Epidurals are a lot safer than previously reported, according to the largest ever prospective medical study into the major complications of epidurals and spinal anaesthetics.
The study, published today in the British Journal of Anaesthesia, found that previous studies have over-estimated the risks of severe complications of these procedures.
The estimated risk of permanent harm following a spinal anaesthetic or epidural is lower than 1 in 23,000 and in many circumstances the estimated risk is considerably lower, says the study.
Researchers from the Royal United Hospital, Bath used data from every hospital in the UK and estimated the complications from the 700,000 spinals and epidurals given every year in the NHS.
All major complications of these procedures were identified and reviewed by an expert panel, which assessed the cause and severity of all permanent injuries.
They found that over a one-year period, there were 14-30 patients who suffered permanent injury and these injuries ranged from numbness in a part of the legs to paraplegia or death. Of the harmed patients 5-13 were paralysed and 3-6 died. The researchers could not be precise because in some cases the cause of injury was not totally clear.
Overall, the study found the risk of permanent injury (of whatever severity) was about 1 in 23-50,000.
The risk of being paralysed by one of these injections was 2-3 times rarer than of suffering any permanent harm.
The risk for women requiring pain relief for labour or Caesarean section was lower still, with the most pessimistic estimate of permanent harm being 1 in 80,000.
Researchers also found that the risk of harm when an epidural is used for surgery is considerably higher than the estimated risk of using it during childbirth: between 1 in 6,000 and 1 in 12,000.
These figures are considerably lower than many previous estimates.
Dr Tim Cook, a consultant anaesthetist at the Royal United Hospital, Bath who led the project, said: “The results are reassuring for patients with all procedures and settings being lower risk than many previous estimates. It is likely that this study will become widely quoted as the definitive estimate of these rare but potentially catastrophic complications.”
However, Dr Cook warned that anaesthetists should not be complacent, adding: “Although complications related to epidurals are rare, the profession still needs to examine how and why these complications arise and make steps to reduce their frequency.”
Writing in an accompanying editorial in the Journal, Dr Donal Buggy, a consultant anaesthetist at the Mater Hospital, Dublin, said the report was, “a triumph not only for its authors and the NHS anaesthetists who delivered it, but also for UK NHS risk management systems, audit databases, and processes”.
British Journal of Anaesthesia 102 (2): 179–90 (2009)