Microclimate
Management –
A new approach
to improve skin
integrity: what
is the clinical
relevance?
Microclimate
Management
Proceedings of a satellite symposium
held at the European Pressure Ulcer Advisory Panel (EPUAP)
29th August 2013
ArjoHuntleigh’s Skin IQTM Microclimate Manager (MCM) is a
fluid resistant, vapour permeable single patient use mattress
cover for use with a pressure distribution surface to help
prevent and treat Category I-IV pressure ulcers. Powered
by the innovative Negative Airflow Technology (NAT),
ArjoHuntleigh’s Skin IQ MCM portfolio is a breakthrough in
microclimate management for the prevention and treatment
of Category I-IV pressure ulcers by pulling away excess
moisture and reducing temperature at the skin/surface
interface, supporting greater patient comfort
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Chairs Introduction
Amit Gefen, Professor in
Biomedical Engineering, Tel
Aviv University, Israel, and
President Elect, EPUAP
Prof. Amit Gefen’ research interests are in the normal
and pathological effects of biomechanical factors
on the structure and function of cells, tissues and
organs, with emphasis on the musculoskeletal system
and applications in chronic wound research. He has
published more than 140 articles in peer-reviewed international journals, many on
chronic wounds and he has also edited several books. He is now editing a book series
on Mechanobiology, Tissue Engineering and Biomaterials published by Springer, and
serving at the Editorial Boards of several international journals, including the Journal of
Biomechanics, Clinical Biomechanics, Medical Engineering & Physics, Computer Methods
in Biomechanics and Biomedical Engineering and the Journal of Tissue Viability. Professor
Gefen has recently taken on the role of President of the European Pressure Ulcer Advisory
Panel.
The development of a new medical device should always start with basic science and
laboratory work. This will provide the theoretical basis for the device. Translational studies
are then needed to establish the theory, and industry can then follow with product
development and testing. Clinical studies will finally be required in order to give us the
full picture, and will help us to decide whether the device is effective. This symposium
discusses the scientific background and clinical experience with a new microclimate
management device aimed at preventing and treating pressure ulcers, and provides
an excellent example of the relationship between the scientific research, product
development, and clinical work that I have just described.
Consequently the learning objectives of this symposium are
threefold:
1. To gain knowledge of concepts of microclimate
and its management
2. To understand the biomedical technology basis
for mechanisms for managing temperature &
moisture at the patient-surface interface
3. To reflect on the clinical relevance of these
concepts on bedside care in practice
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Microclimate
Management
Microclimate management and the
integrity of loaded soft tissues
Dan Bader, Professor of
Bioengineering and Tissue
Health, Faculty of Health
Sciences, University of
Southampton, UK
After completing his PhD, Dan Bader moved to the Oxford
Orthopaedic Engineering Centre at the University of Oxford,
where his research focused on engineering aspects of
pressure ulcer prevention. He later moved to Queen Mary, University of London (QMUL) as
a lecturer in biomaterials and was one of the core research staff in the IRC in Biomedical
Materials. In 1999, he was appointed Professor of Medical Engineering in the Department
of Engineering (QMUL). In 2011, he joined the Faculty of Health Sciences at the University
of Southampton. He has published over 170 refereed scientific papers and edited three
books. Since 2000, he has been a Part-Time Professor in Soft Tissue Remodelling in
the Biomedical Engineering Department at Eindhoven University of Technology, the
Netherlands and, more recently a Visiting Professor in Department of Orthopaedic Surgery
in the University of Malaya.
We associate pressure ulcers with people who spend long periods of time in bed or in
a seated environment, such as the very elderly and infirm, and previously active people
who have had irreversible injuries such as those of the spinal cord - Christopher Reeve is
a famous example. Babies and pre-term infants can also be at risk of acquiring pressure
ulcers, and the use of incubators in the neonate setting provides a good example of the
effects of microclimate management on skin integrity, as underdeveloped tissue will be
especially susceptible to environmental humidity and temperature.
From a bioengineering point of view we need to develop strategies which can support
the environment of all these at-risk patients, by developing monitoring systems to
assess them, by establishing what tolerance their skin tissues have to the loading they
are subjected to, by developing objective screening methods which can be looked at
in conjunction with risk assessment scales, and then by using appropriate prevention
strategies to minimise the risk. Developing personalised or intelligent support surfaces
which can perform all these functions is a highly desirable goal.
