Epinephrine in digital block: color Doppler flow imaging.

BACKGROUND

Epinephrine is currently added to local anesthetics for its advantageous vasoconstrictive effects. Traditionally, however, its use is not advised for digital block anesthesia due to the risk of digital gangrene.

OBJECTIVE

To observe vasoconstrictive effect of epinephrine in digital block anesthesia.

METHODS

Digital blocking with epinephrine containing lidocaine was performed in 24 subjects undergoing surgical procedure of their finger and toes. Digital artery blood flows were studied with color Doppler ultrasonography before digital blocking and at 10th, 60th, and if needed 90th minutes after blocking. Doppler parameters such as peak systolic velocity, end diastolic velocity, and resistive index values were studied.

RESULTS

There were statistically significant decrease of blood flow rates and an increase of resistive index in all patients within 10 minutes. At the 10th minute of digital block, four patients had no measurable blood flow, which was restored within 60 or 90 minutes. Others showed diminished but persistent blood flow, which returned to normal within 60 minutes. No systemic or local complication related with epinephrine usage was observed.

CONCLUSION

Vasoconstrictive effect of epinephrine in local anesthetics is not persistent and resolves within 60 or 90 minutes. Its use seems to be safe in selected patients.