Newer Analgesia Techniques CSE Julian F. Martinez-Tica, M.D. Department of Anesthesiology

INTRODUCTION Labor results in severe pain for most women. The ideal labor analgesia technique should: Considerably reduce the pain of labor. Allow the parturient to actively participate in the birthing experience. Have minimal effect on the fetus or the progress of labor. New labor analgesia techniques approach this goal. The lecture will include mainly combined spinal-epidural analgesia (CSE), spinal opioids, patient controlled epidural analgesia (PCEA), and continuous spinal analgesia (CSA).

INTRODUCTION Regional anesthesia has a well-established role in labor. The technique of combined spinal-epidural CSE analgesia has been described in labor. The main advantage of this method is the speed of onset and completeness of analgesia. The CSE gives rapid, reliable analgesia without motor block, and allows women walk about. We discuss about the history, clinical experience, advantages and disadvantages of the CSE technique.

Table 1 Historical Development of CSE Technique Author Year Surgery Indication Single Segment Same needle Soresi 1937 Gen. surgery Needle-Thru-Ndl .(N-T-N) Coates, Mumtaz 1982 Orthopedic surg. N-T-N Carrie&O’Sullivan 1984 Cesarean section Abouleish et al 1991 Labor analgesia Ndl-Beside-Ndl double barrel Eldor 1988 Lower body surg. Epid and Intrathec. catheters Vercauteren et al 1993 High-risk patients Ndl-Beside-Cath Van Dijk et al 1994 Lower body surg. Double Segment Sacral block followed by SAB Rodzinski 1923 Epidural Block followed by SAB Curelaru 1979 Gen. Surgery

by Julian Martinez Tica Photo Album by Julian Martinez Tica Figure 7. A-C Various possibilities for CSE block failure owing to incorrect technique. A, Length of spinal needle protruding from the tip of the epidural needle is too short. B, Tip of spinal needle “tents” the dura but fails to pierce it. C, Malposition of epidural needle. D, Correct position of epidural and spinal needles.

Table 2 Suggested Drug Doses and Mixture for the CSE Technique in Labor Administration Local Anesthetic Opioid Intrathecal Injection Bup. 0.1%-0.25% 1.0-2.5 mg Fen 20-25 ug or Suf 3-10 ug Epidural Top-ups Bup. 0.1-0.25%, 10-15 mg for 1st stage labor. During 2nd stage of labor or for assisted delivery (e.g. forceps) Fen 20-25 ug or Suf 5-10 ug

Advantages of the Combined Spinal-Epidural Technique The rapid onset and completeness of analgesia during labor. Reliable analgesia without motor block and allows women walk about. Initial epidural needle placement allows the spinal needle to be guided near the dura. The CSE results in lower maternal, fetal, and neonatal blood concentration of local anesthetic than with epidural anesthesia alone. CSE analgesia is associated with more rapid cervical dilation compared with epidural analgesia alone.

Advantages of the Combined Spinal-Epidural Technique 6. The CSE is less likely to result in inadequate anesthesia than either technique alone. 7. With the CSE technique the initial analgesia provided by the intrathecal injection can assist in placing or replacing an unreliable epidural catheter. 8. CSE block may decrease the risk of PDPH 9. Unintended dural puncture with the epidural needle is more likely than with CSE block.

Ambulation With Low-Dose CSE Requires No postural hypotension or symptoms Minimal or no motor block Minimal or no proprioceptive block A cooperative, understanding parturient Monitoring facilities, including the fetus Presenting part of fetus engaged and well applied to cervix

Ambulation with low-dose CSE requires the following precautions Avoid postural hypotension Monitor motor block Avoid aortocaval compression and Valsalva straining Avoid epidural catheter displacement; ensure good fixation of catheter to skin Provide a suitable environment, for example, shoes, safe floors, no cables, and the alike. Simplify IV therapy by use of a hep-lock IV cannula or have the parturient ambulate with an IV pole on wheels.