External factors on tissues such as increased pressure and shear forces can cause
pressure ulcers, but those tissues are also being subjected to ambient conditions of
temperature and humidity. An important statistic, often quoted, is that a 1 degree Celsius
increase in temperature increases the metabolic demand on tissues by about 13%. So
raised skin temperature will necessarily influence the metabolic demands on the tissue.
A study looking at different wheelchair cushion materials showed that rising temperature
will not be dissipated away from that region when it is loaded (i.e. when a human being is
sitting on it), whereas if you have something which is conducting that material (like water),
the temperature profile actually decreases over a period of time. Where a foam support
material increases the temperature, this is mimicked by an increase in the relative humidity
at that loaded support interface.
Many patients who have what we consider to have classic pressure ulcers are also
associated with incontinence. Studies from Belgium 6 or 7 years ago showed that even
expert nurses struggled with identifying the difference between the two states, particularly
between the category I or category II ulcers and incontinent lesions. Many of the ischial
and sacral sores make the tissues more vulnerable in that loaded area if someone is
incontinent. Using the work that was done on incontinence technologies, a number of
4
physical measurements have been developed for assessing the physical characteristics
of the skin, which can be used in pressure ulcer management. Trans Epidermal Water
Loss (TEWL) is a typical method used to evaluate these characteristics, and on how water
evaporates from the skin surface.
Recent work performed in Southampton showed that if you apply a known amount of
moisture to the skin surface, you can then measure how that flux density decreases with
time as the skin dries. The resulting desorption curves allow us to evaluate products such
as barrier creams – we can apply these barrier creams, apply the moisture and then see
how effective they are in evaporating water losses.
Does wet skin matter? The answer is yes. Where there is humidity, associated particularly
with incontinence lesions, there will be a softening of the stratum corneum, the outermost
layer of the skin, and that will inevitably have an effect on the barrier properties of the skin
as well as its mechanical properties. On the other hand, we know very well that dry skin is
considered a risk factor, so we need to control that micro-environment, particularly from
excessive humidity or excessive dry skin.
Several years ago we thought that we might be able to measure tissue metabolites by
looking at sweat collected at the skin surface. We believed that this may be able to provide
some biomarkers which would tell us about the status of the skin.
In order to do this study we needed a temperature controlled room, and we set up
a number of tests where we collected sweat using filter paper, which we attached to
the skin surface of a patient in an unloaded state, and then during periods of loading
and subsequent reperfusion. We then analysed what was in that sweat and looked at
a number of different biomarkers. Sweat purines, for example, are potential markers
associated with ischemic reperfusion damage. We also looked at lactate, since cells
go into anaerobic respiration and produce lactic acid when oxygen is repressed. We
found that during a period of uploading there was an up-regulation of quite a number of
biomarkers which in most cases increased over a period of time. Some of them decreased
back to basal levels relatively quickly and some took much longer to go back to these
levels. This showed that we could collect moisture in the form of sweat, and analyse
whether that tissue was liable to damage or not.
We then wanted to see if we could control the micro-environment in a laboratory setting.
We examined the effect of different sweat flow rates on an air mattress setting that had
both continuous and alternative pressure modes. We wanted to monitor the temperature
and humidity, and examine both materials and air flow rates to see if could control that
environment. We did this by developing an environmental chamber in the laboratory with a
mattress, a sweating body and a sensor array where we could measure both temperature
and humidity. Our humidity and temperature sensors were incorporated within a thick
cotton sheet. Our sweating body was a polyethylene tank filled with water at 37 degrees
Celsius with small tubes with holes in them, allowing us to control the amount of sweat
that was being delivered to that interface and measure the amount of temperature and
humidity that was being delivered as a result of the fluids coming through.
We looked at covering materials at 3 prescribed sweat and air flow rates in continuous
load and alternating pressure. We had 2 prototype materials, one in continuous low
pressure and the other one at alternating pressure. But by using alternating pressure at
the interface, not only were we able to control the humidity, but we actually reached a
peak of about 60% relative humidity before it went down. At high simulated sweat
rates greater than 2.25 mmHg generally the relative humidity reached 100%, but
at lower sweat rates the nature of the prototype covers had a significant effect
on interface humidity levels with time.
