Analgesia For L&D Flashcards
1
Q
Benefits of Analgesia L&D
A
- Decreased catecholamines
- Decreased maternal oxygen consumption
- Decreased hyperventilation
- Indwelling epidural can avoid emergency GA (especially difficult airway, obese, pre-eclamptic, anyone with increased risk of C/S)
2
Q
Increased pain reported by
A
Nulliparous
Fetal malposition/dystocia
Dysfunctional labor
Induced labor
3
Q
What decreases pain sensitivity
A
Upregulation of descending pain modulating pathways (NE & serotonin)
Increased endogenous endorphins
Progesterone mediated tolerance
4
Q
What stage of labor involves uterine contraction & dilation
- involves the cervix, uterus, upper vagina
- visceral afferent fibers enter spinal cord at T10-L1 (paracervical ganglion)
- sympathetic chain at L2 and L3
A
First stage of labor
5
Q
What stage of labor involves the expulsion of the fetus
- involves mid and lower vagina, vulva, perinum
- somatic afferent fibers enter spinal cord at S2-S4 pudendal nerve
A
Second stage of labor
6
Q
What stage of labor involves the delivery of the infant to expulsion of the placenta?
A
Third stage
7
Q
Estrogen competes for which receptor
A
Mu
8
Q
Opioids do what to FHR variability
A
Reduced FHR variability
9
Q
Efficacy and side effects are drug dependent or dose dependent
A
Dose dependent
10
Q
Which systemic opioid does not accumulate in the fetus?
A
Remifentanil 25-50 mcg IV q5-10min
But maternal monitoring required
11
Q
Why is meperidine no longer popular in OB
A
Active metabolite - respiratory neonatal depression and neurobehavioral changes
25-50 mcg IV q2hr
12
Q
Which systemic opioid accumulates in fetal blood
A
Sufentanil
13
Q
Systemic opioid doses for Morphine and Fentanyl
A
Morphine 2-5 mg IV q2-3 hr
Fentanyl 25-50 mcg IV q 30-45 min
14
Q
Which two systemic opioids have a ceiling effect on respiratory depression?
A
Nalbuphine 10-20 mg IV q3-6hr
Butorphanol 1-2 mg IV q4-6 hr
15
Q
Why should nitrous gas be used alone for pain relief?
A
When used alone, no risk of maternal hypoxia and no adverse effects on the neonate
16
Q
What effect does nitrous have on early stages of labor
A
Preserves contractility and no neonatal depression
17
Q
Which regional anesthesia method is not continuous for vaginal delivery
A
Single shot spinal
18
Q
Which regional anesthesia method has a slow onset compared to the others
A
Continuous epidural
19
Q
Which three regional anesthesia methods have the ability to extend to anesthesia for C/S
A
Continuous epidural
Continuous spinal
CSE
20
Q
Epidural requires smaller or larger doses compared to spinal
A
Larger
21
Q
Which regional anesthesia method avoids the need to access neuraxial canal through lumbar interspace? Also requires large volumes/doses May be more technically difficult Higher r/o infxn Risk of inadvertent fetal injection
A
Continuous Caudal
22
Q
Which regional anesthesia methods require low dose LA and opioids?
A
CSE, continuous spinal, single shot spinal
23
Q
Which regional anesthesia method has a higher risk of maternal toxicity and fetal drug exposure; and which has a higher risk of fetal bradycardia?
A
Continuous epidural and CSE
24
Q
Which regional anesthesia method has a complete analgesia with opioid alone thus an increased risk of puritis
A
CSE
25
Which regional method has no dural puncture requirement and which has a large dural picture increased risk of PDPH
Epidural and Spinal
26
Which regional method has a possibility of OD and total spinal if mistaken for epi cath
Continuous spinal
27
Neuraxial contraindications
```
Refusal or inability to cooperate
Elevated ICP
Coagulopathy and recent pharmacologic anticoag
Skin infection at site
Uncorrected Maternal hypovolemia
```
28
Which skin prep is preferred for neuraxial anesthesia?
