Visibility in Endourologic Workup (VIEW): Comparison of Gas and Saline Cystoscopy

Introduction Macrohaematuria often compromises cystoscopic visibility. We therefore compared gas-based versus saline cystoscopy in a standardized ex vivo macrohematuria model to assess visibility, procedure completion, and observed procedural performance. Methods In a monocentric, two-arm, open-label, randomized crossover pilot, physicians performed cystoscopy on ex vivo porcine bladders modified to mimic human access. Macrohematuria was simulated using a blood-analogue solution. Each bladder was distended with ambient air (180 ml; manual syringes; no intravesical pressure control) or saline (180 ml) in randomized sequence. Three predefined intravesical markings served as visibility targets. The primary endpoint was time to identify all the markings; secondary endpoints included subjective visibility (five-point Likert), perceived visual impairment, ease of use, and iatrogenic trauma (modified Objective Structured Assessment of Technical Skills (OSATS)). Paired and nonparametric tests were prespecified for ordinal outcomes. Results Thirteen physicians (urologists and surgical residents) completed both modalities. All participants identified all targets in both conditions. Visibility ratings favored GASCYS (good/excellent 92.3% vs 38.5%; p=0.0019). Ease-of-use ratings uniformly favored GASCYS (p= 0.0012). Perceived visual impairment was lower with GASCYS (trend; p=0.067). Conclusion Ambient-air cystoscopy was feasible in a standardized ex vivo macrohematuria model and was associated with improved perceived visibility and usability, highlighting its potential for further investigation in clinical studies. Clinical evaluation needs to define effectiveness, safety parameters (including gas type and pressure control), and indications for gas distension in diagnostic cystoscopy during hematuria.