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

T10
L1
S2
S4
http//www.manbit.com/oa/oaindex.htm
4
The Intensity of Pain in Labor
http//www.manbit.com/oa/oaindex.htm
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

From Cousins, Neural Blockade
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

From Cousins, Neural Blockade
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-501, 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

• 1310 Patient in active labor, Cx-4 cm, requested
  LEA
• 1314 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
• 1342 1358 Induction of epidural analgesia
• 0.125 bupivacaine total of 12 cc (divided by
  3333)
• No pain relief, no signs of sensory blockade
• 1400 Patient insists on epidural anesthesia
• 1405 Senior anesthesia resident at bedside

9
Timeline (Continued)

• 1404 1425 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
• 1425 1438 LEC activated
• 2 cc 1.5 Lidocaine 10 cc 0.125 Bup (3322)
• Epidural infusion of 0.125 Bup Fent at 10
  cc/hr
• 10 min after some pain relief
• 1610 Called for increased pain, mostly on the
  left side
• 1610 1626 (333) cc bolus with Pt in left
  lateral position
• 1635 No relief, catheter pulled back 1.5 cm,
  rebolused
• 1657 Significant improvement, epidural infusion
  at 12 cc/ hr

10
From   Asato Anesth Analg, Volume
83(3).September 1996.519-522
11
Timeline (Continued)

• 2035 Labor progressed to full cervical dilation.
  Patient complaints of severe bilateral pain in
  low abdomen and vagina.
• 2055 No relief after (333)cc of 0.125 Bup.
  Sensory level -T8
• 2120 Some relief after 75 mcg of epidural
  Fentalyl
• 2150 Severe pain resumes. Called for low outlet
  forceps delivery secondary to arrest of second
  stage
• 2200 Patient in OR 6, in semi-upright
  position, routine monitors on
• 2215 15 cc (5,5,5) of 3 Chloroprocaine
  administered epidurally
• 2220 Adequate sacral anesthesia achieved
• 2242 Baby delivered by low forceps
  instrumentation with Apgar 6/9

12
Etiology and Contributing Factors in
Unsatisfactory Epidural Block
Unsatisfactory epidural block
Patient and surgical factors
Performance factor
Anatomical considerations
Methodology and equipment
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
• Patients 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
• Patients 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)