NON-NEURAXIAL TECHNIQUES FOR LABOR ANALGESIAModerator: Dr. Girish

SharmaPresented By: Dr. Arvind Sethi

INTRODUCTION

labor pain is one of the most intense pain a women can experience.Efforts have been taken for centuries to remove the labor pain, but it has never been easy in the past as it is in the present. While neuraxial analgesia is the gold standard for achieving complete analgesia in labor, many women do not desire such high-tech pain relief. Many women want to ‘Cope with pain of labor ‘ rather than anhilate the pain completely. For many of these women non-neuraxial techniques will suffice.

The Physiology of Pain in Labor

1st stage of labor – mostly visceral Dilation of the cervix and

distention of the lower uterine segment

Dull, aching and poorly localized Slow conducting, visceral C fibers,

enter spinal cord at T10 to L1 2nd stage of labor – mostly somatic

Distention of the pelvic floor, vagina and perineum

Sharp, severe and well localized Rapidly conducting A-delta fibers,

enter spinal cord at S2 to S4

T10

L1S2S4

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The Intensity of Pain in Labor

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NON-NEURAXIAL LABOR ANALGESIA

Pharmacological Non-Pharmacological

Systemic analgesia Parenteral InhalationalTechniques' alternative to regional anesthesia Paracervical block Pudendal block

Minimal Training/Equipment Continuous labor support Touch and massage Therapeutic use of heat and

cold Hydrotherapy Vertical position Specialized Training/Equipment Intradermal water injections Transcutaneous Electrical Nerve

Stimulation Acupuncture/Acupressure Hypnosis

Parenteral opioid analgesia opioid are the most widely used systemic

medications for labor analgesia. Their use does not require specialised equipment

or personnel. Allows the parturient to better tolerate the pain of

labor. Little scientific evidence suggests that one drug is

better than other. Selection of an opioid is based on institutional

tradition/personnel preference Efficacy and incidence of side effects are largely

dose dependent rather than drug dependent

Analgesia (contd)

Although narcotics provide both analgesia & sedation, their S.E are:

1. Maternal: Orthostatic hypotension, nausea, vomiting ,delayed gastric emptying,dysphoria,drowsiness,hypoventilation.

2. Fetal: ↓ beat-to-beat variability of FHR.

3. Neonatal: respiratory depression , neurobehavioral changes.

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Systemic opioids for labor analgesia DRUG Usual

dose Onset

DurationComments

Meperidine

25-50mg IV50-100mg IM

5-10min IV40-45min IM

2-3 hrsMax. neonatal depression 1-4 hrs after the dose

Morphine 2-5mg IV5-10mg IM

3-5min IV20-40min IM

3-4 hrs More neonatal depression than meperidine

Diamorphine

5-7.5mg IV/IM

5-10min IM 90 min More euphoria, less nausea than morphine

Fentanyl 25-50ùg IV100úg IM

2-3min IV10min IM

30-60min Less neonatal depresion than with meperidine

Systemic analgesia contd.Nalbuphine

10-20mg IV/IM

2-3 min IV/IM

3-6 hrs Lower neonatal neurobehavioral scores

Butorphanol

1-2mg IV/IM

5-10min IV10-30min IM

3-4hrs Ceiling effect on respiratory depression

Meptazinol

100mg IM 15 minIM 2-3 hrs Less sedation & respiratory depression

Pentazocine

20-40 mg IV/IM

2-3min IV5-20min IM/SC

2-3 hrs Psychomimetic effects possible

Tramadol 50-100mg IV/IM

10 min IV 2-3 hrs Less efficacy & more side effects than meperidine

Intermittent Bolus Parenteral opioid Analgesia

Given intermitently via s.c ,i.m, i.v route(preferred)

Faster onset of analgesia Ability to titrate dose to effect

MEPERIDINE Most commonly used opioid for labor analgesia 100 mg i.m repeated once after 4 hrs Onset ;45 min Readily crosses placenta by passive diffusion &

equilibrates b/w maternal and fetal compartments in 6 minutes

Fetal exposure to meperidine is highest b/w 2-3 hrs after maternal administration(more respiratory depression in neonates born within 2-3 hrs)

Causes less respiratory depression in neonate than morphine

Metabolised in liver to normeperidine which crosses the placenta & is also formed as a result of fetal and neonatal metabolism( half life = 60 hrs in neonate)

Meperidine contd.

