The sting in the tail: antiseptics and the neuraxis revisited

In 2001, Angelique Sutcliffe developed a progressive and debilitating adhesive arachnoiditis after apparently uneventful spinal anaesthesia for elective caesarean section, for which only hyperbaric bupivacaine 0.5% was administered. The path of her deterioration was steep and inexorable. Within a few days she had severe back pain, with urinary retention following shortly afterwards. Two weeks after delivery, she had signs of raised intracranial pressure, necessitating the insertion of a ventriculoperitoneal shunt to treat obstructive hydrocephalus. She developed worsening and ascending sensory and motor neuropathy in her legs over the following weeks and, having undergone further surgery to treat recurrent raised intracranial pressure, became progressively paraplegic with limited use of her arms. Her magnetic resonance imaging scans show a spinal cord severely damaged as a result of multiple dense adhesions. Infection was ruled out early on as a cause for Ms Sutcliffe's neuropathology, and there was no evidence to support the view that a syringe swap error had led to administration of the wrong drug. After the lengthy delay that often accompanies civil claims, a High Court judge in 2007 had to decide whether she had been negligently treated and, if so, to award monetary compensation. On expert advice, he concluded that, on the balance of probabilities, the injectate had become contaminated with ‘a measurable quantity’ – defined as 0.1 ml or more – of the chlorhexidine 0.5% in alcohol 70% used for skin preparation [1]. I robustly argued against this conclusion in an article in Anaesthesia News, on the grounds that the anaesthetist and operating department practitioner had been quite meticulous in minimising the risk of such chlorhexidine spillage on to the sterile field and that there was absolutely no evidence that such contamination had taken place [2]. Events since 2007 have, however, led me to conclude that the Honourable Mr Justice Irwin got it right, and I got it wrong. Specifically, in June 2010 in Sydney, Australia, Grace Wang, in labour in her first pregnancy, requested epidural pain relief. Chlorhexidine 0.5% in alcohol had been poured into one pot on the sterile field and saline into the other, and the anaesthetist chose the wrong container from which to draw up 8 ml of fluid to flush down the Tuohy needle into the epidural space (personal communication leads me to understand that – contrary to a widely stated view – the chlorhexidine was not colourless, but that the first epidural attempt had led to a bloody tap, the fluid from which had turned the contents of the saline pot pink, thus masking the usual colour difference) [3]. The contrast between these two stories is of course that, in the latter case, we know for certain that chlorhexidine had been administered into the neuraxis, but otherwise they are strikingly similar. Grace Wang's clinical deterioration was, to all intents and purposes, identical to Angelique Sutcliffe's, including the time course, the progressive and relentless neurological deterioration, the need for emergency ventricular drainage and the development of an ascending motor and sensory neuropathy leading to paraplegia and upper limb involvement. This has inevitably led me to re-examine my response to the Sutcliffe case and toconclude that chlorhexidine in alcohol was the probable causative factor. These cases are not isolated examples. Through my own medicolegal practice, I am aware of two further obstetric cases. In the first, an epidural was sited in labour, the patient complaining of severe headache during the procedure. There is no record of how the skin was prepared. The epidural was later topped up for caesarean section, theonly drugs used for labour ordelivery being bupivacaine, levobupivacaine and fentanyl. In the