The 90% minimum effective volume and concentration of ropivacaine for ultrasound-guided median nerve block in children aged 1-3 years: A biased-coin design up-and-down sequential allocation trial.

BACKGROUND

Median nerve block can provide excellent analgesia during open surgery for trigger thumb in children. However, no data on the 90% minimum effective volume (MEV) and concentration (MEC) of ropivacaine for ultrasound-guided median nerve block in pediatric patients have been reported.

DESIGN

A prospective two-phase study with an up-and-down sequential allocation trial using a biased coin design.

PATIENTS

Children aged 1-3 years are experiencing open surgery for trigger thumb.

INTERVENTION

This study has 2 parts, one for MEV and subsequently studied MEC from the former part of the study. The MEV and MEC of ropivacaine for each subsequent patient were determined by the response of the previous patient, with the biased coin design up-and-down sequential allocation trial. The interval of -volume or concentration was -0.1 ml or 0.01%, respectively.

MEASUREMENTS

The MEV and MEC of ropivacaine for ultrasound-guided median nerve block in pediatric patients, were then used to estimate the 99% minimum effective volume (MEV) and concentration (MEC). The patient's general condition, postoperative pain, and adverse events.

MAIN RESULTS

A total of one hundred and eighteen children were enrolled for the study, and 56 and 62 patients were enrolled for the MEV and MEC studies, respectively. The MEV of 0.2% ropivacaine was 1.44 ml (95% CI 1.043 ml, 1.466 ml), and the MEC of 1.5 ml ropivacaine was 0.195% (95% CI 0.159%, 0.197%). There were no adverse events that occurred.

CONCLUSION

For ultrasound-guided median nerve block in children aged 1-3 years old with trigger finger undergoing open surgery, the MEV of 0.2% ropivacaine is 1.44 ml (95% CI 1.043 ml, 1.466 ml), and the MEC of 1.5 ml of ropivacaine is 0.195% (95% CI 0.159%, 0.197%).