Objective: To study the effects of an intrauterine lidocaine infusion on perceived patient pain in first-trimester abortions and to measure serum lidocaine levels.
Methods: A randomized, double-blind, placebo control trial of 80 women receiving either a 10-mL 1% lidocaine (n = 40) or saline (n = 40) intrauterine infusion and a standard paracervical block before first-trimester abortion was undertaken. Women completed a series of 100-mm visual analogue scales to measure their perceived pain (anticipated pain, after speculum insertion, after intrauterine infusion, after cervical dilation, after suction aspiration, and 30 minutes after procedure). Twenty women (10 in each group) volunteered for serum lidocaine levels at 10, 20, 30, 45, and 60 minutes after the lidocaine infusion.
Results: Groups were similar in respect to age, parity, prior abortion, ethnicity, gestational age, level of dysmenorrhea, and complications. Pain scores by visual analogue scale demonstrated no significant difference between groups at any time point during the procedure; in particular, pain during aspiration (saline infusion 51 +/- 26 mm, lidocaine infusion 47 +/- 28 mm; P =.51). Peak serum levels occurred at approximately 10 minutes after lidocaine infusion. The highest level recorded (lidocaine group) was 2.5 microg/mL (toxicity more than 5 microg/mL).
Conclusion: Compared with paracervical block alone, the addition of a 1% intrauterine lidocaine infusion resulted in no improvement in patient perception of pain during first-trimester abortion. No subjects demonstrated symptoms or serum levels of lidocaine toxicity.
Level of evidence: I