INFECTION: THE PATIENT AND ANESTHESIA PROVIDER
Educational Objectives
| The goal of this program is to reduce infectious complications associated with regional anesthesia and improve daily
safety of anesthesia personnel. After hearing and assimilating this program, the clinician will be better able to:
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 | 1. Illustrate the importance and implications of aseptic techniques.
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| 2. Examine infection risks in the febrile or infected patient and the immunocompromised patient.
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| 3. Summarize the infection risks of peripheral nerve blockade.
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| 4. Identify avian influenza A and extremely resistant tuberculosis, which are rarely seen but of grave risk to anesthesia
personnel exposed to airway secretions.
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| 5. Describe the risks associated with more common infections, such as methicillin-resistant Staphylococcus aureus
and Clostridium difficile.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and planning committee 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 and planning committee reported nothing to disclose.
Acknowledgements
Dr. Hebl spoke in Phoenix, AZ, at the Mayo Clinic Symposium on Anesthesia and Perioperative Medicine 2008, held
February 20-23, 2008, and sponsored by Mayo Clinic College of Medicine; Dr. Wiener-Kronish spoke in San Francisco,
CA, at the IARS 82nd Clinical and Scientific Congress, held March 29 to April 1, 2008, and sponsored by the International
Anesthesia Research Society. The Audio-Digest Foundation thanks the speakers and the sponsors for their
cooperation in the production of this program.
| INFECTIOUS COMPLICATIONS ASSOCIATED WITH REGIONAL ANESTHESIA —James R. Hebl, MD, Associate
Professor of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN
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| American Society of Regional Anesthesia (ASRA): recently convened practice advisory on infection risks associated
with regional anesthesia and pain medicine; primary focus 4 topics, 1) importance and implications of aseptic techniques
during regional anesthesia, 2) infection risks of performing regional anesthesia in febrile or infected patient, 3)
infection risks when performed in immunocompromised patient, and 4) infection risks of chronic pain treatment
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Importance and Implications of Aseptic Techniques
| Hand washing: should be considered most important technique in prevention of cross-contamination between health
care provider and patient; use of soap and water only moves bacteria above surface of skin; not effective at killing microorganisms;
alcohol-based antiseptic solution (alcohol content 60%-90%) most effective; remove jewelry (eg, watch,
rings) before hand washing; higher microbial counts identified in those who do not remove jewelry
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| Use of surgical masks: large variation among practitioners; no clearly established standard; effective at protecting
health care worker from blood droplets or other airborne pathogens that originate from patients; however, role in protecting
patients from health care workers more controversial; practice advisory recommends using masks routinely during all
regional anesthesia techniques
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| Antiseptic solutions: povidone iodine (eg, Betadine)—effective against most gram-positive and gram-negative microorganisms;
functions by continuously releasing iodine into environment around cell until it penetrates cell wall and disrupts
protein synthesis; delayed onset (several minutes; accelerated with addition of isopropyl alcohol); limited duration
of effect; inhibited or neutralized by organic compounds (eg, blood); relatively high rate of acute skin reactions that primarily
manifest as localized erythema and irritation; chlorhexidine—in alcohol base or ChloraPrep solution; widely effective
against gram-positive and gram-negative microorganisms; also effective against variety of yeast and viral
components; functions by altering permeability of cell wall of microorganism until apoptosis and cell death; rapid onset
of action; accelerated further with higher concentrations of alcohol; extended duration of effect; not inhibited by organic
compounds; fewer and overall less severe skin reactions than povidone iodine; based on overwhelming evidence, alcohol-
based chlorhexidine solutions significantly reduce likelihood of catheter and catheter-site colonization; should be antiseptic
of choice for all regional techniques, including spinal anesthesia; currently not approved by Food and Drug Administration
(FDA) for use before lumbar puncture (label placed because of lack of clinical testing; povidone iodine not
technically approved by FDA for lumbar puncture either); to date, no adverse outcomes reported with either of these compounds
when used before lumbar puncture
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Infection Risks in Febrile or Infected Patient
