Obstetrical anesthesia

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  • It 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
  • Non-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
  • Unfortunately he was an obstetrtian
  • 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 Bupivacaine 0.25% given in 10 ml-boluses was standard practice until relatively recently but most units has been replaced by more dilute mixtures using 0.1% bupivacaine and 2 ugmL-' fentanyl in 10-15 mL boluses. The lower concentration of local anaesthetic reduces the incidence of hypotension and increases the abil i ty 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.
  • Obstetrical anesthesia

    1. 1. OBSTETRICAL ANESTHESIA
    2. 2. Dr. John Snow born 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. 9/3/2013 2BITEW(IESO)
    3. 3. Does Labor Pain Need Analgesia? 9/3/2013 3BITEW(IESO)
    4. 4. 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 9/3/2013 4BITEW(IESO)
    5. 5. Why have a Caregiver dedicated to pain management during labor and delivery? 9/3/2013 BITEW(IESO) 5
    6. 6. • Labor and delivery result in severe pain for most women. • In an attempt to quantify this pain, parturients were asked to rate their pain during labor. • These results were then compared to values obtained from patients in a general pain clinic and emergency department. • The pain of childbirth was greater than a fractured arm and cancer pain. • Only causalgia and amputation of a digit exceeded the pain of labor and delivery. • Parturients described the pain as sharp, cramping, aching, throbbing, stabbing, hot, shooting, and tight. 9/3/2013 BITEW(IESO) 6
    7. 7. What is the cause of labor pain in stage 1? What type of pain is it? • The pain resulting from the first stage of labor is primarily due to dilatation of the cervix with consequent distention and stretching. • As the uterus contracts, the fetal head pushes against the cervix and causes dilatation. • Therefore, stage 1 pain generally occurs only during uterine contraction. 9/3/2013 BITEW(IESO) 7
    8. 8. • While the majority of pain during this stage occurs from the fetal head pushing against the cervix, there is also pain from pressure and stretching of the uterine muscles, which activate the high-threshold mechanoreceptors. • In the first stage of labor, the pain is visceral. • It is strong and dull, and occurs over the lower abdomen between the umbilicus and the symphysis pubis, laterally over the iliac crest, and posteriorly in the skin and soft tissue over the lower lumbar spines. 9/3/2013 BITEW(IESO) 8
    9. 9. The location of labor pain in stage 1?? • The location of this pain is explained by the concept of referred pain. • The sensory nerves of the uterus and cervix leave the cervix and join the sympathetic nerves as they pass through the hypogastric plexus to the sympathetic chain, synapsing within the dorsal horn of the spinal cord at T10, T11, T12, and L1. 9/3/2013 BITEW(IESO) 9
    10. 10. • This area of the spinal cord receives not only these visceral high-threshold afferents, but also the low-threshold cutaneous afferents of the skin from T10, T11, T12, and L1. • With the convergence of both somatic and visceral fibers within the same area of the spinal cord, the parturient interprets the uterine pain as originating from the cutaneous afferents of these spinal segments. The pain is referred to this area. 9/3/2013 BITEW(IESO) 10
    11. 11. What is the cause of labor pain in stage 2? What type of pain is it? 9/3/2013 BITEW(IESO) 11
    12. 12. • Second-stage pain occurs as the fetus descends through the birth canal. • This results in stretching and tearing of fascia, skin, and subcutaneous tissue. • This somatic pain is transmitted primarily through the pudendal nerve. • The pudendal nerve is derived from the anterior primary divisions of sacral nerves, S2 S3 and S4. • Of note, the fetus often begins to descend during the first stage of labor. • During the transitional stage of the first stage, it is not uncommon for the mother to experience both visceral and somatic pain 9/3/2013 BITEW(IESO) 12
    13. 13. Labor Pain at different Stages of LaborLabor Pain at different Stages of Labor Eltzschig, Leiberman, Camann, NEJM 348; 319:2003Eltzschig, Leiberman, Camann, NEJM 348; 319:20039/3/2013 13BITEW(IESO)
    14. 14. The Physiology of Pain in Labor 11stst stage of laborstage 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 22ndnd stage of laborstage 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 9/3/2013 14BITEW(IESO)
    15. 15. Pain Pathways of LaborPain Pathways of Labor 9/3/2013 15BITEW(IESO)
    16. 16. LaborLabor CardiovascularCardiovascular UrinaryUrinary Neuro-endocrineNeuro-endocrine post-traumatic stress syndrome post-traumatic stress syndrome RespiratoryRespiratory Gastro-intestinalGastro-intestinal 9/3/2013 16BITEW(IESO)
    17. 17. Potential effects of maternal hyperventilation and subsequent hypocarbia on oxygen delivery to the fetus9/3/2013 17BITEW(IESO)
    18. 18. Pathways of labor painPathways of labor pain9/3/2013 18BITEW(IESO)
    19. 19. How do psychological factors influence labor pain? 9/3/2013 BITEW(IESO) 19
    20. 20. While labor is a physiologic process, psychological factors also affect the pain. Anxiety is a particularly powerful factor in reducing pain tolerance.HOW?? Attention, the selective orientation of the receptor system to one source or pattern of stimulation to the exclusion of other sources, either enhances or diminishes the painful experience.  Motivation is another psychodynamic mechanism that can have a marked influence on the physiologic, behavioral, and affective aspects of pain. Breathing exercises divert the mother's attention from the pain of contractions. 9/3/2013 BITEW(IESO) 20
    21. 21. Introduction Pain relief in labor presents unique problems. Labor begins without warning, and obstetrical anesthesia may be required within minutes of a full meal. Vomiting with aspiration of gastric contents is a constant threat that poses serious maternal morbidity and mortality.  Moreover, a host of disorders unique to pregnancy, such as preeclampsia, placental abruption, and chorioamnionitis, all superimposed on unique physiological adaptations of pregnancy, are directly affected by the choice of analgesia and anesthesia selected. 9/3/2013 21BITEW(IESO)
    22. 22. Introduction Anesthesia complications caused 1.6 percent of pregnancy-related maternal deaths Several factors likely have contributed to improved safety of obstetrical anesthesia; the recent trend toward increased use of regional analgesia, rather than general anesthesia, may be the most significant factor. The increased availability of in-house anesthesia coverage almost certainly is another important reason 9/3/2013 22BITEW(IESO)
    23. 23. GENERAL PRINCIPLES  a woman’s request for labor pain relief is sufficient medical indication for its provision.  it is the responsibility of the obstetrician or certified nurse-midwife, in consultation with an anesthesiologist, if appropriate, to formulate a suitable plan for pain relief.  Identification of any of the risk factors, should prompt consultation with anesthesia personnel to permit a joint management plan.  This plan should include strategies to minimize the need for emergency anesthesia in women for whom such anesthesia would be especially hazardous. 9/3/2013 23BITEW(IESO)
    24. 24. 9/3/2013 24BITEW(IESO)
    25. 25. Maternal Risk Factors That Should Prompt Anesthesia Consultation  Marked obesity  Severe edema or anatomical abnormalities of face, neck, or spine, including trauma or surgery  Abnormal dentition, small mandible, or difficulty opening mouth  Extremely short stature, short neck, or arthritis of the neck  Goiter  Serious maternal medical problems, such as cardiac, pulmonary, or neurological disease  Bleeding disorders  Severe preeclampsia  Previous history of anesthetic complications  Obstetrical complications likely to lead to operative delivery— e.g., placenta previa or higher-order multiple gestation9/3/2013 25BITEW(IESO)
    26. 26. Goals for optimizing obstetrical anesthesia services 1. Availability of a licensed practitioner who is credentialed to administer an appropriate anesthetic whenever necessary and to maintain support of vital functions in an obstetrical emergency. 2. Availability of anesthesia personnel to permit the start of a cesarean delivery within 30 minutes of the decision to perform the procedure. 3. Anesthesia personnel immediately available to perform an emergency cesarean delivery during the active labor of a woman attempting vaginal birth after cesarean (Candidates for a Trial of Labor). 4. Appointment of a qualified anesthesiologist to be responsible for all anesthetics administered. 5. Availability of a qualified physician with obstetrical privileges to perform operative vaginal or cesarean delivery during administration of anesthesia. 6. Availability of equipment, facilities, and support personnel equal to that provided in the surgical suite. 7. Immediate availability of personnel, other than the surgical team, to assume responsibility for resuscitation of the depressed newborn (see Chap. 28, Newborn Resuscitation). 9/3/2013 26BITEW(IESO)
