RESUMEN
Mivacurium is a new, non-depolarizing short acting muscle relaxant. It is largely metabolized by hydrolysis by pseudocholinesterase which is known to be under genetic control and to have low activity in a variety of disease conditions. In patients with hepatosplenic schistosomiasis, the synthetic ability of the liver is decreased and cholinesterase activity is lowered. It was, therefore, of interest to study the duration of muscular relaxation by mivacurium in these patients in relation to their plasma cholinesterase activity. The duration of action of mivacurium was found to have a strong negative correlation with the activity of pseudocholinesterase [r = 0.9067]. This correlation indicated a good statistical significance [P <0.01]. The data obtained in the present study suggested that the neuromuscular blocking pattern of mivacurium nearly fits criteria suggested for a short acting non-depolarizing neuromuscular blockers and the anesthetist should be aware of the fact that conditions that lower cholinesterase activity will result in prolonged duration of neuromuscular blockade