The Effects Of
Mixing Bicarbonate Or Lidocaine With Rocuronium On
Injection Pain And Onset Of Rocuronium
Department
of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital,
Seongnam, South Korea
Background:
Rocuronium is a commonly used muscle relaxant for its rapid
onset; however, it induces severe injection pain. We supposed that injection
pain of rocuronium was due to acidity of solution, so pH elevation with
bicarbonate would reduce injection pain of rocuronium and mixing lidocaine HCl
would not reduce pain. We studied effects of bicarbonate or lidocaine on
injection pain and onset of rocuronium
Methods:
We included 95 adult patients with 18 G intravenous
catheter in arm for general anesthesia and they were randomly allocated to three
groups. All patients received 0.6 mg/kg of rocuronium, one group (Group C)
received rocuronium only (pH = 4.04), another group (Group B) received
rocuronium/bicarbonate mixture (rocuronium : bicarbonate = 5 mL : 1 mL, pH of
mixture = 7.14) and the other group (Group L) received rocuronium/2% lidocaine
mixture (rocuronium : 2% lidocaine = 5 mL : 1 mL, pH of mixture = 4.05). The
severity of injection pain was assessed (none, mild, severe). Just after pain
assessment, 2 mg/kg of propofol was injected for loss of conciousness.
Intubation time was considered as the interval from end of injection to 75%
depression of first twitch of twitch of four (TOF) and onset time as the
interval from injection to maximal depression.
Results:
The incidence of injection pain was 96.9% in group C, 93.8%
in group L and 18.8% in group B. The incidence of injection pain in group B was
lower than other groups (P < 0.01). There was no significant difference
between group C and group L. Intubation time and onset time were 79.5±24.4 sec
and 114.3±43.6 sec in group C, 79.4±29.8 sec and 98.4±33.2 sec in group L,
and 80.6±27.0 sec and 115.2±46.2 sec in group B. There was no significant
difference of intubation time and onset time between groups.
Conclusion:
Our result shows that adding bicarbonate to rocuronium is effective to reduce injection pain of rocuronium without change of onset of rocuronium, and mixing lidocaine does not reduce injection pain of rocuronium.