    27. 27. Role of Obstetrician  Every obstetrician should be proficient in local and pudendal analgesia.  Regional analgesia may be administered by the properly trained obstetrician in appropriately selected circumstances.  In general, however, it is preferable for an anesthesiologist or anesthetist to provide this care so that the obstetrician can focus attention on the concerns for the laboring woman and her fetus.  General anesthesia should be administered only by those with special training. 9/3/2013 27BITEW(IESO)
    28. 28. Principles of Pain Relief the experience of labor pain is a highly individual reflection of variable stimuli that are uniquely received and interpreted by each woman individually. These stimuli are modified by emotional, motivational, cognitive, social, and cultural circumstances. The complexity and individuality of the experience suggest that a woman and her caregivers may have a limited ability to anticipate her pain experience prior to labor. Thus, choice among a variety of methods and individualization of pain relief is desirable. 9/3/2013 28BITEW(IESO)
    29. 29. Goals of Labour Analgesia • Dramatically reduce pain of labor • Should allow parturient to participate in birthing experience • Minimal motor block to allow ambulation • Minimal effects on fetus • Minimal effects on progress of labor 9/3/2013 29BITEW(IESO)
    30. 30. What Are the Types of Labor Analgesia? What analgesic options are available for labor? 9/3/2013 30BITEW(IESO)
    31. 31. Types of Labor Analgesia 1. Non-pharmacological analgesia 2. Pharmacological 3. Regional Anesthesia/Analgesia 4. General Anesthesia 9/3/2013 31BITEW(IESO)
    32. 32. NONPHARMACOLOGICAL METHODS OF PAIN CONTROL  Fear and the unknown potentiate pain.  Make a woman who is free from fear, and develop confidence in the obstetrical staff that cares for her  Avoid emotional tension  Lamaze  teaching pregnant women relaxed breathing and their labor partners psychological support techniques.  Motivatation  the presence of a supportive spouse 9/3/2013 32BITEW(IESO)
    33. 33. ANALGESIA AND SEDATION DURING LABOR 9/3/2013 33BITEW(IESO)
    34. 34. ANALGESIA AND SEDATION DURING LABOR • When uterine contractions and cervical dilatation cause discomfort, pain relief with a narcotic such as meperidine, plus one of the tranquilizer drugs such as promethazine, is usually appropriate. • With a successful program of analgesia and sedation, the mother should rest quietly between contractions. • In this circumstance, discomfort usually is felt at the acme of an effective uterine contraction, but the pain is generally not unbearable.9/3/2013 34BITEW(IESO)
    35. 35. Neuraxial Opioids The following opioids have been used: Morphine, fentanyl, sufentanil, meperidine, diamorphine. 9/3/2013 35BITEW(IESO)
    36. 36. Parenteral Agents for Labor Pain Agent Usual Dose Frequency Onset Neonatal Half- Life Meperidine 25–50 mg (IV) 1–2 hr 5 min 13–22.4 hr 50–100 mg (IM) 2–4 hr 30–45 min 63 hr for active metabolites Fentanyl 50–100 g (IV) 1 hr 1 min 5.3 hr Nalbuphine 10 mg (IV or IM) 3 hr 2–3 min (IV) 4.1 hr 15 min (IM) Butorphanol 1–2 mg (IV or IM) 4 hr 1–2 min (IV) Not known 10–30 min (IM) Similar to nalbuphine in adults Morphine 2–5 mg (IV) 4 hr 5 min 7.1 hr 10 mg (IM) 30–40 min9/3/2013 36BITEW(IESO)
    37. 37. 9/3/2013 BITEW(IESO) 37
    38. 38. NEW DRUGS: • Clonidine • Neostigmine • Midazolam 9/3/2013 38BITEW(IESO)
    39. 39. Parenteral Agents Meperidine and Promethazine  Meperidine, 50 to 100 mg, with promethazine, 25 mg, may be administered intramuscularly at intervals of 2 to 4 hours.  A more rapid effect is achieved by giving meperidine intravenously in doses of 25 to 50 mg every 1 to 2 hours.  Whereas analgesia is maximal about 30 to 45 minutes after an intramuscular injection, it develops almost immediately following intravenous administration.  Meperidine readily crosses the placenta, and the half- life is approximately 13 hours or longer in the9/3/2013 39BITEW(IESO)
    40. 40. Butorphanol (Stadol)  This synthetic narcotic, given in 1- to 2-mg doses, compares favorably with 40 to 60 mg of meperidine.  The major side effects are somnolence, dizziness, and dysphoria.  Neonatal respiratory depression is reported to be less than with meperidine, but care must be taken that the two drugs are not given contiguously because butorphanol antagonizes the narcotic effects of meperidine  a sinusoidal fetal heart rate pattern following butorphanol administration 9/3/2013 40BITEW(IESO)
    41. 41. Fentanyl This short-acting and potent synthetic opioid may be given in doses of 50 to 100mcg intravenously every hour. Its main disadantage is a short duration of action, which requires frequent dosing or the use of a patient-controlled intravenous pump. 9/3/2013 41BITEW(IESO)
    42. 42. Efficacy and Safety of Parenteral Agents • Meperidine is the most common opioid used worldwide for pain relief in labor. • There is no convincing evidence demonstrating that alternative opioids are better. • There is no evidence that parenteral opioids influence the length of labor or need for obstetrical intervention. • Epidural analgesia provides superior pain relief. • Intravenous and intramuscular sedation are not without risks.  maternal anesthetic-related deaths were from such sedation- aspiration, inadequate ventilation, and overdosage. Moreover, meperidine or other narcotics used during labor may cause newborn respiratory depression. 9/3/2013 42BITEW(IESO)
    43. 43. Narcotic Antagonists  Naloxone is a narcotic antagonist capable of reversing respiratory depression induced by opioid narcotics.  It acts by displacing the narcotic from specific receptors in the central nervous system.  Withdrawal symptoms may be precipitated in recipients who are physically dependent on narcotics.  For this reason, naloxone is contraindicated in a newborn of a narcotic-addicted mother.  Naloxone, along with proper ventilation, may be given to reverse respiratory depression in a newborn infant whose mother received narcotics. 9/3/2013 43BITEW(IESO)
    44. 44. Nitrous Oxide A self-administered mixture of 50-percent nitrous oxide (N2O) and oxygen provides satisfactory analgesia during labor for many women. Some preparations are premixed in a single cylinder (Entonox), and in others, a blender mixes the two gases from separate tanks (Nitronox). The gases are connected to a breathing circuit through a valve that opens only when the patient inspires.9/3/2013 44BITEW(IESO)
    45. 45. Nitrous Oxide  The use of intermittent nitrous oxide for labor pain ,the following technique suggested: 1) Instruct the woman to take slow deep breaths and to begin inhaling 30 seconds before the next anticipated contraction and to cease when the contraction starts to recede. 2) Remove the mask between contractions and encourage her to breathe normally. No one but the patient or knowledgeable personnel should hold the mask. 3) Instruct a caregiver to remain in verbal contact with the patient. 4) Provide the expectation that the pain will likely not be eliminated, but that the gas should provide some relief. 5) Ensure intravenous access, pulse oximetry, and adequate scavenging of exhaled gases. 6) Use with additional caution after previous opioid administration because the combination can more easily render a woman unconscious and unable to protect her airway. 9/3/2013 45BITEW(IESO)
    46. 46. Regional Analgesia 9/3/2013 46BITEW(IESO)
    47. 47. Regional anesthetic techniques, were introduced to obstetrics in 1900, when Oskar Kreis described the use of spinal anesthesia. Unfortunately he was an obstetrtian 9/3/2013 47BITEW(IESO)
    48. 48. Regional Analgesia Various nerve blocks have been developed over the years to provide pain relief during labor and delivery. They are correctly referred to as regional analgesics. 9/3/2013 48BITEW(IESO)
    49. 49. Regional Anesthesia/Analgesia • Epidural • Spinal • Combined Spinal Epidural (CSE) • Continuous spinal analgesia • Paracervical block • Lumbar sympathetic block • Pudendal block • Perineal infiltration 9/3/2013 49BITEW(IESO)
    50. 50. Sensory Innervation of the Genital Tract Uterine Innervation Pain during the first stage of labor is generated largely from the uterus. Visceral sensory fibers from the uterus, cervix, and upper vagina traverse through the Frankenhäuser ganglion, which lies just lateral to the cervix, into the pelvic plexus, and then to the middle and superior internal iliac plexuses. From there, the fibers travel in the lumbar and lower thoracic sympathetic chains to enter the spinal cord through the white rami communicantes associated with the T10 through T12 and L1 nerves.  Early in labor, the pain of uterine contractions is transmitted predominantly through the T11 and T12 nerves.9/3/2013 50BITEW(IESO)
