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Common Complications in Obstetric Anesthesia

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Common Complications in Obstetric Anesthesia and How to Avoid Them. Tom Archer, MD, MBA UCSD Anesthesia Resident Lecture Series January 23, 2013 – PowerPoint PPT presentation

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Title: Common Complications in Obstetric Anesthesia


1
Common Complications in Obstetric Anesthesia
and How to Avoid Them.
  • Tom Archer, MD, MBA
  • UCSD Anesthesia Resident Lecture Series
  • January 23, 2013

2
My definition of common
  • A complication you will see at least once in a
    career in which you do some OB anesthesia.
  • If you do OB anesthesia regularly, you will see
    most of the following complications many, many
    times.

3
Common OB Anesthesia Complications
  • Difficulty placing spinal or epidural, causing
    patient distress.
  • Sketchy-dural (poor epidural)
  • Post-dural puncture headache (PDPH)
  • Hypotension after neuraxial block

4
Common OB Anesthesia Complications
  • High spinal or epidural? respiratory failure /-
    hypotension
  • Low spinal or epidural ? anesthesia failure
  • Intraoperative pain (incomplete block)
  • Cant intubate (and cant ventilate?) under GA.

5
Common OB Anesthesia Complications
  • Fetal bradycardia after CSE or epidural
  • Post-delivery lower extremity neuropathy

6
I am not going to discuss
  • Local anesthetic or contaminant toxicity to
    nerves (rare in modern practice).
  • Direct needle trauma to nerve roots or spinal
    cord (rare).
  • Epidural abscess or hematoma (rare).
  • Aspiration

7
Difficulty placing spinal or epidural, with
patient distress.
8
Difficulty placing spinal or epidural, with
patient distress.
  • We have all been there, many times. At least I
    have.
  • 20-60 minutes of effort.
  • Patient is in tears. You are sweating.
  • You have called for help. They couldnt do it
    either.
  • Is this inevitable, or is there a way to reduce
    the frequency of such events?

9
Making epidural placement easier for patient and
doctor
  • Management of expectations 5-10 of the time
    the epidural does not work properly. We will do
    our best Dont promise perfection!
  • Achieve patient rapport and cooperation.
  • Demonstrate posture.
  • Reinforce positioning patients straighten up
    over time when in pain.
  • IV fentanyl makes a big difference.

10
Making epidural placement easier for patient and
doctor
  • If you anticipate difficult placement (e.g. an
    obese patient) consider IV fentanyl and
    ultrasound before you start.
  • Dont wait until patient is in tears to give
    fentanyl and to use ultrasound.

11
Can ultrasound make neuraxial block easier?
  • Many practitioners say it is an unnecessary waste
    of time. I disagree, at least in selected cases.
  • Ultrasound can help identify
  • MIDLINE (true location of spinous processes)
  • DEPTH TO LIGAMENTUM FLAVUM
  • SPINAL ROTATION, IF PRESENT

12
Paramedian Sagittal
Paramedian Sagittal Oblique
Most useful views
Transverse
13
Spinous processes are not always
directly cephalad from gluteal
cleft
Tense paraspinous muscles can be mistaken for
spinous processes
Line running cephalad from gluteal cleft
14
Skin surface
Emitted sound
Vertical skin mark
Reflected sound
Ultrasound probe, lateral view
15
Transverse process
16
Skin surface
Ultrasound probe is angled until posterior
longitudinal ligament is the brightest.
Emitted sound
Reflected sound
Best insertion angle is determined for each
patient by maximizing brightness of posterior
longitudinal ligament (PLL) on the ultrasound
screen and remembering that angle for actual
needle insertion. Best angle is usually 5-15
degrees cephalad from a line perpendicular to the
skin.
17
Dura /ligamentum flavum complex
Posterior longitudinal ligament
Interlaminar foramen (black shape inside white
rectangle)
18
Vertical skin mark 1, centered on probe
Horizontal skin mark 2, centered on level of
probe (between spinous processes)
Underlying spinous process (dark blue)
Insertion point is the intersection of horizontal
and vertical lines through skin marks.
Line running cephalad from gluteal cleft
19
Skin surface
10 cm
Ultrasound probe
Best insertion angle
Ultrasound enables us to measure distance to the
ligamentum flavum to within a centimeter or so.
Estimate, if incorrect, is almost always too
small, due to compression of adipose tissue
during the measurement.
20
Sketchy-dural (poor epidural)
21
Sketchy-dural
  • They happen, no matter how good you are.
  • Management of expectations. Dont promise the
    patient a perfect epidural.
  • That said, here is my advice to minimize impact
    of sketchy-durals on our care

22
Sketchy-dural
  • Be honest with yourself. Many sketchy-durals are
    simply not in the right place.
  • Check what is really going on, with ice systemic
    fentanyl can mask a non-epidural.
  • Have a low threshold for replacement.

