Sebastian Schulz-Stübner, Jean M. Pottinger, Stacy A. Coffin, and Loreen A. Herwaldt

INTRODUCTION

Infectious complications related to regional anesthesia are rare. Because most of the information is available in case reports and retrospective surveys, it is likely that these complications are underreported. It is hoped that recent surveillance and prospective registry projects using standardized surveillance definitions and the integration of such in national quality assurance projects (American Society of Regional Anesthesia [ASRA] Acute-POP/AQI) will generate more comprehensive data for risk assessment and evaluation of infection control recommendations in the future. Integration of a structured surveillance tool into the electronic medical record and a hospital’s quality management system will ease the workload for clinicians and facilitate surveillance compliance (Table 1).

While we have to work on reducing infectious complications associated with regional anesthesia because of the potential severe individual consequences, some studies demonstrate a reduction of surgical site infections with the use of local anesthesia—opening the research arena regarding whether the avoidance of general anesthesia, intrinsic properties of local anesthetics, or a combination of both is responsible for this observation.

The objective of this chapter is to summarize information from the literature on infections complications associated with regional anesthesia, as well as to discuss the mechanism and suggest strategies to prevent these complications.

PATHOGENESIS OF INFECTIONS ASSOCIATED WITH CENTRAL NEURAXIAL block

Microorganisms from exogenous or endogenous sources may gain access to the subarachnoid, epidural, or tissue space surrounding peripheral nerves in several ways. Microorganisms from the patient’s or anesthesia practitioner’s flora can be inoculated directly when a catheter or needle is inserted into those spaces. Several reports in the literature suggested that infections are on occasion caused by the anesthesia practitioner’s flora. For example, Trautmann and colleagues reported a case of meningitis caused by a Staphylococcus aureus strain that was identical by pulsed-field gel electrophoresis to the S. aureus isolated from the anesthesiologist’s nose. Rubin et al could trace to a single anesthesiologist Streptococcus salivarius as the responsible agent for six cases of meningitis following spinal anesthesia, and the Centers for Disease Control and Prevention (CDC) reported five cases in Ohio and one case in New York between 2008 and 2009 with the same organisms.

Microorganisms can also enter the epidural space by hematogenous spread from other body sites, such as infected skin, or by migrating along the catheter tract. Several case reports suggested that infection was caused by spread of bacteria from infected sites through the bloodstream to the epidural space. Others maintained that infections at distal sites are not contraindications to epidural anesthesia. For example, Newman concluded that distal infections did not increase the risk of epidural infection because traumatic injuries are often infected, and no epidural catheter-related infections were identified among over 3000 patients who had epidural neural blocks for postoperative or posttraumatic analgesia. Gritsenko and coworkers analyzed the charts of 474 patients who underwent removal of an infected hip or knee prosthesis under neuraxial anesthesia and found in 0.6% of the cases clinical signs of central neuraxial infections (meningitis or epidural abscess) and three other anesthesia-related complications, including a psoas abscess beside an epidural hematoma and back pain.

The anesthetic agents injected into the subarachnoid or epidural space are another possible source of infection. Infections from contaminated multidose vials are likely rare because most anesthetic drugs are weak bases dissolved in acidic solutions that inhibit growth of bacteria and fungi. Besides most multidose local anesthetic solutions contain a bacteriostatic agent. Nevertheless, the case report by North and Brophy suggested that contaminated multidose vials still can be a source of infection. These authors reported an infection in which S. aureus with matching phage types were Isolated from an abscess and a multidose lidocaine vial.

A report by Wong et al described, besides other infection control violations, the use of single-dose medications for multiple patients as the culprit in an outbreak of Klebsiella pneumoniae and Enterobacter aerogenes bacteremia in a pain clinic. Breaches in aseptic technique for medication preparation can be detrimental, especially if a compound pharmacy is involved: In 2012, more than 200 patients suffered fungal infections with Exserohilum rostratum after use of contaminated methypred-nisolone injections for interventional pain procedures in multiple institutions in the United States.