Our new facility contains a temperature and humidity controlled room
within a clinical research centre under research governance, where we
can bring patients into this environment, and measure both physical sensing
and biosensors in that environment. My colleagues and I are very encouraged
by the opportunity to do this work, as microclimate clearly has an influence over
tissue health and integrity. It is important to investigate optimal covering materials for
systems with underlying airflow that controls the interface microclimate, and the ongoing work to develop these textiles and materials has the potential to make a significant
contribution to pressure ulcer management.
Microclimate
Management
5
A novel approach to microclimate
management
Angel Delgado, Director, Global
Clinical Development and
Clinical Sciences, ArjoHuntleigh,
USA
Dr Delgado is the Director of Global Clinical Development
and Clinical Sciences for ArjoHuntleigh and has been
conducting research since 1986 in the fields of cellular
biology, pharmacology, immunology, virology, trauma,
and critical care. Prior to joining ArjoHuntleigh he worked
at Kinetic Concepts Inc. as Director of Clinical Strategy and served 13 years with the
Department of Defense (US Army - MEDCOM, MRMC, DARPA, USASOC, SOCOM, and
JSOC) as an Immunologist/Principal Investigator in the US Army’s Combat Casualty Care
Program, where he received multiple awards and honours. Dr Delgado has published over
65 papers and abstracts in peered reviewed journals and has lectured and presented
around the world.
Until we conquer zero gravity we will not be able to create the ultimate pressure relieving
surface, but we must do everything we can in the meantime. We have come as far as
we can in developing materials to reduce friction and shear - companies already provide
the lowest co-efficient of friction materials and if we increase this further, our patients will
slide straight off the bed. In my view excessive moisture and temperature puts skin under
greater susceptibility to the forces of shear and pressure. We believe that by looking at
moisture and temperature we have the greatest opportunity to develop new therapies for
pressure ulcer prevention.
The Skin IQ Microclimate Management System was developed with this in mind. The
device looks like a cover sheet with a very small fan on the foot end and an opening at
the head end to create a small airflow. The airflow was a feature that we considered very
carefully, as we had two alternatives. We could either blow air or suck air through the
system – positive or negative airflow, in other words. This sounds like a simple problem,
but ultimately we selected negative air flow. Positive air flow is associated with bellowing,
which means that more surface area comes into contact with the tissue, which allows for
more build-up of moisture and temperature. Under positive pressure air goes around a
load (bellowing), not under it where it matters most (microclimate space). But when you
suck air (negative pressure generated airflow), you have a very flat system, and when you
increase the air velocity you see a direct correlation to the Moisture Vapour Transmission
Rate (MVTR) which is how we measure moisture moving through a fabric.
We now understand why previously we were unable able to improve low air loss systems
and had not been able to offer an MVTR greater than 97 g/m2/hr. With our system,
moisture accumulates in a microclimate space, migrating down through the polyurethane
coated nylon layer, which is driven away from underneath the patient and provides a higher
MVTR of 130 g/m2/hr, a significant improvement over the pre-existing range of systems.
We also tested the product without power as we wanted it to have some ability to remove
moisture, and even in that condition we managed to reach 42 g/m2/hr.
6
In terms of humidity, if you put a patient or load onto a surface in a microenvironment
space, with an adequate sweat rate the relative humidity will go up to 100% very rapidly.
As the Skin IQ begins to remove the moisture, once the relative humidity in the area of the
skin that is intimately in contact with the surface is equal to that of the environment of the
room, the system stops removing moisture. This is not the case with positive pressure
low air loss systems. In these systems ambient air runs through a blower, it gets heated
and dried up. Patients on a prolong period of bed rest have their skin beginning to crack
under these conditions, necessitating moisturising creams. This tends not to remove
moisture from the tissue. Our system prevents this from happening. In a hot and humid
environment like Costa Rica, where there is no air conditioning in community hospitals and
the relative humidity of the room is very high, you would need to place a dehumidifier for
the product to be effective. This is because of the innate property of the product to drive
the microclimate conditions to equal those of the environmental conditions.
Skin IQ does not do anything for pressure distribution, so it has to be used in conjunction
with a pressure redistribution surface. With that in mind, we performed a number of tests
to ensure that the product did not affect how that surface performs. When we did an initial
study with an AtmosAir™ 9000, we saw that it did not affect the pressure redistribution
properties at all. Once we had completed that study we asked the Cleveland Clinic to do
a study on other non-powered surfaces and tested competitor products – in all cases the
effect was the same – there was no effect on using the coverlet on any surface and how
they performed on pressure redistribution. This also applies to low air loss and alternative
pressure surfaces.