    51. 51. Pathways of labor painPathways of labor pain9/3/2013 51BITEW(IESO)
    52. 52. Uterine Innervation The motor pathways to the uterus leave the spinal cord at the level of the T7 and T8 vertebrae. Theoretically, any method of sensory block that does not also block the motor pathways to the uterus can be used for analgesia during labor. 9/3/2013 52BITEW(IESO)
    53. 53. Lower Genital Tract Innervation Pain with vaginal delivery arises from stimuli from the lower genital tract.  These are transmitted primarily through the pudendal nerve, the peripheral branches of which provide sensory innervation to the perineum, anus, and the more medial and inferior parts of the vulva and clitoris. The pudendal nerve passes beneath the posterior surface of the sacrospinous ligament just as the ligament attaches to the ischial spine. The sensory nerve fibers of the pudendal nerve are derived from the ventral branches of the S2 through S4 nerves. 9/3/2013 53BITEW(IESO)
    54. 54. Anesthetic Agents • Some preparations that contain dilute epinephrine to prolong the action of the anesthetic will also cause symptoms when a test dose is inadvertently given intravenously. • The dose of each agent varies widely and is dependent on the particular nerve block and physical status of the woman. • The onset, duration, and quality of analgesia can be enhanced by increasing the dose. • This can be done safely by only incrementally administering small-volume boluses of the agent and by carefully monitoring for early warning signs of toxicity. • Administration of these agents must be followed by appropriate monitoring for adverse reactions, and equipment and personnel to manage these reactions must be immediately available. 9/3/2013 54BITEW(IESO)
    55. 55. Most often, serious toxicity follows inadvertent intravenous injection. For this reason, when epidural analgesia is initiated, dilute epinephrine is sometimes added and given as a test dose. A sudden significant rise in the maternal heart rate or blood pressure immediately after administration suggests intravenous catheter placement. Personnel using these agents must be cognizant that these agents are manufactured in more than one concentration and ampule size, which increases the potential for dosing errors. 9/3/2013 55BITEW(IESO)
    56. 56. Some Local Anesthetic Agents Used in Obstetrics Plain Solutions
    57. 57. Anesthetic Agent Usual Concentr ation (%) Usual Volume (mL) Usual Dose (mg) Onset Average Duration (min) Clinical Use Amino-esters 2- Chloropr ocaine 1–2 20–30 400–600 Rapid 15–30 Local or pudendal block 2–3 15–25 300–750 30–60 Epidural (not subarachnoid) for cesarean delivery Tetracain e 0.2 — 4 Slow 75–150 Low spinal block/6%glucose 0.5 — 7–10 75–150 Spinal for cesarean delivery/5%gluco se9/3/2013 57BITEW(IESO)
    58. 58. Amino-amides Lidocaine 1 20–30 200–300 Rapid 30–60 Local or pudendal block 2 15–30 300–450 60–90 Epidural for cesarean delivery 5 1–1.5 50–75 45–60 Spinal for cesarean delivery or puerperal tubal ligation/7.5 %glucose 5 0.5–1 25–50 30–60 Spinal for vaginal delivery/7.5 %glucose 9/3/2013 58BITEW(IESO)
    59. 59. Bupivacaine 0.5 15–20 50–100 Slow 90–150 Epidural for cesarean delivery 0.25 8–10 20–25 60–90 Epidural for labor 0.75 1–1.5 7.5–11 60–120 Spinal for cesarean delivery/8.2 5%glucose Ropivacain e 0.5 15–20 75–100 Slow 90–150 Epidural for cesarean delivery 0.25 8–10 20–25 60–90 Epidural for labor 9/3/2013 59BITEW(IESO)
    60. 60. • Addition of glucose to local anesthetics creates a hyperbaric solution, which is heavier and denser than cerebrospinal fluid. 9/3/2013 60BITEW(IESO)
    61. 61. Toxicity • Systemic toxicity from local anesthetics typically manifests in the central nervous and cardiovascular systems. 9/3/2013 61BITEW(IESO)
    62. 62. Central Nervous System Toxicity Early symptoms are those of stimulation but, as serum levels increase, depression follows. Symptoms may include light-headedness, dizziness, tinnitus, metallic taste, and numbness of the tongue and mouth. Patients may show bizarre behavior, slurred speech, muscle fasciculation and excitation, and ultimately, generalized convulsions, followed by loss of consciousness. The convulsions should be controlled, an airway established, and oxygen delivered. 9/3/2013 62BITEW(IESO)
    63. 63. Central Nervous System Toxicity Succinylcholine abolishes the peripheral manifestations of the convulsions and allows tracheal intubation. Thiopental or diazepam act centrally to inhibit convulsions. Magnesium sulfate, administered according to the regimen for eclampsia, also controls convulsions. 9/3/2013 63BITEW(IESO)
    64. 64. Central Nervous System Toxicity  Abnormal fetal heart rate patterns, such as late decelerations or persistent bradycardia, may develop from maternal hypoxia and lactic acidosis induced by convulsions.  With arrest of the convulsions, administration of oxygen, and application of other supportive measures, the fetus usually recovers more quickly in utero than following immediate cesarean delivery.  Moreover, maternal well-being is usually better served by waiting until the intensity of the hypoxia and the metabolic acidosis have diminished. 9/3/2013 64BITEW(IESO)
    65. 65. Cardiovascular Toxicity • These manifestations generally develop later than those from cerebral toxicity. • They do not always follow central nervous system involvement, because they are induced by higher drug levels. • The notable exception is bupivacaine, which is associated with the development of neurotoxicity and cardiotoxicity at virtually identical serum drug levels. • Because of this risk of systemic toxicity, use of 0.75-percent solution of bupivacaine for epidural injection was proscribed . 9/3/2013 65BITEW(IESO)
    66. 66. Cardiovascular Toxicity  Similar to neurotoxicity, cardiovascular toxicity is characterized first by stimulation and then by depression.  Accordingly, there is hypertension and tachycardia, which soon is followed by hypotension and cardiac arrhythmias.  The latter contribute appreciably to impaired uteroplacental perfusion and fetal distress.  Hypotension is managed initially by turning the woman onto either side to avoid aortocaval compression.  A crystalloid solution is infused rapidly along with intravenously administered ephedrine.  Emergency cesarean delivery should be considered if maternal vital signs have not been restored within 5 minutes of cardiac arrest.  As with convulsions, however, the fetus is likely to recover more quickly in utero once maternal cardiac output is reestablished.9/3/2013 66BITEW(IESO)
    67. 67. Pudendal Block • This block is a relatively safe and simple method of providing analgesia for spontaneous delivery. • The end of the introducer is placed against the vaginal mucosa just beneath the tip of the ischial spine. • The needle is pushed beyond the tip of the director into the mucosa and a mucosal wheal is made with 1 mL of 1-percent lidocaine solution or an equivalent dose of another local anesthetic. • To guard against intravascular infusion, aspiration is attempted before this and all subsequent injections. 9/3/2013 67BITEW(IESO)
    68. 68. Pudendal Block The needle is then advanced until it touches the sacrospinous ligament, which is infiltrated with 3 mL of lidocaine. The needle is advanced farther through the ligament, and as it pierces the loose areolar tissue behind the ligament, the resistance of the plunger decreases. Another 3 mL of the anesthetic solution is injected into this region. Next, the needle is withdrawn into the introducer, which is moved to just above the ischial spine. The needle is inserted through the mucosa and the rest of 10 mL of solution is deposited. The procedure is then repeated on the other side. 9/3/2013 68BITEW(IESO)
    69. 69. 9/3/2013 69BITEW(IESO)
    70. 70. Pudendal Block  Within 3 to 4 minutes of the time of injection, the successful pudendal block will allow pinching of the lower vagina and posterior vulva bilaterally without pain.  It is often of benefit before pudendal block to infiltrate the fourchette, perineum, and adjacent vagina with 5 to 10 mL of 1-percent lidocaine solution directly at the site where the episiotomy is to be made.  Then, if delivery occurs before pudendal block becomes effective, an episiotomy can be made without pain.  By the time of the repair, the pudendal block usually has become effective.  Pudendal block usually does not provide adequate analgesia when delivery requires extensive obstetrical manipulation.  Moreover, such analgesia is usually inadequate for women in whom complete visualization of the cervix and upper vagina, or manual exploration of the uterine cavity, are indicated. 9/3/2013 70BITEW(IESO)
