Post on 01-Aug-2020
A. Borgeat Orthopedic University Clinic of Zurich/Balgrist Switzerland
Failed spinal anesthesia: mechanisms, management and prevention
Why did my spinal fail?
76
14 10
RA RA+GA GA
Survey in UK trauma centers
Sandby-Thomas et al Anaesthesia 2008;63:250,
%
SPA
96 %
n = 100
Success: no inhalation anesthetic agents required for surgery
Failure rate: 17 % associated with :
• lack of free flow of CSF
• use of tetracaine without epinephrine
• an increased administration of IV supplementation
Anesth Analg 1985; 64:705,
n = 329
Success: no GA or supplementary analgesics required
Failure rate: 3 % associated with :
• all were ASA III
• tetracaine (8%)vs lidocaine (2%)
• tetracaine with epinephrine (13%) than without (5%)
→ no other correlation was found
Anesth Analg 1987; 66:363,
n = 200 Failure: If the surgical procedure could not be performed without the addition of GA
Failure rate: 4 %
• 25% due to errors in technique
• 75% due to errors in judgement
Anesth Analg 1988; 67:843,
Failure rate in relation to demographic variables
Variables
Total number of
spinal anesthetics
Successful
spinal anesthetics
Failed spinal
anesthetics
Failure
rate (%)
Sex male female Ethnic group white black hispanic other Age (yrs) 16 - 20** 20 - 40 40 - 60 60 - 80
146 54
60 94 38 8 2 59 55 84
144 48
59 91 34 8
2 55 53 82
2 6
1 3 4 0
0 4 2 2
1.4
11.1*
1.7 3.2
10.5 0
0 6.8 3.6 2.4
* Difference highly significant (p< 0.05) ** Not included in statistically analysis, because number was too small
Munhall et al Anesth Analg 1988; 67:843,
Factors affecting success of failure of spinal anesthesia
Technical factors 1. Identification of subarachnoid space; related to training; ability to
utilize different approaches 2. Documentation of free flow of CSF pre- and postinjection 3. Proper placement of catheter for continuous spinal technique
Pharmacological factors (judgement error) 1. Selection of appropriate local anesthetic and addition of
vasoconstrictor; depending on duration of surgery 2. Selection of appropriate dosage and baricity 3. Selection of appropriate position and interspace; depending on
site of surgery 4. Selection of appropriate technique; single injection versus
continuous catheter technique
Munhall et al Anesth Analg 1988; 67:843,
All types of surgery. No CSF backflow was an exclusion criteria
Failure rate 3,2 %
total failure 41 % (no sensory block)
partial failure 59 % (insufficient block)
independent risk factors - younger age - number of attempts >3 (CI 95 % 1.2 – 6.8) - no adjuvant with LA (CI 95 % 1.2 – 4.5)
age >70 was a factor decreasing the risk of failure (CI 95 % 0.2 – 0.9)
Fuzier et al. RAPM 2011;36:322,
Spinal n = 3227 Epidural n = 1286 94 % success 76 %
Factors associated with failure: Pre-operative failure Intraoperative failure - body mass index - inadequacy of pre-operative block - no previous C section - duration of surgery - C section for acute fetal distress - C section failure elective 0.8% emergency 4.9% - NB: adding an opioid was associated with less failure
Kinsella S.M. Anaesthesia 2008;63:822,
• Prospective cohort study involving 800 parturients (0.5 heavy bupivacaine + morphine 100 ug / Whiteacre 27 G)
• Goal : block at T5 Failure rate 0.5 %
75 % inadequate block
(block at T6)
25 % no block
All failures - sitting position - free flow of CSF Sng et al
Int J Obstet Anesth 2009;18:237,
Br J Anaesth 2009;102:739 Failures associated with spinal bupivacaine
administration
Two conditions are, therefore, absolutely necessary to produce spinal anesthesia: puncture of the dura mater and subarachnoidal injection of an anesthetic agent
Gaston Labat 1922
Failed Spinal Anesthetic
The drug works, but the dosage has not been chosen correctly
Impossibility to reach the subarachnoidal space
The drug has been injected at the right location, but the block does not work as expected
Circulation of the cerebrospinal fluid
