Obstetric Anesthesia Part 1: Forkner Flashcards
What is important information to have about the pregnant patient? (4)
Gravida and parity
Gestational age
Cervical exam
Pt specific concerns such as prior cesarean, multiple gestation, placental abnormalities, preeclampsia, etc.
Who is the patient, baby or mom?
mom
Define gravida and parity.
Gravida = number of times pregnant
Parity = number of babies born
Parity (# # # #)
What does each # represent?
- full-term births
- pre-term births
- losses (spontaneous or otherwise)
- living children
When is gestational age, or, when full-term starts?
38 weeks from gestation
36-37 week babies do worse than 38-39 week babies. True or false
True
What information does the cervical exam include?
Dilation (from 0 - 10 cm)
Effacement: means thinning of the cervix
Station: means where the baby is relative to the cervix
Immediately after delivery CO increases as much as ____%.
80%
Left axis deviation on EKG at term because of displacement of diaphragm by uterus, which also increases the risk of ________.
arrhythmia
What is aortocaval compression also called?
supine hypotensive syndrome
Gravid uterus in supine women causes aortoiliac compression in ___-___% of women.
However it compresses the IVC in _____% of women.
15-20
100%
All women are affected by IVC compression.
What are the respiratory changes in a pregnant woman relating to:
minute ventilation
RR
tidal volume
lung volumes
FRC
increased MV
increased RR
increased TV
DECREASED lung volumes
decreased FRC
What is the most common cause of anesthesia-related mortality?
Loss of airway
Why is gastric emptying more difficult in the pregnant pt?
Upward displacement of the stomach promotes incompetence of the gastroesophageal sphincter.
Gastrin secreted by _____ makes stomach contents more acidic.
the placenta
What are the hematologic changes to:
Red blood cell mass
Hb
Hct
Platelet count
increases ~20%
normal
normal
platelets decrease
Pregnant women experience _____ coagulation and _______ anti-clotting activity.
increased
increased
Note: Pregnant women in a constant state of “chronic compensated disseminated intravascular coagulation” which can easily turn into uncompensated DIC.
Decrease in plasma cholinesterase, not enough to affect succinylcholine clearance significantly. True or false?
True
What is the leading cause of mortality worldwide?
What is the leading cause of death according the the CDC?
What is the leading cause of anesthesia-related maternal mortaility?
hemorrhage
cardiovascular disease
failure to secure the airway
Note: Maternal mortality is on the rise due to rising cesarean rate and more advanced maternal age/comorbidities.
What are other anesthesia-related maternal mortality causes besides failure in securing the a/w? (3)
Pulmonary aspiration of gastric contents
High spinal
Intravascular injection of LA leading to seizure/heart failure
What is the safest and most effective medical intervention for labor pain?
lumbar epidural
What are factors that tend to worsen labor pain? (3)
OP (occiput posterior) delivery, or, face up
Use of oxytocin
Use of forceps
Opioids cannot be given to the pregnant pt. True or false?
False, can be given but are higher risk for baby and mother and are not as effective as epidurals. However, can be best option when epidural is not possible.
Note: If baby gets opioid and cord gets cut, the baby gets the drug and cannot rid of it leading to respiratory depression.
Where does pain during Stage 1 of labor arise from?
uteral and cervical visceral pain which is dull, intense, and crampy pain
The uterus and cervix are innervated by spinal levels ___-____.
T10 - L1
Note: T10 is level of belly button.
Where does pain during stage 2 of labor arise from?
Somatic pain that is sharper, well-localized from the compression of perineal tissue as well as the uterus and cervix as baby passes the vagina.
The perineum is innervated at spinal levels ____ - ____.
sacral innervation at S2-S4
During stage 3 of labor, sudden, severe pain should cause concern for _____ ______.
uterine inversion, which rarely occurs
What is stage 4 of labor?
Puerperal period from after delivery of the placenta until return to non-pregnant physiology usually 2-6 weeks after delivery.
Puerperal: (py-ûrpr-l)
What are the layers encountered when placing an epidural?
Skin
Subcutaneous
Supraspinous ligament
Intraspinous ligament
Ligamentum flavum
Epidural space
Dura
Arachnoid space
Subarachoid space
Where does the spinal cord end?
Where do we aim to place epidural?
L1
L 2-3 or L 4-5
What are contraindications to neuraxial block? (8)
Patient refusal
Thrombocytopenia
Coagulopathy, incl. recent anticoagulants
Infection at site
Untreated intravascular bacteremia
Presence of foreign bodies/hardware in back
Pathologies of spinal cord, eg. spina bifida
2nd stage labor–complete dilation of cervix
What pt information do we need before placing an epidural?
Same info needed for obstetric purposes
In addition, VS including temp, height, weight, airway
Note: Epidural dosing is height-based.
What labs are needed at a minimum before placing an epidural? (4)
Hb
Hct
Platelet count
WBC count
Need X fishbone info.
Shoulders should be as even as possible (if pt scoliotic, as close to neutral position as possible), and relaxed during epidural placement. True or false?