23
Sketchy-dural
  • A disadvantage of IV fentanyl is that the
    analgesia it provides can mask a poor epidural.
  • Ask the patient how her legs feel. The answer
    should be numb or tingly. Fine is NOT a
    good answer it means there is no block!
  • Epidurals requiring more than one MD bolus have a
    higher failure rate for CS.

24
Sketchy-dural
  • What exactly is the problem? Talk with and
    examine the patient.
  • Just doesnt work at all?? replace
  • One sided?? bolus with less-affected side down.
    Next step? pull back one cm. Next step? replace
  • Hot spot but otherwise OK?? Position side with
    hot spot downwards and bolus with stronger
    local anesthetic epinephrine fentanyl.

25
Sketchy-dural
  • Think about other causes of abnormal pain?
    fetal head pressing on nerves, uterine rupture,
    placental abruption, intradural placement.
  • There should be no pain (or much sensation at
    all) with an epidural injection.
  • Discomfort in the back during epidural injections
    suggests intramuscular or subcutaneous injection.

26
Sketchy-dural
  • Consider ultrasound the second time (or the first
    time!) to confirm
  • MIDLINE (true location of spinous processes)
  • DEPTH to ligamentum flavum
  • ROTATION of the spinal column

27
Sketchy-dural goes to CS.
  • Can you do a spinal on top of a sketchy-dural?
  • Yes, but do it carefully and understand that high
    spinal may occur.
  • CSE with low intrathecal dose, or titrated
    epidural are options.

28
Post dural puncture headache(Spinal headache)
29
Post dural puncture headache(PDPH)
  • Third most common cause of lawsuit in OB
    anesthesia.
  • Can be disabling and distressing, particularly
    for a mother trying to take care of a newborn and
    a household.

30
Post dural puncture headache(PDPH)
  • Third most common cause of lawsuit in OB
    anesthesia.
  • Can be disabling and distressing, particularly
    for a mother trying to take care of a newborn and
    a household.

31
PDPH
  • Midline frontal and/or occipital. Not
    lateralized!
  • May extend into neck (stiff neck)
  • Worse with upright posture (usually immediate
    onset, may be delayed 20 minutes)
  • Relief with flat posture (usually immediate).

32
PDPH
  • May be associated with diplopia (abducens palsy)
    and muffled hearing or tinnitus.
  • May be associated with NV.

33
But is it really PDPH?
  • The key question Could it be something else?
  • If you Rx PDPH and it is something else you incur
    two problems unnecessary treatment risk AND
    missed Dx.
  • It could be lactation HA, migraine, subdural
    hematoma, brain tumor, AVM, cortical vein
    thrombosis, dural sinus thrombosis, etc.

34
Yes, it is PDPH
  • Conservative therapy vs. Blood patch?
  • Conservative therapy NSAIDs, other oral
    analgesics, caffeine, fluids, salty foods.
  • Epidural blood patch (EBP) 10-30 mL of patients
    blood injected into epidural space.
  • EBP complications back pain, leg paresthesias
    (common), epidural abscess or adhesive
    arachnoiditis (rare).

35
In favor of EBP
  • Severe disability, gt24 hours of Sx.
  • Patient confined to bed unable to function
  • Associated signs Sx of decreased ICP (abducens
    palsy, hearing changes, NV)

36
In favor of conservative therapy
  • Uncertain Dx.
  • Patient uncomfortable but able to function.
  • If they are sitting up in bed, or walking, when I
    enter the room, I am hesitant to do a blood
    patch.

37
PDPH etiology
  • Traditional theory loss of CSF leads to brain
    settling down in skull, with resultant traction
    on dura and nerves
  • Vasodilation theory loss of CSF leads to
    translocation of CSF to lumbar area with upright
    posture. Volume in skull must remain constant,
    hence? vasodilation HA.
  • Therapeutic efficacy of caffeine and
    vasoconstrictors supports vasodilation theory

38
Hypotension after labor epidural
39
Hypotension after labor epidural
  • Occurs VERY commonly. 30-40 of the time?
  • Consider low dose prophylactic phenylephrine or
    ephedrine after block placement.

