Transcript Slide 1

Hypotension and respiratory
failure after epidural test dose in
a patient from the Birth Center.
Tom Archer, MD, MBA
Clinical Professor and
Director, Obstetric Anesthesia
UCSD Department of Anesthesiology
November 7, 2012
1
UCSD Birth Center (4th floor Hillcrest hospital):
The practice philosophy is “natural” and
“homelike” childbirth, yet with immediate
access to advanced care for mother and
infant.
We strive for an excellent relationship
between midwives, obstetricians, nurses,
anesthesiologists.
2
“…labor support techniques that can help women give
birth with little or no pain medication:
•
•
•
•
•
•
•
Walking during labor
Hydrotherapy (shower or tub)
Birth stools
Birth balls
Breathing techniques
Massage
Music”
UCSD Birth Center website
4
IV fluids and IV pain meds are
available if needed.
• “Should the need arise, intravenous fluids and pain
medication are available.
• If the pain is too challenging, or if a complication
should arise, the option of transferring to the Labor
& Delivery Unit for epidural anesthesia or more
intensive medical care is available.”
UCSD Birth Center website
5
ROM at
home
0305
A long, painful labor is documented in this
time line.
“Strong rectal pressure” 6-7 cm
dilated. Encouraged to get up to
shower. Doula present.
2320
1
0808
Breakfast
0540
2136
1646
Admit to BC. Mild
ctx q5-7 min.
“Pt desires
augmentation with
castor oil.”
Admit to L&D
(awaiting BC
bed). Not in
labor.
2018
“Asking for pain meds”.
“Large emesis after
dinner.” Nubain 10 mg IV.
4 cm dilated.
Painful contractions.
Squatting at bedside.
Uses birthing ball.
FOB and mother
providing labor
support.
0
0:00
4:48
9:36
14:24
19:12
0:00
4:48
Events 8/6/2012
6
0441
0040 Out of shower and into tub.
Pt breathing hard through ctx. Pt
reports a strong urge to push but
able to breathe through them
1
0200
0211
CNM at bedside.
Cervix swollen.
Patient told not to
grunt with
contractions. Pt
requests IV pain
meds.
Out of tub. Unable
to void. To bedsve by cnm,
7+/edematous,
anterior lip more
edematous/0
station. Will order
fentanyl for pain
relief/discourage
involuntary
pushing. Reeval
when fentanyl
wears off and prn.
FHTs 120's,
audible increases,
no decreases.
0
0:00
1:12
2:24
0324
0414
Pt inquiring about an
epidural due to
increase in pressure
with Ctx but very hard
to breathe through
them. Pt received more
IV fentanyl per pt
request. Straight cath
done due to unable to
void (pt able to void
once since 2100). Pt
continues to breathe
hard through ctx to try
and not push
Dozing between uc's
s/p fentanyl. Cont.
To have urge to
push/invol. Push
w/peak of uc's. FHTs
120's. UCs q 3mins.
SVE by CNM 9/C,
edematous anterior
lip/1+station.
Continue expectant
management.
Anticipate
progression to C/C
and NSVB.
3:36
4:48
6:00
7:12
8:24
Events 8/7/2012
7
CNM suggests pt get an epidural due to
swollen anterior lip and pt with uncontrollable
urge to push. Pt and family agrees with POC
0600
1
0625
Anesthesia at bedside pt consented for CLE, pt
states understanding and risks and benefits of
CLE during labor. Agrees to procedure.
0604
0615
Continues to push
involuntarily against rim
cervix with thick anterior lipsoft, stretchy, reduces, but
them comes down again. Vtx
at 1-2+ station. Discussed
w/Dr. M. Alunni- agrees with
CNM plan to transfer to L+D
for CLE. FHTs stable. UCs q
3 mins. Charge RN aware.
Pt to L&D. Pt… denies any
headache, blurred vision or
epigastric pain. Reports +FM.
Placed on monitors, MDs aware of
arrival. Family at bedside, doula at
bedside, call bell within reach.
0
5:52
6:00
6:07
6:14
6:21
6:28
6:36
6:43
6:50
6:57
7:04
7:12
Events 8/7/2012
8
Prior to epidural:
• Painful labor x 10 hours.
• Swollen cervix stuck at 6-7 cm dilation.
• Straight cath x 1 / emesis
• Multiple doses of fentanyl
9
Epidural test dose
• Given to “rule out” IV or IT injection.
• 3 mL 1.5% lidocaine with epinephrine 5
mcgm/mL (1:200,000).
• 45 mg lidocaine
• 15 mcgm epinephrine
10
Epidural test dose
• If IV  increase of HR by 20-30 bpm within
one minute. Uterine contractions can also
cause tachycardia.
• If IT numb/weak legs within 2-3 minutes +
“sympathectomy”.
• Negative test dose does not assure proper
epidural placement!
11
Our case is not unique.
Reg Anesth. 1996 Mar-Apr;21(2):119-23.
