The Use of Pressure Bag Fluid Irrigation During Flexible Cystoscopy Reduces Patient Discomfort

Flexible cystoscopy, is a commonly used diagnostic and surveillance tool in urological practice with better tolerability than rigid cystoscopy and is recommended by the European Association of Urology (EAU) [1, 2]. Despite its improved tolerability, male patients experience discomfort due to resistance at the membranous urethra [3]. Various interventions, including nitrous oxide gas, midazolam, intraurethral lidocaine gel, music, stress balls and DVD videos, have shown limited efficacy in reducing mean pain scores on visual analogue scales (VAS) [4]. A recent randomized control trial observed that manual irrigation via a ‘bag-squeeze’ significantly reduced VAS pain scores, earning a ‘strong recommendation’ by the EAU [5]. Despite this, its reproducibility is limited by human variability in the applied pressure and the need for additional staff. We designed a randomized, double-blind controlled trial evaluating whether standardized pressure bag irrigation reduces pain during flexible cystoscopy. Pre-study UroFlow demonstrated that manual bag squeeze achieves a flow rate of 6–10 mL/s, whereas a pressure bag set to 350 mmHg consistently delivers 10 mL/s via a standard MD Devices cystoscopy giving set through a 16Fr Olympus Flexible Cystoscope, and this was used for the purposes of this study. This trial recruited male patients undergoing Flexible Cystoscopy at Westmead Hospital, Sydney Australia. Prior ethics approval (2023/PID00688) and trial registration (ACTRN12623000799651), was obtained. Eligible participants were over 18 years old, with no additional procedures planned during cystoscopy. Exclusion criteria included patients without (1) chronic pelvic pain, (2) interstitial cystitis/bladder pain syndrome (3) chronic pain syndrome, (4) history of meatal, urethral or bladder neck stenosis, (5) analgesia within 24 h before cystoscopy, and (6) long term IDC for chronic retention. Recruitment commenced in September 2023 and is ongoing. Participants are randomized into three groups: control (gravity drainage with a simulated bag squeeze), Intervention 1 (pressure bag set at 350 mmHg), and Intervention 2 (manual ‘bag-squeeze’). The primary outcome is the mean VAS pain score, immediately post procedure. Secondary outcomes include patient reported outcome measures (PROMIS) surveys at day 7, evaluating for; pain intensity (1a), pain inference (6a), and emotional distress-anxiety (4a). Currently, 68 patients are enrolled and randomized: 29 to the pressure bag arm, 18 to the bag-squeeze arm, and 21 to the control group. Baseline characteristics and proceduralist experience were comparable across groups (Table 1). For the primary outcome, both the pressure bag and bag-squeeze groups reported lower mean VAS pain scores compared to the control group (1.8, 95% CI [0.97–2.63], and 1.9, 95% CI [0.95–2.85], respectively), with no difference in mean pain scores between the pressure bag and bag-squeeze group (− 0.1, 95% CI [−0.95–0.75]). For secondary outcomes, the pressure bag group reported significantly lower scores across items I–V (pain inference regarding activities of daily living), compared to the control group (I: p < 0.001, II: p = 0.0002, III: p = 0.0001, IV: p = 0.021, V: p = 0.036), and was superior to bag-squeeze in items II (p = 0.0002) and III (p = 0.018). The pressure bag group also had lower scores for item IX (overwhelming worry, p = 0.023), while the bag-squeeze group scored lower on item X (uneasiness, p = 0.015). No differences were observed for items VI–VIII (pain interference with social activities, fearfulness and anxiety). Our findings indicate that pressure bag irrigation during flexible cystoscopy significantly reduces mean VAS pain scores compared to gravity drainage and is comparable to manual bag-squeeze. The pressure bag method reduced pain interference in daily activities when compared to the control group and outperformed the bag squeeze method in minimizing pain interference with work around the home and participation in social activities. This is likely due to its consistent irrigation flow and reproducible urethral distension. Elevated irrigation pressure reducing patient-reported pain during flexible cystoscopy has been highlighted in systematic reviews [6]. A key challenge in reproducing these findings is the variability of manual pressure in conventional bag squeeze techniques, which this study overcomes. Study limitations include variability in cultural perceptions of pain and differences in pre-procedural counseling, which may impact patients' self-reported pain scores. A further limitation is the absence of pre-procedural measurements of urethral thickness and prostate size, both of which may act as confounders. Future studies should incorporate these assessments to enhance patient selection and outcome prediction. David Armany: conceptualization, methodology, validation, software, formal analysis, writing – review and editing, writing – original draft. Ankur Dhar: conceptualization, writing – review and editing, software, formal analysis, project administration. Ashan Canasingham: project administration, methodology, writing – original draft, writing – review and editing. Lawrence H. Kim: supervision. Audrey Wang: supervision, writing – review and editing. The study protocol for this trial was reviewed by the Western Sydney Local Health District (WSLHD) Human Research Ethics Committee (HREC) and was approved to take place at Westmead Hospital, Sydney, Australia (2023/PID00688). All enrolled participants have provided informed consent. A copy of the Patient Informed Consent Form (PICF) is available upon request. The authors declare no conflicts of interest.