Presentation on theme: "Regional Analgesia and Anesthesia for Labor and Delivery"— Presentation transcript:
1Regional Analgesia and Anesthesia for Labor and Delivery Marwa A. KhairyAssistant Lecturer of AnesthesiologyAin Shams UniversityOne of the important topic in obstetric anesthesia is the regional anesthesia
2Objectives Describe the pain pathways of labor and delivery Describe labor analgesic techniquesDescribe anaesthesia for caesarean deliveryDescribe the complications of regional techniquesBy the end of this lecture we should able to
4“If we could induce local anaesthesia without the absence of consciousness, which occurs in general anaesthesia, many would see it as a still greater improvement.”Sir James Young after the first maternal death due to anaesthesia in England 1848Scottish doctor and an important figure in the history of medicine. Simpson discovered the anaesthetic properties of chloroform and successfully introduced it for general medical use Simpson first used his anesthetic to help ease the pain during childbirth. Some may have opposed this practice, interpreting it as an act against nature or the will of God. However, A. D. Farr's study has shown that this was a distinctly minority view. Wider acceptance of Simpson's efforts came when Queen Victoria used chloroform during the delivery of Prince Leopold in The anaesthetist was John Snow.
5Dr. John Snowborn 15 March 1813 in York, England.Queen Victoria was given chloroform by John Snow for the birth of her eighth child and this did much to popularize the use of pain relief in labor.
6Regional anesthetic techniques, were introduced to obstetrics in 1900, when Oskar Kreis described the use of spinal anesthesia.Unfortunately he was an obstetrtian
8Analgesia for Labor and Delivery Always controversial!“Birth is a natural process”Women should suffer!!Concerns for mother’s safetyConcerns for babyConcerns for effects on labor
9Labor Pain at different Stages of Labor Eltzschig, Leiberman, Camann, NEJM 348; 319:2003
10The 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 S4
13Potential effects of maternal hyperventilation and subsequent hypocarbia on oxygen delivery to the fetusIt initiates hyperventilation leading to maternal hypocarbia, respiratory alkalosis and subsequent compensatory metabolic acidosis. The oxygen dissociation curve is shifted to the left and thus reduces tissue oxygen transfer, which is already compromised by the increased oxygen consumption associated with labor
14Influence of epidural analgesia on maternal plasma concentrations of catecholamines during labor. Modified from Shnider SM et al. Maternal catecholamines decrease during labor after lumbar epidural analgesia. Am J Obstet Gynecol 1983;147:13-5.
16Goals of Labour Analgesia Dramatically reduce pain of laborShould allow parturient to participate in birthing experienceMinimal motor block to allow ambulationMinimal effects on fetusMinimal effects on progress of labor
17Types of Labor Analgesia Non-pharmacological analgesiaPharmacologicalRegional Anesthesia/AnalgesiaNon-pharmacological methods The advantages of non-pharmacological techniques include their relative ease of administration and minimal side-effects; however, there is little evidence to support the efficacy of many of these techniques, and some may be costly and time consuming. A selection of non-pharmacological techniques are listed below: Transcutaneous electrical nerve stimulation (TENS); see below Relaxation/breathing techniques Temperature modulation: hot or cold packs, water immersion Hypnosis Massage Acupuncture Aromatherapy
19Epidural AnalgesiaProvides excellent pain relief reducing maternal catecholaminesAbility to extend the duration of block to match the duration of laborBlunts hemodynamic effects of uterine contractions: beneficial for patients with preeclampsia.
