Residual anaesthesia drugs – silent threat, visible solutions

We read Bowman et al.'s editorial 1 regarding retention of anaesthetic drugs in intravenous lines with great interest and commend the standards of care proposed. We have taken an interest in this topic ourselves due to a recent incident. A patient in our hospital underwent rapid sequence induction using an indwelling intravenous cannula sited on the ward and after induction, a new cannula was inserted for use during surgery. Several hours later, the original cannula and connector (total dead space 0.7 ml) was flushed before antibiotic administration on a surgical ward. The patient experienced a rapid loss of motor function, leading to respiratory arrest, presumably from accidental administration of retained suxamethonium. After approximately five minutes of bag-valve-mask ventilation, the patient recovered neuromuscular function and reported explicit awareness of events with no physical sequelae. Clinical psychology interviews were conducted and the patient's overriding concern was that measures be taken within our hospital to prevent a recurrence. In our review of this incident we have become aware of the need not only to flush all intravenous cannulae but also to remove any unnecessary cannulae after anaesthesia. This reduces the risk of both administration of retained drugs and cannula-associated infections. Before instigating a safety campaign, we conducted a local survey of practice using visible propofol as a surrogate for an unflushed cannula or connector. This was seen in 32% of cases. In 26% of cases, unnecessary connectors or cannulae remained in place after anaesthesia. Flushing of cannulae was not documented in the anaesthetic record or drug chart of any patient. We have addressed the problem with a local protocol, post-anaesthesia handover documentation and regular repeat audit. A range of safety posters – designed to be intentionally eye-catching – have been placed in areas where anaesthesia is administered or where anaesthetists gather (Fig. 1). These have been found to be particularly effective in maintaining awareness amongst anaesthetists and theatre staff. A subsequent re-survey has demonstrated that only 1.6% of patients had visible propofol in a cannula, no total intravenous anaesthesia connectors were left attached to lines and both written documentation and verbal handover to recovery staff have increased by 36%. Recovery nurses now routinely remove any unused cannulae. As described in Bowman et al.'s article, it is well recognised that the occurrence of critical incidents in general 2, and anaesthesia specifically, is underestimated due to under-reporting and misclassification 3. The danger posed by retained anaesthetic drugs in cannulae has long been recognised as a problem 4. Given this, and the potentially devastating sequelae, it would seem imprudent to view this issue as rare and not take firm action as an anaesthetic community. Analogous to the ‘Stop Before You Block’ campaign regarding wrong-site nerve blockade 5, the development of a highly visible national patient safety initiative to help prevent the accidental administration of anaesthetic drugs would improve patient safety.