Camera monitoring of circulation dynamics using skin perfusion pattern of lower limbs
| ISRCTN | ISRCTN10417167 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN10417167 |
| Secondary identifying numbers | R63796/RE001 |
- Submission date
- 17/07/2019
- Registration date
- 15/08/2019
- Last edited
- 15/06/2020
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Circulatory System
Plain English Summary
Background and study aims
Maintaining adequate perfusion of blood and nutrients to all regions of the body is a key aim for all clinicians, but perfusion is difficult to measure directly. Many indirect whole-body measures are used such as blood pressure. In clinical settings, examination of the skin provides useful information about whole-body perfusion. Clinical examination is known to add more to the overall assessment of a patient's clinical state than just the vital sign measurements. Skin blood flow in healthy individuals varies from almost nothing to up to 60% of the heart's output of blood depending on the circumstances. In situations of circulatory collapse, the body's response is to cut down the amount of blood supplying the skin and redirect them to the more vital areas. This change can be detected on examination as pale (or mottled/marbled appearance of skin) and cool skin, but may also be detected by video cameras. The researchers have previously designed and ran a healthy volunteer study to develop non-invasive and non-contact measurement of blood flow velocity to reflect the underlying circulation. The changes measured by the video camera agreed with the changes detected by conventional methods of monitoring. One of the other findings from this previous study was that the timing and pattern of arrival of pulse/blood flow to different regions of skin does not follow what is known about the anatomical distribution of the larger blood vessels. The sequence by which the skin is perfused is not known, and it is not known whether a general pattern exists which agrees person-to-person. An understanding of this normal pattern may be key to developing a tool which can detect changes in underlying blood flow/heart function by detecting changes in this pattern.
Who can participate?
Healthy men and women aged 18 to 65
What does the study involve?
The normal pattern of blood perfusion is assessed in terms of the sequence and distribution of blood arrival. The researchers will then create changes by giving drugs which will increase and decrease the diameter of blood vessels near the surface of the skin. They will describe the directional changes in perfusion pattern created by these opposite-acting drugs. In the second part of the experiment, the researchers will place a tourniquet to temporarily stop the blood flow into the legs. After 60 seconds, they will deflate the tourniquet and study the sequence in which blood re-fills the leg vessels. This will give an idea of the underlying connection of blood vessels and help create a map of the normal blood perfusion pattern. The study visit will take about 2 hours.
What are the possible benefits and risks of participating?
The participants will be given a £50 voucher for participation. In terms of risks, the participants may experience discomfort during insertion of the drip which will remain in place for the duration of camera recording. The two drugs being used are safe and have been used in heart research in healthy volunteers at higher doses than the researchers intend to use, but may cause increase or decrease in blood pressure, headaches, and breathlessness. In order to minimise the risks, the researchers will be monitoring the participants closely and a dedicated doctor will be present for safety of the participants.
Where is the study run from?
Cardiovascular Clinical Research Facility in the John Radcliffe Hospital, Oxford (UK)
When is the study starting and how long is it expected to run for?
March 2019 to September 2023
Who is funding the study?
Oxford Biomedical Research Centre (UK)
Who is the main contact?
Dr Mirae Harford
mirae.harford@ndcn.ox.ac.uk
Contact information
Scientific
Kadoorie Centre for Critical Care Research and Education
John Radcliffe Hospital
Oxford
OX3 9DU
United Kingdom
 ORCID ID |
0000-0003-2851-1577 |
|---|---|
| Phone | +44 (0)1865223101 |
| mirae.harford@ndcn.ox.ac.uk |
Study information
| Study design | Single-centre non-randomised study |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Non randomised study |
| Study setting(s) | Other |
| Study type | Other |
| Participant information sheet | Not available in web format, please use contact details to request a participant information sheet |
| Scientific title | Optical monitoring of changes in perfusion map of lower limbs compared to traditional haemodynamic monitoring methods in response to pharmacological challenges in healthy volunteers or Mapping Of Lower Limb skIn pErfusion (MOLLIE) |
| Study acronym | MOLLIE |
| Study hypothesis | 1. Changes in peripheral circulation induced by phenylephrine and glyceryl trinitrate can be detected by video-based monitors by tracking changes in the perfusion map of lower limbs (where perfusion map is the chronological order of pulsatile signal arrival to different regions of interest of lower limb skin). 2. Changes in peripheral circulation induced by phenylephrine and glyceryl trinitrate can be detected by video-based monitors by tracking changes in the temperature map of lower limbs. 3. Changes in pulsatile signal of lower limb regions of interest can be used to identify arterial perforator locations. |
| Ethics approval(s) | Approved 16/07/2019, Medical Sciences Interdivisional Research Ethics Committee (Research Services, University of Oxford, Wellington Square, Oxford, OX1 2JD, UK; Tel: +44 (0)1865 616577; Email: ethics@medsci.ox.ac.uk), ref: R63796/RE001 |
| Condition | Perfusion of lower limbs |