| Studies: human and animal studies confirm that lumbar puncture in bacteremic patient appears to increase risk for meningitis;
treatment with antibiotics before lumbar puncture significantly reduces meningitis risk and acts as protective factor
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| Recommendations: 1) despite conflicting results, neuraxial blockade should not be performed in patient with ongoing
untreated systemic infection; incidence of spontaneous infection significantly higher than in general population; 2) bacteremic
patient with evidence of systemic infection may undergo spinal anesthesia if appropriate antibiotic therapy initiated
before dural puncture; insufficient data to definitively support or refute epidural placement under same clinical circumstances;
3) spinal anesthesia may be performed in patient at risk of developing low-grade transient bacteremia after dural
puncture
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Infection Risks in Immunocompromised Patients
| Microorganisms: range of microorganisms capable of causing invasive infection much broader than in general population;
patient has altered inflammatory response that may blunt clinical signs and symptoms of infection; results in delayed
diagnosis; therapy must be prolonged, due to alterations and abnormalities in host defense mechanism; high index
of suspicion important; prevention of infection primary goal; Du Pen study stratified infection risk based on degree of immunocompromise
(eg, infection risk ≈12% in malignant state; increases to ≤82% in HIV-infected patient); found risk for
infection increases with duration of epidural catheterization
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| Regional anesthesia and HIV: central nervous system (CNS) involvement occurs early in HIV infection process, including
infiltration of HIV-infected monocytes into CNS, sequestration of HIV within brain macrophages, and infection
of endothelial cells within CNS that subsequently become engulfed into cortical tissue; risk of anesthesia provider introducing
viral components into CNS during neuraxial technique extremely low; higher likelihood that viral components already
present within CNS; HIV must undergo genetic mutation to survive in CNS; therefore, even if viral components
introduced during neuraxial technique, likelihood of survival in CNS extremely low; limited data show epidural blood
patch does not cause adverse neurologic or infectious complications; authors suggest considering alternative techniques,
but no clinical studies show that alternatives safer or more efficacious than standard blood patch
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| Recommendations: 1) immunocompromised patient undergoing prolonged or extended neuraxial techniques at relatively
high risk (≈15%) for infection; warrants close clinical observation; 2) based on limited data, neuraxial and peripheral
techniques, including blood patching, can be safely performed in HIV patient; 3) epidural techniques do not appear
to increase risk for infectious complications in parturients who have secondary or recurrent herpes simplex virus type 2
(HSV-2); however, some suggest more conservative approach to spinal and epidural anesthesia in presence of first-time
primary HSV-2 infection
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Infection Risks of Peripheral Nerve Blockade
| Perineural catheters: sources of infection include skin contamination, breaches in aseptic technique, local anesthetic
solutions, disconnection of catheters or hubs, and hematogenous spread from remote sites in body; risk factors include
need for intensive care unit (ICU) admission (particularly in trauma patient), duration of use, absence of antibiotic prophylaxis,
and male sex; other factors include anatomic region (eg, femoral catheter may put patient at higher risk than interscalene
catheter), method of catheter placement, type of antiseptic, and whether catheter tunneled
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| INFECTIONS AND THE ANESTHESIA PROVIDER —Jeanine P. Wiener-Kronish, MD, Henry Isaiah Dorr Professor of
Research and Teaching in Anesthetics and Anesthesia, Department of Anesthesia and Critical Care, Harvard Medical
School, and Anesthetist-in-Chief, Massachusetts General Hospital, Boston, MA
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Avian Influenza A Virus
| Influenza: causes 36,000 deaths annually in United States; important components in pathogenesis include hemagglutinin
(H) proteins (used by virus to connect to sialic acid; binding of hemagglutinin and sialic acid promotes release of viral
particles into cell) and neuraminidase (N) proteins (remove sialic acid from cell and allow virus to spread throughout
body); pandemic seen at random intervals; largely caused by new hemagglutinin glycoproteins; virus infects humans and
birds; occasionally, bird viruses attack humans (swine act as intermediary); in 1918, 20 million people died from influenza
(known as Spanish flu; spread quickly among recruits during World War I, especially in cities holding war parades);
