ABSTRACT
Rocuronium bromide is a non-depolarizing muscle relaxant [NDMR]. It has a fast rate of onset of action, intermediate duration and rapid recovery. Mivacurium is a short acting [NDMR] that undergo rapid breakdown by plasma cholinesterase leads to rapid spontaneous recovery. In this study rocuronium, in two small doses 0.3 and 0.45mg/ kg were compared with mivacurium 0.2mg/kg as regard, intubations, onset, clinical duration and reversal either spontaneous or induced, using neostagmine and glycopyrrolate. This study divided into two parts. In part I, quality of neuromuscular block for intubation was studied, 90 patients were allocated randomly to one of three groups [n=30] to receive rocuronium 0.3mg/kg [group 1], rocuronium 0.45mg/kg [group 2] and mivacurium 0.2mg/kg [group 3]. Each group divided into two equal subgroups [a and b]. The trachea was intubated after 60 sec in subgroups la and 2a, after 90 sec in subgroup Ib, 2b and 3a and after 120sec in subgroup 3b. Intubating conditions were graded as excellent, good or poor. In part II, assessment of onset, clinical duration and time for reversal were studied. 90 patients were randomly assigned to one of three groups [n=30], group I received rocuronium 0.3mg/kg, group II received rocuronium 0.45mg/kg and group III received mivacurium 0.2mg/kg. The onset, maximum degree of block and clinical duration were measured. When T[25] was reached, the three groups divided into equal subgroups a and b. Subgroups la, Ila and IlIa undergo spontaneous recovery and subgroups Ib lIb and Illb were received neostagmine 50 micro g/kg and glycopyrrolate 10microg/kg. Results: The frequency of distribution of excellent and good in-tubating conditions were high in subgroups 2b and 3b, but the patients with excellent conditions were more in subgroup 3b, no patient with poor intubating conditions in both subgroups. There were no significant difference between the subgroups Ib, 2a and 3a regarding intubation conditions. The onset was significantly rapid in group II and slow in group III, clinical duration was significantly longer in group II compared with groups I and II. While there were no significant difference, in clinical duration of action, between groups I and II. When spontaneous recovery time TOP [0.7] compared, we found that group III had significantly short spontaneous recovery time. On the other side, group II had significantly long spontaneous recovery time. In groups I and II, the induced recovery time were much rapid than spontaneous. While in group III there was no significant difference between spontaneous or induced recovery. Rocuronium has minimal side effects, provides conditions more suitable for rapid tracheal intubation. With small doses 0.3 and 0.45mg/kg of rocuronium, clinical duration of action became short and recovery, especially induced, became rapid. Rocuronium can be used for short procedures, but a dose of 0.45mg/kg was more accepted as intubating dose especially when intubations were attempted after 90sec. A dose of 0.3mg/kg can be used as intubating dose only under adequate anesthetic depth. Mivacurium as short acting muscle relaxant may be beneficial for short procedures. Also, spontaneous recovery of mivacurium was significantly short while there was no significant difference in induced recovery when compared to rocuronium either 0.3 or 0.45mg/kg, but its delayed onset made it unsuitable for rapid intubations. The principal side effects of mivacurium are facial flushing and transient fall in blood pressure due to moderate histamine release. The duration of action of mivacurium is prolonged in patients with atypical plasma cholinesterase as well as those with end stage liver or renal disease. Mivacurium is indicated for short procedures when anticholinesterase agents must be avoided