Objective: To study the effects of a 4% intrauterine lidocaine infusion on perceived patient pain in first-trimester abortions.
Methods: A randomized, double-blind, placebo-controlled trial of 80 women receiving either a 5-mL 4% lidocaine (n = 40) or saline (n = 40) intrauterine infusion and a standard paracervical block before first-trimester abortion. Women completed a series of 100-mm visual analog scales (anchors: 0 = none, 100 mm = worst imaginable) to measure their perceived pain (anticipated pain, after speculum insertion, after intrauterine infusion, after cervical dilation, after suction aspiration, and 30 minutes postprocedure). Eight women volunteered for serum lidocaine levels after the lidocaine infusion.
Results: Groups were similar in respect to age, parity, prior abortion, ethnicity, gestational age, and level of dysmenorrhea. Pain scores demonstrated a significant difference between groups during cervical dilation (saline 55 mm +/- 26, lidocaine 35 mm +/- 30, P < .01) and during aspiration (saline 71 mm +/- 20, lidocaine 43 mm +/- 30, P < .01). The lidocaine group reported significantly more symptoms (ie, oral numbness and tingling) than the saline group (saline 0/39, lidocaine 16/38, 42%, P < .01). The highest serum lidocaine level recorded was 4.0 microg/mL (lidocaine group). There was no difference in overall satisfaction between the 2 groups.
Conclusion: Compared with paracervical block alone, the addition of a 4% intrauterine lidocaine infusion resulted in a significant reduction in patient perception of pain during first-trimester abortion. Although subjective symptoms of systemic lidocaine effect were common, no subjects demonstrated serum levels consistent with lidocaine toxicity. However, further studies to determine safety are needed.
Level of evidence: I.