Addition of magnesium sulfate to bupivacaine improves analgesic efficacy after tonsillectomy: A randomized trial and a CONSORT analysis.

OBJECTIVES

The main objective of this study was to compare the wound infiltration (peritonsillar fossa) of magnesium sulphate combined with bupivacaine, bupivacaine alone and saline solution on post-tonsillectomy pain in children. The accessory objectives were to evaluate the effect of magnesium sulphate infiltration on prevention of laryngospasm and occurrence of nausea/vomiting.

METHODS

This study is a prospective; double blinded and randomized clinical trial. Seventy-five children undergoing tonsillectomy were enrolled. Patients were randomized into three groups using closed envelop technique. Group 1 (N=24) received saline solution (NaCl), group 2 (N=25) received 0.25% bupivacaine (1mg/kg) and group 3 received magnesium sulphate (5mg/kg) and 0.25% bupivacaine (1mg/kg) after tonsillectomy using three-point technique. Pain was evaluated using mCHEOPS scale. The occurrence of laryngospasm, nausea and vomiting was monitored.

RESULTS

The mCHEOPS scores of the group 3 were significantly lower than those of the group 2 and 1 (P<0.001). Time to first analgesic administration was longer for the group 3 than for the groups 2 and 1 (P<0.001). The mean consumption of additional analgesic drugs was lower for the group 3 than the other groups (P<0.001). There were no episodes of laryngospasm in the group 3 in comparison with the other groups. The difference of the incidence of nausea and vomiting was not statistically significant (P=0.628).

CONCLUSION

The adjunction of magnesium sulphate to bupivacaine proved to provide more efficient pain control than bupivacaine alone. However, the small number of participants and the absence of sampling at the P level of 0.005 do not allow to conclude with absolute certainty.