Labor analgesia

transcript

LABOR ANALGESIA

Saneesh P JSpecialist (A) - Anesthesiology

Sultan Qaboos University Hospital

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Introduction

Childbirth - most painful experiences women will experience in their lifetimeChildbirth pain was “divine retribution for Eve’s disobedience in the Garden of Eden”Many believed it was wrong to treat the pain and escape God’s punishment

Introduction

Several non-pharmacologic techniques have been used to relieve the pain of childbirth throughout history

acupuncturemassagehypnosis

Drugs were not used in Western medicine to relieve pain in childbirth until the mid-1800s

Introduction

English Queen Victoria chose to inhale chloroform for analgesia during the birth of Prince Leopold

John Snow Queen Victoria

Analgesia for Labor and Delivery

Always controversial!

“Birth is a natural process”

Women should suffer!!

Concerns for mother’s safety

Concerns for baby

Concerns for effects on labor

<10% of laboring women in US in 2001 underwent childbirth without analgesiaNeuraxial analgesia is by far the most common form of pain managementDevelopment of increasingly safe techniques for neuraxial analgesia

Pain Pathways in Labor and Delivery

Labor Pain at different Stages of Labor

Non-pharmacological Methods

AcupunctureMassageHypnosisOthers

Lamaze methodLeBoyer techniqueTranscutaneous nerve stimulationHydrotherapyPresence of a support personIntradermal water injectionsBiofeedback

The Ideal Labor Analgesic

Good pain relief

No autonomic block (no hypotension)

No adverse maternal or neonatal effects

No motor block

The Ideal Labor Analgesic

No effect on labor and delivery:No increase in C/S rateNo increase in forceps/vacuum delivery

Patient can ambulate

Economical: cost and personnel

How to Achieve Goals:

Prenatal education classes

Anesthesiologists must become effective educators as well as health care providers

Patients should have realistic expectations regarding the pain of labor and the variability of individual labor patterns

Well-informed patients are more likely to accept the interventions that may become necessary during labor

Anesthesiologists should encourage and facilitate the honest discussion of the risks and benefits of the analgesic/anesthetic techniques available

Parenteral agents

All parenteral opiates cross placentaDegree of depression depends on

specific agentDosetime between administration and deliveryprematurity

Parenteral Agents

MorphinePethidineFentanylKetamine

Inhaled Analgesia

Inhaled anesthetics were the first treatments for labor analgesia used in modern times. However, as volatile anesthetics became more commonly used in childbirth, side effects were more commonly encountered.

Neonatal depressionMaternal gastric aspiration

Inhaled Analgesia

Delivery was complicated by aspiration of gastric contents in 66 women from 44,016 deliveries (0.15%) between 1932 and 1945. The preventive fasting measures - recommended by Mendelson

restricting intakeprovision of non-particulate antacidsimprovement of anesthetic-induction technique

Inhaled Analgesia

Volatile anesthetics are no longer used for labor analgesia. Nitrous oxide, however, is still commonly used worldwide and is welcomed by many parturients as a less invasive approach to pain relief in labor.

Inhaled Analgesia

Typically NITROUS OXIDE is blended with O2 in a 50:50 ratio or slightly greater for patient-inhaled self-administration. ENTONOX

NEURAXIAL ANALGESIA

Neuraxial Analgesia

The most reliable and effective method of reducing pain during labor. However, it is encumbered by small but real and predictable risks.

Neuraxial Analgesia

Assessment of all laboring women for risk factors for neuraxial analgesia and general anesthesia is recommended Sufficient time should be available for adequate, safe evaluation and discussion with the patient.In otherwise healthy women, routine laboratory testing is not required.

Neuraxial Analgesia

Although any laboring woman has the potential to require cesarean section, labor takes many hours and requires adequate nutrition and hydration. ASA has recommended that moderate amounts of clear liquids be allowed during the administration of neuraxial analgesia and throughout labor A period of abstention from solids before the placement of neuraxial analgesia is not required.

Neuraxial Analgesia

Timing of placementCurrent ASA guidelines note that maternal request for labor pain relief is sufficient justification for intervention and the decision should not depend on an arbitrary cervical dilation.

Epidural Analgesia

Epidural analgesia is most commonly initiated after placement of a catheter into the epidural space between L2-3 and L4-5

Epidural Analgesia

IV fluidsMonitoringCTGPositioning

Epidural Analgesia

The “test dose” tests for inadvertent intravascular or intrathecal placement of the catheter. Choice of local anesthetic drugs

BupivacaineRopivacaineAdjuvants – opioids

Epidural Analgesia

Very dilute local anesthetic mixtures (0.0625%) generally do not produce motor blockade and may allow some patients to ambulate (“walking” or “mobile” epidural)

Epidural Analgesia

The long duration of action of bupivacaine makes it a popular agent for labor. Ropivacaine may be preferable because of its reduced potential for cardiotoxicity

Epidural Analgesia

Patient-controlled epidural analgesia (PCEA)

Total drug requirements may be less Patient satisfaction is greater with PCEA compared with other epidural techniques.

PCEA settings are typically a 5-mL bolus dose with a 5–10 min lockout and 0–12 mL/h basal rate; a 1-h limit of 15–25 mL may used.

Complications

HypotensionUnintentional intravascular injection Unintentional intrathecal injection Post-dural puncture headache (PDPH) Epidural abscess/hematomaNeurological deficits (rare)

Other techniques

Combined Spinal & Epidural (CSE) Analgesia Spinal anesthesia

Saddle block

OTHER REGIONAL NERVE BLOCKS

Paracervical blockLA is injected lateral to the cervix at 4 o’clock and 10 o’clock, taking care to avoid vascular structures.

Paracervical blockThe paracervical block is effective to relieve pain of cervical dilation but does not affect cramping pain from contraction of the uterine corpus. However, paracervical block does reduce pain in the second stage of labor.

Pudendal nerve blockThe pudendal nerve is derived from sacral nerve roots and can be blocked with local anesthetic using a transvaginal or transperineal approach to treat pain during the second stage of labor and for episiotomy repair.

Anesthesia for Operative Delivery

Low-dose epidural analgesia can be inadequate for assisted vaginal delivery with forceps or vacuum.

A higher concentration local anesthetic can be administered through an indwelling epidural catheter or a “second-stage spinal” can provide excellent perineal analgesia.

Anesthesia for Operative Delivery

Supplementation of an indwelling epidural catheter with 5 to 10 mL of 1% to 2% lidocaine or 2% to 3% 2-chloroprocaine is usually adequate, depending on whether vacuum or forceps are being used. Pudendal nerve block also can be considered for operative delivery.

Conclusions

Individualize technique to patient’s goals and stage of labor

Optimize management for spontaneous delivery

Provide safe, cost-effective analgesia

discussion

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Labor analgesia

Education