AVOIDING INFECTIOUS AND NEUROLOGIC COMPLICATIONS ASSOCIATED
WITH REGIONAL ANESTHESIA
From the American Society of Anesthesiologists’ 2006 Annual Meeting, October 14-18, 2006
| NO PUS: AVOIDING INFECTIOUS COMPLICATIONS —James R. Hebl, MD, Assistant Professor of Anesthesiology,
Mayo Clinic College of Medicine, Rochester, MN
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| Importance and implications of aseptic techniques
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 | Hand washing: most important technique to prevent cross-contamination from provider to patient, but soap and water
do nothing to kill microorganisms; requires alcohol-based antiseptic solution; healthcare providers who do
not remove rings and watches have higher microbial counts on surface of hands, primarily due to chronic or persistent
colonization
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| Sterile gloves and gowns: provide maximal sterile barrier between provider and patient; gloves should be considered
supplement to, not replacement for, good hand washing; microbial contamination still may occur despite
glove use; no recommendation for routine gown use
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| Surgical mask: no clearly established standard for use; protects healthcare worker from blood-borne pathogens or
blood droplets originating from patient, but role in protecting patient less clear; small body of evidence suggests
mask may increase risk for contamination
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| Antiseptic solutions: most widely used and investigated agents include povidone iodine (Betadine) and chlorhexidine
in isopropyl alcohol base (ChloraPrep); Betadine—effective against most gram-positive and
gram-negative microorganisms; functions by continuously releasing iodine, penetrating cell walls, and discontinuing
protein synthesis; onset somewhat delayed (several minutes); accelerated with addition of isopropyl
alcohol to povidone iodine; limited duration of effect; may be inhibited or neutralized by organic
compounds (eg, blood, pus); commonly associated with acute skin reactions (primarily manifest as
erythema or inflammatory reactions); ChloraPrep—effective against wide array of microorganisms (eg,
bacteria, yeast, viruses); chlorhexidine alters permeability of cell wall; results in apoptosis and cell death;
faster onset than Betadine (accelerated further with addition of isopropyl alcohol); extended duration of effect;
not affected by presence of organic compounds; fewer and less severe skin reactions than Betadine
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| Comparisons under clinical conditions: one study in parturients shows ChloraPrep solution superior in speed of
onset and overall efficacy and potency; other investigators have shown significant reduction in number of colonized
catheters, number of microorganisms detected, and frequency at which catheter insertion sites have
positive culture rate with use of chlorhexidine
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| Recommendations: alcohol-based chlorhexidine solution significantly reduces likelihood of catheter and catheter-site
colonization; no reported complications of neurotoxicity with chlorhexidine or Betadine when used as
antiseptic prior to lumbar puncture (LP); ChloraPrep should be considered antiseptic of choice
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| Regional anesthesia in febrile or infected patient
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| LP-induced meningitis: Eng found spontaneous meningitis rate (rate of meningitis in patients not undergoing LP)
similar to patients who developed meningitis and underwent LP; concluded that, under these circumstances, LP
does not appear to be associated with increased risk for meningitis when performed in bacteremic patients; subsequent
study raised question of risk and concern for meningitis following LP; found children treated with antibiotics,
at time of or prior to LP, had significantly lower risk for meningitis when compared to children not
receiving antibiotics; Carp et al looked at role of antibiotic therapy in protecting against dural puncture–induced
meningitis in animals; concluded that 1) dural puncture appears to increase risk of meningitis in bacteremic patient,
and 2) antibiotic treatment may reduce risk significantly if implemented before dural puncture; meningitis
occurred with true clinically relevant degrees of bacteremia
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| Epidural abscesses: epidural catheter tips may be colonized at high rate, but development of signs and symptoms of
infection rare; most epidural abscesses not thought to be related to indwelling catheter, but rather secondary to
coexisting infection in adjacent skin, soft tissue, or vertebral column, or from remote foci of infection and subsequent
hematogenous spread; Bader concluded that spinal or epidural catheters in patient with suspected chorioamnionitis
may be safe
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| Recommendations: despite conflicting results, most experts suggest neuraxial blockade not be performed in patients
with active, ongoing, untreated systemic infection; decision to perform regional anesthesia (RA) in these
circumstances needs to be made on individual basis, with risks and benefits weighed against extenuating circumstances;
patient with evidence of systemic infection may undergo spinal anesthesia safely, provided appropriate
antibiotic therapy initiated before dural puncture (with demonstrated response to antibiotic); no definitive recommendations
for epidural anesthesia and analgesia in bacteremic patient receiving antibiotics; spinal anesthesia
safe in patient at risk for subsequent low-grade transient bacteremia
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| Role of RA in immunocompromised patient: range of microorganisms that can cause invasive infection in immunocompromised