Effect on progress of labor is contentious

Some obstetricians say that it may prolong the latent phase of labor, others administer it to shorten the length of first stage in cases of dystocia

Sosa et al. concluded that meperidine does not benefit women & should not be used in labor with dystocia because of adverse neonatal outcome

MORPHINE Currently morphine is infrequently prescribed in

labor Significant analgesic but respiratory depressant Rapidly crosses the placenta and a fetal to

maternal plasma conc. ratio of .96 is observed at 5 min.

Elimination half life is longer in neonates than in adults

Crosses BBB more in fetus Greater plasma clearance, shorter elimination

half life, earlier peak metabolite levels occur due to changes in pharmacokinetics during pregnancy

Diamorphine A synthetic derivative of morphine Rapid, effective analgesia with less

nausea & vomiting but more euphoria than morphine

Crosses placenta & associated with respiratory depression

FENTANYL Synthetic opioid with analgesic potency 100 times that of

morphine 800 times that of

meperidine Rapid onset, short duration of action, lack

of active metabolite make it attractive for labor analgesia

Average umbilical –to-maternal conc. ratio remains low at 0.31

The researchers found less sedation, vomiting,no adverse effect on APGAR score or fetal acid-base status

NALBUPHINE Mixed agonist-antagonist opioid analgesic Potency and respiratory depression are

similar with morphine at equianalgesic dose

Ceiling effect on respiratory depression with increasing dose(max. with 30mg dose)

Mean umbilical vein-t0-maternal conc. ratio is higher with nalbuphine than with meperidine

less nausea, vomiting but more maternal sedation than meperidine

BUT0RPHANOL opioid with agonist-antagonist properties 5 times as potent as morphine & 40

times as potent as meperidine Respiratory depression with butorphanol , morphine,meperidine (2mg) = (10mg) (70mg) (4mg) < (20mg) (140mg) Butorphanol(1-2mg) when compared with

meperidine(40-80mg) for labor analgesia , it has less maternal side effects, better analgesia at 30min and 1 hour with no difference in APGAR score.

Butorphanol(cont.)

Butorphanol offers analgesia with some sedation( similar to meperidine+ phenothiazine)

Shorter half life and inactive metabolite.

Favorable neonatal neurobehavioral outcome

A USEFUL AGENT FOR LABOR ANALGESIA

MEPTAZINOL Partial opioid agonist with less sedation,

resp. depression, dependence Neonatal half life =3.4 hrs Higher APGAR score at 1min Limitations; Higher Cost & Availability

PENTAZOCINE Synthetic opioid , both agonist and weak

antagonist 30-60mg equipotent as 10mg morphine Ceiling effect on respiratory depression

occurs at 40-60mg Limitation ;Psycho mimetic effect at

higher doses

TRAMADOL Atypical, weak synthetic opioid Potency 10% that of morphine No respiratory depression More nausea Analgesia not superior to meperidine

PROGRAMMED LABOR(Modern management of labor)Criteria for selection of casesGestational age of 37- 42 weeksCervical dilatation ≥ 4cmCervical status: bishop score >6Engaged head & adequate pelvis No pregnancy induced complication

like APH or medical disorders like Heart disease, DM, HTN, Jaundice.

Programmed labor(contd.) Labor is programmed in the following wayWhen the case is in active phase i.e. os ≥

4cm1) LR (500ml) with 2.5U oxytocin started such that

contractions ≥3 per 10min lasting for 20-40 sec.2) ARM done.3) 2mg of diazepam (1ml) & 6mg of

pentazocine(2ml) diluted with 7ml of normal saline, so that total solution is 10ml. Total 2ml of the solution is given slow iv. Remaining 8ml added to iv fluid post-partum during repair of tear or episiotomy.

4) Inj. drotaverine & tramadol given i.v. and repeated as required.

5) Partographic management of labor is done

Active management of labor with oxytocin, amniotomy and spasmolytic and labor analgesia with tramadol,diazepam & pentazocine is safe, convenient and acceptable.

Marked labor analgesia. There is marked reduction of the total

duration of labor. Marked in LSCS rate. Minimum side effects on mother. No effect on of apgar score of fetus

PATIENT CONTROLLED ANESTHESIAPatient-controlled analgesia (PCA) is commonly

assumed to imply on-demand, intermittent, IV administration of opioid under patient control (with or without a continuous background infusion). This technique is based on the use of a sophisticated microprocessor-controlled infusion pump that delivers a pre-programmed dose of opioid when the patient pushes a demand buttonBesides i.v., alternative routes for PCA delivery are s.c., oral,transmucosal,nasal,intrathecal,epidural,transdermal

PCA has several modes of administration. Most common ;1) demand dosing (a fixed-size dose is self-administered

intermittently) 2) continuous infusion plus demand dosing (a constant-

rate fixed background infusion is supplemented by patient demand dosing)

All modern PCA devices offer both modes. Less common1)Infusion demand ( successful demands are administered as an infusion)2) preprogrammed variable-rate infusion plus demand dosing ( the infusion rate is preprogrammed on an interval clock to vary or turn off altogether by time of day) 3) variable-rate feedback infusion plus demand dosing (microprocessor monitors demands and controls the infusion rate accordingly) .

