Delayed diagnosis of butyrylcholinesterase deficiency with insufficient neuromuscular monitoring and a confounding effect of SedLine® brain function monitoring: a case report

Intraoperative monitoring has always been a vital part of the care of an anaesthetised patient. Neuromuscular monitoring is important to use when patients have received neuromuscular blocking agents. Quantitative neuromuscular monitors are preferred over qualitative monitors and clinical judgement alone in reducing residual neuromuscular block and the associated respiratory complications. Additionally, brain function monitors can be utilised to assess the level of consciousness in anaesthetised patients. These monitors can be useful during surgical procedures and at the conclusion of a procedure to show the progress of a patient emerging from anaesthesia. We describe a case where a lack of neuromuscular monitoring after a single dose of succinylcholine coupled with an overemphasis on SedLine® brain function monitor values delayed the diagnosis of butyrylcholinesterase deficiency in a patient undergoing a mastectomy for breast cancer. This case shows the fundamental importance of using neuromuscular monitors in patients who receive neuromuscular blocking agents. It also stresses the necessity to utilise brain function monitors as clinical aids, but not allow them to hinder thinking about broader differential diagnoses when faced with challenging clinical scenarios.