Introduction: Commonly used in Europe, inhaled nitrous oxide (N2O) is gaining traction in the US as a method to decrease peri-procedural anxiety and pain. At concentrations <50%, N2O is classified as minimal sedation, making it a promising option for many urologic outpatient procedures such as prostate biopsy. The aim of our study was to determine whether self-administered nitrous oxide (SANO) decreases perception of anxiety and pain in patients undergoing transrectal prostate-needle biopsy (TRUS-Bx) and to evaluate its safety profile in the ambulatory setting. Methods: This is a single-center prospective randomized double-blind controlled trial comparing SANO versus oxygen placebo in patients undergoing TRUS-Bx. Pre- and post-procedural pain and anxiety levels were measured using the Visual Analog Scale for pain (VAS-P) and Anxiety (VAS-A). Univariate logistic regression model was used to estimate odds ratio for pain and anxiety dichotomized as VAS 0 vs VAS > 0 and group assignment. Our secondary outcomes included operator ease which was measured by surveying the blinded Urologist, complications and duration of procedure. Results: 128 patients were randomized to SANO or oxygen placebo. Patients in the SANO group had a smaller change in post-biopsy pain score (VAS-P 0.43 vs 1.03; p=0.03), and patients had lower odds of experiencing pain during the procedure (OR: 0.45 (0.21-0.97); p= 0.04) Patients in the SANO group also had a lower anxiety scores evidenced by a larger decrease in post-biopsy anxiety levels (VAS-A score 1.23 vs 0.61; p=0.09), though this did not reach statistical significance. Based on the blinded operator survey, patients randomized to the SANO group tolerated the procedure “better than expected” (61% vs 41%; p=0.02). Procedure time did not differ significantly between groups. There were no significant complications in either group. Conclusions: Patients receiving SANO during transrectal prostate biopsy had significantly lower pain levels and trended towards lower anxiety levels. Blinded Urologists perceived patients in the SANO group tolerated the procedure significantly better than the oxygen group. These encouraging results support the use of SANO to improve patient experience of care during prostate biopsies and may be a particularly promising option for patients with a history of anxiety or apprehension surrounding invasive procedures. SOURCE OF Funding: Disposables (mask) provided by Nitrouseal.