Possible Disadvantages of the CSE Technique Catheter migration through the dural hole -Subarachnoid -Intravenous Drug Leakage -Into the subarachniod space -Change in epidural pressure 3. Risk of Meningitis 4. Inability to test epidural catheter 5. Contamination of CSF

Possible Complications and Side Effects of Intrathecal Opioids for Labor 1.- Pruritus 2.- Nausea / Vomiting 3.- Hypotension 4.- Urinary retention 5.- Uterine hyperstimulation and fetal bradycardia 6.- Maternal Respiratory Depression

Cerebrospinal Fluid (CSF) Flow Through Different Spinal Needles Needle Type Needle Length Time to First CSF Drop in And Size (G) (mm) Needle Hub (sec) Sprotte 22 (Quincke) 90 (120) <1 (20) Sprotte 25 90 1-2 Sprotte 27 90 (120) 2 (160) B-D Whitacre 27 (Spinocan) Sitting Position 120 9.4 (20.7) Lateral Position 120 12.3 (46.8)

Incidence of Postdural Puncture Headache (PDPH) Following Combined Spinal-Epidural Block Surg/Proc No. Patients PDPH(%) Sp. Ndl/Type Reference C-Section 400 0.5 - - Dennison C-Section >1000 0 26G - Brownridge C-Section 300 0.7 26G Q Kumar L&D 62 2.5 26G - Abouleish L&D 1080 0.28 26G GM Birnbach L&D 6000 0.13 27G W Cox Obstetric 219 0.9 25-27 W Newman

Table 3 Suggested Drug Doses and Mixtures for CSE Anesthesia PROCEDURE ADMINISTRATION LOCAL ANESTHETIC OPIOID NOTES Standard CSE for C -Section Intrathecal Injection Bup 0.5%-0.75% 7.5-15.0 mg Fen 20-25 ug Suf 3-5 ug Epi 2-5 ug May be ad Epidural Top-up Bup 0.25-0.5% 10-40 mg Suf 5-10 ug Sequential Bup 0.5% 5.0-12.5 mg Suf 3-5 ug 10-50 mg

Newer Labor Analgesia Techniques Continuous infusion of dilute local anesthetic plus opioid - A common infusion for labor analgesia is: 0.0625% bupivacaine with 2-4 mcg/ml fentanyl, with or without epinephrine, infusing at 10-14 ml/hour. These infusions have provided better pain relief while producing less motor block. Maternal and neonatal drug concentrations have been demonstrated to be safe for both mother and neonate.

Newer Labor Analgesia Techniques Patient controlled epidural analgesia (PCEA) Continuous basal infusion in addition to patient controlled boluses. Provides for a more even block and greater patient satisfaction. Self-administration or self control and maintenance of self- esteem may be vital to a positive experience in childbirth. Reasonable hourly limits are prescribed, and periodic assessments have to be made by an anesthesiologists.

Newer Labor Analgesia Techniques Continuous spinal analgesia with microcatheters -Due to an association with cauda equina syndrome, spinal microcatheters have been restricted by the FDA. -An ongoing multi-institutional study is being undertaken with FDA approval (safety and efficacy of delivering sufentanil and /or bupivacaine into the intrathecal space via a 28g catheter - To date it appears that continuous spinal analgesia for labor using a 28g microcatheter is safe and may offer several advantages.

Continuous spinal analgesia with microcatheters For very high-risk parturients, many anesthesiologists are using spinal “macrocathetes”(standard epidural catheters placed in the spinal space following an intentional wet tap) This technique has a high incidence of spinal headache or Post Dural Puncture Headache (PDPH). It gives the greatest control in providing neuraxial analgesia and anesthesia.

Summary 1.- CSE is a technique of neuraxial blockade that provides greater flexibility and reliability than either spinal or epidural alone. 2.- Single-space, needle-through-needle CSE technique is quickly becoming the most popular method of neuraxial analgesia for labor worldwide 3.- Selective neural blockade is readily achieved with CSE and produces a pain-free parturient who can ambulate.

Summary 4.- The CSE technique could be used in early labor (< 4cm), advanced labor (> 8cm), and second stage of labor. 5.- Small doses of lipid-soluble intrathecal opioids provide excellent analgesia for the first stage of labor. The addition of 1.25-2.5 mg of bupivacaine to the opioid improve the quality of analgesia for the second stage of labor.

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