To assess whether contamination of the anesthetic agent or the equipment (needles, syringes, tubing) is related to subsequent infections, investigators have cultured these items after they have been used with patients or during simulations. In four studies, 0%–29% of used catheters were contaminated, and James and coworkers found that 5 of 101 syringes used to inject anesthetic agents were contaminated. Ross and coworkers drew up 0.25% bupivacaine into control syringes and into syringes used to induce continuous lumbar epidural neural block (test syringe) in 18 obstetric patients. After each dose from the test syringe, the investigators cultured the contents of both the test and the control syringes. Six of 18 test syringes were contaminated with bacteria, compared with only 1 of 18 control syringes. Raedler and associates cultured 114 spinal and 20 epidural needles after use for single lumbar injections. Twenty-four cultures (17.9%) grew microorganisms: 15.7% coagulase-negative staphylococci; 1.5% yeasts; and 0.8% each enterococci, pneumococci, and micrococci. The authors concluded that it is easy to contaminate the needle, and that anesthesiologists need to improve their hygienic measures. Despite finding contaminated equipment or anesthetic solutions, no infected patient was identified; thus, none of the authors was able to correlate contamination with infection. However, Loftus and coworkers examined the contamination of intravenous stopcocks during general anesthesia and showed, for the first time, postoperative infections with the same organism. It is therefore conceivable that contamination during the placement of a regional block, and, even more likely, during handling of continuous catheter systems, can cause infections. Although the risk for such infections would be less likely than that of manipulating intravenous lines.

INFECTIONS ASSOCIATED WITH EPIDURAL block

The numerous case reports in the literature of infections occurring after epidural neuraxial block, attest to the fact that such complications do occur and can be severe (Table 2). Of 57 patients in these case reports, 41 acquired epidural or intraspinal abscesses, 1 developed a subcutaneous abscess, 2 had meningitis without epidural abscess formation, and 1 developed sepsis. Four patients had injections only, 1 patient had injections and several catheters, and the remaining patients had catheters. Among the 38 patients who had catheters and for whom the duration of catheterization was specified, the median duration of catheteriza-tion was 3 days (range 50 minutes to 6 weeks). The median time to onset of the first signs or symptoms of infection was 4 days (range 1 day to 4.8 months) after catheter placement. Staphylococcus aureus caused 27 of 43 infections from which bacterial pathogens were isolated. Pseudomonas aeruginosa caused five infections and Streptococcus spp. caused five. Methicillin-resistant S. aureus (MRSA) was isolated in one case; three patients died.

It should be kept in mind that the number of reported cases does not allow us to assess the true frequency of infections after epidural neural block. However, several investigators have performed studies to assess this risk. When reviewing 350 reports in the literature, Dawkins in 1969 found no reports of infection after thoracic or lumbar epidural block but identified 8 (0.2%) reports of infection after 3767 sacral epidural blocks used for operative procedures and for obstetrics. More recently, Dawson reviewed the literature and found rates of deep infection ranging from 0% to 0.7% and rates of superficial infection ranging from 1.8% to 12%.

Scott and Hibbard surveyed all obstetric units in the United Kingdom and identified one epidural abscess in approximately 506,000 epidural neural blocks. In contrast, Palot and colleagues identified three cases of meningitis in 300,000 patients who had undergone epidural blocks. Three smaller series of obstetric epidural neural blocks (some 12,000 patients) did not identify any infections. Similarly, in a recent study by the French SOS group on complications of regional anesthesia, Auroy and coworkers did not identify any infections in 29,732 epidural neural blocks given for obstetrical procedures. Together, the results of these five studies suggest that four or five serious infectious complications (ie, epidural abscesses or meningitis) occur per 1 million obstetric epidural neural blocks.

A number of studies have assessed infections associated with epidural neural blocks performed for operative procedures or for short-term pain relief. However, these studies reported fewer patients than the studies of epidural neural block for obstetric procedures. Findings from 10 studies are summarized in Table 3. Brooks and collaborators found four infections among 4832 (0.08%) patients undergoing epidural neuraxial block for surgical procedures or for labor and delivery. All four infections occurred in healthy young women who underwent cesarean sections; two infections were superficial (0.04%), and two involved the epidural space (0.04%). In contrast, Holt and colleagues reported 53 (1.8%) local infec-tions and 11 (0.4%) central nervous system infections related to approximately 3000 epidural catheters.The median duration of catheterization was 8 days for patients with local infections and 15 days for those with generalized symptoms (p = .01). Catheters removed from patients with clinical symptoms were more heavily colonized than those removed from asymptomatic patients. However, 59 of 78 catheters with positive cultures were removed because patients were symptomatic, suggesting that this observation may have been affected by ascertainment bias.

