Plain English Summary
Background and study aims
Dengue is emerging as a major public health issue around the world, and is a very common infection in Vietnam. In a small proportion of cases serious complications occur. In particular some patients develop a problem where the small blood vessels become leaky for a few days, allowing the blood plasma to leak out, and sometimes this leads to shock. At the moment there is no specific treatment available to counteract the leaking, but we think that if we can understand what happens to make the small blood vessels leak we may able to treat this complication more effectively. One way to understand what happens is to give a small infusion of a special kind of carbohydrate (Dextran) solution to a person with dengue and look at the way the carbohydrate leaks out of the blood vessels by measuring the concentration of the carbohydrate in the blood and urine at intervals over a couple of hours after an infusion. The technique is quite safe and is used in studies of many conditions where there is a problem with leaking blood vessels, and is also used to find out about changes to the blood vessels during pregnancy.
Who can participate?
Healthy individuals and patients with dengue aged from 18-30 years old.
What does the study involve?
The carbohydrate infusion will be administered over 2 hours with the participants lying comfortably at rest. A special device for blood sampling will be inserted to allow repeated small blood samples to be obtained at intervals during the 2 hours, together with simultaneous urine samples. The rate of clearance of the carbohydrate from the blood to the urine will be compared in the dengue patients during acute illness with the values in the same patients during recovery, and also with the results from the healthy volunteers.
What are the possible benefits and risks of participating?
There are no specific benefits to the participants at the time of the study, apart from the knowledge that their involvement might lead to improved management of dengue cases in the future. There are very few risks to the study participants; occasionally a person may be allergic to the carbohydrate solution, but the same solution is used very frequently in Vietnam as a treatment for dengue and allergic reactions are extremely uncommon here. In any case patients are monitored very closely during the infusion, and all necessary treatment for an allergic reaction is immediately available if this does occur. There may be minor bruising at the site of blood sampling.
Where is the study run from?
The study was run by researchers at the Oxford University Clinical Research Unit (OUCRU) Viet Nam; and Hospital for Tropical Diseases HCMC (HTD).
When is the study starting and how long is it expected to run for?
The study ran from August 2008 to July 2009.
Who is funding the study?
The Wellcome Trust (UK).
Who is the main contact?
The Clinical Trials Unit at the Oxford University Clinical Research Unit Viet Nam
Studies to evaluate the functional characteristics of the microvasculature during dengue infection using dextran clearance techniques and glycocalyx volume measurements
This study forms part of a wider programme of research aiming to establish how the virus and/or the patients immune response to the infection interact with the blood vessel walls to cause these effects.
1. Oxford Tropical Medicine Research Ethics Committee (OXTREC) (UK), 25/06/2008, ref: 21/08
2. Hospital for Tropical Disease Ethics Committee, 20/02/2008
Open label descriptive study
Primary study design
Secondary study design
Non randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
In order to investigate this we will separate healthy volunteers who consent to take part in the study into two groups, 10 assigned to each of the following protocols:
1. The volunteer will rest comfortably in the supine position, while vital signs are taken and two intravenous cannulae are inserted, one in either arm. A baseline blood sample (2 ml) will be drawn, and then after resting for 15 minutes, an infusion of 40 ml of 10% Dextran 40 in 0.9% NaCl (Kraspharma) plus 10 ml of inulin (Inutest, Fresenius), an inert molecule used as the reference for the clearance studies, will be given over 10 minutes. This will be followed by a maintenance infusion of 10% Dextran 40 containing 5% inulin at 1 ml/minute. The volunteer will be asked to empty the bladder at 60 minutes and then all urine produced in the next 20 minutes will be collected. A blood sample (2 ml) will be collected from the contralateral cannula at 70 minutes (i.e. at the mid-point of the 20 minute urine collection). A second blood (130 minutes) and urine (120 - 140 minute collection) sample will be obtained to complete the study. Vital signs will be monitored half-hourly during the procedure. The volunteer will be asked to drink plenty of water during the test to encourage diuresis.
2. The basic protocol is as above, but no maintenance dextran infusion is given after the initial priming bolus. Blood samples (2 ml) will be obtained from the contralateral arm cannula at 10, 20, 30 and 70 minutes following the bolus, together with a timed urine collection from 60 - 80 minutes.
Patients (40) will receive the following treatment:
Adults aged 18 - 30 years presenting to Ward D at the Hospital for Tropical Diseases with suspected dengue during the early febrile phase of the illness will be reviewed daily by a trained study physician, together with daily haematocrit and platelet counts and any other investigations as clinically indicated. Those with evidence of vascular leakage (e.g. rising haematocrit, pleural effusion, ascites or gall bladder wall thickening on ultrasound) but who remain cardiovascularly stable and do not require intravenous fluid therapy will be asked to take part in the study. Following informed consent the dextran studies will be done on day 5 of illness, using one of the protocols described above.
Primary outcome measure
Comparison of dextran clearances during acute dengue infection with convalescent patterns and results from healthy controls
Secondary outcome measures
Comparison of glycocalyx volume measurements during acute dengue infection with convalescent values and results from healthy controls
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. 20 healthy Vietnamese persons aged 18 - 30 years, either sex
2. Informed consent
1. Vietnamese adults aged 18 - 30 years , either sex
2. Admitted to Ward D at HTD with clinical dengue and evidence of vascular leakage
3. Cardiovascularly stable, not requiring intravenous (IV) fluids
4. Informed consent
Target number of participants
Participant exclusion criteria
1. Febrile illness within the last 3 months
1. Medical indication for IV fluid therapy
2. Refusal to consent
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
The Oxford University Clinical Research Unit (OUCRU)
Ho Chi Minh City
University of Oxford (UK)
Clinical Trials and Research Governance
John Radcliffe Hospital
The Wellcome Trust (UK) (grant ref: 077078)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)