20Indications for LEA PAIN EXPERIENCED BY A WOMAN IN LABOR When medically beneficial to reduce the stress of laborACOG and ASA stated“ in the absence of a medical contraindication, maternal request is a sufficient medical indication for pain relief…”
21Contraindications for LEA ABSOLUTEPatients refusalInability to cooperateIncreased intracranial pressureInfectionSevere coagulopathySevere hypovolemiaInadequate trainingRELATIVESystemic maternal infectionPreexisting neurological deficiencyMild or isolated coagulation abnormalitiesRelative (and correctable) hypovolemia
22We are All Ready…Now What? - Last Check Obstetrician is consulted and confirmed LEAPreanesthetic evaluation is performed/verifiedPt’s (and only patient’s) desire to have LEA is reconfirmedPt’s understanding of risks of LEA is reconfirmed
23We are All Ready…Now What? - Last Check Fetal well-being is assessed and reassured
24We are All Ready…Now What? - Last Check Supporting personal is available and present
25We are All Ready…Now What? - Last Check Resuscitation equipment and drugs are immediately available in the area where LEA placed
26Standard Technique of LEA Pre epidural check list is completedAspiration prophylaxisIntravenous hydration (what? When? How?)MonitoringBP every 1 to 2 min for 20 min after injection of drugsContinuous maternal HR during induction ( e.g., pulse oximetry)Continuous FHR monitoringContinual verbal communication
27Standard Technique of LEA 4. Maternal position ( sitting or lateral?)
28Comparison of Sitting and Lateral Positions for Performing Spinal or Epidural Procedures Lying (left lateral)AdvantagesMidline easier to identify in obese women Obese patients may find this position more comfortableCan be left unattended without risk of fainting.No orthostatic hypotensionUteroplacental blood flow not reduced (particularly important in the stressed fetus)DisadvantagesUteroplacental blood flow decreasedOrthostatic hypotension may occurIncreased risk of orthostatic hypotension if Entonox and pethidine have been administeredAssistant (or partner) needed to support patientMay he more difficult to find the midline in obese patient
32Spinal Anesthesia/Analgesia Used mainly for very late in labor because it has limited duration of actionFaster onset than EpiduralAmount of local anesthetic used is much smaller
33Searching For Balanced Labor Analgesia Ambulatory Labor Analgesia (CSE)
34Combined spinal epidural (CSE) Initial reports: two interspace technique-epidural followed by spinalLater evolution of CSE in the direction of needle through needle techniquePostdural puncture headache: 1% or less incidence for CSE with small bore atraumatic needles.
35Advantages of CSE for Labor Analgesia Rapid onset of intense analgesia (the patient loves you immediately!)Ideal in late or rapidly progressing laborVery low failure rateLess need for supplemental bolusesMinimal motor block (“walking epidural”)
36Onset of Analgesia: CSE vs. Epidural Collis et al. Lancet 1995;345:1413
40Eldor needleCombined Spinal Epidural for Obstetric Anesthesia.flv
41Maintenance of epidural analgesia can be achieved by: regular top-ups an epidural infusionpatient-controlled epidural analgesia (PCEA).Regular top-ups:The volume and concentration need to be great enough to provide adequate analgesia, but large volumes may cause too great a spread of block, with attendant hypotension. Bupivacaine 0.25% given in 10 ml-boluses was standard practice until relatively recently but most units has been replaced by more dilute mixtures using 0.1% bupivacaine and 2 ugmL-' fentanyl in mL boluses. The lower concentration of local anaesthetic reduces the incidence of hypotension and increases the ability of the woman to mobilize. The disadvantage of boluses is the possibility of intermittent pain if top-ups are not administered at appropriate intervals and the legal requirement for two midwives to check and administer each top-up can cause problems on busy delivery suites.
