Presentation on theme: "NON-NEURAXIAL TECHNIQUES FOR LABOR ANALGESIA"— Presentation transcript:
1NON-NEURAXIAL TECHNIQUES FOR LABOR ANALGESIA Moderator: Dr. Girish SharmaPresented By: Dr. Arvind Sethi
2INTRODUCTIONlabor 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.
3The Physiology of Pain in Labor 1st stage of labor – mostly visceralDilation of the cervix and distention of the lower uterine segmentDull, aching and poorly localizedSlow conducting, visceral C fibers, enter spinal cord at T10 to L12nd stage of labor – mostly somaticDistention of the pelvic floor, vagina and perineumSharp, severe and well localizedRapidly conducting A-delta fibers, enter spinal cord at S2 to S4T10L1S2S4
5NON-NEURAXIAL LABOR ANALGESIA Pharmacological Non-PharmacologicalSystemic analgesiaParenteralInhalationalTechniques' alternative toregional anesthesiaParacervical blockPudendal blockMinimal Training/EquipmentContinuous labor supportTouch and massageTherapeutic use of heat and coldHydrotherapyVertical positionSpecialized Training/EquipmentIntradermal water injectionsTranscutaneous Electrical Nerve StimulationAcupuncture/AcupressureHypnosis
6Parenteral 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 preferenceEfficacy and incidence of side effects are largely dose dependent rather than drug dependent
7Analgesia (contd)Although narcotics provide both analgesia & sedation, their S.E are:Maternal: Orthostatic hypotension, nausea, vomiting ,delayed gastric emptying,dysphoria,drowsiness,hypoventilation.Fetal: ↓ beat-to-beat variability of FHR.Neonatal: respiratory depression , neurobehavioral changes.
8Systemic opioids for labor analgesia DRUGUsual doseOnsetDurationCommentsMeperidine25-50mg IV50-100mg IM5-10min IV40-45min IM2-3 hrsMax. neonatal depression 1-4 hrs after the doseMorphine2-5mg IV5-10mg IM3-5min IV20-40min IM3-4 hrsMore neonatal depression than meperidineDiamorphine5-7.5mg IV/IM5-10min IM90 minMore euphoria, less nausea than morphineFentanyl25-50ùg IV100úg IM2-3min IV10min IM30-60minLess neonatal depresion than with meperidine
9Systemic analgesia contd. Nalbuphine10-20mg IV/IM2-3 min IV/IM3-6 hrsLower neonatal neurobehavioral scoresButorphanol1-2mg IV/IM5-10min IV10-30min IM3-4hrsCeiling effect on respiratory depressionMeptazinol100mg IM15 minIM2-3 hrsLess sedation & respiratory depressionPentazocine20-40 mg IV/IM2-3min IV5-20min IM/SCPsychomimetic effects possibleTramadol50-100mg IV/IM10 min IVLess efficacy & more side effects than meperidine
10Intermittent Bolus Parenteral opioid Analgesia Given intermitently via s.c ,i.m, i.v route(preferred)Faster onset of analgesiaAbility to titrate dose to effect
11MEPERIDINE Most commonly used opioid for labor analgesia 100 mg i.m repeated once after 4 hrsOnset ;45 minReadily crosses placenta by passive diffusion & equilibrates b/w maternal and fetal compartments in 6 minutesFetal 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 morphineMetabolised 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)
12Meperidine 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 dystociaSosa et al. concluded that meperidine does not benefit women & should not be used in labor with dystocia because of adverse neonatal outcome
13MORPHINE Currently morphine is infrequently prescribed in labor Significant analgesic but respiratory depressantRapidly 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 adultsCrosses BBB more in fetusGreater plasma clearance, shorter elimination half life, earlier peak metabolite levels occur due to changes in pharmacokinetics during pregnancy
14Diamorphine A synthetic derivative of morphine Rapid, effective analgesia with less nausea & vomiting but more euphoria than morphineCrosses placenta & associated with respiratory depression
15FENTANYL Synthetic opioid with analgesic potency 100 times that of morphine800 times that of meperidineRapid onset, short duration of action, lack of active metabolite make it attractive for labor analgesiaAverage umbilical –to-maternal conc. ratio remains low at 0.31The researchers found less sedation, vomiting,no adverse effect on APGAR score or fetal acid-base status
16NALBUPHINE Mixed agonist-antagonist opioid analgesic Potency and respiratory depression are similar with morphine at equianalgesic doseCeiling effect on respiratory depression with increasing dose(max. with 30mg dose)Mean umbilical vein-t0-maternal conc. ratio is higher with nalbuphine than with meperidineless nausea, vomiting but more maternal sedation than meperidine
17BUT0RPHANOL opioid with agonist-antagonist properties 5 times as potent as morphine & 40 times as potent as meperidineRespiratory depression withbutorphanol , 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.
18Butorphanol(cont.)Butorphanol offers analgesia with some sedation( similar to meperidine+ phenothiazine)Shorter half life and inactive metabolite.Favorable neonatal neurobehavioral outcomeA USEFUL AGENT FOR LABOR ANALGESIA
19MEPTAZINOLPartial opioid agonist with less sedation, resp. depression, dependenceNeonatal half life =3.4 hrsHigher APGAR score at 1minLimitations; Higher Cost & Availability
20PENTAZOCINE Synthetic opioid , both agonist and weak antagonist 30-60mg equipotent as 10mg morphineCeiling effect on respiratory depression occurs at mgLimitation ;Psycho mimetic effect at higher doses
21TRAMADOL Atypical, weak synthetic opioid Potency 10% that of morphine No respiratory depressionMore nauseaAnalgesia not superior to meperidine
22PROGRAMMED LABOR (Modern management of labor) Criteria for selection of casesGestational age of weeksCervical dilatation ≥ 4cmCervical status: bishop score >6Engaged head & adequate pelvisNo pregnancy induced complication like APH or medical disorders like Heart disease, DM, HTN, Jaundice.
