A double-blind randomized comparison of lidocaine and saline for cervical anesthesia

To compare bacteriostatic saline and buffered lidocaine for cervical anesthesia to blunt the reported pain during brief suction curettage.

A double-blind randomized clinical trial was conducted on women presenting for pregnancy termination procedures. Participants received either paracervical submucosal injections of bacteriostatic saline or 1% buffered lidocaine just before cervical dilation. Self-reported pain intensity was assessed at three time points during and 30 minutes after the procedure.

Fifty-two of 135 eligible women presenting for pregnancy termination procedures participated in the study. Pain intensity ratings in lidocaine and saline treatment subjects did not differ significantly at any point. Our study had a power of 0.94 to detect more than a 15% difference on the 21-point box scale between the two solutions. Only one patient requested her block be repeated, and she had received lidocaine originally. Furthermore, of those women receiving lidocaine, 11% reported mild toxicity symptoms.

To minimize lidocaine toxicity for a brief suction curettage procedure, bacteriostatic saline or very dilute lidocaine could be considered for the paracervical injection solution. The local anesthetic mechanism may be distention rather than blockage of specific autonomic nerves when there is no waiting period. This would mean that the term paracervical block could be changed to cervical anesthesia.