    71. 71. Complications of Pudendal Block Central Nervous System Toxicity , intravascular injection of a local anesthetic agent may cause serious systemic toxicity. Hematoma formation Rarely, severe infection may originate at the injection site. The infection may spread posterior to the hip joint, into the gluteal musculature, or into the retropsoas space. 9/3/2013 71BITEW(IESO)
    72. 72. Paracervical Block This block usually provides satisfactory pain relief during the first stage of labor. Because the pudendal nerves are not blocked, however, additional analgesia is required for delivery. Usually lidocaine or chloroprocaine, 5 to 10 mL of a 1- percent solution, is injected into the cervix laterally at 3 and 9 o'clock.  Bupivacaine is contraindicated because of an increased risk of cardiotoxicity. Because these anesthetics are relatively short acting, paracervical block may have to be repeated during labor. 9/3/2013 72BITEW(IESO)
    73. 73. Complications Of Paracervical Block Fetal bradycardia(15%) Bradycardia usually develops within 10 minutes and may last up to 30 minutes. The effect may be the consequence of transplacental transfer of the anesthetic agent or its metabolites and in turn, a depressant effect on the fetal heart. For these reasons, paracervical block should not be used in situations of potential fetal compromise. 9/3/2013 73BITEW(IESO)
    74. 74. Spinal (Subarachnoid) Block 9/3/2013 74BITEW(IESO)
    75. 75. Spinal Anesthesia/Analgesia • Used mainly for very late in labor because it has limited duration of action • Faster onset than Epidural • Amount of local anesthetic used is much smaller 9/3/2013 75BITEW(IESO)
    76. 76. Spinal (Subarachnoid) Block • Introduction of a local anesthetic into the subarachnoid space to effect analgesia has long been used for delivery. • Advantages include a short procedure time, rapid onset of the block, and high success rate. • Because of the smaller subarachnoid space during pregnancy, likely the consequence of engorgement of the internal vertebral venous plexus, the same amount of anesthetic agent in the same volume of solution produces a much higher blockade in parturients than in nonpregnant women. 9/3/2013 76BITEW(IESO)
    77. 77. Vaginal Delivery Low spinal block is a popular form of analgesia for forceps or vacuum delivery.  The level of analgesia should extend to the T10 dermatome, which corresponds to the level of the umbilicus. Blockade to this level provides excellent relief from the pain of uterine contractions. 9/3/2013 77BITEW(IESO)
    78. 78. Vaginal Delivery • Several local anesthetic agents have been used for spinal analgesia. • Addition of glucose to any of these agents creates a hyperbaric solution, which is heavier and denser than cerebrospinal fluid. • A sitting position causes a hyperbaric solution to settle caudally, whereas a lateral position will have a greater effect on the dependent side. • Lidocaine given in a hyperbaric solution produces excellent analgesia and has the advantage of a rapid onset and relatively short duration. 9/3/2013 78BITEW(IESO)
    79. 79. Vaginal Delivery • Bupivacaine in an 8.25-percent dextrose solution provides satisfactory anesthesia to the lower vagina and the perineum for more than 1 hour. • Neither is administered until the cervix is fully dilated and all other criteria for safe forceps delivery have been fulfilled. • Preanalgesic intravenous hydration with 1 L of crystalloid solution will prevent or minimize hypotension in many cases. 9/3/2013 79BITEW(IESO)
    80. 80. Cesarean Delivery • A level of sensory blockade extending to the T4 dermatome is desired for cesarean delivery. • Depending on maternal size, 10 to 12 mg of hyperbaric bupivacaine or 50 to 75 mg of hyperbaric lidocaine are administered. • The addition of 20 to 25 g of fentanyl increases the rapidity of the onset of the block and reduces shivering. • The addition of 0.2 mg of morphine improves pain control during delivery and postoperatively. 9/3/2013 80BITEW(IESO)
    81. 81. Complications • Hypotension • Postdural puncture headache • Pruritus • Failed regional block (need for general endotracheal anesthesia) • High spinal block • Chemical meningitis or epidural abscess or hematoma • obese women have significantly impaired ventilation 9/3/2013 81BITEW(IESO)
    82. 82. Incidence (%) from ACOGa Incidence (%) from MFMUb Complication Spinal (n = N/A) Epidural (n = N/A) Combined c (n = N/A) Spinal (n = 27,319) Epidural (n = 18,697) Combi nedc (n = 5,666) Hypotensiond 25–67 28–31 — — — — Postdural puncture headache 1.5–3 2 1–2.8 0.4 0.3 0.4 Pruritus 41–85 1.3–26 41–85 — — — Failed regional block (need for GETA) — — — 1.7 4.0 1.5 High spinal block — — — 0.05 0.08 0.07 Chemical meningitis or epidural abscess or hematoma — — — 0 0 0 9/3/2013 82BITEW(IESO)
    83. 83. HypotensionHypotension  may develop soon after injection of the local anesthetic agent and is the consequence of vasodilatation from sympathetic blockade compounded by obstructed venous return from uterine compression of the vena cava and adjacent large veins.  In the supine position, even in the absence of maternal hypotension measured in the brachial artery, placental blood flow may still be significantly reduced.  Treatment of spinal block hypotension includes uterine displacement, intravenous hydration, and intravenous bolus injections of ephedrine or phenylephrine 9/3/2013 83BITEW(IESO)
    84. 84. HypotensionHypotension  The predominant action of ephedrine is to raise blood pressure by increasing cardiac output rather than vasoconstriction. Phenylephrine is a pure -agonist which, at least until recently, we have generally avoided because of concerns about potential adverse effects on uterine blood flow. 9/3/2013 84BITEW(IESO)
    85. 85. High Spinal Blockade • Most often, complete spinal blockade is the consequence of administration of an excessive dose of local anesthetic agent. • This is certainly not always the case, because accidental total spinal block has even occurred following an epidural test dose. • In complete spinal block, hypotension and apnea promptly develop and must be immediately treated to prevent cardiac arrest. • In the undelivered woman, (1) the uterus is immediately displaced laterally to minimize aortocaval compression; (2) effective ventilation is established, preferably with tracheal intubation; and (3) intravenous fluids and ephedrine are given to correct hypotension. 9/3/2013 85BITEW(IESO)
    86. 86. Spinal (Postdural Puncture) Headache • Leakage of cerebrospinal fluid from the site of puncture of the meninges is thought to be the major factor in the genesis of spinal headache. • Presumably, when the woman sits or stands, the diminished volume of cerebrospinal fluid allows traction on pain-sensitive central nervous system structures. • With severe headache, an epidural blood patch is effective. A few milliliters of autologous blood are obtained aseptically by venipuncture without anticoagulant. This is injected into the epidural space at the site of the dural puncture. Relief is immediate and complications uncommon. 9/3/2013 86BITEW(IESO)
    87. 87. Convulsions • In rare instances, postdural puncture cephalgia is associated with blindness and convulsions. 9/3/2013 87BITEW(IESO)
    88. 88. Bladder Dysfunction • With spinal analgesia, bladder sensation is likely to be obtunded and bladder emptying impaired for the first few hours after delivery. • As a consequence, bladder distention is a frequent postpartum complication, especially if appreciable volumes of intravenous fluid are given. 9/3/2013 88BITEW(IESO)
    89. 89. Oxytocics and Hypertension • Paradoxically, hypertension from ergonovine or methylergonovine injected following delivery is more common in women who have received a spinal or epidural block. 9/3/2013 89BITEW(IESO)
    90. 90. Arachnoiditis and Meningitis • Local anesthetics are no longer preserved in alcohol, formalin, or other toxic solutes, and disposable equipment is used by most. These practices, coupled with aseptic technique, have made meningitis and arachnoiditis rarities • Still, these complications are occasionally occur. 9/3/2013 90BITEW(IESO)
    91. 91. Contraindications to Spinal Analgesia • Obstetrical complications that are associated with maternal hypovolemia and hypotension— such as severe hemorrhage—are contraindications to the use of spinal block. 9/3/2013 91BITEW(IESO)
    92. 92. Absolute Contraindications toAbsolute Contraindications to Regional AnalgesiaRegional Analgesia Refractory maternal hypotension  Maternal coagulopathy  Treatment with once-daily dose of low- molecular-weight heparin within 12 hr Untreated bacteremia Skin infection over site of needle placement Increased intracranial pressure caused by mass lesion 9/3/2013 92BITEW(IESO)