True
How often should the BP be cycled during epidural placement?
At a minimum, q5 minutes.
At what levels do the iliac crests lie?
L4-L5
What are the typical gauges of epidural needles?
17, 18 gauge
How deeply should the epidural catheter be placed in cm?
3-5 cm
A test dose will confirm correct placement of epidural. True or false?
False.
A test dose will tell if the catheter is in in the intrathecal or intravascular space. Dangerous if provider does not realize it is intrathecal!
What must you do with an intravascular epidural catheter.
You must always remove it.
What is the classic test dose for an epidural?
1.5% lidocaine, 1:200,000 epi, 3ml
What symptoms will arise if the epidural is placed intrathecally? (3)
Warmth in bottom
Numbness
Difficulty moving legs
What symptoms will arise if the epidural is placed intravascularly? (4)
Ringing in ears
Metallic taste
Circumoral numbness
Marked increase in HR
What local anesthetics are generally used in epidurals? (2)
Ropivicaine
Bupivicaine (0.05%)
- Both provide excellend sensory block with low motor block
- Injected in 3-5ml boluses
What is a CSE?
Combined spinal and epidural
After the epidural space is found a spinal needle is inserted through the epidural needle.
What are the benefits of CSE?
Near immediate pain relief
Confirmation of epidural space
What are the risks of CSE? (2)
Spinal headache is a small risk
Paresthesia possible if brush nerve root–never inject into paresthesia
What is a subdural placement of epidural?
Cannot be placed intentionally
Ends up between the dura and the arachnoid
Risky because of potential exposure to intrathecal space
What are the risks of epidural placement? (8)
- Inadvertent dural puncture
- Hypotension, which can affect fetus
- Failed block
- Accidental intravascular or intrathecal injection of epidural drugs
- Nerve injury
- Prolongation of 2nd stage of labor
- Epidural hematoma
- Infection
What is a “wet tap”?
What are physical signs of a “wet tap”?
Accidental dural puncture
Back pain, pain shooting in legs, infection
Note: Dramatically increases risk of postdural puncture headache, which results from continual leakage of CSF.
What is done in the event of a “wet tap”?
Needle removed and epidural placed adjacently, or
Catheter is inserted into intrathecal space
What are the pros/cons of a “wet tap” turned into an intrathecal?
Pros: No risk of further wet tap
Reduced risk of headach
Reliable strong block
Cons: risk of high spinal
What are the indications for c-section? ( 7)
- Arrest of dilation
- Arrest of descent
- Nonreassuring fetal HR
- Prior C-section
- Cephalopelvic disproportions
- Prior surgery involving uterus
- Uterine cord prolapse and other serious conditions
What is normal fetal HR?
110-160
Fetal accelerations are bad indications of fetal movement. True or false?
False, periodic accelerations are good relative to movement, stimulation.
Constant tachycardia is bad.
What do early decelations of the fetal HR indicate?
Often associated with head compression as fetus move toward delivery.
What do variable decelerations of the fetal HR indicate?
Can be associated with imbilical cord prolapse
What do late decelerations of the fetal HR indicate?
Suggestive of fetal asphyxia following contractions such that contractions are cutting fetal blood supply.
Note: HR decelerations only measurable fetal responses to stress.
What types of anesthesia may you used for c-section?
epidural
spinal
general
What level block is needed for c-section?
T4 to block peritoneal stimulation
Epidural rather than general anesthesia preferred because: (3)
Mortality rate 17 times greater with general
Pt awakens with greater pain with general
Fetal transfer of induction drugs
All induction drugs transfer to baby. True or false?
False, paralytics do not.
What type of neuraxial block is contraindicated in MS patients?
Spinal, though epidural is not.
What type of LAs are commonly used for epidurals?
Bupivicaine, 0.5%
Lidocaine, 2%
Chlorprocaine, 3%
What is the first sign of hypotension in the awake patient when administering regional?
N/V
Note: Only consider other causes when hypotension is abosolutely ruled out with 3 BP readings. Hypotension is bad for the baby.
Immediately after the baby is born, what drug do you administer?
Pitocin, run wide open to reduce uterine atony and hemhorrage.
Remember, can bleed 700ml/min!
What must you consider during an emergency c-section? (4)
Pt on oxygen ASAP
If epidural in place, dose quickly, but divided doses still apply
If epidural not functioning, spinal or general
If choose general, pt must be draped and prepped PRIOR to induction
What must you consider regarding volatile agents after the baby is delivered?
Lower MAC to reduce uterine atony
May incorporate nitrous
When should you consider redosing the catheter during a c-section?
After 1-1.5 hours
If severe pain not addressed by neuraxial block develops, some providers consider using _______.
ketamine
Note: It preserves a/w reflexes and respirations.
Moms are hypo/hyperglycemic when pregnant.
hyperglycemic
In STAT c-section, how is the induction performed? (2)
RSI
Propofol, Sux used
What is a “hot spot” epidural?
unilateral block