Given that the incidence of infections identified in all studies has been low, the results reported by investigators who calculated the upper boundaries of the infection risk associated with epidural neural block are particularly important because they provide a better estimate of the true risk than do studies that reported only the number of infections and the number of procedures. For example, Strafford and coworkers did not identify skin infections or epidural abscesses among 1458 pediatric patients who had epidural analgesia to control perioperative pain. These investigators calculated the incidence of clinical infection to be 0 with a 95% confidence interval from 0% to 0.03%, or three infections per 10,000 procedures. Auroy and colleagues, as noted previously, did not identify any infections among 29,732 procedures done for deliveries. They calculated 95% confidence intervals of 0/10,000 to 1/10,000 procedures. Darchy and associates evaluated 75 patients, 9 (12%; incidence density rate of 2.7/100 catheter-days) of whom acquired local infections. None of the patients acquired deep infections. Based on these data, Darchy and associates estimated the upper risk of spinal space infections to be 4.8% for catheters that remained in place for 4 days. Of note, these estimates are considerably higher than those of Strafford and coworkers and higher even than the rates found by Du Pen and collaborators among patients with epidural catheters for long-term pain control.

In general, epidural catheters inserted for long-term pain control become infected more frequently than those used for short periods of time. Du Pen and associates identified 30 superficial (9.3/10,000 catheter-days), 8 deep catheter track (2.5/10,000 catheter-days), and 15 epidural space (4.6/10,000 catheter-days) infections among 350 patients who had long-term epidural catheters. Similarly, Zenz and colleagues identified two cases of meningitis among 139 patients (1.4%, or 2.1/10,000 catheter-days) treated for pain due to malignancy. Coombs reported that 10 of 92 (10.9%) cancer patients acquired local infections, and 2 (2.2%) acquired meningitis. Malignancy and reduced immunocompetence might be additional risk factors in the population with long-term catheters.

Whether newly developed transparent dressings with integrated chlorhexidine patches might be beneficial for this vulnerable population remains to be seen.

INFECTIONS ASSOCIATED WITH SUBARACHNOID block

Case reports in the literature indicated that serious infections can occur as complications of subarachnoid neural block (Table 4). Of the 471 infections reported in these case reports, 272 were meningitis, 4 were epidural abscesses, 2 were soft tissue abscesses, 2 were infections of a disk or of a disk space, 1 developed cerebral and spinal abscesses, and 1 was a case of severe necrotizing fasciitis. In the last case mentioned, the authors speculated about a contaminated reused multiuse vial of local anesthetic as the cause. The median time to onset of signs or symptoms of infection was 1 day (range 1 hour to 2 months) for all infections and 18 hours (range 1 hour to 10 days for meningitis). Streptococcal species caused 24 of the 37 infections from which bacterial pathogens were identified; S. aureus caused 2 infections; Pseudomonas spp. caused 4; and an extended spectrum betalactamase Serratia marcescens caused 1. Compared with infections after epidural neural block, infections associated with subarachnoid neural block were more likely to be caused by streptococci, and patients were more likely to recover fully. Table 5 reviews data from 10 studies or reviews that, if taken together, suggest that the rate of infection was approximately 3.5 per 100,000 sub-arachnoid neural blocks.

INFECTIONS ASSOCIATED WITH COMBINED EPIDURAL AND SUBARACHNOID block

At present, there are few reports in the literature about infectious complications as a result of using combined epidural-subarachnoid (CSE) neural block. In 11 case reports of infections with a total number of 12 patients after combined procedures (Table 6), the median time to onset of signs or symptoms of infection was 21 hours (range 8 hours to 9 days) for all infections and 18 hours (range 8 hours to 3 days) for meningitis. Signs or symptoms of epidural abscesses were first noted 1–9 days after the procedures. Streptococcal species caused three of six cases of meningitis, and S. aureus caused all three epidural abscesses. Ten of twelve patients recovered fully. Cascio and Heath assessed rates of infection associated with combined procedures and identified one case of meningitis after about 700 (≈0.1%) CSE neural blocks.

INFECTIONS ASSOCIATED WITH PERIPHERAL NERVE BLOCKS

Continuous regional anesthetic techniques utilizing peripheral nerve blocks have become more popular in recent years for postoperative pain management, especially for orthopedic procedures. Only a few studies have addressed infectious complications related to these procedures. The study by Auroy and coworkers of French anesthesiologists did not identify any infections after 43,946 peripheral blocks. Bergman and colleagues identified 1 patient among 368 patients (405 axillary catheters) who had a local S. aureus skin infection in the axilla after 48 hours of axillary analgesia. The patient recovered fully with antibiotic treatment. Meier and colleagues reported eight superficial skin infections among 91 patients who had continuous interscalene catheters for an average of 5 days. Nseir described a case of fatal streptococcal necrotizing fasciitis following axillary brachial plexus block. Adam reported a psoas abscess complicating a femoral nerve block catheter.

