Anesthesia for Normal Labor and Delivery - PowerPoint PPT Presentation

Loading...

PPT – Anesthesia for Normal Labor and Delivery PowerPoint presentation | free to view - id: c95ad-MmMwO



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Anesthesia for Normal Labor and Delivery

Description:

'The inhalation lasted fifty-three minutes. ... Fetal Bradycardia = FHR 120 bpm for 2min. Riley...Cohen et al. Anesthesiology 1999; A1054 ... – PowerPoint PPT presentation

Number of Views:1866
Avg rating:3.0/5.0
Slides: 78
Provided by: sheila46
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Anesthesia for Normal Labor and Delivery


1
Anesthesia for Normal Labor and Delivery
  • Sheila E. Cohen M.B.,Ch.B. FRCA
  • Stanford University School of Medicine
  • Stanford, California

2
McGill Pain Questionnaire
(Melzack R The myth of painless childbirth.
Pain 19321, 1984)
3
Analgesia for Labor and Delivery
  • Always controversial!
  • Birth is a natural process
  • Women should suffer!!
  • Concerns for mothers safety
  • Concerns for baby
  • Concerns for effects on labor

4
Anesthesia à la Reine
5
(No Transcript)
6
John Snow (1853) on Queen Victorias Anesthetic
for the birth of Prince Leopold
  • The inhalation lasted fifty-three minutes.
    The chloroform was given on a handkerchief in
    fifteen minim doses the Queen expressed herself
    as greatly relieved by the administration.

7
(No Transcript)
8
The Ideal Labor Analgesic
  • Good pain relief
  • No autonomic block (no hypotension)
  • No adverse maternal or neonatal effects
  • No motor block
  • No effect on labor and delivery
  • No increase in C/S rate
  • No increase in forceps/vacuum delivery
  • Patient can ambulate
  • Economical cost and personnel

9
Pain Pathways in Labor and Delivery
Eltzschig, Leiberman, Camann, NEJM 348 3192003
10
Labor Pain at different Stages of Labor
Eltzschig, Leiberman, Camann, NEJM 348 3192003
11
(No Transcript)
12
Fetal pH during Labor and Delivery
pH
13
Analgesia for Vaginal Delivery
  • Systemic narcotics
  • Tranquilizers / hypnotics
  • Inhalation analgesia
  • Acupuncture
  • TENS
  • Psychoanalgesic techniques

14
Placental Transfer of DrugsMaternal, Drug,
Placental and Fetal Factors
  • Lipid solubility
  • Molecular size
  • Total dose of drug
  • Concentration gradient
  • Maternal metabolism and excretion
  • Degree of ionization
  • pKa of drug, maternal and fetal pH
  • Protein binding - mother and fetus
  • Uterine blood flow
  • Time for equilibrium to occur

15
Factors Determining Fetal Drug Levels
(Ralston, 1987)
16
Differential Protein Binding
Differential maternal and fetal protein binding
accounts for differences in total circulating
drug concentrations on both sides of placenta,
when free drug concentrations are actually equal
17
UV/MV Fetal-Maternal Drug Ratios
  • Bupivacaine 0.25-0.3
  • Mepivacaine 0.7
  • Lidocaine 0.5

Correlates with degree of protein binding, but
may not reflect total amount of drug in fetus
because of high lipid solubility leading to
significant tissue uptake
18
(No Transcript)
19
Systemic Opioids in Labor
Advantages
  • Easy administration
  • Inexpensive
  • No needles
  • Avoids complications of regional block
  • Does not require skilled personnel
  • Few serious maternal complications
  • Perceived as natural

20
Systemic Opioids in Labor
Disadvantages
  • All drugs easily cross placenta
  • Pain relief inadequate in most cases
  • Maternal sedation
  • Nausea, vomiting, gastric stasis
  • Fetal heart rate effects
  • Loss of beat-to-beat variability
  • Sinusoidal rhythm
  • Dose-related maternal / neonatal depression
  • Newborn neurobehavioral depression

21
Which Systemic Opioid?Pure Agonists
  • Morphine
  • long half-life, neonatal depression
  • Meperidine
  • neonatal depression (normeperidine effect)
  • nausea, vomiting
  • Fentanyl
  • short duration, minimal newborn effects
  • Alfentanil
  • newborn depression
  • Remifentanil? (what surveillance is needed?)

