Unsatisfactory Epidural Block for Labor Analgesia

1. Unsatisfactory Epidural Block for Labor Analgesia Dmitry Portnoy, MD Anesthesiology Department

2. Terms and Incidence of Unsatisfactory Epidural Block

3. The Physiology of Pain in Labor 1st stage 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 2nd stage 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

4. The Intensity of Pain in Labor

5. Boundaries of the Epidural Space Superior - the foramen magnum Inferior limit - the sacral hiatus and sacro-coccygeal membrane Anterior - the posterior longitudinal ligament covering the bodies of the vertebrae and the intervertebral discs Posterior - periosteum of laminae of the vertebrae and the ligamenta flava Lateral � periosteum of the pedicles and intervertebral foraminae

6. Spread of Epidurally Injected Solutions Epidurally administered drugs must travel through: dura matter arachnoid matter CSF pia matter white matter gray matter Rapid access via �dural cuff� Competing pathways: Uptake into epidural epidural fat Uptake into systemic circulation

7. Preoperative Assessment 34 y/o parturient, G4P3, at term, in active labor, cervical dilation 4 cm, posterior presentation of the fetus, complaints of increasing pain with contractions History Previous LEA x 2 for VSD without complications Tonsillectomy at age 7 y/o, GA without complications NKDA, no relevant medical history Physical examination Wt-102 kg, Ht-5�01��, HR-96, RR-20, BP-117/69, FHR-142 AW exam: MP-II, TMD-5, mouth-4 cm, neck-FROM Low back: mild scoliosis, palpable, but vague landmarks

8. Timeline 13:10 Patient in active labor, Cx-4 cm, requested LEA 13:14 Junior anesthesia resident at bedside 13: 42 Epidural catheter has been placed at L3-L4 Technically somewhat difficult � 3 attempts LOR by air at 8 cm, catheter threaded 5 cm into epidural space Test dose with 3 cc of 1.5% Lidocaine + Epi negative 13:42 � 13:58 Induction of epidural analgesia 0.125% bupivacaine � total of 12 cc (divided by 3+3+3+3) No pain relief, no signs of sensory blockade 14:00 Patient insists on epidural anesthesia 14:05 Senior anesthesia resident at bedside

9. Timeline (Continued) 14:04 � 14:25 LEC placement repeated at L2-L3 2 attempts, during placement patient complained of L. thigh pain LOR by air at 6 cm, catheter threaded 7 cm into epidural space Test dose with 3 cc of 1.5% Lidocaine + Epi - negative 14:25 � 14:38 LEC activated 2 cc 1.5% Lidocaine + 10 cc 0.125% Bup (3+3+2+2) Epidural infusion of 0.125% Bup + Fent at 10 cc/hr 10 min after � some pain relief 16:10 Called for increased pain, mostly on the left side 16:10 � 16:26 (3+3+3) cc bolus with Pt in left lateral position 16:35 No relief, catheter pulled back 1.5 cm, rebolused 16:57 Significant improvement, epidural infusion at 12 cc/ hr

11. Timeline (Continued) 20:35 Labor progressed to full cervical dilation. Patient complaints of severe bilateral pain in low abdomen and vagina. 20:55 No relief after (3+3+3)cc of 0.125 Bup. Sensory level -T8 21:20 Some relief after 75 mcg of epidural Fentalyl 21:50 Severe pain resumes. Called for low outlet forceps delivery secondary to arrest of second stage 22:00 Patient in OR # 6, in semi-upright position, routine monitors on 22:15 15 cc (5,5,5) of 3% Chloroprocaine administered epidurally 22:20 Adequate sacral anesthesia achieved 22:42 Baby delivered by low forceps instrumentation with Apgar 6/9

13. Etiology and Contributing Factors Anatomical considerations Midline epidural structures plica mediana dorsalis (dura matris) - Luyendijk , 1963, epidurography midline adhesion of dura mater - Singh, 1967 epidural plica mediana dorsalis - Savolaine, 1988 using CT dorsomedian connective tissue band - Blomberg, 1986, epiduroscopy median epidural septum Connective tissue plane on both dorsolateral compartments of the epidural space - Gallart, 1990 Spinal nerve root diameter - Galindo, 1975

14. Etiology and Contributing Factors Technique, methodology and equipment  Initial catheter misplacement - incorrect placement Malposition in anterior or paravertebral (lateral) epidural space Transforaminal escape Increased skin-to-epidural space distance Catheter related Catheter migration after initial proper placement The distance of insertion inside the epidural space Uniport versus multiport epidural catheters Catheter malfunction and catheter defects Air for loss-of-resistance technique Method of injecting local anesthetic Patient�s position

15. Etiology and Contributing FactorsPatient-related and other risk factors Inherited and acquired anatomical features Morbid obesity and body mass index greater than 30 Short and tall individuals Previous spinal surgery and a variety of musculoskeletal disorders History of a previous placement of epidural catheter Radicular pain during epidural placement Posterior presentation of the fetus Inadequate analgesia from the initial dose Duration of labor more than 6 hours Technical skills, or performance factor

16. Unsatisfactory Labor Epidural AnalgesiaManagement Options Catheter manipulation Additional volume of local anesthetic Patient�s position manipulation Replacement of the epidural catheter A single shot spinal anesthesia Continuous spinal anesthesia Combined spinal-epidural anesthesia Placement of an additional epidural catheter Supplementation with intravenous medications

17. Management of Unsatisfactory Epidural

18. Management of Unsatisfactory Epidural

19. Labor Epidural Pearls (Humble Suggestions) No epidural is better than complication from one Do not insist unless medically indicated Consider other pain control options when LEC placement is risky Realistic expectations and labor dynamics Constant communication during procedure Treat every dose as a test dose The longer skin-to-epidural distance, the deeper catheter inside the space Do not allow the level to recede No LA with instant onset (not even close to)