Cuvillion and coworkers obtained cultures of 208 femoral catheters when they were removed after 48 hours. Of the catheters, 54% were colonized with potentially pathogenic bacteria (71% Staphylococcus epidermidis, 10% Enterococcus spp., and 4% Klebsiella spp.). These investigators also reported three episodes of transient bacteremia, but they did not identify any abscesses or episodes of clinical sepsis. None of the groups provided information about the aseptic techniques used for catheter insertion.

Compère reported a single infection in 400 continuous popliteal sciatic nerve blocks (0.25%), while Volk and coworkers from the German regional anesthesia network reported in 2009 a 1.3% incidence of infectious complications for peripheral blocks in 3724 procedures compared to a higher rate for neuraxial techniques (2.7% in 5057 procedures).

Between 2002 and 2009, Reisig and coworkers collected data on 10,549 peripheral catheter procedures in an observations study that included the implementation of a comprehensive infection control bundle. While the definitions of inflammation and infection used in this study remain somewhat vague, they could show a rate of 4.2% for inflammation and 3.2% for infections in 3491 procedures before the intervention and a reduction to 2.6% for inflammation and 0.9% for infections in 7053 procedures after the interventions.

Other reports included cases of osteomyelitis following digital blocks and hematoma block for fracture repair, as well as orbital cellulites from sub-Tenon anesthesia,mediastinitis following continuous interscalene block, Aspergillus caldi-oustus infection after unspecified lower back nerve block, and two cases with sepsis after femoral nerve catheters.

All these reports emphasize the importance of maintaining strict asepsis when performing continuing peripheral nerve blocks.

PREVENTION OF INFECTIONS ASSOCIATED WITH REGIONAL ANESTHESIA

Anesthesiologists disagree about the necessity of certain infection control precautions. For example, several surveys indicated that only 50%–66% of anesthesia staff wore masks when performing epidural and subarachnoid neural blocks.

The review of studies on infections associated with epidural anesthesia indicated that there is no consensus regarding patient risk factors for infectious complications of epidural neural block. Few studies assess risk factors for infection associated with epidural or subarachnoid neural blocks, possibly in part because these infections are uncommon. In fact, only one case-control study was performed to evaluate risk factors for infections associated with epidural neural block. Dawson and colleagues evaluated epidural neural blocks performed for postoperative pain relief and found that procedures done between April and August had a sixfold higher risk than those done during other months (95% CI 1.28–28.12, p = .009). The risk of infection was lower if a bag rather than a syringe was used to administer the anesthetic agent (odds ratio 0.17, 95% CI 0.02–1.34, p = .05). Of the two risk factors identified by this study, only the latter, use of syringes, could be addressed by practice changes.

Assuming that the respiratory tract of anesthesia personnel could be a source of infection, Philips and associates conducted a simulation to assess the efficacy of masks. They seated anesthesia staff with and without masks in a room with controlled environment and asked them to speak in front of blood agar plates placed 30 cm away. The number of bacteria on the plates was significantly lower when masks were worn. However, the clinical significance of this finding is unknown.

Chlorhexidine has been shown to reduce the risk of catheter-associated bloodstream infections significantly compared with povidone-iodine. Several investigators have tried to determine whether a particular disinfectant provides more effective skin antisepsis before epidural neural blocks than do other agents. However, none of the studies was large enough to assess rates of infection; instead, the outcomes evaluated were catheter or skin colonization.

Kasuda and colleagues randomly assigned 70 patients to have their skin prepared with either a 0.5% alcoholic solution of chlorhexidine or 10% povidone-iodine. After a median of 49 ± 7 hours, the investigators removed the catheters and obtained cultures of the insertion sites and catheter tips. There was no difference in rates of positive cultures.

Kinirons and associates (the only investigators who reported a power calculation) obtained cultures from catheters removed from 96 children who had epidural catheters longer than 24 hours. The colonization rate was lower for catheters removed from children whose skin was prepared with a 0.5% alcoholic solution of chlorhexidine (1/52 catheters, 0.9/100 catheter-days) than for those removed from children whose skin was prepared with povidone-iodine (5/44 catheters, 5.6/100 catheter-days) (relative risk 0.2, 95% CI 0.1–1.0).