Cerebrospinal fluid Functions • Protection against trauma due to sudden movement • Maintain a uniform pressure upon the brain and cord • Reduced the effective weight of the brain
Characteristics • Produced from blood in the choroid plexuses (90 %) in the fourth
ventricle and is absorbed back into the blood by the arachnoid granulations
• Volume is + 150ml, but a nearly threefold variability in healthy adults has been observed
Spinal failure despite correct dosing and injection technique
• Maldistribution
may be associated with variation concerning spreading of subarachnoidal block
Blomberg R.G. Anesth Analg 1995; 80:875,
Tarlov Cyst
• Fluid-filled nerve root valved or nonvalved cysts found most commonly at the sacral level of the spine
• Asymptomatic TC are present in 5-9 %. Female are more frequently affected
• Treatment is drainage of CSF or surgery
Tarlov Cyst as a cause of spinal failure
Spinal failure despite correct dosing and injection technique
• Maldistribution • Variability in the anatomy of the lumbar
subarachnoid space
Anesthesiology 1998;89: 24,
10 healthy volunteers received a spinal with 50 mg lidocaine in 7.5 dextrose Lumbosacral CSF volumes were calculated using MRI
Positive correlation between CSF volume and sensory block extension and duration of surgical anesthesia, but no correlation with onset of sensory/ motor block and duration of motor blockade
43 81 ml
lumbosacral CSF
n = 2600 failure rate 2,7 %
B U P I V A CAI N E
CSF
adequate block
inadequate block inadequate CSF
concentration
maldistribution 60 %
40 %
73
range 3,36 to 1020 ug.ml-1
Steiner et al. Br J Anaesth 2009;102:839
ug.ml -1
- No association between CSF bupivacaine and spinal block level
- Similar variability between men and women
Ruppen W. et al Br J Anaest 2009;102:832,
Magnetic resonance images of the lumbosacral spine a) Patient with usual thecal dimensions b) Patient with large thecal dimensions
Compare the intrathecal dimensions of the patient in b) to the patient in a)
Spiegel JE and Hess P J Anesth 2007;21:399,
Widening/balloning of the lumbosacral dural sac in 63 – 92 % of patients with Marfan‘s syndrome
Br J Anaesth 2005;94:500,
Spinal failure despite correct dosing and injection technique
• Maldistribution • Variability in the anatomy of the lumbar
subarachnoid space • Inadvertent subdural or epidural injection
Br J Anaesth 2009;102:739
Failed spinal due to altered bupivacaine
- Inadequate sensory block - Prolonged onset of block - Insufficient duration of block - No block
Background 8 spinal failures in 1 week period
276
289 control suspect bupivacaine
bupivacaine was exposed more than 9h to freezing temperatures
chemical alteration (?) Blasiole et al
ASA 2009
mass/charge ratio
Mass spectroscopy
• 16 % failed continuous spinal with hyperbaric lidocaine • Free flow of CSF • CSF lidocaine concentration 420 – 880 ug/ml • Injection of bupivacaine produced anesthesia • Plain lidocaine from the same manufacturing batch
produced anesthesia
J Clin Anesth 1990;2: Sept/Oct
BMC Anesthesiology 2004;4:1,
The world of Na+ channels
• Voltage-gate Na+ channels are crucial for electrogenesis and nerve impulse conduction
• Voltage-gate Na+ channels are important targets for analgesics like LA or carbamazepine
• Recent studies have identified different sodium isoforms
Voltage-gate Na+ channel
Nav1.5 Nav1.6 Nav1.7 Nav1.8 Nav1.9
Pain Inflammation
Pain Inflammation
Pain Inflammation
Ranvier nodes
Cardiac muscle
Nav1.7
• Nav1.7 plays a crucial role in the human ability to perceive pain
• Loss-of-function mutations in the Nav1.7 gene underlie congenital indifference to pain
• No organic dysfunction except for some cases of anosmia or hyposmia
N395K mutation attenuates the
inhibitory effect of lidocaine
Patrick L. et al J Physiol 2007:581:1019,
Pan et al. Can J Anesth 2002;49:636
Sucess of spinal anesthesia
Right place
Right drug
Right dosage
Conclusions
Lumbar punction
Solution injection
Failure
Failure
Failure
Spreading of drug through CSF
Drug action on the spinal nerve roots and cord