Neuromuscular Pharmacodynamic Onset Of Priming Vs. Bolus Rocuronium In Major Burns.  

Tae-Hyung Han.
Department of Anesthesiology and Pain Medicine, Hangang Sacred Heart Hospital, Hallym University, School of Medicine, Seoul, Korea

Background:

When rapid sequence induction is desired such as in major burns or for the treatment of laryngospasm, one would consider modification of conventional dosing regimen of relaxants, either alone or ant mixture of clinically maximum allowable doses of an individual agent, combinations of relaxants, or employing the priming principle. Rocuronium, with a fast onset, an intermediate duration and no hyperkalemia, may well be a suitable alternative to succinylcholine, when it is contraindicated and a rapid onset of paralysis is needed. In this study, the neuromuscular pharmacodynamic onsets of rocuronium 1 mg/kg, priming vs. bolus in patients with major burns, were assessed.

Methods:

Adults, aged 18-59 years, suffering from major burn injury (n = 58), and a control group of non-burns (n = 58) were equally divided into two groups, priming vs. bolus, respectively. Anesthesia consisted of propofol and fentanyl with nitrous oxide and oxygen. Either priming of rocuronium of 10% of ED95 ´ 3 (0.06 mg/kg) followed by 0.94 mg/kg vs. bolus 1 mg/kg were given in both major burns vs. nonburns. Neuromuscular block was monitored with an acceleromyography, using TOF stimulation.

Results:

The times taken to T4 and T0 in major burns groups were significantly different between priming vs. bolus groups (72 ± 28 vs. 132 ± 55 in time to T4, 145 ± 53 vs. 237 ± 123 in time to T0, respectively, P < 0.05). On the contrary, in unburn groups, the times taken to T4 and T0 were similar. Drowsiness was reported more frequently in major burns, whereas heavy eyelids more common in unburns. Priming dose caused 10% incidence of respiratory embarrassment in both unburns and major burns.

Conclusion:

Although the priming principle in major burns provided faster onset more reliably and predictably than bolus, the effect is still unpredictable and quite variable when compared to normal, unburns. NM Monitoring is essential to determine the dose requirement and the adequacy of reversal in major burns.