Over the last 20 years, numerous surveys of the efficacy of thoracic epidural analgesia have been conducted, often within single institutions. Taken together, the most striking clinical feature is the wide variation in pain experienced by patients in the days following major surgery. Early audits recognized that while some patients experienced both excellent pain relief and mobility, others endured severe pain, needing repeated but increasingly ineffective rescue medication. Recent work by Moore et al. describing the bimodal nature of postoperative pain relief gives credence to these findings [21].

The dilemma that many clinicians have, when deciding how to manage pain relief after surgery, is trying to balance the potential benefits of thoracic epidural analgesia, based on evidence and personal and local experience, against the risk of serious adverse events such as epidural hematoma, epidural abscess, and nerve damage.

The problem with local surveys is that, even when conducted over many years, they are unlikely to capture rare events. Similarly, randomized controlled trials (RCTs) , although providing the highest caliber of evidence, are invariably too small to quantify the incidence of serious side effects after thoracic epidural analgesia. Thus, both anesthetists and patients are denied valuable information that may guide clinical practice.

In view of this major limitation, anesthesiologists within the United Kingdom have concentrated, in the main, on conducting national audit projects (NAPs) with the purpose of identifying the incidence of rare complications of anesthesia otherwise impossible to quantify without a national survey. The choice of the third UK national audit project (NAP) was the “Major Complications of Central Neuraxial Block in the United Kingdom” [22]. NAP3 consisted of two parts: the first estimated the denominator, the number of central neuraxial blocks (CNBs) performed annually, and the second calculated the numerator, the incidence of complications over 12 months.

National Audit Projects are now organized and run by the Health Services Research Centre (HSRC) of the National Institute of Academic Anesthesia (NIAA) [24, 25]. In addition, the HSRC coordinates quality improvement initiatives and rapid or “sprint” audits of national practice, drawing in data from each acute hospital. Key to success of national data collection was the creation of a network of approximately 260 local anesthesiologists, or Quality Audit and Research Coordinators (QuARCs) , responsible for coordinating local data collection, and acting as the interface between routine clinical anesthesia and the HSRC. The advantage of such an approach is that it has encouraged many trainees to participate in data collection for the first time and contribute to projects of national importance. Examples of national audits relevant to regional anesthesia include National Hip Fracture Database Anaesthesia Sprint Audit of Practice (ASAP) and Sprint National Anesthesia Project (SNAP) [26, 27].