viruses that appear to be involved in pandemic include H1, H2, H3, N1, N2, and N8 subtypes
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| Avian influenza: H5N1 virus; 340 cases reported as of 2008; no human immunity; worldwide spread; incubation period
3 to 7 days, but lasts for 24 days; signs and symptoms include fever, sore throat and cough, plus diarrhea, lymphopenia,
thrombocytopenia, and severe acute respiratory distress syndrome (ARDS); causes systemic disease; fatality rate 60%;
vaccination in pregnancy recommended when birth expected during influenza season; 90% of infected patients <40 yr of
age (“incredible mortality in that age group”); risk factors include handling of dead poultry (eg, slaughtering, defeathering,
preparing poultry for cooking), and consuming raw or undercooked poultry; human-to-human transmission rare; respiratory
secretions (contain largest viral loads) and all body fluids, including feces, potentially infectious; relationship
between coagulation and infection led to push for research on statins (reduce proinflammatory cytokine increases, possibly
by effect on endothelial nitric oxide synthase and thrombomodulin; increase nitric oxide, decrease thrombosis, and
decrease disseminated intravascular coagulation [DIC] associated with viral and bacterial infection); data also indicate statins
decrease HIV loads, increase CD4 count, decrease replication of cytomegalovirus (CMV), and reduce Salmonella
growth
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| Prevention: anesthesia personnel should use protective covering (eg, gloves, eye protection, tight-fitting N95 surgical
mask or air-powered respirator); take into operating room (OR) only items that can be left in OR (avoid bringing fomites
out of OR); give patient muscle relaxant to avoid coughing; use regional anesthesia to avoid airway manipulation; use filters;
avoid wearing jewelry and “other things that you don’t want contaminated”; practice for these occurrences
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Extensively Drug-Resistant Mycobacterium Tuberculosis
| Introduction: 1.6 million deaths annually worldwide; one-third of world population infected with M tuberculosis (TB);
HIV strongest risk factor for development of TB; 11% of world population in Africa, but comprises “almost one-third” of
cases of global TB; travelers to Africa at increased risk of contracting TB; ≈50% of those infected with HIV die of TB; cell-
immunity defects in HIV-infected patients allow easy contraction of TB; also more difficult to diagnose (fewer bacilli; more
extrapulmonary TB)
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| Treatment: isonicotinic acid hydrazide (INH), rifampin, pyrazinamide, and ethambutol required for 2 mo; followed by 4
mo of INH and rifampin; multidrug-resistant TB (MDR-TB) occurs with resistance to INH and rifampin; TB resistant to
INH, rifampin, moxifloxacin, capreomycin, kanamycin, or amikacin known as extreme drug-resistant TB (XDR-TB); requires
many drugs, prolonged therapy, and treatment still may not be successful; exists in Africa and to smaller extent in
United States (4% of MDR-TB population); XDR-TB seen in HIV population; carefully treat cavitary disease; study
found drug therapy more successful with resection; study from National Jewish Hospital found significantly improved
survival and disease with surgery vs medicine alone (5-fold increase in odds of initial favorable outcome)
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Clostridium Difficile
| Introduction: gram-positive anaerobic spore-forming bacillus; causes pseudomembranous colitis, necrosis of bowel, and
colonic dilatation; new epidemic strain seemingly related to use of gaitfloxacin and moxifloxacin; primarily transmitted
in health care facilities
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| Prevention: wash hands thoroughly; alcohol washes do not kill C difficile spores; speaker uses alcohol wash before
touching patient, then wears gloves, removes gloves after interacting with patient, uses alcohol wash again, and then
washes her hands (“because you don’t know that your patient doesn’t have C difficile”); beginning to be seen in nonhospitalized
populations; easily transmitted
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| Incidence: seen in patients who have some contact with hospital; reported incidence of C difficile-associated diarrhea
≈10%; diarrhea occurs in practically every patient in ICU
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| Presentation: includes diarrhea, abdominal pain, hypotension, fever, and abnormal electrolytes
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| Risk factors: include antibiotics, bowel preparations, nasogastric (NG) tubes, ulcer medication, and length of stay in
ICU; extremely transmissible; complications due to toxins; mortality substantial (≥30%)
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Methicillin-Resistant Staphylococcus Aureus (MRSA)
| Introduction: has moved from hospitals into community; causing more deaths in United States than HIV and AIDS; occurs
at rate of ≈32 per 100,000 (invasive Streptococcus pneumoniae occurs at one-half that rate; group A streptococci occur