    93. 93. In addition to refractory maternal hypotension, disorders of coagulation and defective hemostasis also preclude the use of spinal analgesia. Similarly, subarachnoid puncture is contraindicated when the skin or underlying tissue at the site of needle entry is infected. Neurological disorders are considered by many to be a contraindication, if for no other reason than that exacerbation of the neurological disease might be attributed without cause to the anesthetic agent. Other maternal conditions, such as significant aortic stenosis or pulmonary hypertension, are also relative contraindications to the use of spinal analgesia 9/3/2013 93BITEW(IESO)
    94. 94. Preeclampsia As with significant hemorrhage, severe preeclampsia is another complication in which markedly decreased blood pressure can be predicted when subarachnoid analgesia is used. It has inherent risks of difficult intubation due to airway edema and cerebrovascular accidents due to increased blood pressure. it to be quite controversial, they concluded that with severe preeclampsia, epidural analgesia is preferable to a subarachnoid block and especially preferable to a general anesthetic.9/3/2013 94BITEW(IESO)
    95. 95. Epidural Analgesia Provides excellent pain relief reducing maternal catecholamines Ability to extend the duration of block to match the duration of labor Blunts hemodynamic effects of uterine contractions: beneficial for patients with preeclampsia. 9/3/2013 95BITEW(IESO)
    96. 96. Indications for LEA PAIN EXPERIENCED BY A WOMAN IN LABORPAIN EXPERIENCED BY A WOMAN IN LABOR When medically beneficial to reduce the stress of labor ACOG and ASA stated ““ in the absence of a medical contraindication,in the absence of a medical contraindication, maternal request is a sufficient medical indicationmaternal request is a sufficient medical indication for pain relief…”for pain relief…” 9/3/2013 96BITEW(IESO)
    97. 97. Obstetric conditions where epidural analgesia is more likely to be indicated: •  Pre eclampsia/hypertensive disease •  Prolonged labour •  Two or more babies inutero •  Anticipated instrumental delivery •  Diabetes Mellitus •  Breech presentation for vaginal delivery •  Significant respiratory disease 9/3/2013 BITEW(IESO) 97
    98. 98. 9/3/2013 98BITEW(IESO)
    99. 99. 9/3/2013 99BITEW(IESO)
    100. 100. Contraindications for LEA ABSOLUTEABSOLUTE Patients refusal Inability to cooperate Increased intracranial pressure Infection Severe coagulopathy Severe hypovolemia Inadequate training RELATIVERELATIVE Systemic maternal infection Preexisting neurological deficiency Mild or isolated coagulation abnormalities Relative (and correctable) hypovolemia 9/3/2013 100BITEW(IESO)
    101. 101. We are All Ready…Now What? - Last Check • Obstetrician is consulted and confirmed LEA • Preanesthetic evaluation is performed/verified • Pt’s (and only patient’s) desire to have LEA is reconfirmed • Pt’s understanding of risks of LEA is reconfirmed 9/3/2013 101BITEW(IESO)
    102. 102. We are All Ready…Now What? - Last Check • Fetal well-being is assessed and reassured 9/3/2013 102BITEW(IESO)
    103. 103. We are All Ready…Now What? - Last Check • Supporting personal is available and present 9/3/2013 103BITEW(IESO)
    104. 104. We are All Ready…Now What? - Last Check • Resuscitation equipment and drugs are immediately available in the area where LEA placed 9/3/2013 104BITEW(IESO)
    105. 105. Epidural Analgesia • Relief from the pain of labor and childbirth, including cesarean delivery, can be accomplished by injection of a local anesthetic agent into the epidural or peridural space. • This potential space contains areolar tissue, fat, lymphatics, and the internal venous plexus. • These latter vessels become engorged during pregnancy such that the volume of the epidural space is appreciably reduced. • Entry for obstetrical analgesia is usually through a lumbar intervertebral space, and less often through the sacral hiatus and sacral canal for caudal epidural analgesia. • Although one injection may be used, these usually are repeated through an indwelling catheter, or they are given by continuous infusion using a volumetric pump. 9/3/2013 105BITEW(IESO)
    106. 106. Standard Technique of LEA 1. Pre epidural check list is completed 2. Aspiration prophylaxis 3. Intravenous hydration (what? When? How?) 4. Monitoring – BP every 1 to 2 min for 20 min after injection of drugs – Continuous maternal HR during induction ( e.g., pulse oximetry) – Continuous FHR monitoring – Continual verbal communication 9/3/2013 106BITEW(IESO)
    107. 107. Standard Technique of LEA 4. Maternal position ( sitting or lateral?) 9/3/2013 107BITEW(IESO)
    108. 108. Comparison of Sitting and Lateral Positions for Performing Spinal or Epidural Procedures Sitting Lying (left lateral) Advantages • Midline easier to identify in obese women • Obese patients may find this position more comfortable • Can be left unattended without risk of fainting. • No orthostatic hypotension • Uteroplacental blood flow not reduced (particularly important in the stressed fetus) Disadvantages • Uteroplacental blood flow decreased • Orthostatic hypotension may occur • Increased risk of orthostatic hypotension if Entonox and pethidine have been administered • Assistant (or partner) needed to support patient • May he more difficult to find the midline in obese patient 9/3/2013 108BITEW(IESO)
    109. 109. 9/3/2013 109BITEW(IESO)
    110. 110. 9/3/2013 110BITEW(IESO)
    111. 111. 9/3/2013 111BITEW(IESO)
    112. 112. Influence 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.
    113. 113. Continuous Lumbar Epidural Block Complete analgesia for the pain of labor and vaginal delivery necessitates a block from the T10 to the S5 dermatomes.  For cesarean delivery, a block extending from the T4 to the S1 dermatomes is desired. The spread of the anesthetic depends upon the location of the catheter tip; the dose, concentration, and volume of anesthetic agent used; and whether the mother is head-down, horizontal, or head-up. 9/3/2013 113BITEW(IESO)
    114. 114. Individual variations in the epidural space anatomy also will affect the block, and in some cases, synechiae may preclude a completely satisfactory block. It also should be recognized that the catheter tip might move from its original location during the course of labor. • Appropriate resuscitation equipment and drugs must be available during administration of epidural analgesia. 9/3/2013 114BITEW(IESO)
    115. 115. Technique for Labor Epidural Analgesia 1. Informed consent is obtained, and the obstetrician consulted. 2. Monitoring includes the following: Blood pressure every 1–2 min for 15 min after giving a bolus of local anesthetic. Continuous maternal heart rate monitoring during analgesia induction. Continuous fetal heart rate monitoring. Continual verbal communication. 3. Hydration with 500 to 1000 mL of lactated Ringer solution. 4. The woman assumes a lateral decubitus or sitting position. 9/3/2013 115BITEW(IESO)
    116. 116. 5. The epidural space is identified with a loss-of-resistance technique. 6. The epidural catheter is threaded 3–5 cm into the epidural space. 7. A test dose of 3 mL of 1.5%lidocaine with 1:200,000 epinephrine or 3 mL of 0.25%bupivacaine with 1:200,000 epinephrine is injected after careful aspiration and after a uterine contraction—this minimizes the chance of confusing tachycardia that results from labor pain with tachycardia from intravenous injection of the test dose. 8. If the test dose is negative, one or two 5-mL doses of 0.25%bupivacaine are injected to achieve a cephalad sensory T10 level. 9. After 15–20 min, the block is assessed using loss of sensation to cold or pinprick. If no block is evident, the catheter is replaced. If the block is asymmetrical, the epidural catheter is withdrawn 0.5–1.0 cm and an additional 3–5 mL of 0.25%bupivacaine is injected. If the block remains inadequate, the catheter is replaced. 10. The woman is positioned in the lateral or semilateral position to avoid aortocaval compression. 11. Subsequently, maternal blood pressure is recorded every 5–15 min. The fetal heart rate is monitored continuously. 12. The level of analgesia and intensity of motor block are assessed at least hourly 9/3/2013 116BITEW(IESO)
    117. 117. Complications of epidural analgesia • Total Spinal Blockade • Ineffective Analgesia • Hypotension • Central Nervous Stimulation • Maternal Pyrexia • Back Pain 9/3/2013 117BITEW(IESO)
    118. 118. Effect on Labor • report that epidural analgesia prolongs labor and increases the need for oxytocin stimulation. • increase the need for instrumental delivery due to prolonged second-stage labor 9/3/2013 118BITEW(IESO)
    119. 119. Fetal Heart Rate • Compared with intravenous meperidine, no deleterious effects were identified. • In fact, reduced beat-to-beat variability and fewer accelerations were more common in fetuses whose mothers received • Based on their systematic review of eight studies, Reynolds and co-workers (2002) found that epidural analgesia was associated with improved neonatal acid–base status compared with that with meperidine. 9/3/2013 119BITEW(IESO)