High spinal anesthesia after epidural test dose administration in five
obstetric patients.
Richardson MG, Lee AC, Wissler RN.
Source
Department of Anesthesiology, University of Rochester School of Medicine and Dentistry, Rochester,
NY 14642, USA. [email protected]
Abstract
BACKGROUND AND OBJECTIVES:
A commonly used test dose in parturients receiving continuous lumbar epidural analgesia for labor
consists of 3 mL of dextrose-free 1.5% lidocaine with 1:200,000 epinephrine.
METHODS:
of 1,962 obstetric epidural anesthetics administered over a 17-month period, unintentional
subarachnoid placement of the epidural catheter was detected by injection of the test dose in five
laboring patients. The characteristics of the resulting subarachnoid blocks were studied.
RESULTS:
After negative aspiration for cerebrospinal fluid in each case, test dose
injection resulted in the rapid onset of high sensory block with
associated motor and sympathetic block, accompanied by significant
hypotension requiring aggressive treatment.
CONCLUSIONS:
While this test dose appears to be a sensitive indicator of an unexpected subarachnoid catheter, the
resulting excessive spinal blocks in these laboring patients raise the question of its safety.
12
Question
• Is it safe and reasonable to give vasopressors
prophylactically when a high spinal occurs?
13
Prophylactic ephedrine
and phenylephrine
• Wise decision to give a combination of
phenylephrine and ephedrine to this patient
to prevent problems which probably would
have developed.
• High spinal is both a respiratory and a
circulatory emergency.
14
Questions
• Why does neuraxial anesthesia sometimes
cause hypotension?
• Besides hypotension, what other signs and
symptoms accompany a high block?
15
Major syndromes for high spinal
•
•
•
•
•
Hypotension
Bradycardia
Respiratory failure
Cardiac arrest
Specifically: cardiac arrest in pregnant patient.
16
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/modules/pelvic_autonomic_module/pelvic_page02.html
Sympathetic efferents exit
spinal cord from T1 to L2.
High sympathectomy:
Blockade of T1-T4  warm
vasodilated hands, further
reduced SVR, Horner’s
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/modules/pelvic_autonomic_module/pelvic_page02.html
Most vascular resistance is supplied by the muscular arterioles,
measuring 0.1mm in diameter and smaller.
Sympathectomy dilates resistance arterioles, reducing SVR.
19
http://www.cvphysiology.com/Blood%20Pressure/BP019.htm
http://www.biosbcc.net/doohan/sample/htm/vessels.htm
T5-L2 sympathectomy causes pooling of blood in the splanchnic
vessels, reducing venous return and CO.
20
Splanchnic vasculature has alpha and beta receptors at multiple sites.
Beta 2 dilates
hepatic veins
Alpha 1+2
constrict
splanchnic
capacitance
vessels
Alpha 1+2 constrict
splanchnic arteries
21
Figure modified by Archer TL
Decreased venous return and
cardiac output due to sympathectomy
is exacerbated by obstruction of IVC.
22
If IVC is open, venous return is unimpeded
and cardiac output is maximized.
23
http://www.manbit.com/OA/f28-1.htm
Manbit
images
If IVC is obstructed, venous return is
blocked and cardiac output is reduced.
http://www.manbit.com/OA/f28-1.htm
24
Blood pressure
• (MAP-CVP) =
CO
x
• MAP =
x
SVR
CO
CO depends on
venous return, which
depends on venous
tone and IVC patency.
SVR.
SVR depends on
resistance of arterioles
(0.1 mm diameter and
smaller).
25
Cardiac arrest with high spinal
• Why?
• Hypoxia
• Hypotension
• Bradycardia
26
27
Bradycardia after high spinal:
two common explanations
• Blockade of T1-T4 “cardioaccelerator fibers”
 unopposed vagal tone bradycardia
• Bezold-Jarisch reflex: decreased right atrial
and ventricular filling bradycardia
• (B-J reflex can be thought of as an attempt to
“give time for the heart to fill with blood.”)
28
Given late!
29
Diagram modified by Archer TL
Vigilance!
• Talk with patient for test dose. “Heart pounding, legs
numb or weak”. Have Ambu bag and pressors
immediately available.
• Give 2-3 minutes for test dose to be positive. Consider
dosing epidural fentanyl 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.
30
Routine monitoring after
neuraxial block for C-section
• Talk with patient (“How are you doing…?,”
“Are your legs feeling different…?”)
• “Take a deep breath.” Observe.
• “Squeeze my fingers” (bilateral)
• Warms hands and / or dilated hand veins?
31
Treatment of spinal induced
hypotension and bradycardia:
• “Left lateral position/O2/fluids/vasopressors”
• Ephedrine and possibly atropine (or
glycopyrrolate).
• Early use of epinephrine if these are not
effective.
• ?Airway support (Ambu bag and ? Intubation)
32
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.”
Obstet Gynecol. 2011 Nov;118(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.
