labor epidural analgesia

1. Labor Epidural Analgesia Dmitry Portnoy, MD Anesthesiology Department

2. 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

3. The Intensity of Pain in Labor

4. 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

5. 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

6. Indications for LEA PAIN 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, maternal request is a sufficient medical indication for pain relief�� Points of controversy When? Who? How?

7. Contraindications for LEA ABSOLUTE Patients refusal Inability to cooperate Increased intracranial pressure 2 mass lesion Infection at the site of needle placement Frank coagulopathy Severe hypovolemia Inadequate training RELATIVE Systemic maternal infection Preexisting neurological deficiency Mild or isolated coagulation abnormalities Relative (and correctable) hypovolemia Poor communication

8. 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 Fetal well-being is assessed and reassured (obstetrician?, midwife?, yourself?) Supporting personal is available and present Resuscitation equipment and drugs are immediately available in the area where LEA placed

9. Standard Technique of LEA Pre epidural check list is completed Aspiration prophylaxis (?) UTMB � 30 cc Bicitra Intravenous hydration (What? When? How?) 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 Maternal position ( sitting or lateral?) Sterile technique � not negotiable

10. Standard Technique of LEA (cont.) 7. Loss-of-resistance technique of your choice Catheter is threaded 3 to 5 cm into the space Secure taping (sponge? tegaderm? loop? tape?) Testing the catheter Aspiration test (say NO to big syringe!) Test dose (what? when? how?) 11. Inducing LEA ( Treat every bolus as a test dose!) 12. Assessment of LEA (sensory, motor, autonomic) 13. Repeat assessment every 1 to 2 hours

12. 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

13. 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

14. Etiology and Contributing Factors(Patient-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

15. 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

16. Management of Unsatisfactory Epidural

17. Management of Unsatisfactory Epidural

18. Labor Epidural Pearls (Humble Suggestions) Not always epidural is worth its risks Do not insist unless medically indicated Consider other pain control options when LEC placement is risky No epidural analgesia with instant onset (not even close to) 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

19. Avoiding Epidural Disasters (made ridiculously simple) Maintain constant verbal contact with patient Always aspirate before each injection Observe for passive return through the catheter Do not inject more than 4 ml of LA at a time Observe the patient at least 1.5-2 min between boluses If in doubts, repeat test dose. Still in doubts? Replace it After all, be mentally prepare to treat Convulsions Total spinal Cardiovascular collapse and arrest