Microvascular Sex and Age-related Day-to-day Variability in Healthy Subjects
Conditions: Healthy Subjects
Sponsor: Vårdcentralen Åby

2023-09-05 
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Microvascular Sex and Age-related Day-to-day Variability in Healthy 
Subjects  
- 
Study protocol  
 
NCT-number: 06009939 
  
 
 
 
Document revision history 
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Summary of change  
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Objec3ves  
The aim of this study is to learn more about the microcirculaCon in the skin by examining sex 
and age-related day-to-day variability in healthy subjects. 
Design 
ProspecCve observaConal study. In the study, four groups will be compared: Men aged 20-30 
years, women aged 20-30 years, men aged 50-60 years and women aged 50-60 years. In total 
48 parCcipants will be included- 12 from each group.  
Background 
The microcirculaCon consists of arterioles, capillaries and venules and is essenCal for 
nutrients and oxygen to be delivered to the Cssue as well as waste products to be removed. 
The skin is oOen used as a model for studying the microcirculaCon.  
 
FlowmoCon is the rhythmical variaCons in measured skin blood ﬂow that arise due to global 
and local regulaCons of the vessels and can be studied using frequency analysis of Cme-
resolved blood ﬂow signals. 
 
There are many ways to study the microcirculaCon, most commonly are noninvasive opCcal 
techniques which measures the reﬂecCon of light used. In this study the single point 
technique EPOS and a larger area technique called PSI-X will be used. EPOS, based on laser 
doppler ﬂowmetry (LDF) and diﬀuse reﬂectance spectroscopy (DRS), analyze speed-resolved 
perfusion, variaCons in red blood cell Cssue fracCon, oxygen saturaCon and vessel diameter. 
PSI-X, based on mulC-exposure laser speckle contrast imaging (MELSCI) and mulCspectral 
imaging (MSI), analyze convenConal perfusion, speed-resolved perfusion and oxygen 
saturaCon.  
Methods  
To study day-to-day variability, each subject’s data will be collected on two separate 
occasions within 7 days.  
 
Occasion 1 
Once arriving to the lab, the subject will answer the following quesCons by ﬁlling in a 
quesConnaire: 
1. The subjects age and gender. 
2. If the subject is biologically female- Usage of anCconcepCon medicaCon? 
3. If the subject is biologically female- Number of days since the ﬁrst day of the subject’s 
period cycle, alternaCvely number of years since the subject’s most recent period 
cycle? 
4. How many minutes a week does the subject engage in high intensity workout (such 
as running, football ect)? 
5. How many minutes a week does the subject engage is low intensity workout (such as 
hiking, biking, gardening work ect)? 
6. ConformaCon to not have eaten two hours and not used nicoCne, caﬀeine, or alcohol 
three hours prior to the experiment.  
7. ConformaCon that the subject do not have a chronic disease such as diabetes, 
rheumaCsm ect.  

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Once the quesCons are ﬁlled in, the subject will receive informaCon about the experiment 
and gets the opportunity to ask quesCons, thereaOer a consent form is signed. The subject’s 
height and weight will be measured and BMI calculated. The subjects skin type will be 
determined using the Fitzpatrick scale.  
 
An acclimaCzaCon period of 15 minutes begins and the subject will remove socks and lay 
down. While the subject rests the equipment will be set up. A blood pressure cuﬀ is placed 
around the upper arm as well as around the ankle. An EPOS-probe is placed on the dorsal 
side of the foot as well as the volar side of the forearm. A marker pen is used to mark the 
skin around the probes which enables the probe to be place on the same locaCon on the 
next measurement. A vacuum pillow is set up to posiCon the arm and minimize movement 
artefacts. Once ﬁve minutes has passed, the subject’s blood pressure and pulse are noted. 
ThereaOer the PSI-X camera is set up and angled to ﬁlm the plantar side of the foot from 
about 25 cm. The subject is asked to lay as sCll as possible during the measurement.  
 
Once the acclimaCzaCon period has passed, the lights in the lab are turned oﬀ and the 
measurement will begin. Firstly, baseline data will be collected as the subject rest for 10 
minutes without provocaCon. ThereaOer the blood pressure cuﬀ on the ankle will inﬂate to 
250 mmHg for ﬁve minutes whilst data is collected. Lastly data is collected for ﬁve minutes 
aOer the blood pressure cuﬀ deﬂates. ThereaOer the PSI-X camera is moved and angled to 
ﬁlm the forearm from a 25 cm distance. Baseline data will be collected on the arm as the 
subject rest for 10 minutes without provocaCon. ThereaOer the blood pressure cuﬀ on the 
upper arm will inﬂate to 250 mmHg for ﬁve minutes whilst data is collected and lastly data is 
collected for ﬁve minutes aOer the blood pressure cuﬀ deﬂates. The temperature within the 
room is noted before and aOer the measurement.  
 
Occasion 2 
When arriving to the lab, the subject will conﬁrm to not have eaten 2 hours and not have 
consumed caﬀein or alcohol 3 hours prior to the experiment. ThereaOer the subject will 
remove socks and lay down as the acclimaCzaCon period begins. A blood pressure cuﬀ is 
placed around the upper arm as well as around the ankle. The EPOS-probes are placed 
within the marked skin areas from the previous measurement. A vacuum pillow is set up to 
posiCon the arm and minimize movement artefacts. Once ﬁve minutes has passed, the 
subject’s blood pressure and pulse are noted. ThereaOer the PSI-X camera is set up and 
angled to ﬁlm the plantar side of the foot from about 25 cm. The subject is asked to lay as 
sCll as possible during the measurement.  
 
Once the acclimaCzaCon period has passed, the lights in the lab are turned oﬀ and the 
measurement will begin. Firstly, baseline data will be collected as the subject rest for 10 
minutes without provocaCon. ThereaOer the blood pressure cuﬀ on the ankle will inﬂate to 
250 mmHg for ﬁve minutes whilst data is collected. Lastly data is collected for ﬁve minutes 
aOer the blood pressure cuﬀ deﬂates. ThereaOer the PSI-X camera is moved and angled to 
ﬁlm the forearm from a 25 cm distance. Baseline data will be collected on the arm as the 
subject rest for 10 minutes without provocaCon. ThereaOer the blood pressure cuﬀ on the 
upper arm will inﬂate to 250 mmHg for ﬁve minutes whilst data is collected and lastly data is 

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Issue 01 
collected for ﬁve minutes aOer the blood pressure cuﬀ deﬂates. The temperature within the 
room is noted before and aOer the measurement.