SINCE the discovery of “spinal anesthesia” in 1885 by J. Leonard Corning and its subsequent application in humans by Augustus Bier in 1898, close scrutiny has been paid to possible complications related to this technique. Although neurologic complications after spinal anesthesia, including aseptic meningitis, were described as early as 1936, it was not until the Woolley and Roe cases in 1947 that these complications were highly publicized. In these cases, two relatively young healthy males became paraplegic after spinal anesthesia secondary to contamination of the syringes and spinal needles by an acidic descaler.1Ever since, clinicians continue to improve and modify this technique to increase safety and minimize complications. In this issue of Anesthesiology, Baer2presents a review of cases of post–dural puncture meningitis (PDPM) purportedly related to a dural puncture. In another report in this issue of the journal, Ruppen et al. 3present a meta-analysis of well over one million parturients describing the incidence of serious neurologic injuries, including infection, after epidural analgesia and anesthesia.
A statement on regional anesthesia approved by the House of Delegates of the American Society of Anesthesiologists*states that regional techniques are best performed by an anesthesiologist who possesses competence and skills necessary for safe and effective performance. Although the statement mentions that recognition of complications and provision of appropriate postprocedure care is the duty of the physician, there is no reference to sterile technique. More importantly, a physician booklet drafted by the American Society of Anesthesiologists Task Force on Infection Control†recommends the use of maximal sterile barrier precautions during central venous catheter infection but does not address neuraxial techniques. Baer2correctly points out that unlike regional techniques, guidelines for the prevention of intravascular catheter–related infections were developed by practitioners who insert catheters, including intensivists and anesthesiologists.4They emphasize the use of maximal sterile barrier precautions during central venous catheter infection and the preferred use of 2% chlorhexidine preparation for skin antisepsis. Sterile precautions including cap, mask, sterile gown, sterile gloves, and large sterile drape have been demonstrated to reduce the incidence of intravascular catheter–related bloodstream infections when compared with standard precautions, including sterile gloves and small drapes.5
This begs the question of whether the same precautions ought to be used for the placement of neuraxial anesthesia. Central venous catheter–related infections are more common than neuraxial-related infections, and the use of maximum sterile barriers while placing central lines was targeted by the Agency for Healthcare Research Quality as a practice that needs more widespread implementation.6Interestingly, although there are no data supporting the use of all components of maximal precautions when performing neuraxial techniques, aseptic practice for neuraxial techniques varies tremendously between practitioners.7–9Despite the abundance of data cited by Baer2demonstrating that aerosolized organisms often originate from the physician performing a dural puncture, some even question the use of a surgical mask while performing these techniques. Even in the presence of laminar airflow in operating rooms, bacterial counts measured on settle plates at head and waist height were higher when either hat or mask was not worn.10The increase in count was greater when a mask was not worn, and the absence of both hat and a mask led to an exponential increase.10Other basic components of aseptic technique are often breached. Although the bactericidal effect of skin disinfectants (povidone iodine and chlorhexidine) peaks at 2 min,4it is common to leave skin cleansing as the last step before skin infiltration, which does not leave adequate time for disinfectants to be effective. Medications are frequently drawn up without a filter needle, although microparticles are often found in local anesthetics or other sterile solutions after the syringe has been filled.11
Some have expressed skepticism that true sterile technique is actually practiced. Pointing to the many possible breeches leading to potential contamination, they have emphasized the need for a consensus conference to clarify the meaning of good aseptic practice for neuraxial techniques.7,12To this end, the American Society of Regional Anesthesia and Pain Medicine convened a consensus conference on infectious risks of regional anesthesia in March 200413; results of this proceeding will be published later this year in Regional Anesthesia and Pain Medicine and stress the need for hand washing (electronic personal communication, Joseph M. Neal, M.D., Staff Anesthesiologist, Virginia Mason Medical Center, Seattle, Washington, and Editor-in-Chief, Regional Anesthesia and Pain Medicine , April 2006). It has been strongly supported by well-designed studies that the use of sterile gloves does not replace the need for hand hygiene.4Interestingly, the Agency for Healthcare Research Quality has also targeted improved hand-washing compliance as one of the top research item topics for patient safety.6Furthermore, although the consensus stopped short of recommending an alcohol-based chlorhexidine antiseptic solution for skin disinfection before neuraxial techniques, it did come to the conclusion that this solution has a faster and stronger bactericidal effect when compared with povidone iodine (electronic personal communication, Joseph M. Neal, M.D., April 2006). However, an alcohol-based chlorhexidine antiseptic solution is not approved by the Food and Drug Administration for spinal technique‡because of controversial data on its neurotoxicity. Although the data on facemasks is not as strong, there is evidence that upper mouth commensals have been implicated in cases of PDPM.2Because it is close to impossible to predict whether a practitioner performing a neuraxial technique will need to talk with the patient or assistant, or cough or sneeze, it would also seem prudent to wear a facemask when performing this procedure. Although Baer2states that all aspects of sterile technique are part of the “standard-of-care defense,” there is no data that support the use of sterile gowns during the performance of neuraxial techniques.