Advantages of PCA

Superior pain relief with lower doses of drug

Less risk of maternal respiratory depression

Less placental transfer of drug Less need for anti-emetic agents Higher patient satisfaction

Limitations

Despite frequent administration, small doses of opioid may not be effective for fluctuating intensity of labor pain

Risk to fetus & neonate remains unclear

Variable doses & lockout intervals have been used

Most appropriate drug, dose ,dosing schedule have not been defined

opioid USED FOR PCA DRUG Patient

Controlled Dose

Lockout interval

Meperidine 10-15mg 8-20min

Nalbuphine 1-3mg 6-10min

Fentanyl 10-25úg 5-12min

Remifentanil (bolus)(background infusion with bolus dose)

0.4-0.5úg/kgInfusion rate0.05úg/kg/minBolus;0.25úg/kg

2-3min

INHALATIONAL ANALGESIAPRINCIPLE An attractive option since pregnancy causes decreased FRC increased minute ventilation Rapid equilibration b/w inspired and alveolar

conc.of inhaled agent Features of inhalational agent that make it suitable

for labor analgesia are related to 1) Nature of labor pain: pain is felt 10-20 sec. after

onset of uterine contraction & lasts for 40-60 sec. 2) Blood gas solubility: low inhalation at onset of

contraction results in analgesic blood levels which rapidly falls out at the end of contraction

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INHALATIONAL ANALGESIA

ENTONOX: NITROUS OXIDE(50%)+ OXYGEN(50%) Provides partial pain relief during labor as well as at

delivery. 50% N2O in O2.(Pre-mixed in a blender)Poynting

effect involves dissolution of gaseous O2 bubbled through liquid N2O with vaporization of liquid to form gaseous mixture.

It’s administered with a mask / mouthpiece in a manner such that the parturient remains awake, cooperative & in control of her airway to prevent pulmonary aspiration of gastric contents.

Does not prolong labor or interfere with uterine contractions but administration > 20 minutes may result in neonatal depression.

Dec. risk of neonatal depression when compared with narcotics.

Instruct pt. to inhale deep in b/w the contraction Inhale 30 sec. before the next anticipated

contraction & cease with receding of contraction In b/w mask may be removed which is held by

pt. Inform that total relief of pain will not occur but

gas will provide some relief IV line, pulse oximetry Methoxyflourane, Enflurane,Isoflurane do not

have any adv. over nitrous oxide

SEVOFLURANE MOST COMMONLY USED VOLATILE

HALOGENATED AGENT 0.8% sevoflurane is optimal conc. for

labor analgesia Investigators concluded that sevoflurane

can provide useful analgesia for labor & is superior to Entonox

Initial studies of intermittent sevoflurane are promising , but larger studies are needed to assess the incidence of maternal compromise

Drawover oxford Miniature vapouriser

PARACERVICAL BLOCK Provides satisfactory pain relief during

first stage Goal: to block

paracervical(Frankenhauser’s) ganglion which is immediately lateral & posterior to cervicouterine junction

Does not adversely affects labor provides good analgesia in first stage

without the annoying sensory & motor blockade

Does not relieve pain during late first stage& second stage of labor

Technique: Patient in modified lithotomy position(pillow below

pt.’s right buttock to correct dextrorotation of uterus

Use a needle guide to define & limit the depth of injection & to reduce the risk of vaginal & fetal injury

Introduce needle & needle guide into left/right lateral vaginal fornix at 4’0’ clock or 8’0’ clock position (with left hand for left and right hand for rt. side.

Needle is advanced through vaginal mucosa and to a depth of 2-3mm

5-10 ml of local anesthetic(without epinephrine) is injected on each side

Maternal complications Vasovagal syncope Lacerations of vaginal mucosa Systemic local anesthetic toxicity Parametrial hematoma Postpartum neuropathy Paracervical or subgluteal abscess

Fetal Complications1)Fetal injury from direct injection of LA into fetal

scalp(advanced labor>8cm) leading to systemic toxicity

2)Fetal Bradycardia in 15% cases because of drug induced uterine artery vasoconsriction,CNS

depression. myocardial depression decreased placental perfusion because of

uterine hypertonia as a result of post paracervical block causing increase in uterine activity

Manipulation of fetal head,uterus,uterine vessels produce reflex bradycardia

PUDENDAL BLOCK Goal is to block the pudendal nerve distal

to its formation by the ant. division of S2-S4 but proximal to its division into branches.