43Continuous Infusion of Dilute Local Anesthetic Plus Opioid Better pain relief while producing less motor block.Maternal and neonatal drug concentrations safe.Regimen0.0625% % bupivacaine with 2-3 mcg /ml fentanyl, with or withoutepinephrine, infusing at ml/hour
44Patient Controlled Epidural Analgesia (PCEA) Advantages:Flexibility and benefit of self administrationAbility to minimize drug dosageReduced demand on professional timeDisadvantages:May provide uneven blockAddition of a basal infusion provides:More even block producing greater patient satisfaction
45Continuous Spinal Analgesia Use of spinal microcatheters restricted by FDA in 1992 due to reports of Cauda Equina Syndrome28 or 32-G catheters for 22 or 26-G spinal needlesOngoing multi-institutional study with FDA approval for evaluating the safety and efficacy of delivering sufentanil and/or bupivacaine via 28-G cathetersContinual spinal anesthesia has many potential advantages as compared to single shot spinal or continuous epidural techniques. While the classical technique required use of large bore epidural needles, a 32-gauge microcatheter inserted through a 26 gauge spinal needle was described in 1987 and subsequently removed from the market by the FDA. Since spinal microcatheters are not available for clinical use in the US, in order to perform a continuous spinal anesthetic, the anesthesiologist intentionally pierces the dura with an epidural needle and then threads the epidural catheter 3-4cm within the intrathecal space. Catheter placement can be tested by aspiration of CSF. Since a catheter is being used, smaller doses of local anesthetic can be given in an incremental fashion. This is particularly advantageous in the high risk parturient such as those with cardiac disease, respiratory disease, morbid obesity, and those with neuromuscular disease. In order to reduce the risk of headache following this technique the epidural needle should be turned so that it is parallel to the dural fibers at the time of insertion. In addition, to further reduce the risk of headache, it has been suggested that several steps be taken including leaving the epidural catheter in situ for more than 12 hours and injecting a bolus of preservative-free normal saline prior to removal of the catheter (22).
46Continuous Spinal Analgesia Results still preliminary but it appears safe for labor analgesia and may offer some advantagesSome routinely use spinal macrocatheters through standard epidural needles for obese parturients or parturients with kyphoscoliosis
49Bupivacaine Standard local anaesthetic in obstetrics Highly protein bound to α1-glycoprotein and has a long duration of action, both of which minimize the fetal dose.The maximum safe dose of bupivacaine is 3 mg/kg.
50LevobupivacaineBinds to cardiac sodium channels less intensely than dextrobupivacaine,Less cardiotoxicity than bupivacaine.
51Ropivacaine Is a propyl homologue of bupivacaine Cleared more rapidly after IV injection than bupivacaine40% less potent, equipotent doses (0.0625% bupivacaine≈0.1% ropivacaine), therefore, probably no advantage in terms of toxicity
52LidocaineMay not provide analgesia comparable to bupivacaine, umbilical vein/ maternal vein ratio: twice than bupivacaine
53Neuraxial Opioids The following opioids have been used: Morphine, fentanyl, sufentanil, meperidine, diamorphine.
56Anesthesia for Cesarean Section The choice of anesthesia depend on:The indication for the CSThe urgency of the procedureThe medical condition of the mother and the fetusThe desire of the mother
57Anesthesia for Cesarean Section GA associated with higher risk of airway problems .Incidence of failed tracheal intubation in pregnant women is 1 in 200 to 1 in 300 casesAnesthesia2000;55:690-4Maternal death due to anesthesia is the sixth leading cause of pregnancy related death in USAObstet Gynecol 1996;88:161-7
58Anesthesia for Cesarean Section The risk of maternal death from complications of GA is 17 times as high as that associated with Regional anesthesiaIn USA the shift from GA to RA for CS resulted in decrease in anesthesia related maternal mortality from 4.3 to 1.7 per 1 million live birth Anesthsiology 1997;86:277-84
59Epidural anesthesia Advantage Disadvantage Titration (volume dependent, not gravity dependent), decreased likelihood of hypotensionIncremental dose (for longer operation)DisadvantageDural puncture :1/200-1/500 in experienced hands, higher in training institutionIf unintentional dural puncture, PDPH incidence is 50-85%Slower onset
60Spinal anaesthesiaHyperbaric bupivacaine 0.5% is the drug most commonly used for spinal anaesthesia for Caesarean section.Pregnant patients require a smaller dose than the nonpregnant population (why?)The dose used via a standard lumbar approach is typically 2.0–2.75 ml.no significant correlation between age, height, weight, body mass index and length of vertebral column and the final block height achievedAnesthesiology1990; 72: 478–482.