    120. 120. Cesarean Delivery • These results are consistent with the belief of many investigators that the epidural administration of dilute solutions of local anesthetic is less likely to increase cesarean delivery rates than concentrated solutions. 9/3/2013 120BITEW(IESO)
    121. 121. Contraindications • actual or anticipated serious maternal hemorrhage,actual or anticipated serious maternal hemorrhage, infection at or near the sites for puncture, and suspicioninfection at or near the sites for puncture, and suspicion of neurological diseaseof neurological disease • Rolbin and colleagues (1988) advise against epidural analgesia if the platelet count is below 100,000/L. Conversely, Rasmus and associates (1989) found no cases in which bleeding was caused by regional analgesia in thrombocytopenic women. • They recommended consideration of this method if the patient might be difficult to intubate or ventilate. The American College of Obstetricians and Gynecologists (2002b) has concluded that women with platelet counts of 50,000 to 100,000/L may be considered potential candidates for regional analgesia. 9/3/2013 121BITEW(IESO)
    122. 122. Anticoagulation • Women receiving anticoagulation therapy who are given regional analgesia are at increased risk for spinal cord hematoma and compression. • The American College of Obstetricians and Gynecologists (2002b) has recommended the following for women taking anticoagulants: • Women receiving unfractionated heparin therapy should be able to receive regional analgesia if they have a normal activated partial thromboplastin time (aPTT). 9/3/2013 122BITEW(IESO)
    123. 123. Cont… • Women receiving prophylactic doses of unfractionated heparin or low-dose aspirin are not at increased risk and can be offered regional analgesia. • For women receiving once-daily low-dose low- molecular-weight heparin, regional analgesia should not be placed until 12 hours after the last injection. • Low-molecular-weight heparin should be withheld for at least 2 hours after the removal of an epidural catheter. • The safety of regional analgesia in women receiving twice-daily low-molecular-weight heparin has not been studied sufficiently. 9/3/2013 123BITEW(IESO)
    124. 124. Severe Preeclampsia–Eclampsia • As previously discussed, ideal labor analgesia for women with severe preeclampsia is controversial. • Obstetrical concerns include hypotension induced by sympathetic blockade, dangers from pressor agents given to correct hypotension, and potential for pulmonary edema following infusion of large volumes of crystalloid. • Conversely, general anesthesia with tracheal intubation may result in severe, sudden hypertension further complicated by pulmonary or cerebral edema or intracranial hemorrhage.9/3/2013 124BITEW(IESO)
    125. 125. • Over the past two to three decades, most obstetrical anesthesiologists have come to favor epidural blockade for labor and delivery in women with severe preeclampsia. • There seems to be no argument that epidural analgesia for women with severe preeclampsia–eclampsia can be safely used when specially trained anesthesiologists and obstetricians are responsible for the woman and her fetus (ACOG) • Epidural analgesia provided superior pain relief without a significant increase in maternal or neonatal complications. 9/3/2013 125BITEW(IESO)
    126. 126. Intravenous Fluid Preload • Women with severe preeclampsia have remarkably diminished intravascular volume compared with normal pregnancy. • And also aggressive volume replacement increases the risk for pulmonary edema, especially in the first 72 hours postpartum • Importantly, this risk can be reduced or obviated with judicious prehydration—usually with 500 to 1000 mL of crystalloid solution. 9/3/2013 126BITEW(IESO)
    127. 127. • Moreover, vasodilation produced by epidural blockade is less abrupt if the analgesia level is achieved slowly with dilute solutions of local anesthetic agents. • This allows maintenance of blood pressure while simultaneously avoiding infusion of large volumes of crystalloid. • With vigorous intravenous crystalloid therapy, there is also concern about development of cerebral edema. • the majority of cases of pharyngolaryngeal edema were related to aggressive volume therapy. 9/3/2013 127BITEW(IESO)
    128. 128. Epidural Opiate Analgesia • Their mechanism of action derives from interaction with specific receptors in the dorsal horn and dorsal roots. • Apparently both cerebral and spinal opioid receptors are stimulated by these narcotics. • Opiates alone usually will not provide adequate analgesia, and they most often are given with a local anesthetic agent such as bupivacaine. • The major advantages of using such a combination are the rapid onset of pain relief, a decrease in shivering, and less dense motor blockade. 9/3/2013 128BITEW(IESO)
    129. 129. Continuous Infusion of Dilute Local Anesthetic Plus Opioid • Better pain relief while producing less motor block. • Maternal and neonatal drug concentrations safe. RegimenRegimen 0.0625% - 0.08% bupivacaine with 2-30.0625% - 0.08% bupivacaine with 2-3 mcg /ml fentanyl, with or withoutmcg /ml fentanyl, with or without epinephrine, infusing at 10-12 ml/hourepinephrine, infusing at 10-12 ml/hour 9/3/2013 129BITEW(IESO)
    130. 130. Searching For Balanced LaborSearching For Balanced Labor AnalgesiaAnalgesia Ambulatory Labor AnalgesiaAmbulatory Labor Analgesia (CSE)(CSE) 9/3/2013 130BITEW(IESO)
    131. 131. Combined Spinal–epidural Techniques • may provide rapid and effective analgesia for labor as well as for cesarean delivery. • an introducer needle is first placed in the epidural space. A small-gauge spinal needle is then introduced through the epidural needle into the subarachnoid space—this is called the needle-through-needle technique. • A single bolus of an opioid, sometimes in combination with a local anesthetic, is injected into the subarachnoid space, the spinal needle is withdrawn, and an epidural catheter is then placed. The use of a subarachnoid opioid bolus results in the rapid onset of profound pain relief with virtually no motor blockade. • The epidural catheter permits repeated dosing of analgesia. 9/3/2013 131BITEW(IESO)
    132. 132. Combined spinal epidural (CSE) Initial reports: two interspace technique-epidural followed by spinal Later evolution of CSE in the direction of needle through needle technique Postdural puncture headache: 1% or less incidence for CSE with small bore atraumatic needles. 9/3/2013 132BITEW(IESO)
    133. 133. • combined method produced excellent immediate pain relief. 9/3/2013 133BITEW(IESO)
    134. 134. Advantages of CSE for Labor Analgesia Rapid onset of intense analgesia (the patient loves you immediately!) Ideal in late or rapidly progressing labor Very low failure rate Less need for supplemental boluses Minimal motor block (“walking epidural”) 9/3/2013 134BITEW(IESO)
    135. 135. 9/3/2013 135BITEW(IESO)
    136. 136. Combined Spinal epidural 9/3/2013 136BITEW(IESO)
    137. 137. Espocan CSE Needle (B. Braun)Espocan CSE Needle (B. Braun) 9/3/2013 137BITEW(IESO)
    138. 138. Espocan CSE Needle (B. Braun)Espocan CSE Needle (B. Braun) 9/3/2013 138BITEW(IESO)
    139. 139. Eldor needle Combined Spinal Epidural for Obstetric Anesthesia.flv 9/3/2013 139BITEW(IESO)
    140. 140. Maintenance of epidural analgesia can beMaintenance of epidural analgesia can be achieved by:achieved by: regular top-ups an epidural infusion patient-controlled epidural analgesia (PCEA). 9/3/2013 140BITEW(IESO)
    141. 141. Intermittent bolus injections: Bupivacaine: 0.125%-0.375%, 5-10 ml, duration:1-2 hr Ropivacaine: 0.125%-0.25%, 5-10 ml, duration: 1-2 hr Lidocaine: 0.75%-1.5%, 5-10 ml, duration: 1- 1.5 hr 9/3/2013 141BITEW(IESO)
    142. 142. Neuraxial Labor Techniques 9/3/2013 142BITEW(IESO)
    143. 143. Does epidural analgesia affect the course of labor? 9/3/2013 BITEW(IESO) 143
    144. 144. Local Infiltration for Cesarean Delivery 9/3/2013 144BITEW(IESO)
    145. 145. Local Infiltration for Cesarean Delivery • Local block is occasionally useful to augment an inadequate or "patchy" regional block that was given in an emergency. • On more rare occasions, local infiltration may be used to perform an emergency cesarean to save the life of the fetus in the absence of any anesthesia support. 9/3/2013 145BITEW(IESO)
    146. 146. 9/3/2013 146BITEW(IESO)
    147. 147. Local anesthetic block for cesarean delivery.Local anesthetic block for cesarean delivery.9/3/2013 147BITEW(IESO)
    148. 148. Local Infiltration for Cesarean Delivery :Technique • READING ASSIGNMENT 9/3/2013 148BITEW(IESO)