CHG
| Immediate action, residual activity, effectiveness against wide range of microorganisms
29
Which skin prep is contraindicated
Providine iodine and iodine base
30
What are the disadvantages of Epidurals
Side effects
Prolongs labor (15-20 min)
Inhibits ability to push
Fetal bradycardia after CSE
31
Which neuraxial anesthesia has the most effective mode in pain relief, best benefit to risk ratio, safest for CS, provides anesthesia for 1st and 2nd stages of labor, provides a differential blockade
Epidural
32
Preload patient with how many cc’s of fluid before an epidural
250-500
33
True or False: Temperature increase is likely in epidural
True
34
What physiological changes do you consider with epidural placement
Hormonal : Progesterone in CSF, Alkalinity of CSF (give acid prophylaxis)
Epidural veins engorged
Physical: exaggerated flexion causes aortocaval compression, iliac crest level
35
What happens with intravascular injection of epidural test dose
HR changes 20 BPM within 45 seconds
| Circum-oral numbness/ringing in ears
36
What happens with subarachnoid injection with epidural test dose
Rapid onset of sensory and motor blockade
| With/without hypotension
37
What should you do after injection of epidural test dose?
Aspirate
| Check BP q5 min after bolus up to 15-30 min
38
What is the most commonly used amide LA in OB (concentration too)…
0.25% bupi
39
What about bupi limits placental transfer?
Its highly protein bound
40
What is the onset and peak of bupi
Onset 8-10 min
| Peak 20
41
How long does 8-10 mls of 0.25% bupi lasts?
2 hours
42
Why would you want diluted bupi (0.125%)?
You would want diluted bupi to provide a differential blockade (sensory)
And you are able to give more volume to provide adequate analgesic spread
43
What are the continuous infusions of bupi?
0.0625 or 0.125% with fentanyl 2mcg/ml
44
What bupi concentration is contraindicated with epidurals?
0.75%
45
Which is the ester LA with the fastest onset of action for epidurals?
2-Chloro
| Metabolized by pseudocholinesterase
46
5-10mls of 2% 2chloro provides relief for how long
40 min
47
Which LA adversely effects the efficacy of subsequent epidural bupi and opioids by antagonizing mu and kappa receptors
2 chloro
48
What makes 2 chloro the best choice for stat CS for fetal distress?
Fetal acidosis doesn’t increase placental transfer
49
Intermediate duration of action (between 2chloro and bupi)
Lidocaine
50
Concentrations of Lidocaine used for epidurals
1% and 0.75%
51
Lidocaine crosses placenta much or less easier than bupi?
Much Easier
52
What effect does IV lidocaine have on UBF
Decreases UBF with vasoconstriction
53
Which LA provides a strong motor block
Lidocaine
54
Which LA provides an increased risk of neurotoxicity if injected into the subarachnoid space?
Lidocaine
55
What are the epidural bolus and continuous infusions doses for bupi?
Bolus 0.065-0.25% initially 5-10ml slowly titrate more to expand segmental block
Continuous 0.065-0.125% (fentanyl 1-2mcg/ml)
56
Lidocaine is not used for epidurals due to placental transfer, strong motor block, and _______
Tachyphylaxis
57
What is a top off dose of bupi?
0.25% 4-10 ml
58
Someone calls you saying that the catheter is in the epidural space but the extent of the block is inadequate
What steps do you take?
1. Is infusion rate high enough? Have they used bolus option?
2. fetal malpresentation? (Not getting enough relief depending on their position)
3. Inject dilute solution of LA with or without opioid
4. Alter maintenance technique
5. If unsuccessful replace catheter
59
Someone calls you for an asymetric block
| What do you do?
1. Inspect and withdraw 1cm and resecure
2. Inject dilute LA with or without opioids
3. Alter maintenance technique
4. Place less blocked side in dependent position
5. If unsuccessful replace catheter
60
Someone calls you that the catheter is in the epidural space but there is breakthrough pain
What do you do?
1. Is the infusion rate high enough? Have they used the bolus option?
2. Inspect catheter site and withdraw 1cm
3. Inject more concentrated solution of LA with/without opioid
4. Alter maintenance technique
5. If unsuccessful replace catheter
61
What effect does epidural analgesia have on uterine activity
Decreases it for 10-15 min but resumes to normal within 30
| Affects more intensity of uterine contractions instead of frequency
62
What does epidural analgesia do to pitocin?
Inhibits secretion of it
63
Uterine vasoconstriction happens when with epidural analgesia?