22
IV-PCA Fentanyl during Labor A suggested regimen
  • Loading dose of 50-100 mcg
  • No background infusion
  • 10-12.5 mcg bolus
  • 8-10 min lockout
  • 4 hour limit - 300 mcg
  • Pulse oximeter if large doses given

23
(No Transcript)
24
(No Transcript)
25
Which Systemic Opioid?Agonist-Antagonists
Ceiling effect for respiration and
analgesiaMaternal sedation prominent
  • Nalbuphine
  • Butorphanol
  • Buprenorphine

26
Potential Fetal/Neonatal Effects of Maternal
Sedation
  • Low 1 and 5 min Apgar scores
  • Respiratory acidosis
  • Naloxone, ventilatory assistance may be needed
  • Neurobehavioral depression - dose dependent
  • Prolonged observation in NICU occasionally needed

27
(No Transcript)
28
Neurologic and Adaptive Capacity Score (NACS)
(Anesthesiology, 1982)
29
Neonatal Neurobehavioral Effects of Maternal
Systemic Medication
  • Transient, global depression of behavior related
    to presence and quantity of drug in newborn
  • Most effects gone by 3rd day all by 10 days
  • Important to differentiate from sinister causes

30
Inhalation Analgesia for Vaginal Delivery
(N2O 30-50 very low concentration volatile
agents)
  • Advantages
  • Easy to administer (no needles or PDPH)
  • Satisfactory analgesia variable
  • Minimal neonatal depression

31
Inhalation Analgesia for Vaginal Delivery
(N2O 30-50 very low concentration volatile
agents)
  • Disadvantages
  • Decreased uterine contractility (except N2O)
  • Rapid induction of anesthesia in pregnancy
  • Risk of unconsciousness and aspiration
  • Difficulties with scavenging in labor rooms

32
Analgesia for Labor and Delivery
Local and regional techniques
  • Local infiltration
  • Pudendal block
  • Paracervical block
  • Paravertebral (lumbar sympathetic block)
  • Epidural - lumbar (caudal)
  • Spinal
  • Combined spinal-epidural (CSE)

33
Analgesic Blocks for Labor and Delivery
34
Paracervical Block
35
Regional Analgesia for Labor
  • Lumbar epidural
  • Segmental (T10-L1)
  • Extended (T10-S5)
  • Caudal epidural (S5-T10)
  • Spinal (LA opioids)
  • CSE (opioids LA)

36
Fetal / Neonatal Effects of Regional Analgesia in
Labor
  • Uterine perfusion maintained
  • Profound hypotension ? possible fetal compromise
  • LA toxicity - extremely rare
  • FHR changes
  • baseline variability
  • periodic decelerations (due to? maternal
    catechols?)
  • Apgar scores, acid-base status, unaffected
  • Neurobehavioral effects absent with current agents

37
The Ideal Labor Analgesic
  • Good pain relief
  • No autonomic block (no hypotension)
  • No adverse maternal or neonatal effects
  • No motor block
  • No effect on labor and delivery
  • No increase in C/S rate
  • No increase in forceps/vacuum delivery
  • Patient can ambulate
  • Economical cost and personnel

38
How to Achieve Goals
  • What you put in
  • Drugs, concentrations, combinations
  • How you deliver it
  • Intermittent boluses, continuous, PCEA
  • How much you give
  • Low vs. high infusion rates

39
(No Transcript)
40
(No Transcript)
41
Ropivacaine vs. Bupivacaine in Labor - What are
the Relative Potencies?
  • Ropivacaine is only 60 as potent as bupivacaine
    (2 MLAC studies)
  • Claims for reduced toxicity and motor block must
    consider relative potency
  • Do very dilute agents pose risk of toxicity?
  • Newer agents very expensive

(Polley et al. Anesthesiology, 1999. Capogna
et al. BJA, 1999)
42
Relative Analgesic and Motor Blocking Potencies
of Epidural Bupivacaine and Ropivacaine in Labor
(Lacassie et al. Anesth Analg 200295204)
43
Relative Motor Blocking Potencies of Epidural
Bupivacaine and Ropivacaine
CONCLUSIONS
  • Motor block potency ratio is the same as sensory
    block potency ratio
  • Ropivacaine is only 0.66 as potent as bupivacaine
  • No difference in mode of delivery

(Lacassie et al. Anesth Analg 200295204)
44
Potencies of Levobupivacaine and Bupivacaine in
Labor
Lyons et al. Br J Anaesth 199881 899
45
Epinephrine Use in Labor
  • May transiently slow labor
  • Increases motor block
  • Improves analgesia ( 1600K works)
  • Epinephrine test dose often avoided in labor
  • Low specificity - maternal heart rate very
    variable
  • Low sensitivity - ? response to sympathomimetics
  • Increases motor block - prevents ambulation
  • Potential for ? UBF with repeated doses
  • Very dilute agents - whole first dose is test
    dose.