Potential underreporting of cases of PDPM in the United States is another important teaching of Baer's article.2Data from other countries suggest that the incidence of PDPM is as high as 1.3 per 10,000 performed spinals (approximate range of 1:50,000 to 1:10,000); Baer's statistics suggest that the US rate is higher. The 1:10,000 figure is similar to the average risk of deadly accidents on roads or fatal undesirable healthcare outcomes.14If the US risk of PDPM is greater than 1:10,000, the risk of this procedure may be greater than patients' or physicians' perceptions of standard or acceptable risk. Besides recognizing and accepting this complication, anesthesiologists should be aware of the changes needed to achieve safety in medicine.15There are often many barriers to promoting a shift in culture, and leadership is required to advance system changes. These include the need to limit discretion and autonomy, the need to standardize practices, the need for senior leadership arbitration, and the need for simplification.14The recently drafted guidelines by the American Society of Regional Anesthesia and Pain Medicine have already started to address some of these barriers.
The decreased incidence of regional anesthesia–related maternal mortality16and the increased availability of regional anesthesia techniques over the past two decades17account for the marked increase in regional anesthesia and analgesia used by parturients. Even our colleagues in obstetrics have recognized that regional anesthetic–related complications are low.18In a recent multicenter prospective observational study on complications of anesthesia for cesarean delivery sponsored by the National Institutes of Health and written exclusively by obstetricians,18there were no regional anesthesia–related mortalities and a very small proportion of high spinals. Other complications such as failed regional, spinal headache, and blood patch were more common. Of note, there were no cases of epidural abscess or hematoma, or meningitis. In this issue of Anesthesiology, Ruppen et al. 3conduct the largest analysis to date on serious neurologic complications with epidural techniques in obstetric patients. The results are not surprising in view of the results of a recent European report demonstrating that parturients have a lower incidence of major or severe complications related to neuraxial techniques when compared with the general population.19Although epidural infection or hematoma and persistent injuries were in the single digits per million cases, transient neurologic injuries were present in 1 in 3,900 women.3Auroy et al. 20recently wrote in an editorial in this journal that in addition to knowing rates of complication, we must find the reasons. Unfortunately, we are unable to extract from the analysis of Ruppen et al. the risk factors, possible reasons for complications, or whether complications were related to the epidural technique per se . It is also difficult to determine whether combined spinal–epidural techniques were included in the analysis. One of the largest studies included does mention that combined spinal–extradural was not quantified and indeed was treated as epidural blockade in some cases.19Furthermore, some of the studies used in the metaanalysis were not looking specifically at neuraxial techniques per se . Only if we review all complications and their patterns thoroughly, as has been done by Baer, are we going to be able to develop preventive measures such as strict aseptic technique that could potentially decrease their incidence.
These two articles should be a reminder that although neuraxial techniques are largely safe and effective, potential complications can be severe. Ruppen et al. 3provides some numbers that support previous statistics on epidural techniques and neurologic complications; Baer2reminds us that there are some precautions, such as the use of facemasks during neuraxial techniques, that are essential, even if ignored by some. Patient safety includes errors of commission and errors of omission.6,15If nothing else, these two articles should increase our understanding of factors that may lead to serious complications and heighten our awareness of presenting signs and symptoms. Evidence has clearly shown that aseptic techniques are effective in reducing contamination and complications in other sterile procedures such as central venous lines. Likewise, data clearly show that lack of some sterile technique such as the use of masks creates situations (higher bacterial counts) that may be potentially harmful.21If we are to avoid the complications that 60 yr into the future will seem obvious, we must institute uniform sterile safety practices that have been proven, or seem by common logic to be prudent, and continue to study techniques used in other arenas to determine their utility.
The author thanks Eleanor R. Menzin, M.D. (Longwood Pediatrics, Children's Hospital Boston, Boston, Massachusetts), for a thorough review of this editorial view and Joseph M. Neil, M.D. (Staff Anesthesiologist, Virginia Mason Medical Center, Seattle, Washington, and Editor-in-Chief, Regional Anesthesia and Pain Medicine ), for his limitless help describing the American Society of Regional Anesthesia and Pain Medicine consensus conference on infectious risks of regional anesthesia in March 2004.
Department of Anesthesiology, Perioperative and Pain Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts. dhepner@partners.org
