2024 556 analgesia and anesthesia with Notes.pdf

Analgesia & Anesthesia During Labor & Birth Kirby Adlam, PhD, APRN-FPA, CNM Objectives Identify the different categories of drugs administered during labor and birth, summarizing the pharmacologic considerations for each. Identify the different types of anesthetics administered during labor and birt...

Analgesia & Anesthesia During Labor & Birth Kirby Adlam, PhD, APRN-FPA, CNM Objectives Identify the different categories of drugs administered during labor and birth, summarizing the pharmacologic considerations for each. Identify the different types of anesthetics administered during labor and birth, summarizing the pharmacologic considerations for each. Describe potential maternal and fetal risks and benefits of drugs and anesthetics administered during labor and birth. Explain the effects of local, pudendal, spinal and epidural anesthesia on labor, birth and the fetus. Summarize the potential effects of drugs and anesthetics used during labor and birth on the normal progression of labor and birth. Use of Language Gender-inclusive language (person/ people/ they/ them /patient) is used in this presentation as is woman/women in some cases. Such language acknowledges the long history of gender discrimination targeting women in healthcare publications. Inclusive language does not seek to undermine or remove the importance of women in giving birth. Genderneutral language sets a standard for professionals to serve people with diverse experiences What is Pain? Unpleasant sensory and emotional experience Always subjective “Result of complex interplay between physical, biological, psychological, and cultural factors, each of which contributes to the overall percep;on of the experience” (Varney, 2019) Pain Pathways First stage of Labor: Visceral/Cramping Uterus and cervix and referred to abdominal wall, lumbosacral region, iliac crests, gluteal areas, thighs Pain signal enter spinal cord T10-L1 Transition- greater nociceptive input beginning somatic pain from vaginal distention Second Stage of Labor: combination of visceral and somatic pain from distention of vaginal and perineal tissue via pudendal nerve S2-S4 Adverse Consequences of Labor Pain Hyperventilation Lightheadedness Tingling Decreased placental perfusion Elevated catecholamines Decreased placental perfusion Psychological effects Postpartum psychological trauma Increased risk for postpartum depression Definitions Analgesia: Drugs used to relieve pain without causing loss of consciousness Anesthesia: Reversible loss of feeling or sensation in a part or all of the body Systemic Opiates Overview: No need for anesthesiologist When neuraxial anesthesia is contraindicated/undesir ed Increasing sedation & respiratory depression with repeat doses Optimal labor opioid: Rapid onset Rapid metabolism & elimination Minimal maternal/fetal/neonatal SE Narcotics /Opiates IV and IM (and PO post partum) Side effects common to all opioids: Respiratory depression Orthostatic hypotension Delayed gastric emptying Nausea Vomiting Opiate Receptors Mu, kappa, delta Opiates differ in AGONIST and/or ANTAGONIST effects at receptor sites An agonist is a drug that activates certain receptors in the brain Receptors differ in the extent to which they involve respiratory function Opiate Receptors Different opiates have different AGONIST and ANTAGONIST effects when bound to the various receptors Sensitivity & effects on individuals varies by 1) degree of opiate naiveté and 2) perhaps genomic polymorphisms (poorly understood) Sensitivity and response differences may not be predictable; THEREFORE, WE START WITH LOWEST DOSES Opiate Side Effects of Concern Maternal SE: Heavy sedation Respiratory depression Dizziness Orthostatic hypotension Fall risk Nausea/vomiting Dysphoria Disorientation Impaired bonding/ breastfeeding Delayed gastric emptying Fetal SE: Decreased FHR variability Pseudosinusoidal FHR pattern Neonatal respiratory depression Lowered Apgars, cord pH Altered neonatal neurobehaviors and breastfeeding Opiates: analgesic vs. sedative effects Most research show little if any actual analgesic effect All opioids have sedative effects What are you/the patient trying to accomplish with the drug? Morphine: “gold standard” for opiates- not necessarily gold for labor 10-20 mg IM, 2.5-5 IV (latent labor) Can be used with Phenergan IV/IM or Vistaril (IM only) Some studies show no significant analgesic effect>>primarily sedative Long lasting active metabolites Long half life for babies SE significant respiratory depression; N/ V Minimal data on labor effects Nalbuphine (Nubaine) Primarily kappa agonist; mu agonist/antagonist Dose 10 mg IM/IV BOTH agonist and antagonistic , ie, it BLOCKS some opiod effects, including resp depression “ceiling effect” Pain reduction and SE’s similar to Demerol with less respiratory depression. No active, long-lasting metabolites No effects on labor found Breastfeeding: temporary impaired sucking; no effect on found Avoid in opioid