33
Pt given test dose…at this time, pt states she feels FHR remains in the 90s, FSE
like she is going to fall, pt supported and placed
applied at this time.
lying on left side at this time.
0645
Time out and skin
incision.
Terbutaline given en route
0655?
0651
0703
1
0646
0650
OB resident
called to room as
FHR
deceleration at
this time, pt
turned lying right
side, 02 10 L via
FM and fluid
bolus infusing. Pt
examined as
charted at this
time.
Pt awake, unable
to grasp fingers,
ambu mask on at
this time.
Anesthesia
remains at bedside
0654
0704
Pt transferred to DR 3 for
emergency cesarean section
Uterine
incision
0702
0705
0650
Splash prep to
abdomen, foley
placed, pt lying
on table with
left lateral
displacement,
bovie pad to
right thigh,
venodynes
bilateral LE.
Called to LDR 8 for
FHR decel x 3minss/p "high" CLE. Dr.
Alunni at bedside
evaluating pt. To
OR.
Viable
baby boy
born at this
time, infant
handed to
peds per
MD
0
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Events 8/7/2012
7:00
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7:06
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Fetal distress after high spinal—
Why?
• Hypoxia– not present in this case.
• Hypotension– probably avoided in this case.
• Reduced placental perfusion (aortocaval
compression)– possibly present in this case.
• “Hyperstimulation”
35
• What is the “big picture” of fetal distress in
labor?
36
Figure 1 Healthy, abundant uteroplacental perfusion
Upper body
Open
IVC
Minimal collateral
venous return to
heart via lumbar and
azygos system
Uncompressed
aorta and iliac
arteries
Fetal O2
supply
37
Figure 2 Uterine contractions periodically deprive placenta of perfusion.
Upper body
Open
IVC
Minimal collateral
venous return to
heart via lumbar and
azygos system
Uncompressed
aorta and iliac
arteries
Fetal O2
supply
Uterine contractions
38
Figure 3 Hyperstimulated uterine contractions deprive placenta of perfusion even more.
Upper body
Open
IVC
Minimal collateral
venous return to
heart via lumbar and
azygos system
Uncompressed
aorta and iliac
arteries
Fetal O2
supply
Hyperstimulated
uterine contractions
39
Figure 4 Aortocaval compression reduces placental perfusion pressure.
Upper body
Increased collateral
venous return to
heart via lumbar
and azygos system
Compressed
IVC
ACC
Uterine mass
Compressed
aorta and iliac
arteries
ACC
Fetal O2
supply
40
Figure 5 Aortocaval compression and hyperstimulation produce hypoxia.
Upper body
Increased collateral
venous return to
heart via lumbar
and azygos system
Compressed
IVC
ACC
Uterine mass
Compressed
aorta and iliac
arteries
ACC
Fetal O2
supply
Hyperstimulated uterine
contractions
41
Intrauterine resuscitation?
• Remember this concept!
• Is fetal distress due to something that can be
fixed in utero (e.g. hypotension or uterine
hypertonus)? If so, CS may be avoidable.
• If fetal distress is due to something
irreversible, that cannot be fixed in utero (e.g.
placental abruption) then CS is needed.
42
“Hyperstimulation”– excessive uterine contractions.
Common syndrome is rapid pain relief in the presence of oxytocin augmentation.
FIGURE 22-2 Prolonged fetal bradycardia resulting from excessive oxytocin-induced
hyperstimulation of the uterus after intravenous infusion of meperidine (Demerol) and
promethazine (Phenergan) into the same tubing. The heart rate is returning to normal at
the end of the tracing, after appropriate treatment (signified by the notes “Pit off,” “O2 6 L/min,”
and “side”). Note that fetal heart rate variability was maintained throughout this asphyxial
stress, signifying adequate central oxygenation.
43
Intrathecal opioids are associated with fetal bradycardia– mechanism uncertain.
44
Abrao et al (2009) in a RCT found
CSE with sufentanil and
bupivancaine to be associated with
more uterine hypertonus than CLE.
IUPC was used for intrauterine
pressure measurement.
45
Uterine “hyperstimulation”
• Especially associated with IT lipid soluble
opioids (sufentanil, fentanyl) but can occur
after rapid pain relief by any means.
• Often associated with oxytocin (Pitocin)
augmentation of labor.
• Can occur up to 30 minutes after
administration.
46
Uterine “hyperstimulation”
• Proposed mechanism: pain relief decreased
maternal epinephrine decreased uterine
relaxant effect of epinephrine increased
uterine tone placental insufficiency.
47
“Events were explained to family
by anesthesia team”
Very important to talk with the patient
after an adverse outcome.
Listen. Learn what happened from the patient’s
point of view.
Apology for what happened. Is not an admission
of guilt. “We are sorry that this happened.” 48
The fetus floats at the far end of a tunnel of oxygen delivery.
If the tunnel is blocked, the fetus dies.
http://darksideofthecatalogue.wordpress.com/2011/11/22/light-at-the-end-of-the-tunnel-is-glowing-thing-23-12/
49
The End