Advances in Labor Analgesia

Contents

Introduction PCEA CSE

Pros Cons Review article

Protocols and Cocktails Discussion

INTRODUCTION

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

Adding opioids < MB

“Walking” epidurals: < MB meant better outcomes No evidence of improved labor

pattern/outcome with ambulation Women don’t walk even if they can Monitoring problems Techniques that allow “walking” may be

“better” whether or not patient ambulates

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

PCEA

Introduced in 1988

Small basal dose

PCEA less med overall

PCEA VS. CONTINUOUSGambling et al., Can J Anaesth 1988

Epidural initiated: 8 ml0.25% BUP

0.125% BUP

PCA: 4 ml basal, 4 ml bolus, Lockout 20 min, 16 ml/hr max

CIEA: 12 ml/hr infusion

PCEA VS. CONTINUOUSGambling et al., Can J Anaesth 1988

PCEA (n=14) CIEA (n=11) ______________________________________________________________

Duration (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

PCEA + CI vs. PCEA only Both groups provide good analgesia Both use less than continuous No benefit with basal rate over demand

only

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

BACKGROUND VS. DEMAND ONLY?Ferrante et al. 1994

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

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

PCEA compared to CEI in an ultra-low-dose regimen for labor pain relief : a randomized study

Eriksson, 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 > 5

CONCLUSIONS: PCEA group used less drug ( 5.2 v 6.9ml/hr) PCEA group had shorter labor (296min v

357min, p< 0.001) Pts titrated themselves to VAS ~ 3

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

Issues with PCEA

Patient/Nurse education Treat pain early Emphasize that we are available Call us if 2 PCEA attempts don’t work ONLY patient pushes button

Equipment

Record keeping

Maintain patient contact

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

CSE

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?

Advantages of CSE

Rapid onset of analgesia

Reliable, fewer failed, or patchy blocks

Effective sacral analgesia in advanced labor

Less motor block

Better patient satisfaction

Aids epidural localization in difficult backs

Faster cervical dilation in early nulliparas

Side effects are acceptably low

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).

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 < 3 within 5min in CSE

group, only 17/24 in the epidural group

Does a few minutes advantage in analgesic onset matter?

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

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

A number of mechanisms may explain this advantage:

1. 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

2. There may be passage of LA from the epidural space into the IT space via the dural hole

3. There may be synergism between epid and spinal blocks, such that one enhances the other

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

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

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

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

Side Effects PDPH

Fetal bradycardia/FHR changes

Pruritus

Infection

Neurotrauma

Other side effects

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

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

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

Other side effects Hypotension Subarachnoid migration Respiratory depression

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 < 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?

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

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

Causes of Failure for CSE Technique

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

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

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

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

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

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 < 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

884 Consented

First request for analgesia;Cervical examination performed

750 Randomly assigned(cervix <4.0cm)

134 Not eligible(cervix≥4.0cm)

Standard care13 Excluded 9 Excluded

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

141 cervix <4.0cm215 Cervix ≥4.0 cm or no cervical examination

226 Cervix ≥4.0 cm or no cervical examination

138 Cervix <4.0 cm

Hydromorphone(1mg Intravenously +1 mg intramusculary)

Third request foranalgesia

Epidural test dose

Epidural bolus: 15 ml(bupivacaine, 1.25 mg/ml); patient-controledAnalgesia begun

Standard care

Epidural bolus: 15 ml(bupivacaine, 0.625 mg/ml with fentanyl, 2mcg/ml); PCEA begun

Systemic opioid

Intrathecal opioid

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)

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

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%)

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

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

PROTOCOLS AND COCKTAILS

UCSF

CSE: 2.5mg BUP + 25mcg fentanyl

No test dose

Infusion started

Brigham and Women’s 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

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

MHMC

PCEA as detailed before

CSE: 1.25mg BUP + 15mcg fentanyl + epinephrine

DISCUSSION