61Combined spinal epidural(CSE) Combines the rapid onset and efficacy of the spinal technique with the ability to:Extend anaesthesia if surgery is prolongedProvide excellent postoperative epidural analgesia.Combined Spinal Epidural for Obstetric Anesthesia.flv
64Complications of regional anesthesia Post Dural Puncture Headache (PDPH)severe, disabling fronto-occipital headache with radiation to the neck and shoulders.present 12 hours or more after the dural punctureworsens on sitting and standingrelieved by lying down and abdominal compression.
66Complications of regional anesthesia Differential diagnosis of post-dural punctureheadache in the obstetric patient:1. Non-specific headache2. Caffeine-withdrawal headache3. Migraine4. Meningitis5. Sinus headache6. Pre-eclampsia7. Drugs (amphetamine, cocaine)8. Pneumocephalus-related headache9. Intracranial pathology (hemorrhage, venous thrombosis)
67Complications of regional anesthesia Management of PDPHConservative:Bed restEncourage oral fluids and/or intravenous hydrationCaffeine - either i.v. (e.g. 500mg caffeine in 1litre of saline) or orallyRegular AnalgesiaReassurance
69Complications of regional anesthesia The new method of prevention of post-dura puncture headache (maintaining CSF volume):1. Injecting the CSF in the glass syringe back into thesubarachnoid space through the epidural needle2. Passing the epidural catheter through the dural holeinto the subarachnoid space3. Injecting of 3-5 ml of preservative free saline into thesubarachnoid space through the intrathecal catheter4. Administering bolus and then continuous intrathecallabor analgesia through the intrathecal catheter5. Leaving the subarachnoid catheter in-situ for a totalof h
70Complications of regional anesthesia Cardiovascular complicationsHypotension (can lead to cord ischaemia)BradycardiaEffects on the course of labour and on the fetus
71Effect of epidural analgesia on the progress and outcome of labour The recently published guidelines on intrapartum care by the UK national institute of health and clinical excellence indicate that epidural analgesia is:Not associated with a longer first stage of labour or an increased chance of a caesarean birthAssociated with a longer second stage of labour and an increased chance of an instrumental birth.
72Effect of epidural analgesia on the progress and outcome of labour The most important factors determining labour outcome are:Low concentrations of local anaestheticsOxytocinMaternal pushing in the second stage of labour should, if possible be delayed!
73Complications of regional anesthesia Neurological complicationsNeedle damage to spinal cord, cauda equina or nerve roots.Spinal haematomaSpinal abscessMeningitis and ArachnoiditisNeurotoxicity
74Complications of regional anesthesia MiscellaneousVenous puncture e.g. of dural veinsCatheter breakageExtensive block (including unplanned blocks)ShiveringBackache - Long-term backache is not a complication of neuraxial techniques although there will always be some local bruising.
75Complications of regional anesthesia Drug side effectsNausea and vomiting (opiates)Respiratory depression (opiates)AnaphylaxisToxicity (including intravascular injection of local anaesthetics)
76Toxicity of local anaesthetics: Causes:An overdose of local anaesthetic is given,Large dose of local anaesthetic is inadvertently given intravenously.The recommended protocol is• Take a 500 ml bag of intralipid 20% and immediately give a 100 ml bolus over 1 minute
77Toxicity of local anaesthetics • Infuse at a rate of 400 ml over 20 minutes• Give two further boluses of 100 ml at 5-minute intervals if Circulation is not restored• Continue infusion at a rate of 400 ml over 10 minutes until stable circulation is restored.Airway, ventilatory and cardiovascular support should be maintained via standard protocols. It may be >1 hour before recovery
79Conclusion“The delivery of the infant into the arms of a conscious and pain-free mother is one of the most exciting and rewarding moments in medicine.”Moir DD. Extradural analgesia for caesarean section. Br J Anaesth 1979; 51: 1093.