? 2
1 OB pts have increases circ blood volume
2 vessels are already dilated in well hydrated pts
what are the doses of NTG for uterine relaxation?
250-500mcg
even up to 1000mcg
(minimal hypotension)
cardiotocography
fetal HR monitor
baseline fetal HR
HR between contractions
normal fetal HR
120-160bpm
bradycardic fetal HR
<120bpm
tachycardic fetal HR
> 160bpm
fetal heart rate variability
healthy fetu the HR constantly fluctuates (associated with fetal movement)
absence of variability of heart rate is a sign of what
fetal distress
what else can cause absence of variability other than fetal distress?
general anesthesia
short term variability
variability that occurs every heart beat
long term variability
variability over a longer period can be a difference from 6-25 bpm
which is normally present? short term or long term variability
both are normally present in healthy fetus
decel
fetal heart rate deceleration refers to a drop in fetal heart rate
what are the 3 types of decel patterns
early (type I) decel
late (type II) decel
variable (type III) decel
early decel (type I)
decrease in HR occurs at onset of uterine contraction
late decel (type II)
decrease in HR occurs after the onset of contraction
variable decel (type III)
decrease in HR is variable in intensity, duration, and timing
what are type I decel most likely caused by?
vagal response (compression of fetal head)
what is the most ominous/threatening type of decel?
late (type II) decel with variability loss
what are type II decels caused by?
fetal hypoxia (uteroplacental insufficiency)
what are type III decels caused by
umbilical cord compression and decompression
normal respiratory rate for newborns
30-60 breaths/min
APGAR score
neonatal wellbeing score
1-10 (10 best)
done at 1 (survival) and 5min (neurologic outcome)
normal fetal pH?
> 7.25
when is the fetal pH considered acidotic?
<7.2
before delivery these things should be done/assessed: 5
1 fluid bolus given prior to neuraxial block
2 IV solutions containing dextrose should be used with caution
3 every pt should have a type and screen
4 NPO- modest liquid for uncomplicated labor, high risk= stricter restrictions
5 ASA status 2 or higher
how much of a fluid bolus should be given to patients prior to neuraxial block?
anywhere from 500-1,500mL
what can giving dextrose solutions cause in the fetus?
fetal hypersecretion of insulin post delivery and fetal acidosis
why should every pregnancy have a type and screen
because they all have potential for unexpected massive hemorrhage
what drugs should be avoided before the baby is delivered? 3
NSAIDS
versed
narcotics
why avoid NSAIDS?
suppress uterine contractions and promote closure of ductus arteriosus
what are the two reasons to avoid versed?
potential for post delivery fetal apnea
for awake c-section the mother wants to remember
does versed have a negative effect on fetal wellbeing at low doses (1-2mg)?
no
why would you avoid narcotics?
post delivery fetal apnea
-although low dose fent (1mcg/kg) does not appear to affect apgar scores
5 options for SVD
epidural spinal obstetrician nerve blocks IV nubain (nalbuphine) nitrous oxide
what is the most popular analgesic option for SVD?
epidural because it can keep them comfortable for hours and hours
what is the most common local anesthetic for epidural and why
marcaine
motor sparing quality
what 3 things need to be done prior to placing an epidural?
1 pt receives an adequate fluid bolus
2 lab show normal platelets
3 adequate cervical dilation
does an epidural prolong labor?
yes stage 1 by 12 min and stage 2 by 42 min
why would you do spinal for SVD
if pt is in late stages of labor and there isnt enough time for epidural onset
what is the spinal dose for SVD?
3-6mg of marcaine for motor sparing
paracervical nerve block for SVD
injected vaginal submucosa
relieve 1st stage labor pain
high incidence of fetal bradycardia
pudendal nerve block for SVD
transvaginal and perineal infiltration of local
relieve 2nd stage labor pain
IV nubain for SVD
narcotic agonist/antagonist
treats itching from intrathecal narcotics
nitrous oxide for SVD
pts start breathing in gas at start of contrac`tion and wears off in a few breaths
walking epidural
narcotics only
or
lower dose/infusion rates of local
A patient is hurting at some point after their epidural was started. They either never were comfortable to begin with, or they were initially comfortable but started having pain as they approached the second stage of labor. How should this patient be managed?
- Inform patients that epidurals take care of sharp pain but not pressure.
- Bolus 5-8mL local anesthetic to increase the block density, preferable with a “Stronger” drug (2% lidocaine).
