Advances in Labor Analgesia

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Advances in Labor Analgesia

• Luis Lahud, M.D.
• Norman Bolden, M.D.
• Department of Anesthesiology
• MetroHealth Medical Center
• May 3rd, 2005
• Cleveland, OH

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Contents

• Introduction
• PCEA
• CSE
• Pros
• Cons
• Review article
• Protocols and Cocktails
• Discussion

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INTRODUCTION
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• From 1985 to present use of epidural analgesia
  for labor has increased from 10 to over 50 of
  laboring women in the U.S.
• Advances include low dose epidurals, walking
  epidurals, PCEA, and CSE
• Early increased doses of LA increased SE
• PDPH 7-10
• OB/GYN perspective

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• Adding opioids lt MB
• Walking epidurals lt MB meant better outcomes
• No evidence of improved labor pattern/outcome
  with ambulation
• Women dont walk even if they can
• Monitoring problems
• Techniques that allow walking may be better
  whether or not patient ambulates

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Effect of Low-Dose Mobile vs. Traditional
Epidural Techniques on Mode of Delivery A
Randomized Controlled TrialCOMET Study, Lancet
2001

• 1054 nulliparous women were randomized into 3
  groups to receive either a traditional epid
  (0.25 BUP), a low-dose CSE, or a low-dose
  infusion epid
• Increased rate of normal vaginal delivery with
  CSE and low-dose infusion
• Decreased rate of instrumental vaginal delivery
• Increased rate of CS with traditional epidural

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PCEA
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• Introduced in 1988
• Small basal dose
• PCEA less med overall

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PCEA VS. CONTINUOUSGambling et al., Can J
Anaesth 1988
Epidural initiated 8 ml 0.25 BUP
0.125 BUP
CIEA 12 ml/hr infusion
PCA 4 ml basal, 4 ml bolus, Lockout 20 min, 16
ml/hr max
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PCEA VS. CONTINUOUSGambling et al., Can J
Anaesth 1988
PCEA (n14) CIEA (n11) ____________________
__________________________________________ Durat
ion (h) 7.0 0.6 5.8 0.6
demands/hr 1.9 0.4 1.2 0.2 Dose of
BUP/hr 11.2 0.85 15.2 0.5
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• PCEA CI vs. PCEA only
• Both groups provide good analgesia
• Both use less than continuous
• No benefit with basal rate over demand only

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• Ferrante et al. 1994
• Background infusion increases drug use by 30
• No obvious benefit in pain relief
• Background infusion decreases physician top-ups
• Only physician administer top-ups associated
  with hypotension

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BACKGROUND VS. DEMAND ONLY?Ferrante et al. 1994

• Bupivacaine 0.125 with 2 mcg/ml fentanyl
• Loading dose 0.5 bupivacaine for S5 T10 level

Group N CI (ml/h) DD (ml) Lockout (min) BUP/hr (mg)-1rst stage BUP/hr (mg)-2nd stage Physician visits/doses
DO 15 0 3 10 9.7 1.3 6.7 1.5 12 4.2
CI (3) 15 3 3 10 11.8 1.4 8.9 0.8 8.3 3
CI (6) 15 6 3 10 11.7 0.9 12.2 1.0 1.6 1.2
CI (12) 15 12 0 N/A 16.0 0.7 16.7 1.1 7.0 3.1
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PCEA compared to CEI in an ultra-low-dose regimen
for labor pain relief a randomized
studyEriksson, Gentele and Olofsson Acta
Anaesthesiologica Scandinavica 2003

• 80 parturients (40 per group)
• Ropivacaine 0.1 SUF 0.5mcg/ml
• Test dose 5ml loading dose
• PCEA 4ml doses, 20min lockout
• CEI 6ml/hr
• Rescue 5ml if VAS gt 5

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• CONCLUSIONS
• PCEA group used less drug ( 5.2 v 6.9ml/hr)
• PCEA group had shorter labor (296min v
  357min, plt 0.001)
• Pts titrated themselves to VAS 3

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PCEA at MH

• Test dose
• Loading dose 6 -10cc of 0.125 BUP with 2mcg/cc
  of fentanyl
• Basal infusion 8 12cc of 0.11 BUP with
  2mcg/cc of fentanyl
• Demand dose 5cc with 15 min lockout max 30cc/hr