patient much greater than in general population; patient has altered inflammatory response
that may mute clinical signs and symptoms of infection (delays diagnosis); patient often needs prolonged therapy
(host defense mechanism altered or dysfunctional); Du Pen study found most common complications occurred at
exit site, epidural space, and deep tract; duration of therapy associated with elevated risk; superficial and exit site
infections caused primarily by local skin contaminants; treated successfully by applying topical Betadine and antibiotic
ointment; deeper tract infections and epidural infections necessitate removal of entire catheter system and
implementation of parenteral antibiotics
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| Recommendations: immunocompromised patient receiving extended or prolonged epidural blockade appears to be
at higher risk for infectious complications; risk increases with duration of therapy, warranting close observation;
epidural anesthesia or analgesia does not appear to increase risk of infection in parturients with recurrent or secondary
herpes simplex virus (HSV) type-2; however, patient with primary HSV type-2 infection undergoing spinal
anesthesia may be at higher risk; epidural opioids may increase risk of HSV type-1 reactivation (may be due
to effect on trigeminal ganglia in otherwise partially immunocompromised host); critically ill and immunocompromised
intensive care unit (ICU) patient may be at higher risk for epidural catheter infection, compared to general
non-ICU patient; surgical intervention rarely necessary
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| NO PAIN: AVOIDING NEUROLOGIC COMPLICATIONS —Joseph M. Neal, MD, Clinical Professor of Anesthesiology,
University of Washington School of Medicine, and Anesthesiology Faculty, Virginia Mason
Medical Center, Seattle, WA
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| Risk for neurologic complications: whether in neuraxis or periphery, chance of permanent complication 0 to 4
per 10,000 patients; neurologic complication more likely to be permanent, whereas most peripheral complications
tend to be temporary and less devastating; Lee found spinal and epidural anesthesia causes most neuraxial injuries;
same complications seen in conjunction with pain management and ophthalmic anesthesia
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| Neuraxis: injury caused by needle or catheter (injure spinal cord, nerve root, or vascular supply to spinal cord or
nerve root) or mass lesions (cause hematoma and infection); injury can occur due to anatomic anomalies,
eg, variations in termination of spinal cord (usually L3 to L4), inadequate fusion of ligamentum flavum at
midline (needle penetrates too deeply and injures spinal cord), and progressive narrowing of anterior-to-
posterior diameter of epidural space when ascending cephalad; elderly tend to have higher risk for spinal
stenosis (less room for mass effect); with interscalene approach, needle also can penetrate too deeply and
enter spinal cord (distance from skin to vertebral bodies and spinal cord extremely short)
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| Mechanical injuries: in either midline or paramedian approach, “there’s really relatively little damage that we
can do to the spinal cord unless we go too deep”; plexopathy occurs from damage to spinal nerve roots with inappropriately
lateral needle; spinal nerve roots also at risk with transforaminal techniques (damage to artery;
particulate matter injected); animal data suggest that as local anesthetics damage spinal nerve roots (particularly
posterior nerve root), there may be some clinical correlation in transient neurologic symptoms; vascular
damage—through direct needle trauma or particulate injected into vasculature (migrates to spinal cord and
impairs circulation); most cases of anterior spinal artery syndrome seen in elderly patient with atherosclerotic
disease (not due to blood pressure); transforaminal technique can cause damage to major reinforcing artery or,
more likely, inject particulate matter that goes downstream to spinal cord
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| Extradural mass lesions: spinal cord and mass competing for space in spinal canal; epidural lipomatosis rare, but
may be seen in young healthy parturient; hypertrophy of ligamentum flavum seen recently; pressures of mass
eventually exceed venous outflow or arterial inflow, causing ischemia
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| Periphery: direct needle trauma to nerve (rare) or injection within nerve bundle (intrafascicular injection breaks
apart nerve-blood barrier; local anesthetics and epinephrine cause neurotoxicity)
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| Diagnosis: magnetic resonance imaging (MRI) preferred for suspected neuraxial injury (computed tomography
[CT] provides lower-quality information); electromyography (EMG) and nerve conduction studies best for peripheral
nerves; test early with neurologist who understands needs (to document and possibly uncover occult
nerve dysfunction)
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| Treatment: rapid neurosurgical consultation and imaging required for compromised spinal cord (decompression required
within 8 hr for meaningful recovery); peripheral injury requires vigilance and referral to neurologist (85%
recovery within 2 wk; <1% have lingering injury at 1 yr)
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| Asleep vs awake: block performed in anesthetized or heavily sedated patient takes away ability to recognize paresthesia,
pain on injection, or systemic toxicity; warning signs do not occur in every patient; once warning
signs occur, damage already may be done; no definitive studies; studies seem to indicate that injecting while
needle in spinal cord causes major injury; studies in periphery indicate some awake patients with injury have
no pain on injection; intrafascicular or intraperineurial injection exposes nerve to toxic doses of local anesthetics
