In children, nitrous oxide decreases pain on injection of propofol mixed with lidocaine.

PURPOSE: To investigate if 50% nitrous oxide reduces the pain during injection of propofol mixed with lidocaine in children.

METHODS

Healthy children undergoing iv induction of general anesthesia for elective surgery were recruited into this prospective, randomized, double-blind study. None of the patients received any premedication except for eutectic mixture of local anesthetics cream. Before induction of anesthesia with propofol 1% mixed with lidocaine 0.05% (propofol dose 3 mg x kg(-1)), the treatment group received 50% N(2)O in O(2) and the control group received 100% oxygen. Pain due to propofol administration was rated with a four-point behavioural scale: none, mild, moderate or severe.

RESULTS

There were 28 subjects in the control group and 26 subjects in the treatment group. Demographic data were similar in both groups. The incidence of pain at induction was 4% after N(2)O and 36% in the control group, P < 0.01. No patients had severe pain. Most patients had mild pain. Three of the ten patients with pain in the control group had moderate pain. The number needed to treat was 3:1.

CONCLUSION

Nitrous oxide reduces pain during induction with propofol mixed with lidocaine in healthy children.