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Issues with PCEA

• Patient/Nurse education
• Treat pain early
• Emphasize that we are available
• Call us if 2 PCEA attempts dont work
• ONLY patient pushes button
• Equipment
• Record keeping
• Maintain patient contact

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PCEA CONCLUSIONS

• Easy modification of existing practice
• Fewer MD visits required
• May allow lower concentration of drugs with
  better analgesia
• Lower drug usage
• Very popular with patients

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CSE
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• The ideal labor analgesic
• Rapid onset
• Long duration
• Easy to administer
• No side effects on mother
• No side effects on baby
• Allow ambulation, unrestricted expulsive efforts
• No effect on length of labor or mode of delivery
• Is CSE the ideal labor analgesic?

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Advantages of CSE

• Rapid onset of analgesia
• Reliable, fewer failed, or patchy blocks
• Effective sacral analgesia in advanced labor
• Less motor block

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• Better patient satisfaction
• Aids epidural localization in difficult backs
• Faster cervical dilation in early nulliparas
• Side effects are acceptably low

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Rapid Onset of Analgesia

• Most dramatic feature analgesia is often nearly
  complete before the epidural cath is taped up and
  the tray discarded
• Van de Velde randomized 110 parturients to epid.
  BUP 0.125 w sufentanil and epinephrine or IT
  sufentanil. The time to effective analgesia was
  significantly shorter in the CSE group (326 22
  vs. 766 79sec).

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• Nickells randomized women to epid. or SA BUP and
  fentanyl. The time to first painless contraction
  was shorter in the CSE group ( 10 5.7 vs. 12.1
  6.5min)
• Hepner randomized women to receive 10ml of
  0.0625 BUP fentanyl 2mcg/ml epinephrine
  bicarbonate epidurally or 25mcg fentanyl and
  2.5mg BUP IT
• 26/26 patients had a VAS lt 3 within 5min in CSE
  group, only 17/24 in the epidural group
• Does a few minutes advantage in analgesic onset
  matter?

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Better Blocks

• Quality of analgesia is improved by CSE
• Norris retrospectively compared epid. and CSE
  techniques in 1661 women who received either
  technique and found a lower incidence of failed
  blocks and a greater incidence of bilateral
  symmetrical analgesia w CSE

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• A retrospective analysis in a large academic
  medical center involving near 20 thousand
  patients found incidences of overall failure, IV
  epid cath, wet tap, inadequate epid analgesia
  and cath replacement were all lower in patients
  receiving CSE
• Sacral analgesia is difficult to obtain with
  conventional epidural, CSE is good at providing
  it
• CSE is an obvious choice in advanced labor

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• A number of mechanisms may explain this
  advantage
• One cannot obtain CSF using the
  needle-through-needle technique unless the epid
  needle is positioned near the mid line of the
  actual epid space
• There may be passage of LA from the epidural
  space into the IT space via the dural hole
• There may be synergism between epid and spinal
  blocks, such that one enhances the other

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Less Motor Block

• CSE associated with less total LA use for a given
  degree of analgesia
• In a randomized trial, Collis found 12/98
  patients in the CSE group, compared to 32/99 in
  the epid group had leg weakness at 20min
• The difference widened to 10 vs. 80 at 5hr
• MB may be minimized or made equivalent to CSE
  with use of low dose and/or PCEA for epid
  analgesia
• Requirements for anesthesiologist intervention
  are lower w CSE regardless of technique

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Better Patient Satisfaction

• Several studies have found better patient
  satisfaction scores with CSE vs. conventional
  epid. Others have found no difference, but none
  have found better satisfaction with conventional
  epid analgesia

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Better in Difficult Backs

• No randomized trial has yet appeared
• CSE has been associated with improved chances of
  adequate analgesia in parturients with scoliosis
  or other causes of a difficult back

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Progress of Labor

• Patients progress rapidly through labor
• One explanation for an apparent increase in FHR
  abnormalities occurring after CSE is this rapid
  progress
• 2 large randomized trials have confirmed an
  increase in the spontaneous vaginal delivery rate
  with CSE vs. conventional epid analgesia
• As is the case with epidural analgesia, the CS
  rate is not increased with CSE

