Comparison of four strategies to reduce the pain associated with intravenous administration of rocuronium.

BACKGROUND I.V. rocuronium produces intense discomfort at the site of injection in conscious patients. Four strategies to reduce or prevent this discomfort were studied. METHODS Two hundred and fifty adult patients, ASA I-III, were randomized into five groups of 50 patients in a blinded, prospective study. The control group received rocuronium 10 mg alone. For the remaining four groups, rocuronium 10 mg was mixed with sodium bicarbonate 8.4% 2 ml, fentanyl 100 micro g, lidocaine 2% or normal saline. The pH and osmolality of all mixtures were measured. Patient data were analysed using ordinal logistic regression. Osmolality and pH data were analysed using the Kruskal-Wallis test with Dunn's multiple comparison test. RESULTS When compared with rocuronium alone, only the addition of saline failed to significantly reduce the pain reported by patients. The addition of fentanyl reduced the complaint of pain by 1.9 times (P<0.049) and the addition of lidocaine 2% reduced it by 3.6 times (P<0.0001). Sodium bicarbonate 8.4% reduced the reporting of pain by 18.4 times (P<0.0001). CONCLUSIONS Sodium bicarbonate 8.4%, when added to rocuronium, markedly reduces the experience of pain during the i.v. administration of a small dose of rocuronium.