egional anesthesia is extremely beneficial to the obstetric patient, but like all procedures, it is not without risks. While the list of potential complications is long,¹ the incidence of serious complications appears to be quite low. We must, however, do all that we can to prevent them.

A recent closed claims analysis highlighted meningitis and abscess as significant causes of injury to the neuraxis, although most demonstrated good recovery.² The issue of infection has caused appropriate concern with numerous recent review articles and editorial comments in the literature.^3-6 The focus has been on better defining sterile techniques for neuraxial anesthesia. A study published in 2002 showed that practices varied widely among 367 obstetric anesthesiologists in Australia and New Zealand regarding aseptic techniques, finding in one survey that while 87 percent felt gowns were essential, only 26 percent felt the same about caps and 71 percent for face masks. In the same survey, 1 percent did not think gloves were essential!⁷

At the ASA 2005 Annual Meeting in Atlanta, Orin F. Guidry, M.D., then ASA President-Elect, asked the Task Force on Practice Guidelines for Neuraxial Opioids to evaluate this issue and consider writing guidelines for infection control practice for neuraxial anesthesia. It was widely believed that infection after neuraxial anesthesia is an issue that extends well beyond obstetrical anesthesiology practice and that guideline development should include multiple subspecialists within our Society.

When considering this challenge, the obvious questions are: 1) How much of a problem is this? 2) Do we not have standards already? and 3) Can we write guidelines that are evidence-based? The most difficult issue is determining the elusive true incidence of the two main infectious complications, i.e., epidural abscess and meningitis, after neuraxial anesthesia. In the best review (1966-1998 literature search) of this topic, Loo et al.¹ found eight cases of epidural abscess reported in obstetric regional anesthesia but a further five cases of spontaneous infection. In the same review, 15 cases of bacterial meningitis were noted. Even with under-reporting, (i.e., many cases are not reported), these are rare events in parturients. A recent meta-analysis (1966-2005 review period) suggested that the incidence of deep epidural infection in larger, more recent studies was seven per 1 million,⁴ while an older series by Scott⁸ in the United Kingdom (U.K.) found one epidural abscess in 505,000 epidural blocks in obstetrics.

When considering meningitis, a survey of 42,000 spinal and combined spinal-epidural anesthetics in U.K. parturients noted one case⁹ versus a retrospective study of surgical patients in Brazil that found three cases for a rate of one in 12,709.¹⁰ While alarmists have suggested the incidence of meningitis after spinal anesthesia may be as high as one in 10,000, I suggest that this is not the case in obstetric anesthesia. We must be cautious in quoting the incidence of such extremely rare events because, in fact, we just do not know and likely will not — not without an extremely large survey with mandatory reporting, even with as many as 2.4 million women per year in the United States having a regional anesthetic!

We know, however, that infections do occur and can be catastrophic. Many believe the incidence can be reduced with improved, consistent infection control methods. There is presently no national standard in this area, and practice varies widely. What is appropriate? Do you wash your hands before putting on gloves? Should we wear a face mask and head cover? What is the best agent for disinfection of the skin? What really defines good infection control for neuraxial anesthesia? Unlike the guidelines for central venous catheter placement, it is unlikely that we will ever show conclusively that more rigid, uniform infection control procedures will be effective in reducing neuraxial infection in obstetric anesthesia because the incidence of infection is just too low. As we develop a policy for better infection control, however, there is room for the “use of logic and common sense,” as Professor Felicity Reynolds so aptly wrote.³ We must do the best we can using the case reports and indirect evidence that do exist. It is thus likely that the task force will ultimately create a practice advisory since there does not appear to be enough data for evidence-based guidelines. What might this advisory look like?

The American Society of Regional Anesthesia and Pain Medicine (ASRA) convened a consensus conference on infectious risks of regional anesthesia in March 2004.¹¹ These proceedings have now been published.¹² While they were not written specifically for obstetric anesthesia, they are very thoughtful, and in my view, any future statement from ASA will likely be similar to these recommendations. As we consider a practice advisory or guidelines as a Society, we will need to discuss some of the more controversial items. Any document developed will be presented to ASA members for comment and ultimately voted upon in the ASA House of Delegates. Many in the United Kingdom, for example, suggest that wearing a gown is necessary, while others say there is no data to support this.⁵ When considering more basic concerns, however, I think there is a compelling argument that thorough hand washing and use of sterile gloves (a supplement to, not replacement for, hand washing!) and a fresh surgical mask and head cover are vital. Is chlorhexidine and alcohol a better skin antiseptic choice than povidone-iodine or iodophor in isoprophyl alcohol? Certainly this topic and others should be explored by the task force.

In the view of many, we need well-thought-out, more uniform sterile technique practices for neuraxial anesthesia. These will be developed by the Task Force on Practice Guidelines for Neuraxial Opioids. The task force will hold an open forum on the subject during the ASRA 32nd Annual Regional Anesthesia Meeting and Workshops on April 19, 2007, in Vancouver, British Columbia, Canada. When there is not direct evidence, we must use logic and common sense and seek a broad consensus within the ASA membership. This also is an area for further study and investigation.

In the meantime, your mother was right — wash your hands regularly and think carefully about your infection control technique.

References:
1. Loo CC, Dahlgren G, Irestedt L. Neurological complications in obstetric regional anaesthesia. Int J Obstet Anesth. 2000; 9:99-124.
2. Lee LA, Posner KL, Domino KB, Caplan RA, Cheney FW. Injuries associated with regional anesthesia in the 1980s and 1990s: A closed claims analysis. Anesthesiology. 2004; 101:143-152.
3. Reynolds F. Infection as a complication of neuraxial blockade (editorial). Int J Obstet Anesth. 2005; 14:183-188.
4. Ruppen W, Derry S, McQuay H, Moore RA. Incidence of epidural hematoma, infection, and neurologic injury in obstetric patients with epidural analgesia/anesthesia: Meta-analysis. Anesthesiology. 2006; 105:394-399.
5. Hepner DL. Gloved and masked – will gowns be next? The role of asepsis during neuraxial instrumentation. Anesthesiology. 2006; 105:241-243.
6. Baer ET. Post-dural puncture bacterial meningitis. Anesthesiology. 2006; 105:381-393.
7. Sellors JE, Cyna AM, Simmons SW. Aseptic precautions for inserting an epidural catheter: A survey of obstetric anaesthetists. Anaesthesia. 2002; 57:584-605.
8. Scott DB, Hibbard BM. Serious non-fatal complications associated with extradural block in obstetric practice. Br J Anaesth. 1990; 64:537-541.
9. Holloway J, Seed PT, O’Sullivan G, Reynolds F. Paraesthesiae and nerve damage following combined spinal epidural and spinal anaesthesia: A pilot survey. Int J Obstet Anesth. 2000; 9:151-155.
10. Videira RL, Ruiz-Neto PP, Brandao Neto M. Post spinal meningitis and asepsis. Acta Anaesthesiol Scand. 2002; 46:639-646.
11. Hebl JR, Horlocker TT. You’re not as clean as you think! The role of asepsis in reducing infectious complications related to regional anesthesia. Reg Anesth Pain Med. 2003; 28:376-379.
12. Hebl JR. The importance and implications of aseptic techniques during regional anesthesia. Reg Anesth Pain Med. 2006; 31:311-323.

Samuel C. Hughes, M.D., is Professor of Clinical Anesthesia and Perioperative Care, University of California-San Francisco and Director of Obstetric Anesthesia, San Francisco General Hospital, San Francisco, California. He is a member of the Task Force on Infection Control and Committee on Occupational Health.