Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT06039098 |
| Other study ID # |
317751 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
January 5, 2023 |
| Est. completion date |
August 20, 2023 |
Study information
| Verified date |
February 2024 |
| Source |
Queen Mary University of London |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
We aim to acquire data using DCS on patients who are undergoing invasive ICP and ABP
monitoring on ITU as part of their normal treatment.
Data will then be correlated to derive various parameters including CBF and BFI.
All interventions are entirely non-invasive.
Description:
Cerebral Autoregulation (CA) is the complex process whereby the body maintains constant blood
flow to the brain (cerebral blood flow, CBF) over a wide range of mean arterial pressures
(MAP) in order to provide constant oxygenation and nutrition supply to cerebral tissue. By
balancing blood and cerebrospinal fluid (CSF) pressures, CA dynamically stabilises cerebral
perfusion pressure (CPP) and hence blood flow. Disordered CA may result in reduced oxygen and
nutrient delivery to the brain tissue leading to hypoxic and ischaemic damage resulting in
significant morbidity and mortality.
High intracranial pressure (ICP) is frequently associated with failing CA. Hence ICP is
routinely monitored in patients suffering from traumatic brain injury (TBI) and other
conditions which may result in CA failure. Raised ICP contributes to the majority of
mortalities following severe TBI. All currently available ICP monitoring systems require
insertion of an electrical or pneumatic transducer into the cranial cavity, usually sited
within the brain parenchyma but occasionally into the subdural space (between the brain and
the skull) or into the ventricles. This is currently only performed by neurosurgeons and
carries a small but significant risk of haemorrhage or infection.
Non-invasive ICP and hence CA monitoring would eliminate the risk of complications, could be
used by all healthcare professionals, would extend the use to outside a hospital settings and
may extend the range of conditions to benefit from ICP monitoring.
This project pilots an approach to expand our understanding of the basic physiological
interplay between intracranial pressure, arterial blood pressure, and cerebral blood flow in
adult in-patients.
A recently-developed form of near-infrared (NIR) optical sensing known as Diffuse Correlation
Spectroscopy (DCS) offers an opportunity to investigate cerebral blood flow at the bed-side
continuously. DCS measures blood flow in the microvasculature of the brain by determining a
blood flow index (BFi).
A similar technology based on near-infrared spectroscopy (NIRS), was recently successfully
applied by the Chief Investigator in the same population in the same manner as in the current
proposal (IRAS ID: 219476, approved by the East of England - Cambridge Central Research
Ethics Committee (18/EE/0276) on 14/02/19). We therefore have extensive experience working
with optical instruments in these patient groups.
In this proposal we will use a custom DCS research instrument. This research instrument is
designed to measure microvascular cerebral blood flow for neuroscience and neurological
research applications. While this device is a bespoke instrument, built with this study in
mind, it is based on established research technologies and has been tested successfully in
more than 20 healthy volunteers and in a range of quality-control experiments to date. It
uses a forehead-mounted optical probe that contains near-infrared light sources that can
illuminate the brain tissue non-invasively and continuously. The light's path within brain
tissue is modulated by the flow of blood in the cerebral microvasculature and it is
ultimately absorbed or backscattered. The backscattered light is collected at a different
point within the probe.
The interplay between mean arterial blood (MAP) (measured by means of an intra-arterial
catheter (part of normal medical care for patients on ITU) or a non-invasive finger-cuff) and
ICP affects the morphology of the pulsatile flow in the cerebral microvascular, so the
analysis of these signals in unison will help us better understand the relationship between
ICP (which is measured clinically), MAP (which is measured clinically) and cerebral blood
flow (which is not). This in turn could help support new research into head injury
management, notably ICP-targeted treatment regimes. Ultimately this could lead to significant
improvements in secondary injury-related mortality, length of hospital stay and reduced
post-trauma disability. In addition the non-invasive nature of the monitor could extend the
range of medical conditions that may benefit from ICP and CA monitoring including stroke,
brain tumour surveillance, hydrocephalus, pre-hospital care of trauma patients, routine
anaesthetic and ICU monitoring systems and screening of patients with headache in primary
care.
In addition, if successfully developed, this technology is likely to be extremely relevant to
low and middle income countries where access to neurosurgeons (and hence ICP monitoring) is
extremely limited.
