Value of muscle relaxant action monitoring in prolonged mivacurium induced neuromuscular blockade

A case of neuromuscular blockade of about 200 min of duration, in a 9-year-old boy from mivacurium 0.15 mg . kg(-1) is reported, The diagnosis was delayed, after onset of the first signs of recovery, due to the lack of monitoring of neuromuscular transmission, The neuromuscular blockade was reversed with neostigmine 0.04 mg . kg(-1). Complete reversal required fifty minutes, The presence of an abnormal genetic variant of pseudocholinesterases was demonstrated by the measurements of pseudocholinesterase activity and dibucaine number, The importance of monitoring of neuromuscular transmission for diagnosis and treatment of mivacurium-induced neuromuscular blockade is underlined.