    149. 149. General Anesthesia • The increased safety of regional analgesia has increased the relative risk of general anesthesia. • The case-fatality rate of general anesthesia for cesarean delivery is estimated to be approximately 32 per million live births compared with 1.9 per million for regional anesthesia • Failed intubation occurs in approximately 1 of every 250 general anesthetics administered to pregnant women, a 10- fold higher rate than the nonpregnant population. • The American College of Obstetricians and GynecologistsThe American College of Obstetricians and Gynecologists (2002b) has concluded that this relative increased morbidity(2002b) has concluded that this relative increased morbidity and mortality suggest that regional analgesia is the preferredand mortality suggest that regional analgesia is the preferred method of pain control and should be used unlessmethod of pain control and should be used unless contraindicatedcontraindicated9/3/2013 149BITEW(IESO)
    150. 150. Patient Preparation • Prior to anesthesia induction, several steps should be taken to help minimize the risk of complications for the mother and fetus. These include the use of antacids,  lateral uterine displacement, and preoxygenation. 9/3/2013 150BITEW(IESO)
    151. 151. Induction of Anesthesia Thiopental Ketamine 9/3/2013 151BITEW(IESO)
    152. 152. Thiopental • This thiobarbiturate given intravenously is widely used and offers the advantages of ease and extreme rapidity of induction as well as prompt recovery with minimal risk of vomiting. • Thiopental and similar compounds are poor analgesic agents, and the administration of sufficient drug given alone to maintain anesthesia may cause appreciable newborn depression. • Thus, thiopental is not used as the sole anesthetic agent, but rather is administered in a dose that induces sleep. 9/3/2013 152BITEW(IESO)
    153. 153. Ketamine • This agent also may be used to render the patient unconscious. • Given intravenously in low doses of 0.2 to 0.3 mg/kg, ketamine may be used to produce analgesia and sedation just prior to vaginal delivery. • Doses of 1 mg/kg induce general anesthesia. • Ketamine may prove useful in women with acute hemorrhage because, unlike thiopental, it is not associated with hypotension. • Conversely, it usually causes a rise in blood pressure, and thus it generally should be avoided in women who are already hypertensive. • Unpleasant delirium and hallucinations are commonly induced by this agent. 9/3/2013 153BITEW(IESO)
    154. 154. Intubation • Immediately after the patient is rendered unconscious, a muscle relaxant is given to facilitate intubation. • Succinylcholine, a rapid-onset and short-acting agent, commonly is used. • Cricoid pressure—the Sellick maneuver—is used to occlude the esophagus from induction until intubation is completed by a trained assistant. • Before the operation begins, proper placement of the endotracheal tube must be confirmed. • Such confirmation includes auscultation of bilateral breath sounds and end-tidal carbon dioxide analysis. 9/3/2013 154BITEW(IESO)
    155. 155. Failed Intubation Although uncommon, failed intubation is a major cause of anesthesia-related maternal mortality. A history of previous difficulties with intubation as well as a careful assessment of anatomical features of the neck, maxillofacial, pharyngeal, and laryngeal structures may help predict a difficult intubation. Even in cases where the initial assessment of the airway was uneventful, edema may develop intrapartum and present considerable difficulties.  Morbid obesity is also a major risk factor for failed or difficult intubation. 9/3/2013 155BITEW(IESO)
    156. 156. Management of failed intubation  start the operative procedure only after it has been ascertained that tracheal intubation has been successful and that adequate ventilation can be accomplished.  Even with an abnormal fetal heart rate pattern, initiation of cesarean delivery will only serve to complicate matters if there is difficult or failed intubation.  Frequently, the woman must be allowed to awaken and a different technique used, such as an awake intubation or regional analgesia.9/3/2013 156BITEW(IESO)
    157. 157. • Following failed intubation, the woman is ventilated by mask and cricoid pressure is applied to reduce the chance of aspiration. • Surgery may proceed with mask ventilation or the woman may be allowed to awaken. • In those cases where the woman has been paralyzed, and where ventilation cannot be reestablished by insertion of an oral airway, laryngeal mask airway, or use of a fiberoptic laryngoscope to intubate the trachea, a life-threatening emergency exists. • To restore ventilation, percutaneous or even open cricothyrotomy is performed, and jet ventilation begun. 9/3/2013 157BITEW(IESO)
    158. 158. Gas Anesthetics Once the endotracheal tube is secured, a 50:50 mixture of nitrous oxide and oxygen is administered to provide analgesia.  Usually, a volatile halogenated agent is added to provide amnesia and additional analgesia. 9/3/2013 158BITEW(IESO)
    159. 159. Volatile Anesthetics  The most commonly used volatile anesthetic in the United States is isoflurane.  Both isoflurane and halothane are potent, nonexplosive agents that produce remarkable uterine relaxation when given in high, inhaled concentrations.  Their use in high concentrations is restricted to those uncommon situations in which uterine relaxation is a requisite rather than a hazard.  They are used for internal podalic version of the second twin, breech decomposition and replacement of the acutely inverted uterus.  As soon as the maneuver has been completed, anesthetic administration should be stopped and immediate efforts begun to promote myometrial contraction to minimize hemorrhage.  Because of cardiodepressant and hypotensive effects, these agents may intensify the adverse effects of maternal hypovolemia.  Halothane and isoflurane occasionally have been associated with hepatitis and massive hepatic necrosis.9/3/2013 159BITEW(IESO)
    160. 160. Anesthesia Gas Exposure and Pregnancy Outcome • Without exception, all anesthetic agents that depress the maternal central nervous system cross the placenta and depress the fetal central nervous system. As a result, personnel responsible for the care of the newborn immediately following delivery with a general anesthetic should be prepared to provide respiratory support. • Ideally, induction-to-delivery time should be minimized when general anesthesia is used. • In one study, Datta and colleagues (1981) concluded that fetal exposure of more than 8 minutes was associated with increased neonatal depression. Kavak and co-workers (2001) randomly assigned 84 women scheduled for elective cesarean delivery to either spinal analgesia or general anesthesia. • There were no significant differences in short-term measures of neonatal outcome, including Apgar scores, umbilical artery blood gas determinations, or length of stay. 9/3/2013 160BITEW(IESO)
    161. 161. Extubation • The tracheal tube may be safely removed only if the woman is conscious to a degree that enables her to follow commands and is capable of maintaining oxygen saturation with spontaneous respiration. • Typically, the stomach is emptied via a nasogastric tube prior to extubation. 9/3/2013 161BITEW(IESO)
    162. 162. Aspiration • Massive gastric acidic inhalation causing pulmonary insufficiency from aspiration pneumonitis. • Such pneumonitis has in the past been the most common cause of anesthetic deaths in obstetrics and therefore deserves special attention. • Procedures mentioned previously that are important to effective prophylaxis include use of antacids, skillful intubation accompanied by cricoid pressure, emptying of the stomach with a nasogastric tube, and use of regional analgesia when possible. 9/3/2013 162BITEW(IESO)
    163. 163. Fasting • Clear liquids such as water, clear tea, black coffee, carbonated beverages, and fruit juices without pulp may be allowed in uncomplicated laboring women. • Obvious solid foods should be avoided. • "a fasting period of 8 hours or more is preferable for uncomplicated parturients undergoing elective cesarean delivery." • Despite these precautions, it should be assumed that any woman in labor has both gastric particulate matter as well as acidic contents. 9/3/2013 163BITEW(IESO)
    164. 164. Pathophysiology • if the pH of aspirated fluid was below 2.5, severe chemical pneumonitis developed. • The right mainstem bronchus usually offers the simplest pathway for aspirated material to reach the lung parenchyma, and therefore the right lower lobe is most often involved. • In severe cases, there is bilateral widespread involvement. 9/3/2013 164BITEW(IESO)
