Caution over use of sticker labels or additional marks to create ‘stop’ moment in ‘stop before you block’

A ‘stop’ moment should be undertaken before performing a local anaesthetic or regional block to prevent wrong-side block. This guidance was produced by the Safe Anaesthesia Liaison Group (SALG) and then included in the National Safety Standards for Invasive Procedures (NatSSIPs) 1. There are several measures proposed to force the ‘stop’ moment, from checklists to signs on ultrasound machines 2, or the novel ‘mock before you block’ technique 3, 4. In this context, we write to express concern about the recent correspondence that advocates either making additional ‘anaesthetic’ marks 5, or placing anaesthetic labels 6 on the side to be blocked, as a means of forcing the ‘stop’ moment. The NHS instructions on skin marking for surgery can be found in the same NatSSIPs document 7 and in a previous NPSA document 8 and have been further explained 9. The National Patient Safety Agency Patient Safety Alert ‘World Health Organization (WHO) surgical safety checklist’ (2009) determines “that the overall responsibility for the site marking for regional blocks lies with the operating surgeon. The anaesthetist should only proceed with a regional block after confirming that the site for surgery has been marked” 10. Therefore, the national consensus is that the only mark on the patient should be a surgical mark, made as an arrow near the incision site. On behalf of the national organisations representing patient safety in anaesthesia, we believe that the use of any additional marks, including labels, is contrary to the NHS guidance. Moreover, use of such additional marks has the potential to cause error, including perhaps wrong-side surgery if the label is not removed. Indeed, we are now aware of several incidents of wrong-side block emanating from Trusts where such sticker label policies are in force. It is possible that when the label is accidently placed on the side opposite to be blocked, an ‘invisible gorilla’ effect can occur, wherein the original surgical site mark becomes invisible as the practitioner then concentrates solely on the (misplaced) sticker. We encourage all anaesthetists to follow the national guidance on operative site marking, and refrain from introducing local policies relying on additional marks or labels to the surgical side. There are many proposed interventions such as signs on ultrasound machines 2, ‘mock before you block’ 3, 4 or electronic alerts 11 that do not contravene the guidance. We remind colleagues that the only mark that should be used is the surgical site mark, and this should be the sole focus of attention when identifying the side to be blocked.