40
Hypotension after labor epidural
  • 95 of fetal distress after epidural is due to
    hypotension.
  • The other 5 may be uterine hypertonus due to
    rapid pain relief (discussed later).
  • Both things might be happening.
  • When there is fetal distress? palpate uterus!

41
Hypotension after labor epidural
  • Routine therapy for hypotension (in absence of
    uterine hyperstimulation) is
  • Position change (Left or right side down).
  • Fluid bolus
  • Vasopressors
  • Oxygen, if there is fetal bradycardia.

42
Hypotension with labor epidural
  • Treat hypotension early, treat often.
  • Prevention with low-dose vasopressor has very
    little downside.
  • Is there a role for non-invasive cardiac output
    measurement in labor to detect occult IVC
    obstruction?

43
Physiology of post-block hypotension
44
Sympathetic efferents exit spinal cord from T1 to
L2. Low sympathectomy Blockade of
T5-L2? Splanchnic vasodilation and pooling.
Reduced venous return (CO), especially with IVC
obstruction. Reduced SVR.
17
http//health.usf.edu/nocms/medicine/anatomylab/mo
dules/pelvic_autonomic_module/pelvic_page02.html
45
Sympathetic efferents exit spinal cord from T1 to
L2. High sympathectomy Blockade of T1-T4 ?
warm vasodilated hands, further reduced SVR,
Horners syndrome, ? bradycardia. Blockade of
T5-L2? Splanchnic vasodilation and pooling.
Reduced venous return (CO), especially with IVC
obstruction. Reduced SVR.
18
http//health.usf.edu/nocms/medicine/anatomylab/mo
dules/pelvic_autonomic_module/pelvic_page02.html
46
T5-L2 sympathectomy causes pooling of blood in
the splanchnic vessels, reducing venous return
and CO.
20
47
Splanchnic vasculature has alpha and beta
receptors at multiple sites.
Alpha 12 constrict splanchnic capacitance vessels
Alpha 12 constrict splanchnic arteries
Beta 2 dilates hepatic veins
21
Figure modified by Archer TL
48
Decreased venous return and cardiac output due
to sympathectomy is exacerbated by obstruction
of IVC.
22
49
If IVC is open, venous return is unimpeded and
cardiac output is maximized.
23
http//www.manbit.com/OA/f28-1.htm
Manbit images
50
Given late!
29
Diagram modified by Archer TL
51
Avoid cardiac arrest after neuraxial block
  • Talk with patient during test dose. Heart
    pounding, legs numb or weak? Have Ambu bag and
    pressors immediately available.
  • Allow 2-3 minutes for test dose to be positive.
    Consider dosing epidural fentanyl 100 mcgm after
    test dose since it will augment block but not
    burn any bridges.
  • Stay with patient 15-30 minutes after initiation
    of block to r/o hypotension, hyperstimulation or
    excess block. Do charting. Start infusion. Make
    sure nurse will stay with patient after you
    leave.

30
52
Cardiac arrest in labor room do the CS in the
labor room!
  • Four minute rule start CS within 4 minutes of
    arrest. Deliver baby within 5 minutes to avoid
    neonatal brain damage.
  • Our findings imply that perimortem cesarean
    delivery during actual arrest would require more
    than 5 minutes and should be performed in the
    labor room rather than relocating to the
    operating room.

33
Obstet Gynecol. 2011 Nov118(5)1090-4. Labor
room setting compared with the operating room for
simulated perimortem cesarean delivery a
randomized controlled trial. Lipman S, Daniels K,
Cohen SE, Carvalho B.
53
High spinal (or epidural)
54
Sympathetic efferents exit spinal cord from T1 to
L2. High sympathectomy Blockade of T1-T4 ?
warm vasodilated hands, further reduced SVR,
Horners syndrome, ? bradycardia. Blockade of
T5-L2? Splanchnic vasodilation and pooling.
Reduced venous return (CO), especially with IVC
obstruction. Reduced SVR.
18
http//health.usf.edu/nocms/medicine/anatomylab/mo
dules/pelvic_autonomic_module/pelvic_page02.html
55
High or Total Spinal
  • A circulatory as well as respiratory emergency.
  • You will have to assist or control ventilation.
  • You must recognize situation immediately and act
    rapidly and with confidence so that patient does
    not panic (too much).