    165. 165. • The woman who aspirates may develop evidence of respiratory distress immediately or as long as several hours after aspiration, depending in part on the material aspirated and the severity of the process. • Aspiration of a large amount of solid material causes obvious signs of airway obstruction. • Smaller particles without acidic liquid may lead to patchy atelectasis and later to bronchopneumonia. • When highly acidic liquid is inspired, decreased oxygen saturation along with tachypnea, bronchospasm, rhonchi, rales, atelectasis, cyanosis, tachycardia, and hypotension are likely to develop. At the sites of injury, pulmonary capillary leakage results in protein-rich fluid containing numerous erythrocytes exuding from capillaries into the lung interstitium and alveoli to cause decreased pulmonary compliance, shunting of blood, and severe hypoxemia. Radiographic changes may not appear immediately and they may be quite variable, although the right lobe most often is affected. Therefore, chest radiographs alone should not be used to exclude aspiration. 9/3/2013 165BITEW(IESO)
    166. 166. Treatment  Respiratory rate and oxygen saturation as measured by pulse oximetry are the most sensitive and earliest indicators of injury. • As much of the inhaled fluid as possible should be immediately wiped out of the mouth and removed from the pharynx and trachea by suction. • If large particulate matter is inspired, bronchoscopy may be indicated to relieve airway obstruction. • If clinical evidence of infection develops, however, then vigorous treatment is given. • When acute respiratory distress syndrome develops, mechanical ventilation with positive end-expiratory pressure may prove lifesaving. 9/3/2013 166BITEW(IESO)
    167. 167. What anesthetic options are available for cesarean delivery? What options are available for pain control following cesarean delivery? What anesthetic risks accompany preeclampsia? Is fetal outcome any different between regional and general anesthesia? 9/3/2013 BITEW(IESO) 167
    168. 168. THANK YOU!! 9/3/2013 168BITEW(IESO)
    169. 169. 9/3/2013 169BITEW(IESO)
    170. 170. 9/3/2013 BITEW(IESO) 170
    171. 171. 9/3/2013 BITEW(IESO) 171
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    174. 174. Anesthesia for Cesarean Section 9/3/2013 174BITEW(IESO)
    175. 175. Anesthesia for Cesarean Section The choice of anesthesia depend on: • The indication for the CS • The urgency of the procedure • The medical condition of the mother and the fetus • The desire of the mother 9/3/2013 175BITEW(IESO)
    176. 176. Anesthesia 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 cases Anesthesia2000;55:690-4 • Maternal death due to anesthesia is the sixth leading cause of pregnancy related death in USA Obstet Gynecol 1996;88:161-7 9/3/2013 176BITEW(IESO)
    177. 177. Anesthesia for Cesarean Section • The risk of maternal death from complications of GA is 17 times as high as that associated with Regional anesthesia • In 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 9/3/2013 177BITEW(IESO)
    178. 178. Epidural anesthesia • AdvantageAdvantage – Titration (volume dependent, not gravity dependent), decreased likelihood of hypotension – Incremental dose (for longer operation) • DisadvantageDisadvantage – Dural puncture :1/200-1/500 in experienced hands, higher in training institution – If unintentional dural puncture, PDPH incidence is 50-85% – Slower onset 9/3/2013 178BITEW(IESO)
    179. 179. Spinal anaesthesia • Hyperbaric 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 achieved Anesthesiology1990; 72: 478–482.9/3/2013 179BITEW(IESO)
    180. 180. Combined spinal epidural(CSE) Combines the rapid onset and efficacy of the spinal technique with the ability to: Extend anaesthesia if surgery is prolonged Provide excellent postoperative epidural analgesia. Combined Spinal Epidural for Obstetric Anesthesia.flv 9/3/2013 180BITEW(IESO)
    181. 181. Medication Spinal Epidural Local anesthetic Bupivacaine 12 mg (range 9–15) Lidocaine 2%; Fentanyl 15–35 ug 50–100 ug Morphine 0.1 mg 3.75 mg Optimal Neuraxial Medication Combinations for Cesarean Delivery 9/3/2013 181BITEW(IESO)
    182. 182. Complications of Regional Anesthesia 9/3/2013 182BITEW(IESO)
    183. 183. Complications of regional anesthesia Post Dural Puncture Headache (PDPH)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 puncture worsens on sitting and standing relieved by lying down and abdominal compression. 9/3/2013 183BITEW(IESO)
    184. 184. Complications of regional anesthesia PDPH syndromePDPH syndrome 1. Photophobia 2. Nausea 3. Vomiting 4. Neck stiffness 5. Tinnitus 6. Diplopia 7. Dizziness 9/3/2013 184BITEW(IESO)
    185. 185. Complications of regional anesthesia Differential diagnosis of post-dural punctureDifferential diagnosis of post-dural puncture headache in the obstetric patient:headache in the obstetric patient: 11. Non-specific headache 2. Caffeine-withdrawal headache 3. Migraine 4. Meningitis 5. Sinus headache 6. Pre-eclampsia 7. Drugs (amphetamine, cocaine) 8. Pneumocephalus-related headache 9. Intracranial pathology (hemorrhage, venous thrombosis) 9/3/2013 185BITEW(IESO)
    186. 186. Complications of regional anesthesia Management of PDPHManagement of PDPH Conservative:Conservative: Bed rest Encourage oral fluids and/or intravenous hydration Caffeine - either i.v. (e.g. 500mg caffeine in 1litre of saline) or orally Regular Analgesia Reassurance 9/3/2013 186BITEW(IESO)
    187. 187. Complications of regional anesthesia Management of PDPHManagement of PDPH OthersOthers 1. Theophylline 3. Sumatriptan 4. Epidural saline 5. Epidural dextran 6. Subarachnoid catheter 7. Epidural blood patch 9/3/2013 187BITEW(IESO)
    188. 188. Complications of regional anesthesia The new method of prevention of post-duraThe new method of prevention of post-dura puncture headache (maintaining CSF volume):puncture headache (maintaining CSF volume): 1. Injecting the CSF in the glass syringe back into the subarachnoid space through the epidural needle 2. Passing the epidural catheter through the dural hole into the subarachnoid space 3. Injecting of 3-5 ml of preservative free saline into the subarachnoid space through the intrathecal catheter 4. Administering bolus and then continuous intrathecal labor analgesia through the intrathecal catheter 5. Leaving the subarachnoid catheter in-situ for a total of 12-20 h 9/3/2013 188BITEW(IESO)
    189. 189. Complications of regional anesthesia Cardiovascular complicationsCardiovascular complications Hypotension (can lead to cord ischaemia) Bradycardia Effects on the course of labour and on the fetusEffects on the course of labour and on the fetus 9/3/2013 189BITEW(IESO)
    190. 190. Effect 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 birth Associated with a longer second stage of labour and an increased chance of an instrumental birth. 9/3/2013 190BITEW(IESO)
    191. 191. Effect of epidural analgesia on the progress and outcome of labour The most important factors determiningThe most important factors determining labour outcome are:labour outcome are: • Low concentrations of local anaesthetics • Oxytocin • Maternal pushing in the second stage of labour should, if possible be delayed! 9/3/2013 191BITEW(IESO)
    192. 192. Complications of regional anesthesia Neurological complicationsNeurological complications Needle damage to spinal cord, cauda equina or nerve roots. Spinal haematoma Spinal abscess Meningitis and Arachnoiditis Neurotoxicity 9/3/2013 192BITEW(IESO)
    193. 193. Complications of regional anesthesia MiscellaneousMiscellaneous Venous puncture e.g. of dural veins Catheter breakage Extensive block (including unplanned blocks) Shivering Backache - Long-term backache is not a complication of neuraxial techniques although there will always be some local bruising. 9/3/2013 193BITEW(IESO)
    194. 194. Complications of regional anesthesia Drug side effectsDrug side effects Nausea and vomiting (opiates) Respiratory depression (opiates) Anaphylaxis Toxicity (including intravascular injection of local anaesthetics) 9/3/2013 194BITEW(IESO)
    195. 195. Toxicity of local anaesthetics: Causes:Causes: An overdose of local anaesthetic is given, Large dose of local anaesthetic is inadvertently given intravenously. The recommended protocol isThe recommended protocol is • Take a 500 ml bag of intralipid 20% and immediately give a 100 ml bolus over 1 minute 9/3/2013 195BITEW(IESO)
    196. 196. Toxicity 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 cardiovascularAirway, ventilatory and cardiovascular support should be maintained viasupport should be maintained via standard protocols. It may be >1 hourstandard protocols. It may be >1 hour before recoverybefore recovery 9/3/2013 196BITEW(IESO)
    197. 197. Is There Still Place For General Anesthesia? 9/3/2013 197BITEW(IESO)
    198. 198. Conclusion “The delivery of the infant into the arms of aThe delivery of the infant into the arms of a conscious and pain-free mother is one of theconscious and pain-free mother is one of the most exciting and rewarding moments inmost exciting and rewarding moments in medicine.”medicine.” Moir DD. Extradural analgesia for caesarean section. BrMoir DD. Extradural analgesia for caesarean section. Br J Anaesth 1979; 51: 1093.J Anaesth 1979; 51: 1093. 9/3/2013 198BITEW(IESO)

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