at rate of 3.6 per 100,000); suggested that almost 100,000 infections in 2005 came from MRSA; heretofore, USA 100
pulsed-field type MRSA seen in hospital; most were resistant to ≥3 drug categories; now seeing USA 300 community-associated
MRSA; constitutes ≈50% of S aureus isolates seen
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| Community-acquired vs hospital-acquired: community-acquired strains (USA 300) associated with skin infection;
occur in those who are young and sexually active, or prisoners, or those exposed to antibiotics; produce significant
toxin known as Panton-Valentine leukotoxin (PVL; destroys white blood cells); associated with extensive tissue necrosis;
toxin itself probably not necessary for invasion (bacteria have armory of virulence products and never rely on just one);
make phenol-soluble modulins that damage neutrophils; other risk factors include sharing needles, towels, soap, bed linens,
and sports equipment; treated with vancomycin, trimethoprim sulfamethoxazole (TMP-SMZ), gentamicin, and
ciprofloxacin (should be last drug used because of resistance); overall mortality “isn’t so high,” but increased in patients
>65 yr of age; higher mortality at extreme ages; mortality 60% with septic shock, ≈32% with pneumonia; mortality rates
higher in health care-associated community-onset MRSA; hospital-acquired mortality rates lower than community-acquired;
estimates suggest almost 19,000 onset bacteremias from MRSA; invasive MRSA can have health care or community
origin; occurrence of MRSA higher in urban areas
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| Treatment: data must reach anesthesia personnel quickly to change prophylactic antibiotic, if necessary; if patient known
to have MRSA, give vancomycin instead of standard prophylactic; chlorhexidine washes standard for surgical patients,
especially those at high risk or in ICU
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Suggested Reading
Bergman BD et al: Neurologic complications of 405 consecutive continuous axillary catheters. Anesth Analg 96:247,
2003; Borgeat A et al: Clinical evaluation of a modified posterior anatomical approach to performing the popliteal
block. Reg Anesth Pain Med 29:290, 2004; Capdevila X et al: French Study Group on Continuous Peripheral Nerve
Blocks. 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; Centers for
Disease Control and Prevention (CDC): Extensively drug-resistant tuberculosis--United States, 1993-2006.
MMWR Morb Mortal Wkly Rep 56:250, 2007; Delaney JA et al: Mortality after infection with methicillin-resistant Staphylococcus
aureus (MRSA) diagnosed in the community. BMC Med 6:2, 2008; Du Pen SL et al: Infection during
chronic epidural catheterization: diagnosis and treatment. Anesthesiology 73:905, 1990; Hebl JR: The importance and implications
of aseptic techniques during regional anesthesia. Reg Anesth Pain Med 31:311, 2006; Horlocker TT et al:
Regional anesthesia in the immunocompromised patient. Reg Anesth Pain Med 31:334, 2006; Horlocker TT et al: Regional
anesthesia in the immunocompromised patient. Reg Anesth Pain Med 31:334, 2006; Maki DG et al: Prospective
randomised trial of povidone-iodine, alcohol, and chlorhexidine for prevention of infection associated with central venous
and arterial catheters. Lancet 338:339, 1991; Moen V et al: Severe neurological complications after central neuraxial
blockades in Sweden 1990-1999. Anesthesiology 101:950, 2004; Neuburger M et al: Inflammation and infection complications
of 2285 perineural catheters: a prospective study. Acta Anaesthesiol Scand 51:108, 2007; Park MM et al: Outcome
of MDR-TB patients, 1983-1993. Prolonged survival with appropriate therapy. Am J Respir Crit Care Med 153:317,
1996; Rathmell JP et al: Infectious risks of chronic pain treatments: injection therapy, surgical implants, and intradiscal
techniques. Reg Anesth Pain Med 31:346, 2006; Riggs MM et al: Asymptomatic carriers are a potential source for transmission
of epidemic and nonepidemic Clostridium difficile strains among long-term care facility residents. Clin Infect Dis
45:992, 2007; Segers P et al: Prevention of nosocomial infection in cardiac surgery by decontamination of the nasopharynx
and oropharynx with chlorhexidine gluconate: a randomized controlled trial. JAMA 296:2460, 2006; Ungchusak K
et al: Probable person-to-person transmission of avian influenza A (H5N1). N Engl J Med 352:333, 2005; Wedel DJ et
al: Regional anesthesia in the febrile or infected patient. Reg Anesth Pain Med 31:324, 2006; Wedel DJ et al: Regional
anesthesia in the febrile or infected patient. Reg Anesth Pain Med 31:324, 2006; Wells CD et al: HIV infection and multidrug-resistant
tuberculosis: the perfect storm. J Infect Dis 196 Suppl 1:S86, 2007; Writing Committee of the Second
World Health Organization Consultation on Clinical Aspects of Human Infection with Avian Influenza A (H5N1) Virus:
Update on avian influenza A (H5N1) virus infection in humans. N Engl J Med 358:261, 2008; Zager EM et al: Multidrug-resistant
tuberculosis. BMC Infect Dis 8:10, 2008.
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