56
High or Total Spinal
  • Say three things
  • Youre going to be OK.
  • This happens sometimes when the spinal goes too
    high.
  • Im going to help you breathe.

57
High or Total Spinal
  • Do this
  • Unwrap circle system tubing and mask and close
    down pop-off valve.
  • Put mask on face and assist ventilation. Explain
    what you are doing. Patient is panicking.

58
High or Total Spinal
  • Do this
  • Feel for a pulse and if weak (or just
    empirically) give ephedrine 10-25 mg. Atropine
    for bradycardia.
  • Check BP, but all that really matters is
    ventilation and a good pulse.

59
High or Total Spinal
  • Should you intubate?
  • It depends, but ventilation trumps intubation.
  • Ventilation even trumps aspiration.
  • My rule of thumb LOC, total apnea? intubate. But
    stabilize BP and oxygenation first, even before
    intubation!

60
Low spinal
61
Low spinal
  • Hyperbaric (bupivacaine) solution will pool in
    the dural sac below the sacral promontory if
    patient is allowed to sit for too long after the
    intrathecal injection.
  • Trendelenburg position often used to move level
    up but no proof it really works.

62
Low spinal
  • Cough often used to move level up-- but no
    proof it really works.
  • Tburg flexion of thighs on the abdomen
    straightens lumbar curve and raises
    intra-abdominal pressure.
  • I believe this works.

63
Supine position Sacral promontory can be a
barrier to cephalad spread
Seated injection and prolonged upright posture
allow pooling of hyperbaric solution
Hyperbaric solution injected here can pool here
Modified from Delaney Radiologists
64
Avoiding a low spinal
  • Have patient lie down rapidly after intrathecal
    injection. Have her position herself on the OR
    table. Trendelenberg? Cough?
  • Flexion of thighs on the abdomen to flatten
    lumbar curve and to increase intra-abdominal
    pressure.

Image from Boba, Inc.
65
Repeat the spinal?
  • Bupivacaine takes 15-20 minutes for full effect,
    so dont rush it.
  • Beware of high or total spinal if you repeat the
    injection.
  • Hows the airway?
  • Epidural may be better.

66
Fetal bradycardia after neuraxial analgesia
67
Fetal bradycardia after neuraxial analgesia
  • Classic scenario for hypertonic uterus is
    Patient has oxytocin augmentation of labor and
    severe pain. CSE with lipid soluble narcotic is
    given? rapid pain relief. Fetal bradycardia
    occurs 10-30 minutes after the block. Loss of
    beta stimulus?
  • May or may not be accompanied by hypotension, but
    hypertonic uterus is a separate phenomenon,
    requiring uterine relaxation. Correction of BP is
    not enough!

68
Figure 2 Uterine contractions periodically
deprive placenta of perfusion.
Upper body
Uncompressed aorta and iliac arteries
Minimal collateral venous return to heart via
lumbar and azygos system
Open IVC
Fetal O2 supply
Uterine contractions
69
Uterine hyperstimulation due to excessive
oxytocin augmentation of labor Solution is NOT
always emergency CS. Rather, it is INTRAUTERINE
RESUSCITATION using TIME and TERBUTALINE or NTG
Tak Yeung Leung, MDa, b, , (Professor), Terence
T. Lao, MDa (Professor)
70
Detecting uterine hyperstimulation
  • Key maneuver is to think of the possibility and
    to evaluate uterine tone by palpation or IUPC
    during fetal bradycardia.
  • Recognition of uterine hyperstimulation and
    reversal with terbutaline SC or NTG SL or IV can
    avoid an unnecessary CS!

71
Intraoperative pain during CS
72
Intraoperative pain during CS
  • Management of expectations dont promise a
    pain-free experience.
  • Discuss intraoperative pain management options
    ahead of time. What will patient tolerate?
  • Mild discomfort? fentanyl local infiltration?

73
Intraoperative pain during CS
  • More discomfort? Fentanyl, midazolam ketamine
    (low dose and maintain responsivenss). Keep your
    suction at the ready.
  • Severe discomfort? RSI/ GA.

74
Choice of neuraxial technique when airway is bad.
  • Consider avoiding CSE if airway is bad epidural
    may fail, leaving patient with surgery underway
    and disappearing block.
  • If airway is bad, straight epidural or continuous
    spinal anesthesia may be a better choice than
    CSE, since you know it works from the outset,
    before surgery starts.