In terms of performance, we asked the Cleveland Clinic to take every competitor in the
market that had a microclimate management claim. This test had to be blinded (i.e. we
were unable to identify specific competitor products) but this still showed that Skin IQ was
the superior management tool by over 30% over the second highest performing product.
We also noted during our study that when Skin IQ was applied the temperature of the
skin dropped by 1.1 degrees Celsius. We might not get excited at first over a 1 degree
temperature drop, but as pointed out earlier, this significantly reduces the tissue demand
for oxygen and nutrients and this allows tissues to withstand considerably more stress.
We did a comfort study, using an 11 point questionnaire for several patients lying on
the different surfaces. Even though comfort is a subjective assessment the study
demonstrated a statistical significant difference and confirmed that the Skin IQ was more
comfortable than the surface alone.
In terms of antimicrobial properties, we inoculated the Skin IQ with 106 Staph aureus,
allowing it to incubate for 24 hours then we plated the bacteria onto standard microbiology
agar plates and after 48 hours we quantified the number of bacteria. We noted a
significant reduction in colony forming units (cfu) recorded as log reduction in bacteria.
Additionally, the polyurethane coated nylon layer acted like a barrier – fungi, bacteria,
or viruses were not able to penetrate the top layer, which in itself is coated with an
antimicrobial agent. So as soon as the bacteria come into contact with the fabric it begins
to die. We also did a study where we inoculated the surface with a simulated wound fluid,
and noted a significant odour reduction starting on Day 7 and continuing though Day 60.
Skin IQ was launched in 2010 and since that time the body of evidence supporting its
effectiveness and safety has been building up in the peer reviewed literature. Our next
objective is to widen the work that we have already begun with clinicians so that
we can understand their experiences in using this device while caring for
their patients.
Microclimate
Management
7
The microclimate management
approach to improving clinical
outcomes
Jean de Leon, Professor,
Department of Physical
Medicine and Rehabilitation,
University of Texas
Southwestern Medical Center,
Dallas, USA
In addition to her above role, Dr de Leon currently serves
as a wound care consultant for CMS on several technical
expert panels and has served as a member of the National Quality forum Steering
Committee on Home Health, Pressure Ulcer Prevention and Treatment, and Patient Safety
Measures and Complications.
Dr de Leon received her medical degree from the University of Oklahoma and completed
her residency in Physical Medicine and Rehabilitation at the University of Texas Health
Science Center in San Antonio. She has been published in Advances in Skin and Wound
Care, Ostomy Wound Management, the International Wound Journal and many other
journals. She speaks nationally and internationally on skin and wound care.
When presented with a new product, one of the most difficult things a clinician has to
assess is how it fits into practice. As a medical director I have the responsibility for not only
showing clinical benefit, but also financial advantage.
Before considering the Skin IQ product I had no idea what microclimate represented
and where it should fit into my practice. How does microclimate affect the outcome of a
pressure redistribution surface? When assessing a patient I would go from a non-powered
pressure distribution surface to something powered, depending on his or her condition.
So when I heard that I had the potential to improve the MVTR regardless of what kind of
surface I used I was sceptical, and it took several months for me to find a patient who I
felt to be a suitable candidate for this new treatment.
During this session I describe in some detail my experiences with 9 patients who
presented with pressure ulcers. These patients had several concomitant conditions
ranging from head and neck cancer, congestive heart failure, renal disease, HIV, secondary
MRSA, cirrhosis and vascular disease. In some cases a full turning regime was not
possible. They were treated with the Skin IQ, a moisture barrier ointment and in one case
NPWT. In many instances (depending on the condition of the patient) healing occurred
within 7 days, often without breakdown re-occurring after treatment, and the patients
proceeded to rehabilitation. In one case the patient expired although some healing was
observed before she deteriorated. We also experienced some reversals when a patient
was taken off Skin IQ in favour of other treatments and reintroduction to a powered
surface.
Looking at the first 21 patients we treated, 8 had rashes and were placed on our standard
foam pressure resistant surface with the cover. They healed in an average on 9.6 days and
during this time they did not break down. We also treated 5 patients with moisture related
partial thickness breakdown – healing for these patients took an average of 13.4 days with
a moisture barrier cream and the Skin IQ.