23Programmed 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 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
24Active 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
25PATIENT CONTROLLED ANESTHESIA Patient-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 ares.c., oral,transmucosal,nasal,intrathecal,epidural,transdermal
26PCA has several modes of administration. Most common ;demand dosing (a fixed-size dose is self-administered intermittently)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) .
27Advantages of PCA Superior pain relief with lower doses of drug Less risk of maternal respiratory depressionLess placental transfer of drugLess need for anti-emetic agentsHigher patient satisfaction
28LimitationsDespite frequent administration, small doses of opioid may not be effective for fluctuating intensity of labor painRisk to fetus & neonate remains unclearVariable doses & lockout intervals have been usedMost appropriate drug, dose ,dosing schedule have not been defined
29opioid USED FOR PCA DRUG Patient Controlled Dose Lockout interval Meperidine10-15mg8-20minNalbuphine1-3mg6-10minFentanyl10-25úg5-12minRemifentanil(bolus)(background infusion with bolus dose)úg/kgInfusion rate0.05úg/kg/minBolus;0.25úg/kg2-3min
30INHALATIONAL ANALGESIA PRINCIPLEAn attractive option since pregnancy causesdecreased FRCincreased minute ventilationRapid equilibration b/w inspired and alveolar conc.of inhaled agentFeatures of inhalational agent that make it suitable for labor analgesia are related to1) Nature of labor pain: pain is felt sec. after onset of uterine contraction & lasts for 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
31INHALATIONAL 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.
34Instruct pt. to inhale deep in b/w the contraction Inhale 30 sec. before the next anticipated contraction & cease with receding of contractionIn 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 reliefIV line, pulse oximetryMethoxyflourane, Enflurane,Isoflurane do not have any adv. over nitrous oxide
35SEVOFLURANE MOST COMMONLY USED VOLATILE HALOGENATED AGENT 0.8% sevoflurane is optimal conc. for labor analgesiaInvestigators concluded that sevoflurane can provide useful analgesia for labor & is superior to EntonoxInitial studies of intermittent sevoflurane are promising , but larger studies are needed to assess the incidence of maternal compromise
37PARACERVICAL BLOCKProvides satisfactory pain relief during first stageGoal: to block paracervical(Frankenhauser’s) ganglion which is immediately lateral & posterior to cervicouterine junctionDoes not adversely affects laborprovides good analgesia in first stage without the annoying sensory & motor blockadeDoes not relieve pain during late first stage& second stage of labor
38Technique:Patient in modified lithotomy position(pillow below pt.’s right buttock to correct dextrorotation of uterusUse a needle guide to define & limit the depth of injection & to reduce the risk of vaginal & fetal injuryIntroduce 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 2-3mm5-10 ml of local anesthetic(without epinephrine) is injected on each side
40Maternal complications Vasovagal syncopeLacerations of vaginal mucosaSystemic local anesthetic toxicityParametrial hematomaPostpartum neuropathyParacervical or subgluteal abscess
41Fetal Complications1)Fetal injury from direct injection of LA into fetal scalp(advanced labor>8cm) leading to systemic toxicity2)Fetal Bradycardia in 15% cases because ofdrug induced uterine artery vasoconsriction,CNS depression. myocardial depressiondecreased placental perfusion because of uterine hypertonia as a result of post paracervical block causing increase in uterine activityManipulation of fetal head,uterus,uterine vessels produce reflex bradycardia
42PUDENDAL BLOCKGoal 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 applicationAdministered shortly before deliveryAnalgesia 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
43Technique Transvaginal—preffered Transperineal A tubular introducer is placed against vaginal mucosa just beneath the tip of ischial spineA 15cm ,22G needle is pushed through introducer 1-1.5cm beyond the introducer into the mucosa1ml of 1% lignocaine is injected into mucosa after aspirationSacrospinous ligament is infiltrated with 3ml of lignocaine3ml is injected into loose areolar tissue behind the sacrospinous ligamentneedle is withdrawn into introducer & moved to just above the ischial spine & rest of 10ml is injected into mucosa
45Pudendal block(cont.)within 3-4 min successful block is achieved(allows pinching of lower vagina & posterior labia without pain and loss of anal reflexCOMPLICATIONSIntravascular injectionHematoma from perforation of blood vesselsSecondary infection at the injection site which may spread to hip joint, gluteal muscles.
47Continuous Labor Support Patient’ sense of isolation adversely affects her perception of labor.A meta-analysis evaluated results from 16 studies that included more than 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.
48Warm compresses on localized areas of body Touch & MassageEffleurage, Counter pressure to alleviate back discomfort, light stroking, and merely a reassuring pat.Therapeutic use of heat & coldWarm compresses on localized areas of bodyIce packs on low back or perineum to decrease pain perception
49HydrotherapySimple shower or tub bath or a whirlpool or large tub specially equipped for pregnant women.Decreases anxiety and pain and increases uterine contraction efficiency
50Vertical 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.
51Intra-dermal Water Injections Intra-dermal water injections are used to treat lower back pain which is a common complaint during laborThe afferent nerve fibres that innervate the lower back, enter the spinal cord at T10 through L1 spinal segments.Technique: approx 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)
53the injections themselves are acutely painful for about 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 fetuscts
54Transcutaneous Electrical Nerve Stimulation (TENS) Involves transmission of low-voltage electrical current to surface electrodes placed over lower back in the region of T10-L1Reduces 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.
55Acupuncture/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.HypnosisLimitations;Ante partum training sessions are required.Trained hypnotherapist must be available during laborOffers no clear benefit
56Childbirth 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.