| Intervention | 1. Infusion of phenylephrine to induce peripheral vasoconstriction 2. Infusion of glyceryl trinitrate (GTN) to induce peripheral vasoconstriction 3. Tourniquet application to lower limb followed by tourniquet release The aim of this study is to describe the normal pattern of blood perfusion in terms of the sequence and distribution of blood arrival. The researchers will then create changes in the cardiovascular state by giving drugs which will increase and decrease the diameter of blood vessels near the surface of the skin. They will describe the directional changes in perfusion pattern created by these opposite-acting drugs. In the second part of the experiment, the researchers will place a tourniquet to temporarily stop the blood flow into the legs. After 60 seconds, they will deflate the tourniquet and study the sequence in which blood re-fills the leg vessels. This will give an idea of the underlying connection of blood vessels and help create a map of the normal blood perfusion pattern. Proposed timeline: 00:00 – 00:10 Consent check, measure height/weight/skin colour 00:10 – 00:20 History and examination 00:20 – 00:30 IV cannulation, IV infusion set up 00:30 – 00:40 Positioning in bed, check equipment set up (trial recording), set up reference devices 00:40 Recording starts 00:40 – 00:50 Rest period with no intervention 00:50 – 01:05 15-minute infusion drug 1 01:05 – 01:35 20-minute Washout period 01:35 – 01:50 15-minute infusion drug 2 01:50 – 02:20 20-minute Washout period 02:20 – 02:25 Tourniquet inflation and release 02:25 End of study Post study: final check, medical review prior to leaving |
| Intervention type | Other |
| Primary outcome measure | Skin perfusion pattern at rest and change to the pattern post-exposure to phenylephrine and glyceryl trinitrate (GTN). Measured using composite measures from three different cameras measuring in visible, near-infrared, and infrared spectrum. Measures taken will include the strength of pulsatile signal measured at skin surface, absolute skin colour change when under constant lighting and angle, skin surface temperature gradient from proximal to distal areas, blood flow measurement using laser speckle contrast imager. Measurements will be taken at baseline, at one-minute intervals with increasing dose of phenylephrine and GTN, and at stable infusion maximal dose. |
| Secondary outcome measures | Current secondary outcome measures as of 17/02/2020: 1. Pulse transit time between proximal and distal regions of interest estimated from the photoplethysmographic signal using the camera set up as described for the primary outcome measure at baseline, at one-minute intervals with increasing dose of phenylephrine and GTN, and at stable infusion maximal dose 2. Surface temperature gradient between proximal and distal regions of interest measured using the camera set up as described for the primary outcome measure at baseline, at one-minute intervals with increasing dose of phenylephrine and GTN, and at stable infusion maximal dose 3. Proportions of visible skin surface with pulsatile photoplethysmographic component measured using the camera set up as described for the primary outcome measure at baseline, at one-minute intervals with increasing dose of phenylephrine and GTN, and at stable infusion maximal dose 4. Colour changes with increasing phenylephrine and GTN infusion measured using the camera set up as described for the primary outcome measure at baseline, at one-minute intervals with increasing dose of phenylephrine and GTN, and at stable infusion maximal dose 5. Description of the chronological order of skin perfusion when the lower limb is reperfused following the application and removal of a lower limb tourniquet, measured using the camera set up as described for the primary outcome measure continuously during the planned one-minute tourniquet application and in the 5 minutes following tourniquet release Previous secondary outcome measures: Chronological order of skin perfusion when lower limb is reperfused following application and removal of a lower limb tourniquet. Measured using the same camera set up as primary outcome measure, across all exposed regions of skin of lower limb (from mid-thigh to mid-shin). Measurements will be taken continuously during the one-minute tourniquet application and in the 5 minutes following tourniquet release. |
| Overall study start date | 01/03/2019 |
| Overall study end date | 30/09/2023 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | Both |
| Target number of participants | 30 |
| Participant inclusion criteria | Healthy males and females between the ages of 18 to 65 |
| Participant exclusion criteria | 1. Patient whose anatomy, condition, or other required monitoring precludes the use of the camera equipment or thoracic bioimpedance monitor kit. Examples include skin disorders such as eczema, scleroderma or psoriasis 2. Allergy to silver chloride ECG sensors 3. Hyperthyroidism (intravenous phenylephrine contraindicated) 4. Any regular medication except combined oral contraceptives 5. Pregnant or breastfeeding 6. History or current psychiatric illness 7. History or current neurological conditions (e.g. epilepsy) 8. History of cardiovascular disease making phenylephrine or GTN unsafe |
| Recruitment start date | 01/10/2019 |
| Recruitment end date | 31/05/2021 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centre
Headley Way
Oxford
OX3 9DU
United Kingdom
Sponsor information
University/education
Clinical Trials and Research Governance
Joint Research Office
Block 60
Churchill Hospital
Old Road
Headington
Oxford
OX3 7LE
England
United Kingdom
| Phone | +44 (0)1865 572221 |
|---|---|
| karl.shepherd@admin.ox.ac.uk | |
| Website | https://www.admin.ox.ac.uk/researchsupport/ctrg |
"ROR" |
https://ror.org/052gg0110 |
Funders
Funder type
Research organisation
No information available
Results and Publications
| Intention to publish date | 01/09/2021 |
|---|---|
| Individual participant data (IPD) Intention to share | No |
| IPD sharing plan summary | Not expected to be made available |
| Publication and dissemination plan | It is anticipated that the project outcome will be written up for peer-reviewed publication with the possibility of being presented in conferences. The results may be shared internally within the department/university, and may be shared on a public website for Kadoorie Centre for Critical Care Research and Education which will be available to the public. The researchers will offer to contact any participants who express an interest in the results with the outcome of the project. |
| IPD sharing plan | The datasets generated during and/or analysed during the current study are not expected to be made available as the data from the camera cannot be completely anonymised. In the ethics application this was extensively discussed and it was decided that the dataset will be held in a secure setting behind two doors and restricted access within Kadoorie Centre for Critical Care Research and Education and Institute of Biomedical Engineering secure server. |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Protocol article | protocol | 11/06/2020 | 15/06/2020 | Yes | No |
Editorial Notes
15/06/2020: Publication reference added.
17/02/2020: The secondary outcome measures were updated.
16/08/2019: The recruitment start date was changed from 01/08/2019 to 01/10/2019.
17/07/2019: Trial's existence confirmed by ethics committee.