dependent patient- withdrawal Meperidine (Demerol) IV 25-50mg, IM 50-100 mg) Long lasting active metabolites Weaker mu and kappa agonist Used with Phenergan/promethazine Lower risk of respiratory depression than MS Minimal or no analgesic effect>>sedative SE timing dependent: N/V, resp depression, long half lives, slow clearance esp. for baby, Little if any direct effect on labor?? Affects Breast feeding Fentanyl (Sublimaze) Fentanyl - 25-100 mcg IV (rapid onset/short duration)Fentanyl PCA (when epidural is contraindicated) Most studies are on PCA administration High affinity for mu receptors, potent agonist: at best modest pain relief with minimal SE’s Analgesia similar to Demerol, but fewer adverse SE ( NV, newborn resp depression) Little if any direct effect on labor?May slow active phase? Dec FHR variability minute in colostrum Often used for PPH, manual exploration Butorphanol (Stadol) Dose 1-2 mg IV or IM Mu and Kappa receptors BOTH agonist and antagonistic , ie, it BLOCKS some opiod effects, including resp depression “ceiling effect” Pain reduction and SE’s similar to Demerol with less respiratory depression. No active, long-lasting metabolites No known effects on labor Breastfeeding: no effect found Avoid in opioid dependent patient- withdrawal Naloxone (Narcan) Antagonist: IV, IM, SQ Adult – 0.4-4 mg Neonate – 0.01-0.015 mg/kg/dose Displaces opioid from receptor site Opioid antidote Reversal of respiratory depression (mom and baby) caused by systemic opiates in labor Short duration - may need repeated doses Systemic analgesics used for labor and vaginal delivery Drug Class Dose 25 to 50 mcg IV Fentanyl Opioid Onset 1 to 3 minutes IV PCA: Loading dose 50 to 100 mcg IV 1 to 3 Patient bolus 10 to minutes 25 mcg IV Lockout 5 to 12 minutes Duration Comments 30 to 60 minutes IV 30 to 60 minutes Short-acting, potent respiratory depressant; best used by PCA. PCA only, start with low dose and titrate to effect; ultrashort acting, PCA: Bolus 15 to 50 potent respiratory depressant. 30 to 60 3 to 4 Oxygenation and respiratory rate mcg IV seconds minutes Lockout 1 to 5 should be continuously monitored and 1:1 nursing should be strongly minutes considered. 5 minutes Active metabolite is normeperidine, a 25 to 50 mg IV IV potent respiratory depressant; 2 to 3 hours neonatal effect most likely if delivery 10 to 15 occurs between 1 and 4 hours after 50 to 100 mg IM minutes IM administration. 3 to 5 2 to 5 mg IV Infrequently used during labor; greater minutes IV 2 to 4 hours neonatal respiratory depression than 10 to 20 5 to 10 mg IM meperidine. minutes IM Remifentanil Opioid Meperidine (Demerol) Opioid Morphine Opioid Nalbuphine 10 mg IV Mixed opioid agonist/antagonis t 10 mg IM 2 to 3 Less nausea and vomiting than with minutes IV 3 to 6 hours meperidine; ceiling of respiratory 10 to 15 depression. minutes IM Drug Butorphanol (Stadol) Pentazocine (Talwin) Class Dose Onset 5 to 10 minutes IV Duration Mixed opioid 1 to 2 mg IV or IM 30 to 60 4 to 6 hours agonist/antagonist minutes IM 2 to 3 minutes IV Mixed opioid 30 to 60 mg IV/IM 2 to 3 hours agonist/antagonist 10 to 20 minutes IM Promethazine Phenothiazine (Phenergan) Hydroxyzine (Vistaril) Antihistamine Ketamine (Ketalar) Phencyclidine derivative Midazolam (Versed) Benzodiazepine Diazepam (Valium) Benzodiazepine Comments Maternal sedation similar to meperidine and phenothiazine; ceiling of respiratory depression; dysphoria. Ceiling of respiratory depression; dysphoria. May be used with opioids to mitigate nausea and vomiting; may produce 25 mg IM 10 to 20 3 to 4 hours hypotension. IV administration may (preferred) or IV minutes cause extravasation injury; administer slowly. May be used with opioids to mitigate nausea and vomiting; not used IV 25 to 50 mg IM 30 minutes 4 hours (painful on injection). IV dose should not exceed 1 mg/kg per 30 minutes; psychotomimetic effects 10 to 20 mg IV >“Twilight sleep” Inhaled NO2: Safety VERY SAFE all stages of labor IF: Correct dose Self administered, ONLY ( do not hold or attach mask) PRN Do not mix with sedatives/opioids>> “twilight sleep” Inhaled Nitrous Oxide in Labor Fetal/neonatal side effects: Crosses placenta No effect on FHR tracing Quickly removed from neonatal lungs by breathing No neonatal respiratory depression No effects on breastfeeding Labor effects: No effects on contraction frequency and labor progress Procedure: Woman holds mask tightly sealed over her face Starts inhaling 30 seconds before onset of contraction & through it Exhaling into the mask (scavenging) Safety concerns: Prolonged high-dose exposure (unlikely in labor) & effects on fetal brain Considered safe in all stages of labor Occupational exposure Inhaled NO2: other uses Perioperative Manual uterine exploration Lac repair (similar to local) D&C Labor exams for sensitive women IV or epidural placement External cephalic version (Berlit, 2013) NO2: Staff safety Odorless, colorless gas Environmental effects on staff: some association with infertility, SAB, PTL in dental