and vasoconstrictors; majority suggest avoiding peripheral nerve block that could reach neuraxis (eg, psoas
block, interscalene block) in asleep or heavily sedated adult; too few data on other peripheral nerve blocks and
lower extremity blocks to make recommendation (children potentially different because of risk-benefit ratio)
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| Persistent paresthesia: peripheral nerve stimulator may decrease incidence of paresthesia, but no evidence of decreased
injury; paresthesia-seeking techniques (eg, peripheral nerve stimulation, ultrasonography) all seem
equally safe (insufficient data to recommend one technique over another or to link paresthesia or painful injection
to injury)
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| Preexisting neurologic disease: Mayo Clinic data suggest choice of RA vs general anesthetic does not affect outcome;
recommendations indicate no risk in performing blocks on these patients; however, consider using less local
anesthetic or lower concentration of local anesthetic; consider avoiding epinephrine in diabetic patients
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| Transforaminal steroid injection: continued use always should be performed under realtime fluoroscopy (inject
dye; movement of dye toward spinal cord should warn against injecting steroid; digital subtraction better)
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Suggested Reading
Bader AM et al: Anesthesia for cesarean delivery in patients with herpes simplex virus type-2 infections. Reg
Anesth 15:261, 1990; Bader AM et al: Regional anesthesia in women with chorioamnionitis. Reg Anesth 17:84,
1992; Baker AS et al: Spinal epidural abscess. N Engl J Med 293:463, 1975; Bergman BD et al: Neurologic
complications of 405 consecutive continuous axillary catheters. Anesth Analg 96:247, 2003; Capdevila JA: Catheter-related
infection: an update on diagnosis, treatment, and prevention. Int J Infect Dis 2:230, 1998; Capdevila X
et al: Continuous peripheral nerve blocks in hospital wards after orthopedic surgery: a multicenter prospective analysis
of the quality of postoperative analgesia and complications in 1,416 patients. Anesthesiology 103:1035, 2005;
Carp H et al: The association between meningitis and dural puncture in bacteremic rats. Anesthesiology 76:739,
1992; Cohen S et al: Bupivacaine 0.01% and/or epinephrine 0.5 µg/ml improve epidural fentanyl analgesia after
cesarean section. Anesthesiology 89:1354, 1998; Crone LA et al: Recurrent herpes simplex virus labialis and the
use of epidural morphine in obstetric patients. Anesth Analg 67:318, 1988; Dahlgren N et al: Neurological complications
after anaesthesia. A follow-up of 18,000 spinal and epidural anaesthetics performed over three years. Acta
Anaesthesiol Scand 39:872, 1995; Du Pen SL et al: Infection during chronic epidural catheterization: diagnosis
and treatment. Anesthesiology 73:905, 1990; Eng RH et al: Lumbar puncture-induced meningitis. JAMA 245:1456,
1981; Hodgson PS et al: Procaine compared with lidocaine for incidence of transient neurologic symptoms. Reg
Anesth Pain Med 25:218, 2000; Kindler C et al: Extradural abscess complicating lumbar extradural anaesthesia
and analgesia in an obstetric patient. Acta Anaesthesiol Scand 40:858, 1996; Lee LA et al: Complications associated
with peripheral nerve blocks: lessons from the ASA closed claims project. Int Anesthesiol Clin 43:111, 2005;
Lee LA et al: Injuries associated with regional anesthesia in the 1980s and 1990s: a closed claims analysis. Anesthesiology
101:143, 2004; Moen V et al: Severe neurological complications after central neuraxial blockades in
Sweden 1990-1999. Anesthesiology 101:950, 2004; Rathmell JP et al: Acute post-surgical pain management: a
critical appraisal of current practice, December 2-4, 2005. Reg Anesth Pain Med 31:1, 2006; Teele DW et al: Meningitis
after lumbar puncture in children with bacteremia. N Engl J Med 305:1079, 1981; Wang LP et al: Incidence
of spinal epidural abscess after epidural analgesia: a national 1-year survey. Anesthesiology 91:1928, 1999; Wang
LP et al: Long-term outcome after neurosurgically treated spinal epidural abscess following epidural analgesia.
Acta Anaesthesiol Scand 45:233, 2001; Wedel DJ, Horlocker TT: Regional anesthesia in the febrile or infected
patient. Reg Anesth Pain Med 31:324, 2006.
Educational Objectives
| The goal of this program is to reduce the incidence and management of infectious and neurologic complications associated
with regional anesthesia. After hearing and assimilating this program, the participant will be better able to:
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| 1. Explain the importance and implications of aseptic techniques.
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| 2. Summarize the role of regional anesthesia (RA) in the febrile or infected patient and the immunocompromised
patient.
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| 3. Evaluate the risks for neurologic complications associated with RA.
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| 4. Review the pathophysiology of neuraxial injuries associated with RA.
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| 5. Summarize the diagnosis and treatment for neurologic complications associated with RA and review current
recommendations to avoid such complications.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty members to disclose
relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any
identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary
business or commercial interest. For this program, the faculty reported nothing to disclose.
Acknowledgements
Drs. Hebl and Neal spoke at the American Society of Anesthesiologists’ Annual Meeting, held October 14-18, 2006,
in Chicago, Illinois. The Audio-Digest Foundation thanks the speakers and the ASA for their cooperation in the production
of this program.
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