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Reliability and Performance of the IRRAflow® System for Intracranial Lavage and Evacuation of Hematomas - A Technical Note

Publikation: Working paper/Preprint Preprint


Background Intraventricular hemorrhage (IVH) is a severe condition with poor outcomes and high mortality. IRRAflow® (IRRAS AB) is a new technology introduced to accelerate IVH clearance by minimally invasive wash-out. The IRRAflow® system performs active and controlled intracranial irrigation and aspiration with physiological saline, while simultaneously monitoring and maintaining a stable intracranial pressure (ICP). We addressed important aspects of the device implementation and intracranial lavage.

Method To allow versatile investigation of multiple device parameters, we designed an ex vivo lab setup. We evaluated 1) compatibility between the IRRAflow® catheter and the Silverline f10 bolt (Spiegelberg), 2) the physiological and hydrodynamic effects of varying the IRRAflow® settings, 3) the accuracy of the IRRAflow® injection volumes, and 4) the reliability of the internal ICP monitor of the IRRAflow®.

Results The IRRAflow® catheter was not compatible with Silverline bolt fixation, which was associated with leakage and obstruction. Design space exploration of IRRAflow® settings revealed that a balanced saline influx and efflux required adjustments of the drainage bag to adapt to different irrigation rates. High irrigation rates could be compensated by lowered drain bag height and vice versa. Appropriate settings included irrigation rate 20 ml/h with a drainage bag height at 0 cm, irrigation rate 90 ml/h with a drainage bag height at 19 cm and irrigation rate 180 ml/h with a drainage bag height at 29 cm. We found the injection volume performed by the IRRAflow® to be stable and reliable, while the internal ICP monitor was compromised in several ways due to the proximal location of the pressure sensor within the cassette of the device rather than within the parenchyma of the brain. Furthermore, we observed a significant mean drift difference of 3.16 mmHg (variance 0.4, p=0.05) over a 24-hour test period with a mean 24-hour drift of 3.66 mmHg (variance 0.28) in the pressures measured by the IRRAflow® compared to 0.5 mmHg (variance 1.12) in the Raumedic measured pressures.

Conclusion Bolting of the IRRAflow® catheter using the Medtronic Silverline® bolt is not recommendable. Increased irrigation rates are recommendable followed by a decrease in drainage bag level. ICP measurement using the IRRAflow® device was unreliable and should be accompanied by a control ICP monitor device in clinical settings.

Competing Interest Statement
The authors have declared no competing interest.

Clinical Trial

Funding Statement
Aarhus University provided funding in the order of 1,800,000 DKK supporting the PhD study associated with the trial and a grant support was received from IRRAS, 2,857,000 m DKK in the course of the study period. The trial protocol was designed by sponsor-investigator Aarhus University Hospital. The funding bodies have peer reviewed the trial protocol but have had no role in the design of the study, in the analysis, and interpretation of data or in the writing of this manuscripts.

Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.


The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study abides by the ethical principles of the Declaration of Helsinki, Good Clinical Practice Guidelines, and ISO-14155 standards, with approval from the Danish Central Region Committee on Health Research Ethics. Journal no. 1-10-72-34-21

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.


I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).


I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

StatusUdgivet - 8 jul. 2023
SerietitelmedRxiv : the preprint server for health sciences

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