After receiving an epidural, a patient still feels pain on one side. How should she be managed?
- Have her lay on the side that’s hurting
- Pull the catheter back 1-2 cm
- Pull the catheter and start another epidural
generalized c-section outline 9
1 pt arrive in OR 2 ABX administered 3 analgesic method carried out 4 pt in LUD positioning 5 vasopressions given if spinal anesthesia performed 6 surgery start and baby delivered 7 pitocin given after placenta delivered 8 zofran and decadron admin 9 additional drugs given for pain control
nausea and vomiting prevention
during c-section usually caused by hypotension
prevented by rapid/prophylactic admin of ephedrine or phenylephrine
why would some patients get nausea even though they are normotensive? 2
1 dominance of parasympathetic
2 vagal stimulation during procedure
what two treatments can be used for a woman who has nausea in normotension?
zofran
robinul (not atropine bc atropine crosses the placenta)
4 anesthetic options for a c-section
spinal
epidural
CSE
GA
when would you not chose a spinal?
pt has working epidural
pt has CI to neuraxial
pt is hemorrhaging/hypotensive
urgent/emergent c section
post op pain control for c section under spinal
0.2-0.4 mg duramorph
or
5mcg precedex
indications for c-section under epidural
if they have a working epidural in place, dose to T4
when will you not use epidural for c section
CI to neuraxial
urgent/emergent c section without epidural in place
when will you maybe use an epidural for c section
hemorrhage after epidral placement
patchy epidrual block
what can you do for a c section with a patchy epidural
dose to T4
remove epidural and place spinal
convert to GA
risk of spinal after epidural
high spinal or total spinal
While you are on call, the labor and delivery department informs you that the obstetrician on call would like to do a C-section in the next 30 minutes. It is non-emergent. From an anesthetic management standpoint, what is the first question you should ask? What is the second question you should ask?
- Do they have an epidural?
2. Does the epidural work?
While on call, the labor and delivery department calls you to come to the OR in the obstetric unit STAT for an emergent C-section. In addition to wanting to know if they have an epidural and whether or not it works, what do you want to know?
What is the emergency?
If the patient is hemorrhaging, they will need a general anesthetic (to avoid the sympathectomy).
If the patient is NOT hemorrhaging, they can consider dosing the epidural with chloroprocaine if there is time.
case outline for c-sectioin under spinal anesthesia (4)
- perform spinal with marcaine+duramorph
- dose pressors/ place in LUD
- admin pitocin after baby and placenta delivered
- dose zofran and consider toradol
how long does intrathecal duramorph provide analgesia for?
12-24 hr
total spinal
neuraxial block rises above cervical region and produces respiratory arrest and unconsciousness
is the patient more likely to stay conscious with a high epidural or high spinal? why?
high epidural because the epidural space only extends to foramen magnum
explain how you could get a high spinal from bolusing an epidural with saline or local
bolusing the epidural causes the dural sac to compress and any local that had diffused there will travel cephalad
A 28-year old, G2P1 is undergoing a repeat, non-emergent C-section under spinal anesthesia. PMH is unremarkable, and she has a Mallampati class I airway. When the patient’s spinal block is tested prior to starting, it appears “patchy,” meaning that the mother can feel some pain. What are the anesthetic options for this patient?
- RSI with general anesthesia, or
2. Can consider N20/ketamine to support the block
A 32-year old, G1P0 is undergoing a non-emergent C-section under spinal anesthesia. PMH includes morbid obesity and a Mallampati class IV airway. When the patient’s spinal block is tested prior to starting, it appears “patchy.” What are the anesthetic options for this patient?
- Can consider N20/ketamine to support the block
2. RSI with general anesthesia
A parturient had a spinal block for a C-section. After the baby has been delivered, the mother is uncomfortable with pain. How should she be managed?
IV narcotics
Prior to a C-section, a laboring pregnant patient develops a high spinal. She is conscious, but starts to panic because she feels like she can’t breathe. SpO2 is currently 96% on a nasal cannula at 4L. How should she be managed at this point?
- Reverse Trendelenburg
- Possible assist ventilation (with possible N20)
- Blood pressure support
- Prepare for intubation
Prior to a C-section, a laboring pregnant patient develops a high spinal and goes unconscious (this is referred to as a “total” spinal). How should she be managed?
