Transcript C36_Phil Popham

Failed spinals in obstetrics: cause, prediction,
prevention and management
Phil Popham
Royal Women’s Hospital, Melbourne
Failed spinals in obstetrics: cause, prediction,
prevention and management
I’m sure that was in the
right place...
Phil Popham
Royal Women’s Hospital, Melbourne
Plus ça change:
“..for successful analgesia it is necessary to enter the
lumbar dural sac effectually with the point of the needle,
and to discharge through this, all the contemplated dose
of the drug, directly and freely into the cerebrospinal fluid,
below the termination of the cord.”
Barker A. Clinical experiences with spinal analgesia in 100 cases. Br Med J 1907;665–676
The steps to a
successful block
Find, and fully pierce, the dura with the needle
Inject the planned dose of LA
Achieve satisfactory spread in CSF
Achieve appropriate drug action on nerve roots
To paraphrase:
To paraphrase:
Right place
To paraphrase:
Right place
Right drug
To paraphrase:
Right place
Right drug
Right dose
What could possibly go wrong??
All as straightforward as parking a car in the garage...
What could possibly go wrong??
Failure:
Partial
Incomplete block
Complete
Partial failure...
• Extent: failure to reach a given dermatomal
level
• Quality: failure to produce adequate block
• Duration: failure to last as long as needed
...is diagnosed by...
• Extent: modality of checking block, interval
since injection
• Quality: modality of checking block,
interval since injection, need for other
supplementation
• Duration: when it starts to hurt...
Complete failure...
• Complete absence of sensory or motor
block
...is diagnosed by...
• Complete absence of sensory or motor
block
• Despite waiting “long enough” for the block
to develop
• 15 minutes
Cochrane database Syst Rv. 2004 CD 003765
Incidence of failure
•Prospective
• 3.1% in 1891 patients
•
Tarkkila P. Incidence and causes of failed spinal anesthetics in a University Hospital: a prospective study. Reg Anesth 1991; 16: 48–
51
• 4% in 200 patients
•
Munhall R, Sukhani R, Winnie A. Incidence and etiology of failed spinal anesthetics in a university hospital. Anesth Analg 1988; 67:
843–8
Incidence of failure
•Retrospective
• 2.7% in 2314 patients
•
Pan PH, Bogard TD, Owen MD. Incidence and characteristics of failures in obstetric neuraxial analgesia and anesthesia: a
retrospective analysis of 19,259 deliveries. Int J Obstet Anesth 2004; 13: 227–33
• 17% in 100 patients
•
Levy J, Isles J, Ghia J, Turnbull C. A retrospective study of the incidence and causes of failed spinal anaesthetics in a university
hospital. Anesth Analg 1985; 64: 705–10
Mechanisms of failure
• Anatomical
• Technique
• Drug
Anatomical failure
Anatomical failure
Anatomical failure
• Inability to locate intrathecal space:
• Positioning
• Anatomical abnormality (ank spond,
kyphosis, kyphoscoliosis, lordosis)
• Hardware (Harrington rods)
C,P
C,P
C,P
Anatomical failure
• Identification of fluid aspirate
• Intradermal cyst (most commonly
sebaceous cysts from hair follicles)
• Lipaceous material, discernible click on
cyst puncture, no free flow of fluid
• May contain keratin particles
Kell, Gudin, Brull. J Clin Anaesth 1996;8;603–604
C,P
Anatomical failure
• If impalpable, all intradermal cysts are
likely to be small, with little free fluid or
with viscous content.
• Free aspiration of fluid therefore unlikely.
C,P
Anatomical failure
• Identification of fluid aspirate
• LA infiltration under pressure may
create fluid filled cyst
• Aspirated fluid will have different
composition to CSF
Boon, Abrahams, Meeting. Clin Anat 2004;17;544–553
El-Behesy, James, Koh, Hirsch, Yentis. Br J Anaesth 1996;77;784–785
C,P
Anatomical failure
• Intrathecal sac
• Dural ectasia: large lumbosacral dural
sac
• Repeated injections needed
• Noted in Marfan’s syndrome (even
during CSA)
Hirabayashi et al. Can J Anaesth 1996;43;1072–5
Lacassie et al. Br J Anaesth
P
Anatomical failure
• Intrathecal sac
• Trabeculae in subarachnoid space
• Presence of a subdural space
Parkinson Am J Anat 1991;192;498–509
Haines Anat Rec 1991;230;3–21
Haines Neurosurgery 1993; 32;111–120
P
P
Anatomical failure
William of Ockham (1285–1349)
English Franciscan friar
Law of parsimony or succinctness
Frustra fit per plura quod potest fieri per pauciora
Frustra fit per plura quod potest fieri per pauciora
It is futile to do with more things that which can be
done with fewer
Frustra fit per plura quod potest fieri per pauciora
It is futile to do with more things that which can be
done with fewer
Of competing hypotheses which are equal in other
respects, select the one which makes the fewest
new assumptions.
Frustra fit per plura quod potest fieri per pauciora
It is futile to do with more things that which can be
done with fewer
Of competing hypotheses which are equal in other
respects, select the one which makes the fewest
new assumptions.
The simplest explanation is more likely to be the
correct one
Anatomical failure
Tarlov cysts
Tarlov cysts (1938)
• Extradural meningeal dilatations
• Encase posterior spinal nerve root sheaths
• Mainly lumbosacral
• Idiopathic, post-trauma or surgery
• Radicular pain
• Narrow neck in continuity with CSF
• Current adult incidence estimated 4.5–9%
Failure of technique
• Partial penetration of dura
• Partial dislodgement of needle
• Loss of injectate
BJA 2009;102;739–748
BJA 2009;102;739–748
Failure of drug
• Wrong drug or agent...