Sato and coworkers enrolled 60 patients who were undergoing back operations under general anesthesia. After preparing the site with either 0.5% alcoholic chlorhexidine or 10% povidone-iodine, the investigators obtained skin biopsies. Cultures from skin prepared with the alcoholic chlorhexidine were less likely to be positive (5.7%) than were cultures from skin prepared with povidone–iodine (32.4%; p < .01). However, microscopy was as likely to identify bacteria in the hair follicles of skin prepared with the alcoholic solution of chlorhexidine (14.3%) as skin prepared with povidone-iodine (11.8%).

This has led to the recommendation to use alcoholic chlorhexidine for skin preparation despite some concerns about potential neurotoxicity. The latter might be the reason American Society of Anesthesiologists (ASA) members were equivocal on the issue during the consensus process, while external experts were in favor of the recommendation.

Sviggum et al published the experiences from the Mayo Clinic analyzing almost 12,000 spinal anesthetics between 2006 and 2010 that used alcoholic chlorhexidine. They did not observe any change in neurological complications, considering the practice to be safe. Unfortunately, no data about infectious complications were reported.

The safety of alcoholic chlorhexidine was underlined in an experimental study by Doan and coworkers. They found damage to neuronal cell cultures with chlorhexidine as well as with 10% iodine they could also show that a relevant toxic concentration of skin disinfectants cannot be reached if the puncture is performed through dry skin. Therefore, allowing the skin to completely dry once disinfected before performing the block is more important than the choice of the solution in order to prevent any neurotoxic effect.

Malhotra et al demonstrated in a study of 309 healthy volunteers that single application of 0.5% chlorhexidine gluconate in 70% ethanol was as effective as two applications.The fact that infections rarely complicate neuraxial blocks suggests that the infection control practices used for these procedures are usually adequate. Given the very low rates of infection associated with epidural and subarachnoid neural block, it will be difficult to prove that additional infection control practices such as wearing masks and using full barrier precautions (ie, the anesthesiologist wears a cap, mask, sterile gloves, and sterile gown and uses a large drape to cover the patient) reduce the risk of infection. However, bacteria that colonize the skin, respiratory tract, or water caused most reported infections after epidural and subarachnoid neural blocks. Masks have been shown to decrease spread of organisms when anesthesiologists are talking. Thus, a mask would allow the anesthesiologist to talk to the patient while doing the procedure and could decrease the risk of contaminating the insertion site with oral or respiratory flora. This has also been incorporated in the ASA “Practice Advisory for the Prevention, Diagnosis, and Management of Infectious Complications Asso-ciated With Neuraxial Techniques.”

Furthermore, epidural and subarachnoid neural blocks are at least as invasive as placing central venous catheters, and the consequences of subsequent infections are at least as bad as those for catheter-associated bloodstream infections. Because the use of full barrier precautions reduces the incidence of catheter-related bloodstream infections, aseptic measures similar to those used for placing central venous catheters should be used during the placement of catheters that will remain in place for several days or longer. While the ASA practice advisory still uses the term hand washing before putting on sterile gown and gloves, hand disinfection with an alcoholic hand rub (with 70% alcohol) is the internationally preferred standard.

Anesthesia personnel should observe their patients closely for signs and symptoms of infection so that infections can be diagnosed and treated immediately. Pegues and coworkers reviewed medical records from 1980 to 1992 of patients who had short-term epidural catheters to identify those who acquired infections. They followed patients prospectively from January 1993 until June 1993.170 In 1990, they introduced a standardized procedure for inspecting temporary epidural catheters. During the entire 12.5-year period, the investigators identified seven infections, all of which occurred after catheters were inspected routinely. The increased incidence of infection could have resulted from ascer-tainment or misclassification bias associated with the retrospective review or from increased use of epidural catheters for pain management during the later time period. On the other hand, it could indicate that infections were not diagnosed when catheters were not inspected routinely for signs of infection.

Because it may be difficult to draw up opioids in a sterile manner from ampoules, some have suggested that these drugs be drawn through a filter into a syringe, which is then double wrapped and sterilized in ethylene oxide. However, the benefit of such extreme precautions is highly hypothetical.Brooks and coworkers were among the first to implement and report on structured infection control measures for continuous neuraxial blocks in their hospital. In 2008, we reviewed the literature and compared the infection control recommendations of the ASRA and the German Society of Anesthesiology and Intensive Care (DGAI) and noticed some discrepancies, especially regarding the use of masks and gowns or filters. In 2010, new guidelines by the ASA were developed in a consensus process among ASA members and external experts to clarify some of the issues. However, the evidence supporting many of the recommendations remains sparse, and extrapolation from other areas of practical implementation of infection control is needed.