hygienists (for Old free flow systems, not new FDA approved systems with scavenging) “scavenging systems” and pressure valves mitigate measured levels dosimetry badges available Pudendal Block Regional anesthesia technique Perineal distension in labor Perineal repair Fast acting Lasts 60-90 minutes Used in 2nd and 3rd stage of labor Broader coverage that local infiltrations No disruption of tissue to be repaired Pudendal Block Placement 1 % Lidocaine (no epinephrine) 10 ml per side Minimal maternal/fetal risks Potential complication: Hematoma Systemic toxicity with IV administration (aspirate) Neuraxial Analgesia Types: Epidural Spinal (intrathecal injection) Combined spinal/epidural Trained provider needed: Anesthesiologist Nurse anesthetist (CRNA) Neuraxial Analgesia Epidural >>> Spinal >>> Neuraxial Analgesia: Contraindications Consult with anesthesiologist if uncertain Refusal/inability to cooperate Spinal column abnormalities/spinal surgery Significant thrombocytopenia (< 50-60,000) Certain coagulopathies Localized infection Sepsis Maternal hemodynamic instability Skill/comfort of provider Labor Epidural Analgesia The most effective relief of labor pain High satisfaction rate Epidural space: Nerve roots Fat Lymphatics Blood vessels Effect > medication type & dose Labor Epidural Analgesia Epidural indications: Active labor pain Operative vaginal delivery C-section To decrease duration of pushing Medications: Local anesthetic (motor block) Bupivacaine (local anesthetic) – 0.250.5% Long duration Excellent sensory block Preserves some motor function Fentanyl/Remifentanil (potent synthetic opiates) Epidural – Fetal Side Effects FHR decelerationbradycardia Maternal hypotension Uterine hyperactivity & Increased uterine tone (opiates) More common with combined epidural/spinal Terbutaline 0.25 mg IV/SQ Epidural - Maternal/Fetal Side Effects Maternal hypotension (50%) Decreased vascular tone & venous return, peripheral vasodilation Incorporate pre-hydration (current evidence does not support unless combined spinal/epidural) Decreased uterine blood flow FHR decelerations (10-20 minutes after epidural) Spontaneous resolution IVF bolus Ephedrine (5-10 mg IV) Bladder distension Loss of sensation/motor control to void Bladder relaxation Catheter placement Epidural side effects Puritis from opiate component. (Zofran, Nubain) Nausea & vomiting secondary to hypotension? Opiate? (Zofran, Benadryl) Increased maternal temperature/fever Not fully understood Altered maternal thermoregulation More common in nulliparas, IOL, multiple SVEs, internal monitors Prolonged epidural >>> more fevers Neonates – more septic work-ups, but no increase in sepsis Epidural: Maternal Side Effects Postdural puncture (spinal) headache (1-4%) Oral analgesics Hydration Caffeine Blood patch Systemic toxicity CNS and CV symptoms from local Incorporate test dose (Lidocaine & epinephrine) anesthetic High spinal Hypotension, diaphragmatic paralysis Epidural & Labor Progress Multiple confounding variables Conflicting studies Duration of first stage C-section rates (most show no increase) Operative vaginal deliveries Are people in early dysfunctional labor more likely to receive epidurals? Some women have accelerated labor after epidural Decreased catecholamine levels (improved contractility) Would they speed up regardless? Some labors slow down after the epidural Would they slow down regardless ? Epidural & Labor Progress Increased duration of second stage of labor Decreased/no sensation to bear down Pelvic floor relaxation Persistent Occiput Posterior malposition Malposition > Epidural Epidural > Malposition Timing of epidural placement (latent vs. active labor) No increase in duration of labor No increase in C/S and operative deliveries No significant increase in maternal temperature Callahan, 2023 Spinal Anesthesia Intrathecal (subarachnoid) space: CSF Spinal nerves Blood vessels Intrathecal opiates Rapid onset Limited duration (90 minutes) Risks/Side effects: Fetal bradycardia Maternal pruritus, N/V “CSE” Combined Spinal/Epidural “Needle-throughneedle” technique Medicine deposited in subarachnoid space and epidural catheter placed in epidural space (continuous/PCEA infusion) Rapid onset of analgesia (5-10 minutes) Used in transition/2nd stage of labor King, T.L. & Brucker, M.C. (2019). Varney's Midwifery, 6th ed. Jones & Bartlett Learning, LLC.: Burlington, MA. SBN-13: 978-1284160211 References Practice guidelines for obstetric anesthesia: an updated report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia. Anesthesiology. 2016 Feb;124(2):270-300. Berlit, et al Effectiveness of nitrous oxide for postpartum perineal repair: A randomised controlled trial, Eur. J. Obstet. Gynecol. Reprod. Biol. 170 (2013) 329–332.. Callahan EC, Lee W, Aleshi P, George RB. Modern labor epidural analgesia: implications for labor outcomes and maternal-fetal health. Am J Obstet Gynecol. 2023 May;228(5S):S1260-S1269. doi: 10.1016/j.ajog.2022.06.017. Epub 2023 Mar 20. PMID: 37164496.