Toxic epidural ravages mother
Julie Robotham
The Age, August 21, 2010
...Epidural administration of chlorhexidine - used to
clean skin before injections and strong enough to
neutralise resistant hospital bacteria - is so rare that
Ms X's doctors have identified only one other case.
Angelique Sutcliffe, from Britain, was paralysed for
life after the chemical entered her epidural in 2001.
But this was just a droplet - a fraction of the eight
millilitres infused into...
Failure of drug
• Wrong dose
• Agent
• Baricity
• Positioning
• Often offset by use of larger than needed
dose
Failure of drug
• ED95 bupivacaine for C/S: 11.0–11.2 mg
• Low dose spinal may use 5–6 mg combined
with opiate in attempt to minimise side
effects
• But at the expense of reducing safety
margin for adequate anaesthesia
Anesthesiology. 2004 Mar;100(3):676-82
Loss of injectate
• Heavy bupivacaine 0.5% 2.4 mL plus fentanyl
15µg:
• each drop from 5 mL syringe = 0.06 mL
• each drop from 2 mL syringe = 0.045 mL
• Volume lost during spinal injection occurs in
about 65% cases, when:
• loss from 2 mL syringes is greater, but
small (0.06 mL)
Randall & Yentis, IJOA 2002;11;23
Drug batch failure
• IJOA 2003/2004
• UK, NY
• Specific batch numbers identified
• Unopened vials returned to manufacturer,
all complied with QC
• In USA, opened vials sent to FDA, same
result.
Wood M, Ismail F. Inadequate spinal anaesthesia with 0.5% Marcain Heavy (Batch 1961).
International Journal of Obstetric Anesthesia 2003; 12: 310–311
pH effects
• Retrospective review of CSA in orthopaedics
• Inadequate block produced by incremental 0.2%
bupivacaine (diluted with N/S from 0.5%) treated by
1% lidocaine (diluted with N/S from 2%)
• Postulated that:
• dilution with N/S lowered pH of both solutions
• greater fall in non-ionised bupivacaine led to more
failures
• Lidocaine rescue increased total dose of LA and
increased pH, promoting greater block
• 0.5% bupivacaine pH = 5.4
• 0.5% bupivacaine plus fentanyl (10µg/mL)
pH = 4.3
• For pH to produce significant effects on LA
availability, there would have to be tissue
acidosis...
LA resistance
• Most commonly suggested with a family or
personal history of “failed” LA injections
• Postulated sodium channel mutation...
LA resistance
• Most commonly suggested with a family or
personal history of “failed” LA injections
• Postulated sodium channel mutation...
• ...that has yet to be identified
Glycosylated nerve
roots
• Anecdotal evidence of increased incidence
of failed spinals in insulin dependent
diabetic patients
• Glycosylation of nerve roots renders them
resistant to penetration of LA?
Bierhaus, Haslbeck, Humpert et al.J Clin Invest 2004; 114: 1741–51.
Podwall , Gooch Curr Neurol Neurosci Rep 2004; 4: 55–61.
Pop-Busui, Sima, Stevens. Diabetes Metab Res Rev 2006; 22: 257–73.
Glycosylated nerve
roots
• Anecdotal evidence of increased incidence
of failed spinals in insulin dependent
diabetic patients
• Glycosylation of nerve roots renders them
resistant to penetration of LA?
• ...that has yet to be identified
Bierhaus, Haslbeck, Humpert et al.J Clin Invest 2004; 114: 1741–51.
Podwall , Gooch Curr Neurol Neurosci Rep 2004; 4: 55–61.
Pop-Busui, Sima, Stevens. Diabetes Metab Res Rev 2006; 22: 257–73.
Prediction
• Past history
• Obvious anatomical abnormality
Prevention
• Do it correctly the first time:
• Suitable equipment
• Suitable drugs
• Suitable technique
• Suitable testing
Management
• Testing the block is mandatory
• Motor block test first, then sensory
• Differential sensory loss with cold, light
touch, blunted pinprick, sharp pinprick
• Height of block may not correlate with
quality of anaesthesia (esp if anxious)
NO block
Unilateral block
Inadequate spread or
patchy block
Inadequate duration
NO block
Wrong drug
Wrong place
Unilateral block
Positioning
Anatomical abnormality
Inadequate spread or
patchy block
Wrong dose
Anatomical abnormality
Inadequate duration
Wrong dose
Wrong drug
NO block
Wrong drug
Wrong place
CSE
GA
Repeat spinal
Unilateral block
Positioning
Anatomical abnormality
Re-position
CSE
Repeat
Inadequate spread or
patchy block
Wrong dose
Anatomical abnormality
CSE
Augmentation
GA
Repeat spinal (different baricity?)
Inadequate duration
Wrong dose
Wrong drug
Augmentation
GA
But potential pitfalls of
further RA...
• If initial partial block, subsequent injection being made
into an area of partially blocked nerves...
• If suspected barrier to spread of LA, may be the same
in a subsequent injection...
• Danger of spinal cord damage if injection made above
L2
Dragon pearls
• Likely commonest causes of partial or
complete failure are needle dislodgement or
Tarlov cyst puncture
• Suggested best management is to do a CSE
at another interspace