8
4 patients with category III, IV and UTS (unable to stage) wounds had an average healing
rate of 0.41cm2/day and 1.53cm3/day with Skin IQ. This compares with the pressure
ulcer healing rate for sacral wounds at our facility in 2008, which was 0.48cm2/day and
0.99cm3/day with patients treated on Low Air Loss (LAL) mattresses. 2 patients with sacral
post-surgical wounds had an average healing rate of 0.99cm2/day and 4.85cm3/day while
on our standard foam pressure redistribution surface with Skin IQ. In 2008 the healing rate
was 0.43cm2/day and 1.18cm3/day.
While these results were not powered to have statistical significance, they led us to
conclude that the healing rates using Skin IQ were comparable (or no worse) than those
we had encountered before and we are comfortable that we did not impede the progress
of our patients from an outcome point of view over previous treatment.
With this in mind, we can consider the potential health economic conclusions from this
change in treatment:
The total number of hospital days of therapeutic support surface usage while assessing
Skin IQ was 584 days for patients with rashes, partial and full thickness break down. The
cost of LAL rental, our prior practice, would have been USD $18,600 to this institution
while the cost of the Skin IQ cover purchase in the same population was USD $4,095 in
my facility.
For patients with full thickness skin breakdown, the total number of hospital days of
therapeutic support surface usage was 191 days at a potential cost of USD $6,080 for
LAL rental. The cost of Skin IQ cover purchase in the same population was USD $1,170.
This is therefore a potential 81% savings with the additional benefit of discharging the
patient home with the cover, as we had done with some of the patients described above.
In summary, I learned through this experience that while I had never considered looking at
therapies that do anything other than redistribute pressure, microclimate management has
the potential to give the skin resistance and therefore has a role in wound healing. Personal
clinical experience suggests to me that avoiding an active surface and putting the patient
on a foam mattress plus the cover can have impressive results while providing significant
savings, and I would be interested in hearing about the experience of clinicians working
with this product in other facilities, and indeed other countries.
Microclimate
Management
9
Key Points:
Dan Bader:
• A one degree Celsius increase in temperature increases the
metabolic demand on tissues by about thirteen per cent
• Moisture levels at the patient support interface must be
controlled to ensure tissue health and integrity
• There is a need to establish optimal cover materials with
underlying air-flow to control the interface microclimate to the
individual
Angel Delgado:
• By looking at moisture and temperature we have the greatest
opportunity to develop new therapies for pressure ulcer
prevention
• The velocity of negative air flow (as used in Skin IQ) has a direct
correlation with Moisture Vapour Transmission Rate (MVTR)
• Skin IQ has no effect on pressure redistribution
Jean de Leon:
• Skin IQ has the potential to improve the MVTR regardless of
what kind of pressure redistribution surface is being used
• Skin IQ did not impede the progress of our patients from an
outcome point of view over previous treatment with powered
surfaces
• At the same time using Skin IQ in conjunction with a nonpowered surface demonstrated significant health economic
benefits in our clinic
Disclosure
The opinions expressed by authors are their own and based on
their clinical experience and not necessarily those of ArjoHuntleigh
and should not be considered as product or treatment claims of
the Skin IQ™ MCM.
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Microclimate
Management
11
Only ArjoHuntleigh designed parts, which are designed specifically for the purpose, should be used on the equipment and products supplied by ArjoHuntleigh. As our policy is one of
continuous development we reserve the right to modify designs and specifications without prior notice.
® and ™ are trademarks belonging to the ArjoHuntleigh group of companies. © ArjoHuntleigh, 2013
www.ArjoHuntleigh.com
ArjoHuntleigh AB International Headquarter
Neptunigatan 1
SE-211 20 MALMÖ
Sweden
Tel +46 413 645 00
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01.ZZ.101.1.GB-INT.1.AHG October 2013
GETINGE GROUP is a leading global provider of products and systems that
contribute to quality enhancement and cost efficiency within healthcare and life
sciences. We operate under the three brands of ArjoHuntleigh, GETINGE and
MAQUET. ArjoHuntleigh focuses on patient mobility and wound management
solutions. GETINGE provides solutions for infection control within healthcare
and contamination prevention within life sciences. MAQUET specializes in
solutions, therapies and products for surgical interventions and intensive care.