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| ID | Type | Description | Link |
|---|---|---|---|
| 2026-00787 | Other Identifier | EKNZ (Ethikkommission Nordwest- und Zentralschweiz) |
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Macroscopic haematuria is a common urological emergency. Diagnostic cystoscopy is the gold standard for identifying the bleeding source; however, blood and clots within the bladder significantly impair endoscopic visibility when saline is used as the distension medium.
Air-based cystoscopy, a technique first described in the 19th century, exploits the immiscibility of gas and blood to maintain clear visualisation even during active bleeding. Despite its theoretical advantages, no randomised clinical data exist to support its use.
AIROSCOPY is a prospective, randomised, controlled, single-centre superiority study comparing air-based versus saline-based flexible cystoscopy in patients with macroscopic haematuria (Grade III-V). Patients are randomised 1:1. Only the index cystoscopy (first randomised modality) contributes to all study endpoints. A second cystoscopy with the alternative modality is performed solely for patient safety to ensure no diagnostic disadvantage from study participation. This second examination is not analysed.
The primary endpoint is identification of the bleeding source during the index cystoscopy (binary: yes/no). Secondary endpoints include time to source identification, total procedure duration, urologist-rated visibility (Likert scale), and patient comfort (Likert scale).
Background: Continuous bladder irrigation (CBI) is the current standard management for haematuria, but can delay diagnostic cystoscopy. Gas-based cystoscopy may allow earlier and clearer visualisation of the bladder mucosa.
Design: Prospective, randomised (1:1), controlled, parallel-group, open-label, single-centre superiority trial. Randomisation is stratified by haematuria grade and history of transurethral resection (TUR-B/P), using REDCap.
Intervention: Index cystoscopy with either air (up to 240 ml by syringe) or saline (up to 240 ml by syringe), according to randomisation. A second cystoscopy with the alternative medium follows immediately, exclusively to ensure no diagnostic disadvantage for the patient (results not analysed).
Sample size: N=40 (20 per arm), based on detection rates of 86% (air) vs. 38% (saline), two-sided α=0.05, 80% power, with 20% attrition allowance.
Statistics: Chi-square test (Fisher's exact test) for the primary endpoint; risk ratio and risk difference with 95% CI reported.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Air Cystoscopy | Experimental | Flexible cystoscopy using air as the distension medium (up to 240 ml, manually administered via bladder syringe). This is the index cystoscopy for patients randomised to air. |
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| Saline Cystoscopy | Active Comparator | Flexible cystoscopy using 0.9% saline as the distension medium (up to 240 ml, manually administered via bladder syringe). Standard-of-care procedure. This is the index cystoscopy for patients randomised to saline. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Air-based flexible cystoscopy | Procedure | Flexible cystoscopy with manual air insufflation (up to 240 ml) via bladder syringe for bladder distension and visualisation. |
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| Measure | Description | Time Frame |
|---|---|---|
| Identification of the underlying cause of macroscopic haematuria during the index cystoscopy | Binary outcome (yes/no). Assessed in real time by the operating urologist during the index procedure and documented immediately after completion. 'Yes' if a specific bleeding source (e.g., tumour, prostate bleeding, stone, vascular lesion) is identified; 'No' otherwise. | Immediately after completion of the index cystoscopy (intraoperative) |
| Measure | Description | Time Frame |
|---|---|---|
| Time to source identification | Minutes from insertion of the cystoscope to first identification of the bleeding source during the index cystoscopy. | Intraoperative |
| Total procedure duration | Minutes from insertion to removal of the cystoscope during the index cystoscopy. |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Lasse Petersen, Dr. med. univ. | Contact | +41 56 486 3083 | lasse.petersen@ksb.ch |
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Kantonsspital Baden AG, Department of Urology | Baden | Canton of Aargau | 5404 | Switzerland |
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Flexible cystoscopy using air as the distension medium (up to 240 ml, manually administered via bladder syringe). This is the index cystoscopy for patients randomised to air.
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| Saline-based flexible cystoscopy | Procedure | Flexible cystoscopy with manual saline irrigation (up to 240 ml, 0.9% NaCl) via bladder syringe for bladder distension and visualisation. |
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| Intraoperative |
| Urologist-rated visibility | 5-point Likert scale (1 = very poor to 5 = excellent), completed by the operating urologist immediately after the index cystoscopy. | Immediately after index cystoscopy |
| Patient comfort | Description: 5-point Likert scale (1 = very uncomfortable to 5 = very comfortable), completed by the patient immediately after the index cystoscopy. | Immediately after index cystoscopy |