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Side Effects

• PDPH
• Fetal bradycardia/FHR changes
• Pruritus
• Infection
• Neurotrauma
• Other side effects

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• PDPH
• Rate 1
• CSE technique might actually decrease the
  incidence of dural puncture with the epid needle
  by allowing the anesthesiologist to confirm an
  equivocal loss of resistance by passage of a
  pencil point spinal needle rather than advancing
  the large bore epid needle futher

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• Fetal bradycardia/ FHR changes
• Incidence of 11-30
• Meta - analysis of 24 randomized trials including
  over 3,500 patients comparing CSE to conventional
  epid analgesia found no difference in the rate of
  FHR changes but an increase in the risk of
  bradycardia
• Usually a reduction in uterine activity
  (decreasing or interrupting oxytocin
  administration, or short acting tocolytic
  administration), raising maternal BP, position
  change, or simply patience will resolve the
  problem

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• The meta analysis showed no difference in the
  rate of CS due to bradycardia or for all
  indications, and neonatal Apgar scores were
  equivalent
• Pruritus
• 3-95 of patients
• Effect is time limited, peak at 30min and largely
  resolved within 1hr
• Prophylactic Ondansetron
• Patient satisfaction remains high

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• Other side effects
• Hypotension
• Subarachnoid migration
• Respiratory depression

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On the other hand..

• How fast do we need a block to be?
• Nickells et al. noted that the time to first
  painless contraction with CSE was 10 5.7 vs.
  12.1 6.5min with the epid technique. With a
  mean difference of 2min, how clinically
  significant is this?
• In the study by Hepner mentioned before at 5min
  the VAS was lt 3 in 26/26 with a CSE vs. 17/24
  with an epid However, no difference in maternal
  satisfaction, motor blockade or number of times
  the anesthesiologist was called to intervene.
• Why pay more for CSE?

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Walking and CSE vs. Epidural

• No data to suggest a real difference in labor
  outcome
• More maternal satisfaction with being mobile but
  outcome is the same
• Instrumental delivery rate and CS rates are
  virtually the same
• Epid can be used to allow mobility if that is
  your goal

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Side Effects of CSE

• Collis et al. (1994) found the failure rate of
  the IT portion as high as 10. Duration of the
  spinal portion 90min (mean) and highly variable
• Norris et al. noted the spinal part failed in
  4.9
• Expected side effects include pruritus, mild
  decrease in maternal BP, PDPH
• Best and worst of both worlds

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Causes of Failure for CSE Technique
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Infection

• Meningitis and epid abscess have been reported
• There are least 8 cases of spinal meningitis
  related to a CSE
• There is also a case of epid abscess after a CSE
  for labor
• Conversely spinal anesthesia for elective CS does
  not carry these risks

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Neurotrauma

• Cord trauma has been reported with the CSE
  technique in at least 5 cases
• In a report of 7 cases with damage to the conus
  medullaris following spinal anesthesia by
  Reynolds of Saint Thomas Hospital in London, 4
  were patients who had received a CSE and 3 after
  a single shot spinal (6 in total were obstetric
  patients)
• In all cases, an atraumatic needle was used, 25
  or 27 gauge Whitacre and the anesthesiologist
  believed to be at L2-3

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• Epid has proven to be relatively safe over many
  years. If placed in error at T12-L1, for example,
  there is little concern in good hands
• A CSE at that level is a disaster, with
  penetration of the cord likely
• In 43 of women the cord extends to L2
• Numerous studies have shown that we are often 1-2
  spaces off, which can cause cord trauma with a
  CSE

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• Van Gessel et al. demonstrated that 59 of dural
  punctures were performed 1 or 2 spaces higher
  than assumed
• Broadbent et al. demonstrated in a group of
  experienced anesthesiologists that when they
  believed they were at L3-L4, in 85 of the cases
  the space was 1 to as many as 4 segments higher

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FHR Changes

• Numerous studies of varying quality
• Bradycardia more frequent
• Management LUD, fluids, oxygen, treat BP if
  applicable, IV or SL NTG has been shown to be
  effective in treating fetal bradycardia
  associated with uterine hyperactivity
• However, there is no data demonstrating an
  increased risk of CS due to CSE