Intubate and resuscitate
case outline for c-section under epidural anesthesia 6
1 give abx ASAP in OR
2 raise epidural block to T4
3 pt in LUD
4 admin pitocin after baby and placenta delivered
5 dose duramorph in epidural prior to epidural catheter removal
6 give zofran and toradol
If you are called to perform the anesthesia for a non-emergent C-section on a patient whose epidural is working effectively, how should that patient be managed from an anesthetic standpoint?
Dose to T4 gradually with lidocaine (or chloroprocaine)
If you are called to perform the anesthesia for a non-emergent C-section on a patient whose epidural is “patchy” (not working completely), what are the anesthetic options?
- Supplement the block with ketamine/N20
- RSI
- Try and dose the epidural to T4 and see what happens
- Pull the epidural catheter and perform a spinal with a reduced dose
should you do a spinal after a patchy/failed epidural?
some say no
some say you can but you need to lower the dose by 20-30%
Let’s say that for this emergent C-section case, the patient is obese, has a Mallampati IV airway, and also does not have an epidural. What options does an anesthetist have in this scenario?
RSI with videoscope and LMA as a backup
Let’s say that for this emergent C-section case, the patient has an epidural that is “patchy” (not working very effectively). What options does an anesthetist have in this scenario?
- If the airway looks easy, perform an RSI
- If the airway looks difficult, perhaps think about dosing the epidural to T4 with chloroprocaine and/or trying ketamine/N20
Let’s say that for this emergent C-section case, the patient has an epidural that is working effectively. How should this patient be managed?
Dose to T4 immediately with chloroprocaine/bicarb
A laboring pregnant patient is taken to the OR to undergo a C-section for failure to progress. The epidural was dosed to T4 with 15mL of 3% chloroprocaine. 30 minutes into the procedure, the patient starts complaining of pain. How should this patient be managed at this point?
5-10mL epidural bolus of local anesthetic
3 opteions for postop pain control for c-sections under epidural
- duramorph 2-4mg through epidural prior to pulling it
- order an epidural PCA (walking epidural)
- order an IV PCA (if you forget to dose duramorph before you pull the catheter)
what is the most common method of postop pain control for c-section with epidural
duramorph in epidural prior to pulling
how long does epidural duramorph provide analgesia for?
18-26 hr
PCA
patient controlled analgesia
advantage to c-section under GA
- can be started quickly
- no sympathectomy
- avoids risk of epidural hematoma in pts with low platelet or bleeding disorders
disadvantages to c-section under GA
- increased fetal exposure to drugs
- exposed to airway risk including aspiration
- mother isnt awake for birth of child
- increased risk of PPD
when should the anesthetist induce the patient?
when the patient is drapped and prepped and the surgeon is ready with knife in hand
indications for c-section under GA 5
1 emergency with no block in place
2. hypotensive and will not tolerate sympathectomy
3. any contraindication to neuraxial anesthesia or if they request GA
4. spinal or epidural fails
5. pt gets apnea from high spinal
placenta previa
placenta covers the cervical os
symptom of placenta previa
painless vaginal bleeding
placental abruption
placeta detaches from uterus and lead to massive bleeding
placenta accreta
placenta grows through uterine wall, cause massive bleeding from both organs
when would you choose propofol as the induction agent for GA c-section?
non hemorrhaging normotensive parturients
when would you choose ketamine as the induction agent for GA c-section?
internally bleeding or hypotensive parturients
when should ketamine be avoided for c-sections?
hypertensive or preeclamptic patients
case outline for c-section under GA 7
- give abx ASAP in OR
- induce patient
- place in LUD
- paralyze if needed
- admin pit after baby and placenta are delivered
- give zofran, fentanyl and reversal (maybe toradol)
- plan on IV PCA for postop pain control
do muscle relaxants cross the placenta?
no
are fasiculations more or less noticable in pregnant patients?
less noticeable due to progesterone?
A laboring pregnant patient is taken to the OR to undergo a C-section for failure to progress (non-emergent). Past medical history includes preeclampsia and thrombocytopenia. General anesthesia is planned. After induction, the anesthesiologist is unable to intubate the patient. What should be done at this point?
awaken the mother
What if the patient in the previous example was having an emergent C-section for type II fetal decelerations. What is the correct thing to do if intubation is unsuccessful?
Place an LMA and hold cricoid pressure until the patient can be intubated
how do you reverse muscle relaxants in pregnant pts
neostigmine with atropine
(atropine crosses placenta, robinul does not)
