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Trial registered on ANZCTR


Registration number
ACTRN12624001040550
Ethics application status
Approved
Date submitted
9/07/2024
Date registered
28/08/2024
Date last updated
28/08/2024
Date data sharing statement initially provided
28/08/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
Assessing a new technique for Intracranial pressure Recording Without Invasion or Needles
Scientific title
Assessing Intracranial Pressure Recording Without Invasion or Needles using retinal photoplethysmography in adults.
Secondary ID [1] 312484 0
Nil
Universal Trial Number (UTN)
Trial acronym
IRWIN
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Idiopathic Intracranial Hypertension 334337 0
Hydrocephalus 334338 0
Raised Intracranial Pressure 334339 0
Traumatic Brain Injury 334340 0
Condition category
Condition code
Neurological 330990 330990 0 0
Other neurological disorders
Eye 331348 331348 0 0
Diseases / disorders of the eye

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
All subjects will need to have their pupils dilated using Tropicamide 1% 2 drops 5 min apart, so that we can view the retina and take the necessary video photographs. Dilation does blur the vision for 2 hours and so subjects will be advised not to drive for 2 hours after dilation. We then apply a contact lens on the eye after topical anaesthesia (Oxyprobucaine 2%) so that the retina can be viewed and intraocular pressure altered. Multiple video-recordings of the retina and retinal vessels are taken, which are later analysed. The contact lens is made of medical grade polymethyl methacrylate, lathed and polished to have zero optical power. A standard retinal camera is attached behind the contact lens and records video recordings of the central retinal vessels. The pupil dilation takes 20 minutes and the anaesthesia of the cornea takes one minute with the video recording taking 20 to 60 minutes. There is no follow-up required because all of the measurements needed are taken at the one sitting. So there is no need to monitor adherence. The only intervention is the dilation and the installation of the anaesthetic drops to allow contact lens imaging to take good quality video recordings of the retina.

The new technique uses photoplethysmography, which is a system for measuring pulsation amplitudes in the retinal vessels. We have invented this technique and have published five papers, illustrating and validating the technique and demonstrating its accuracy in terms of predicting intracranial pressure. The system has been developed on a large benchtop optical set up. With this study, we have compressed the optical elements and camera into a small portable system which can be handheld. The underlying optical and analytical system with contact lens remains exactly the same, but the form factor has been reduced in size to allow an operator to hold the instrument in one hand.
Intervention code [1] 329002 0
Diagnosis / Prognosis
Comparator / control treatment
All Intracranial pressure (ICP) estimates are compared to either, 1) Lumbar puncture ICP measurement, 2) External ventricular drain ICP measurement, or 3) clinical judgement and utility by neurologist or neurosurgeon. The reference comparator is with lumbar puncture.
Control group
Active

Outcomes
Primary outcome [1] 338754 0
Intracranial pressure estimates will be calculated by the analytical system attached to the photoplethysmography device..
Timepoint [1] 338754 0
Primary time point will be immediately after the invasive intracranial pressure is measured, or, in the absence of an invasive intracranial pressure measurement when a radiological estimate of whether intracranial pressure is elevated or normal, is made following the photoplethysmography and restricted to within one week of the photoplethysmography.
Secondary outcome [1] 437351 0
Utility of ICP report to clinician, and comparison with clinical judgement of intracranial pressure elevation likelihood.
Timepoint [1] 437351 0
Straight after photoplethysmography.

Eligibility
Key inclusion criteria
Suspected raised ICP, consideration of need for either lumbar puncture, direct brain (eg EVD) pressure monitoring or revision of Ventricle-Perioneal (or other relevant) CSF shunt.

Healthy volunteers can be enrolled to test optimal postural positioning for the contact lens photoplethysmography. No invasive ICP procedures would be performed.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
corneal eye disease, poor view of retina in both eyes.

Study design
Purpose of the study
Diagnosis
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Single group
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Bland Altman, Correlation coefficient, mean absolute error
sensitivity and specificity and ROC AUC for 2ndry outcomes.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
13/09/2024
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
50
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
WA

Funding & Sponsors
Funding source category [1] 316903 0
Government body
Name [1] 316903 0
Government of Western Australia Department of Health: Future Health Research and Innovation Fund.
Country [1] 316903 0
Australia
Primary sponsor type
Hospital
Name
Lions Eye Institute
Address
Country
Australia
Secondary sponsor category [1] 319152 0
None
Name [1] 319152 0
Address [1] 319152 0
Country [1] 319152 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 315662 0
Sir Charles Gairdner and Osborne Park Health Care Group Human Research Ethics Committee
Ethics committee address [1] 315662 0
https://www.scgh.health.wa.gov.au/Research/Department-of-Research/My-Project/HREC
Ethics committee country [1] 315662 0
Australia
Date submitted for ethics approval [1] 315662 0
23/08/2022
Approval date [1] 315662 0
09/02/2023
Ethics approval number [1] 315662 0
RGS0000005478

Summary
Brief summary
We have developed a non-Invasive Intracranial Pressure Measurement via a Modified Photoplethysmography Technique. We have published several papers, demonstrating the accuracy of the system, which was large and unwieldy. We have shrunk the system down so that it can now be held by an examiners hand and used in patients who were bedbound, or have other medical problems. We wish to measure the accuracy and utility of such a portable photoplethysmographic system in assessing intracranial pressure. If the system is accurate, then it could save many patients from requiring invasive lumbar puncture or external ventricular drain when they have conditions where elevated intracranial pressure is thought to be a factor.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 135418 0
Prof William Morgan
Address 135418 0
Lions Eye Institute, 2 Verdun St, Nedlands, WA, 6009
Country 135418 0
Australia
Phone 135418 0
+61 417091663
Fax 135418 0
Email 135418 0
[email protected]
Contact person for public queries
Name 135419 0
Prof Bill Morgan
Address 135419 0
Lions Eye Institute, 2 Verdun St, Nedlands, WA , 6009
Country 135419 0
Australia
Phone 135419 0
+61417091663
Fax 135419 0
Email 135419 0
[email protected]
Contact person for scientific queries
Name 135420 0
Prof Bill Morgan
Address 135420 0
Lions Eye Institute,2 Verdun St, Nedlands, WA , 6009
Country 135420 0
Australia
Phone 135420 0
+61417091663
Fax 135420 0
Email 135420 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
Deidentified pressure data and pressure (intracranial pressure) calculations from the photoplethysmography.
When will data be available (start and end dates)?
At the end of the trial and after primary publication of the results for 5 years after publication of results.
Available to whom?
Upon reasonable request to the study investigators.
Available for what types of analyses?
correlation and teaching
How or where can data be obtained?
Upon reasonable request to the principal investigator via email ([email protected]) at the Lions Eye Institute.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.