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Contact Information:

Dr Alice C L Ong
-
alice.ong@nnuh.nhs.uk


Study Location:

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Be Part of Research - Trial Details - Do abnormalities in the control of brain blood flow account for dizziness on standing or after meals in older people?

Do abnormalities in the control of brain blood flow account for dizziness on standing or after meals in older people?

Not Recruiting

Open to: All Genders

Age: Senior

Medical Conditions

Syncope


This information is provided directly by researchers and we recognise that it isn't always easy to understand. We are working with researchers to improve the accessibility of this information.


Orthostatic hypotension is where there is a large fall in blood pressure when a person stands from a lying position. Post-prandial hypotension is where a fall in blood pressure occurs within 2 hours of starting a meal. Both are common in older people. Previous studies have suggested that both these conditions can affect up to two thirds of those over 65 years of age. Both conditions can produce symptoms such as dizziness which can lead to health problems such as falls and hip fractures. Therefore these conditions have a tremendous impact on confidence and independence in older people. It has also been suggested by previous studies that death rates are higher. However, not all patients with a fall in blood pressure with standing or after meals have symptoms such as dizziness or light-headedness. On the other hand, some patients report symptoms suggestive of these conditions but do not have a significant fall in blood pressure. Cerebral autoregulation refers to how the body normally maintains a good blood flow within the circulation of the brain despite brief changes in blood pressure e.g. standing from a lying position. The stiffness or hardening of the arteries with age may also have an impact on cerebral autoregulation. There has been no investigation into why some patients who have orthostatic hypotension or post-prandial hypotension have symptoms and others do not. It may be that some people are less able to adapt to changes in blood pressure because of an underlying problem in cerebral autoregulation or increased hardening of arteries. Some patients have both conditions, but there has been little study into whether or not artery stiffness or maintenance of blood flow to the brain is the underlying problem in one or both conditions. The aim of this study is to investigate whether there is impairment in brain blood flow control (cerebral autoregulation) in orthostatic hypotension and post-prandial hypotension and whether this influences the presence or absence of symptoms.

Start dates may differ between countries and research sites. The research team are responsible for keeping the information up-to-date.  

The recruitment start and end dates are as follows:

15 Feb 2011 01 Mar 2013

Patients and volunteers (e.g. relatives) recruited to the study are divided into four groups for the orthostatic hypotension study and two groups for the post-prandial study based on whether they have a history suggestive of post-prandial hypotension.
The orthostatic hypotension study groups are as follows:
1. No orthostatic hypotension without symptoms
2. No orthostatic hypotension with symptoms
3. Orthostatic hypotension without symptoms
4. Orthostatic hypotension with symptoms
The post-prandial hypotension study groups are as follows:
1. No postprandial hypotension
2. Post-prandial hypotension
On the day of the test participants have their height and weight measured, followed by a basic clinical examination of the heart, lungs and the nervous system. Basic tests of heart rate and blood pressure response to standing, deep breathing, valsalva (blowing into a syringe) and handgrip are undertaken. Arterial stiffness is estimated using the time it takes for a pulse to travel the distance between the carotid artery in the neck and the femoral artery at the top of the leg. Changes in blood flow in the brain are measured using an ultrasound probe over the surface of the skull (transcranial Doppler) in a lying position and nearly standing position (i.e. a tilted position using a special bed). This is for a maximum of 30 minutes for the orthostatic hypotension study and 60 minutes for the post-prandial hypotension study. Those who feel light-headed are returned to a lying position immediately. Capillary blood sugar is checked by gently pricking the finger with a needle. This is only done once for the orthostatic hypotension study, but is done three times on each of the two days for the post-prandial study. For those taking part in the post-prandial study, participants are randomly allocated to drink Lucozade (containing glucose) or a sparkling water and sugar-free orange squash on two separate dates, whilst monitoring brain blood flow, blood pressure and heart rate changes. Observation between these groups for these parameters are looked at in the lying and nearly standing positions (tilted position) and analysed.


Anyone who can give informed consent and whom is over the age of 60 years of age can take part. They should not have atrial fibrillation (a condition where the heart beats very irregularly) or be on medication to slow the heart beat down as this can affect tests. This includes drugs such as atenolol and digoxin. Participants should be reasonably mobile as the study involves being tilted on a special bed.

You can take part if:



You may not be able to take part if:


1. Known autonomic neuropathy2. Irregular heart rhythm such as atrial fibrillation3. On drugs known to affect autonomic function4. Uncontrolled high blood pressure5. Stroke6. Known carotid artery stenosis7. Severe cognitive impairment8. Severe physical impairment


Below are the locations for where you can take part in the trial. Please note that not all sites may be open.

  • Norfolk and Norwich University Hospitals NHS Foundation Trust
    Norwich
    NR4 7UY

This study will provide information as to whether there is poor adaptation in the blood circulation in patients with orthostatic hypotension and post-prandial hypotension. The measurements will be compared to people with no orthostatic hypotension with or without symptoms. This will allow the targeting of treatments for this condition to improve quality of life for older people and reduce associated complications including falls and fractures. The main risk of taking part is provocation of symptoms if participants have a history of this. There is slight discomfort when a finger-prick blood sample is taken.

Dr Alice C L Ong
-
alice.ong@nnuh.nhs.uk



The study is sponsored by University of East Anglia (UK) and funded by Dunhill Medical Trust (UK).




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Read full details for Trial ID: ISRCTN92525381

Or CPMS 9951

Last updated 13 December 2017

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