If it’s placed intravascularly
64
CSE doses
10 mcg of sufentanil and 2.5 mg of bupi
| 25 mcg of fentanyl and 2.5 mg of bupi
65
Which needle is inserted first with CSE
Epidural with positive LOR
| Then spinal inserted to reach intrathecal space
66
What causes CSE to have a rostral spread?
Volume in epidural compresses intrathecal space
| Achieving a higher level with a smaller dose
67
Neuraxial anesthesia method for an unintended intrathecal placement of a planned epidural catheter?
Continuous spinal
68
Continuous spinal has what doses?
Fentanyl 10-25mcg with bupi 1-2.5mg
| Bupi 0.125% with fentanyl 2mcg/ml run at 1-1.5 ml/hr
69
When is a single shot spinal or “saddle block” done?
Immediately prior to delivery with patient in sitting position for 3-5 min
70
For what stage of labor is a saddle block done for?
STAGE 2 - S2-S4
71
What LAs are used for single shot spinal?
25-50mg of lido
4-6mg of tetra
6-8mg of bupi
72
How do you make a single shot spinal adequate for stage 1 of labor
Give larger amounts of LA to get to T10 level
73
What neuraxial anesthesia method is useful for forceps delivery and breech babies
Single shot spinal
74
Fluid bolus for single shot spinal
500-1000ML
75
When is saddle block performed with contractions?
Between them to minimize cephalad spread
76
Level of block following a spinal is affected by what three things
Baricity of LA
Position of patient
Drug dosage
77
Which neuraxial anesthesia method is available for patient with lumbar fusion history
Caudal block
78
Co-administration of opioid with LA decreases or increases pruritis
Co-admin of opioid and epi decreases or increases pruritis
Decreases
| Increases
79
What other side effects are there for neuraxial anesthesia besides hypotension and pruritis
Fever, shivering, urinary retention
80
Tx of pruritis for neuraxial anesthesia
Centrally acting opioid agonist/antagonist or partial agonist-antagonist
- narcan 40-80mcg IV, 1-2 mcg/kg/hr infusion
- Nalbuphine 2.5-5mg IV
- naltrexone 6mg PO
Benadryl
81
What hormone enhances the cardiac toxic potential of bupi?
Progesterone
82
How can you prevent PDPHA
- Spinal needle 25-27g
- U/S
- caffeine and hydration
83
Tx for PDPHA
```
Intrathecal catheter placement
Analgesics
Horizontal position
Caffeine
Sumatripan (imitrex)
Epidural blood patch epidural access 12-20 ml of pt’s blood
```
84
Which nerve injury is associated with the compression between the descending fetal head and sacrum
Also associated with mid to high forceps use
Lumbosacral trunk L4 L5
85
Nerve injury associated with injury in the lithotomy position bc of hyperacute hip flexion and use of retractors during CS
Femoral L2-L4 and lateral femoral cutaneous nerve L2-L3
86
Nerve injury associated with incorrect lithotomy positioning with knee extension and external hip rotation
Sciatic L4, L5 S1-3
87
Nerve injury with lithotomy positioning from acute flexion in thigh to groin
Esp with obese women
Obturator L2-L4
88
Nerve injury from lithotomy that shows foot drop
Common peroneal L4-5 S1-2
89
Saphenous nerve injury is affected from what
Lithotomy
90
What complications can you see with paracervical block
Maternal rare
Fetal transient bradycardia
Direct injection into presenting part
91
DOA of paracervical block
30-60 min
92
Which block Does not affect duration of labor
Paracervical
93
How do you perform paracervical block
```
Inject 2ml of LA under epithelium, not deeper than 3mm
NO EPI
At 3, 5, 7, 9 o’clock
Optional 2 and 10 oclock
Aspirate prior to injection
```
94
What are the two approaches for pudendal block
Transvaginal and transperineal
95
What are the complications from pudendal block besides provider needle stick?
Maternal hematoma, systemic toxic reaction, trauma to sciatic, puncture of rectum, fetal injection
96
Steps for a pudendal block
```
Needle embedded in sacrospinous ligament
Need LOR
Aspirate through 180 degree rotation
3-5ml of LA injected
Needle advanced 1cm further and another 3-5ml solution injected
```
97
Which drug is safer for uterine relaxation and episiotomy repair ?
Uterine relaxation - NTG
| Episiotomy repair - local and ketamine < 0.5 mg/kg
98
If you must do GA, which induction drugs are preferred with GA
Thiopental, prop, ketamine, or etomidate