46
Epidural Opioids in Labor
  • Inadequate analgesics used alone
  • Synergize with local anesthetics
  • Speed onset of analgesia
  • Improve quality of analgesia
  • Permit use of very dilute LA solutions
  • Help relieve persistent perineal pain and
    unblocked segments
  • Optimal recipe and maximum safe dose not
    determined

47
(No Transcript)
48
Which Epidural Opioid in Labor?
Fentanyl and Sufentanil
  • Rapid onset, few side effects
  • Sufentanil slightly more effective
  • No significant fetal drug accumulation (? less
    with sufentanil)
  • No serious adverse neonatal effects with either

49
Light or Ultra-light Analgesic Techniques
  • Bupivacaine
  • Ropivacaine OPIOID
  • Levobupivacaine

50
Continuous Infusion Epidural
  • A larger volume of a more dilute agent is more
    effective for labor analgesia than a smaller
    volume of higher concentration

PCEA
  • Good analgesia
  • Patient autonomy
  • Less need for MD interventions
  • Cost effective

51
Effect of Low-Dose Mobile vs. Traditional
Epidural Techniques on mode of delivery A
randomized Trial
(Comet Study UK , Lancet 200135819)



Patients
Bupivacaine 0.25
Bupivacaine 0.1 fentanyl
Bupiv 2.5 mg Fent 25 mcg
52
(No Transcript)
53
Ultra-Light Bupivacaine-Sufentanil PCEA
technique for Labor Analgesia(Stanford Technique)
  • Block initiated with 15-20 ml bolus 0.125
    bupivacaine sufentanil 10 mcg
  • PCEA solution
  • 0.0625 bupivacaine sufentanil 0.3-0.4 mcg/ml
  • PCEA settings
  • Basal infusion 10-15 ml/hour
  • Bolus 12 ml
  • Lockout 15 min

54
Physician Administered Boluses
55
IT Opioid Analgesia (CSE)
56
Advantages of CSE (opioids local anesthetic)
for Labor Analgesia
  • Rapid onset of intense analgesia (the patient
    loves you immediately! ???)
  • Ideal in late or rapidly progressing labor
  • Very low failure rate
  • Less need for supplemental boluses
  • Minimal motor block (walking epidural)
  • Side effects vs standard epidural?

57
Median Upper and Lower Level of
DecreasedPinprick Sensation after Intrathecal
Sufentanil 10 µg
10 µg
(Cohen et al. Anesth Analg, 1993)
58
(No Transcript)
59
Onset of Analgesia CSE vs. Epidural Collis et
al. Lancet 19953451413
60
Rare but Serious Problems
61
The Problem
62
Epinephrine Levels after Analgesia

Cascio et al. Can J Anaesth 1997 44605-609
63
Fetal Bradycardia After Labor Analgesia
Pain Relief
Decreased Circulating Epinephrine
Increased Uterine Tone
Decreased Uterine Blood Flow
Fetal Bradycardia
64
Fetal Heart Rate Changes after Analgesia CSE vs.
Epidural
Nielsen et al. Anesth Analg 1996 837426
Palmer et al. Anesth Analg 19988(3)577-81Riley
et al. Anesthesiology 1999 A1054Eberle et al.
Am J Obstet Gynecol 1998 179150-155
65
Fetal Heart Rate after CSE - Selection Bias May
Contribute to Higher Incidence of Fetal
Bradycardia -
Riley...Cohen et al. Anesthesiology 1999 A1054
Fetal Bradycardia FHR lt 120 bpm for gt 2min
66
Greater Pain Scores and Cervical Dilation Before
Analgesia May Contribute to Bias
Riley...Cohen et al. Anesthesiology 1999 A1054
(n 196)
67
Management of FHR Changes
  • Left uterine displacement
  • Maternal position change
  • O2 administration
  • STOP OXYTOCIN!
  • Fetal scalp stimulation
  • Nitroglycerin 400 µg sublingual X 2 (or more)
  • 100 µg IV repeated as needed
  • Terbutaline 0.25 mg, subcutaneous
  • Treat hypotension
  • Ephedrine - ? epinephrine level ? UBF

68
Other Problems
69
Spinal Needle DesignRiley, Cohen et al.
Longer needle subsequently successful in all
these cases.
70
(No Transcript)
71
(No Transcript)
72
(No Transcript)
73
CSE vs. Epidural Labor AnalgesiaRisk of Headache
Norris et al, Anesthesiology 200195913
(n2183)
74
Strategies to Decrease Complications with CSE
  • Decrease dose of opioid
  • Fentanyl 15-20 µg
  • Sufentanil 2.5-5 mg
  • Combine with
  • Local anesthetic (bupivacaine 1.25-2.5 mg)
  • Epinephrine?
  • Clonidine?
  • (Neostigmine?)

75
Current Recommendations for CSE
  • Use lowest effective dose of opioid, dont repeat
  • Monitor BP, FHR, Respiration, (SpO2 if indicated)
  • Expect potentiation of epidural doses
  • All mixtures hypobaric - avoid prolonged sitting
    position after block
  • Treat hypotension and uterine hypertonus
  • Naloxone and resuscitation equipment available
  • Same or greater surveillance as after epidural

76
Controversial Areas
  • Effects on labor and delivery process
  • Maternal temperature elevation
  • Drug choice - are new agents better?
  • Epidural vs. CSE

77
Conclusions
  • Individualize technique to patients goals and
    stage of labor
  • Optimize management for spontaneous delivery
  • Provide safe, cost-effective analgesia
About PowerShow.com