75
Cant intubate under GA
76
Cant intubate under GA
  • A few comments only
  • 1) Pregnancy involves weight gain and airway
    edema.
  • 2) Pre-eclampsia and pushing make 1) worse.
  • 3) Nose bleeds easily in pregnancy.

77
Cant intubate under GA
  • 4) Position every patient assuming you will have
    to intubate her (e.g. ramp, Glidescope, etc,
    available if need foreseen).
  • 5) Avoid CSE if airway is unfavorable for
    intubation. The reason is epidural part of CSE
    may fail when you try to activate it.
  • 6) Continuous epidural or spinal is better if
    airway is bad. That way you know anesthesia will
    work as long as you need it, before surgery
    starts.

78
Management of cant intubate situation
  • Elective procedure? awaken patient and secure
    airway by other means (e.g. AFOI).
  • Emergency procedure? LMA?, careful ventilation,
    good paralysis (avoids coughing and retching).

79
Post-delivery lower extremity neuropathy
80
Post-delivery lower extremity neuropathy
  • Post-delivery does not Due to anesthesia
  • Vast majority of post-delivery neuropathies are
    due to nerve stretch, pressure, compression or
    ischemia not due to needle damage or local
    anesthetic toxicity.
  • Obstetric palsy from fetal head, forceps or
    positioning. Often seen without anesthesia.

81
Post-delivery lower extremity neuropathy
  • So, relax when you see these patients!
  • You probably did not (directly) cause it-- and it
    will almost certainly resolve over time.
  • On the other hand listen well, be sympathetic
    and get proper consultation and therapy.
  • Do not be dismissive of the problem!

82
Post-delivery lower extremity neuropathy
  • Take a good history and do a good physical.
  • Rule out signs and symptoms of meningitis, spinal
    hematoma or infection.
  • Do not hesitate to get Neurology consultation.
  • Stay in touch with the patient.

83
Obstetric palsy
  • From nerve compression within the pelvis, by
    fetal head, forceps or retractors.
  • Often blamed on neuraxial anesthesia.

84
Pelvic brim is the red line. Fetal head is
engaged when biparietal diameter is below
pelvic brim. Fetal head or forceps can damage
nerves (lumbosacral trunk or obturator) at sacral
promontory portion of pelvic brim.
http//www.obstetricexcellence.com.au/questions-an
d-answers/engagement-of-the-foetal-head
85
Pelvic brim
86
Peripheral nerves in the pelvis. Pelvic brim
Dote Anatomy Topics
87
Vulnerable nerves in pelvis Lateral femoral
cutaneous (at inguinal ligament) Lumbosacral
trunk Obturator Femoral Sciatic
Cited in Wong et al
88
Safeguards to Minimize Peripheral Nerve
Compression
  •   
  • Be watchful for patient positioning that
    contributes to nerve compression     
  • Avoid prolonged use of the lithotomy position
    regularly reduce hip flexion and abduction.    
  • Avoid prolonged positioning that may cause
    compression of the sciatic or peroneal nerve.   

F. Reynolds in Chestnut
89
Safeguards to Minimize Peripheral Nerve
Compression
  • Place the hip wedge under the bony pelvis rather
    than the buttock.    
  • Use low-dose local anesthetic/opioid combinations
    during labor to minimize numbness and allow
    maximum mobility.     
  • Encourage the parturient to change position
    regularly.     

F. Reynolds in Chestnut
90
Peripheral Neuropathy Syndromesin Obstetrics
  • Meralgia Paresthetica lateral femoral
    cutaneous nerve (pure sensory) numbness of
    lateral thigh. Common in pregnancy.
  • Femoral nerve damage from prolonged hip flexion?
    weak quadriceps. Cant straighten leg and climb
    stairs.

91
Peripheral Neuropathy Syndromesin Obstetrics
  • Foot drop Impaired foot dorsiflexion due to
  • Common peroneal nerve at fibula (leg holders)
  • Lumbosacral trunk at pelvic brim (fetal head)
  • Impaired dorsi- and plantar-flexion of foot and
    numbness below knee Sciatic nerve damage.
    Pressure on buttock during long CS? Diabetic
    patient?
  • Impaired adduction of thigh and inner thigh
    numbness obturator palsy at pelvic brim

92
The End
93
Extra slides
94
Spinal nerve roots are within the spinal canal.
Dorsal root ganglion is at intervertebral foramen.
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