Provide satisfactory anesthesia for vaginal delivery & outlet forceps application

Administered shortly before delivery• Analgesia produced in lower birth canal &

perineum provides maternal comfort for low forceps delivery & episiotomy.

Advantages: easy to administer, not a/w maternal hypotension/ fetal distress.

Disadvantage: incomplete analgesia at the time of delivery, since pain of uterine contraction is unaffected

Technique Transvaginal—preffered Transperineal A tubular introducer is placed against vaginal mucosa just

beneath the tip of ischial spine A 15cm ,22G needle is pushed through introducer 1-

1.5cm beyond the introducer into the mucosa 1ml of 1% lignocaine is injected into mucosa after

aspiration Sacrospinous ligament is infiltrated with 3ml of lignocaine 3ml is injected into loose areolar tissue behind the

sacrospinous ligament needle is withdrawn into introducer & moved to just

above the ischial spine & rest of 10ml is injected into mucosa

Pudendal block(cont.) within 3-4 min successful block is

achieved(allows pinching of lower vagina & posterior labia without pain and loss of anal reflex

COMPLICATIONS Intravascular injection Hematoma from perforation of blood

vessels Secondary infection at the injection site

which may spread to hip joint, gluteal muscles.

NON-PHARMACOLOGIC ANALGESIA

Continuous Labor Support

Patient’ sense of isolation adversely affects her perception of labor.

A meta-analysis evaluated results from 16 studies that included more than 13000 women who were randomly assigned to receive either continuous labor support or usual care .Women who received one-on one support were less likely to use any type of analgesia & were more likely to have short labor, spontaneous vaginal delivery and were better satisfied.

Touch & Massage Effleurage, Counter pressure to alleviate

back discomfort, light stroking, and merely a reassuring pat.

Therapeutic use of heat & cold

Warm compresses on localized areas of body

Ice packs on low back or perineum to decrease pain perception

Hydrotherapy

Simple shower or tub bath or a whirlpool or large tub specially equipped for pregnant women.

Decreases anxiety and pain and increases uterine contraction efficiency

Vertical position

INCLUDE Sitting, Standing, Walking, Squatting women reported less pain in

vertical positions than in horizontal positions(supine,lateral)

Walking neither enhanced nor impaired active labor & was not harmful to mothers or their infants.

Intra-dermal Water Injections

Intra-dermal water injections are used to treat lower back pain which is a common complaint during labor

The afferent nerve fibres that innervate the lower back, enter the spinal cord at T10 through L1 spinal segments.

Technique: approx. 0.05-0.1 ml of sterile water is injected intradermally to form a small bleb over each posterior superior iliac spine on both sides & at 3cm below & 1cm medial to each spine(Four injections)

cts the injections themselves are acutely painful for about 20-30 seconds, but as the injection pain fades. so does the lower back pain.

A simple method of reducing severe low back pain without adverse effects on mother and fetus

Transcutaneous Electrical Nerve Stimulation (TENS) Involves transmission of low-voltage electrical

current to surface electrodes placed over lower back in the region of T10-L1

Reduces pain by nociceptive inhibition at a presynaptic level in dorsal horn by limiting central transmission.Electrical stimulation activates low-threshold myelinated nerves.

Afferent inhibition inhibit propogation of nociception along unmyelinated small “c” fibres by blocking impulses to target cells in substantia gelatinosa of the dorsal horn.

TENS also enhances release of endorphins and dynorphins centrally.

Acupuncture/Acupressure Four randomized control trials found that pain score

were lower in women randomized assigned to receive acupuncture treatment, as was the rate of use of other modes of analgesia. A shorter duration of the active phase of labor and a reduction in use of oxytocin in acupuncture group was observed.

Hypnosis Limitations; Ante partum training sessions are required. Trained hypnotherapist must be available during

labor Offers no clear benefit

Childbirth preparation classes and non-pharmacologic analgesic techniques are not comparable with regional analgesia techniques for relief of labor pains. So whether it is useful for anesthetist to have knowledge of these techniques? Our active participation in the childbirth education classes may help patients receive more accurate information about the risks and benefits of analgesia/anesthesia for labor, vaginal delivery. We can encourage instructors to prepare pt. for the unexpected as “Typical labor” may infact be atypical. Thus patients will perceive anesthetist as an integral part of obstetric team.

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