Use of MEOPA (nitrogen monoxide-oxygen mixture) as analgesic for prostate biopsies.

Objective: To determine the tolerance of prostate biopsies in the case of co-administration of an analgesic gas composed of a ready for use mixture of nitrogen monoxide and oxygen (MEOPA) (marketed under the trade name of Kalinox(R)), and intrarectal instillation of xylocaine gel by comparing the results with those obtained in a control group only receiving intrarectal xylocaine instillation. Material and Methods: Non-randomized, prospective study conducted on 100 cases, with a control group composed of the first 22 patients (before availability of MEOPA in the department), followed by 78 patients treated with MEOPA. A questionnaire was completed by the patient and by the outpatient nurse caring for the patient. Results: A very significant reduction (p=0.003) of the VAS pain score (from 3.86 to 2.38) and a highly significant improvement (p<0.001) of global tolerance of the procedure based on the nurse's estimation of pain (VAS scale) were observed. The MEOPA group also presented a significant improvement of pain in patients who had previously undergone a series of prostate biopsies (p=0.043). The satisfaction rate was higher in patients receiving MEOPA, although 28.2% of patients experienced adverse effects, all minor and bothersome in only 3.81% of cases. Conclusion: The MEOPA analgesic method as a complement to intrarectal xylocaine instillation considerably improved tolerance of the procedure with no major adverse effects and without prolonging the procedure or the surveillance. It is simple to use, safe and effective.