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The Risk of Cesarean Delivery with Neuraxial
Analgesia Given Early vs. Late in LaborWong et
al, NEJM, February 17, 2005

• Epid analgesia initiated early in labor (cervix lt
  4cm dilated) has been associated with an
  increased risk of CS. It is unclear whether this
  is due to the analgesia or to other factors
• Women who request analgesia early in labor
  frequently receive systemic opioid analgesia
• Hypothesis Initiating and maintaining neuraxial
  analgesia early in labor with IT opioid as part
  of a low dose LA technique would not increase the
  risk of CS when compared with systemic opioid
  analgesia

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884 Consented
Systemic opioid
First request for analgesia Cervical examination
performed
Intrathecal opioid
134 Not eligible (cervix4.0cm)
750 Randomly assigned (cervix lt4.0cm)
13 Excluded
9 Excluded
Standard care
362 Assigned to hydromorphone (1mg intravenously
1mg intramuscularly) And included in analysis
353 received intervention
366 Assigned to fentanyl (25mcg intrathecally and
epid test dose) and included in analysis 360
received intervention
6 delivered before second request for analgesia
2 delivered before second request for analgesia
720 second request for analgesia cervical
examination performed
215 Cervix 4.0 cm or no cervical examination
226 Cervix 4.0 cm or no cervical examination
141 cervix lt4.0cm
138 Cervix lt4.0 cm
Hydromorphone (1mg Intravenously 1 mg
intramusculary)
Epidural bolus 15 ml (bupivacaine, 0.625 mg/ml
with fentanyl, 2mcg/ml) PCEA begun
Third request for analgesia
Epidural test dose
Epidural bolus 15 ml (bupivacaine, 1.25 mg/ml)
patient-controled Analgesia begun
Standard care
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Results

• 728 subjects were included in the analysis
• The groups were similar at baseline, except that
  the systemic analgesia group had a greater of
  subjects with dilation 1.5cm at first request
  for analgesia (42 vs. 30.9)
• The rate of CS was not significantly different
  between the groups (IT 17.8 vs. 20.7 SA)

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• No significant difference in the rate of
  instrumental vaginal delivery between the groups
  (IT 19.6 vs. 16 SA)
• No significant differences in the indications for
  CS or in the of subjects who received oxytocin
  however, the maximal rate of oxytocin infusion
  was higher in the systemic analgesia group

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• Average pain score between 1st and 2nd request
  for analgesia was significantly lower in the IT
  analgesia group, so was duration of neuraxial
  analgesia
• Higher incidence of prolonged and late
  decelerations in FHR in IT group
• Neonatal outcomes were not significantly
  different between the groups
• Greater incidence of 1min Apgar scores below 7 in
  the SA group (24 vs. 16.7)

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• In this randomized trial IT opioid analgesia as
  compared with SA in early labor did not increase
  the rate of CS
• The data suggests that an early request for
  analgesia, or increased use of analgesics early
  in labor may be markers for other risk factors
  for CS
• Women who have more pain and require more
  analgesia may be at increased risk for CS

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• Analgesia may have indirect effects in the
  progress of labor
• IT fentanyl decreases maternal concentration of
  circulating epinephrine
• It is possible this decreases epinephrine-induced
  tocolysis, resulting in faster labor
• An alternative explanation is that SA negatively
  influences the progress of labor

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PROTOCOLS AND COCKTAILS
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UCSF

• CSE 2.5mg BUP 25mcg fentanyl
• No test dose
• Infusion started

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Brigham and Womens Hospital

• PCEA 20ml BUP 0.125 fentanyl 2mcg/ml, then 6
  ml/hr infusion, 6ml bolus, 15min lockout
• CSE 2.5mg BUP fentanyl 25mcg
• No test dose, start PCEA

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Northwestern

• PCEA 0.0625 2 mcg/ml fentanyl. 15ml/hr basal
  infusion, 5ml bolus, 10min lockout, 30ml/hr max.
  If patient requires manual rebolusing they change
  to 0.11 BUP
• CSE early labor 25mcg fentanyl test dose
• Regular labor or multip 15mcg fentanyl 2.5mg
  BUP test dose. Start PCEA

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MHMC

• PCEA as detailed before
• CSE 1.25mg BUP 15mcg fentanyl epinephrine

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DISCUSSION