The ASA “Practice Advisory for the Prevention, Diagnosis, and Management of Infectious Complications Associated With Neuraxial Techniques” has published the following guide-lines for the placement of neuraxial blocks:

• Before performing neuraxial techniques, a history and physical examination relevant to the procedure and review of relevant laboratory studies should be conducted to identify patients who may be at risk of infectious complications. Consider alternatives to neuraxial techniques for patients at high risk.
• When neuraxial techniques are indicated in a known or suspected bacteremic patient, consider administering preprocedure antibiotic therapy.
• Selection of neuraxial technique should be determined on a case-by-case basis, including consideration of the evolving medical status of the patient.
• Lumbar puncture should be avoided in the patient with a known epidural abscess.
• Aseptic techniques should always be used during the preparation of equipment (eg, ultrasound) and the placement of neuraxial needles and catheters, including the following:
  • Removal of jewelry (eg, rings and watches); hand washing; and wearing of caps, masks (covering both mouth and nose and consider changing before each new case), and sterile gloves
  • Use of individual packets of antiseptics for skin preparation
  • Use of chlorhexidine (preferably with alcohol) for skin preparation, allowing for adequate drying time
• Sterile draping of the patient.
• Use of sterile occlusive dressings at the catheter insertion site.
• Bacterial filters may be considered during extended continuous epidural infusion.
• Limit the disconnection and reconnection of neuraxial delivery systems to minimize the risk of infectious complications.
• Consider removing unwitnessed accidentally disconnected catheters.Catheters should not remain in situ longer than clinically necessary.The following recommendations are given for the diagnosis and management of infectious complications after neuraxial block:
• Daily evaluation of patients with indwelling catheters for early signs and symptoms (eg, fever, backache, headache, erythema, and tenderness at the insertion site) of infectious complications should be performed throughout the patients’ stay in the facility.
• To minimize the impact of an infectious complication, promptly attend to signs or symptoms.
• If an infection is suspected:
  • Remove an in situ catheter and consider culturing the catheter tip.
  • Order appropriate blood tests.
  • Obtain appropriate cultures.
  • If an abscess is suspected or neurologic dysfunction is present, imaging studies should be performed, and consultation with other appropriate specialties should be promptly obtained.
• Appropriate antibiotic therapy should always be administered at the earliest sign or symptom of a serious neuraxial infection.
• Consultation with a physician with expertise in the diagnosis and treatment of infectious diseases should be considered.

However, guidelines and standard operating procedures alone are not enough to ensure proper aseptic technique. Friedman and coworkers showed in a videotape analysis of 35 epidural placements by second-year residents a significant increase in manual skills with growing experience, but there was no increase in aseptic technique. This highlights the need for a special focus on aseptic technique in residency and during infection control audits of anesthesia providers.

PERIPHERAL BLOCKS AND PERIPHERAL CONTINUOUS CATHETERS

Recent studies indicated that infection control protocols similar to the recommendations for neuraxial block can reduce the incidence of infectious complications associated with placement of continuous peripheral nerve catheters. Unfortunately, the effectiveness of each step is hard to assess, a problem familiar from all the other recommended approaches in infection con-trol, such as the ones for prevention of central line–associated bloodstream infections or ventilator-associated pneumonia.

With the increasing use of real-time ultrasound, the correct handling of the ultrasound probe becomes an additional concern. To maintain the aseptic field, the cable and the probe should be covered with a sterile sheath to avoid contamination in the case of needle contact. Sterile contact gel or sterile saline should be used within the sheath. Puncture aids fixating the needle to the probe must be sterile. After the procedure, ultrasound probes need to be cleaned removing any residual gel and disinfected with an appropriate disinfectant that cannot damage the probe. Alternative techniques using ultraviolet light to disinfect ultrasound probes are under investigation.

SUMMARY

Although rare, infectious complications from regional anesthe-sia and analgesia do occur and can be serious. Recent guidelines offer practice recommendations especially for neuraxial blocks. Table 7 summarizes the key recommendations for decreas-ing the risk of infections related to regional anesthesia proce-dures. Surveillance systems should be implemented as part of national quality assurance programs to allow benchmarking and process optimization as well as providing data from large population databases, which would be beneficial in addressing some of the unanswered questions about infections after regional anesthesia procedures.

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