PRESSURE INJURY PREVENTION

Comparison of support surface
performance characteristics forflap and graft applications

Authors: Sara Tackson PT, MPT, CWS, Eur Ing David Newton M.Eng, C.Eng,
MIET, MIEEE, Carroll Gillespie MS, BSN, RN, CWOCN, Jonathan Busby MSc,
BSc (Hons) RN, Debbie Rozario RN

Summarya support surface that takes into account the individuals
specific needs, including level of immobility and inactivity, theneed to influence microclimate control and shear reduction,
the size and weight of the individual and the number, severity
and location of existing pressure injuries.3

Despite widespread adoption of prevention strategies,
pressure injuries remain a significant problem across all
healthcare settings. The underlying cause and formation ofpressure injuries is multifaceted with a number of contributing
factors, notably impaired mobility.1 New insights on pressure
injury development suggest three major contributors to cell
damage namely deformation, inflammation and ischemia2and suggests that cell deformation damage can happen in amatter of minutes with ischemic tissue damage manifesting
within several hours. This new perspective demonstrates
the importance of minimizing exposure to sustained tissue
deformation (pressure, shear) and highlights the importanceof early detection in pressure injury prevention.2 This isparticularly the case in critical tissue conditions involving
sensitive anatomical locations e.g. the sacrum or surgicalwound sites such as a flap or skin graft.

Over recent years, an increasing body of evidence suggeststhat microclimate between the skin and the support surface
plays a role in the development of pressure injuries. The term
microclimate refers to the temperature, humidity and airflow
next to the skin.1 Managing microclimate helps improve tissue
tolerance to pressure, friction and shear.4
While the majority of pressure injuries heal without the needfor surgical intervention, a significant number of deep tissue
and full thickness injuries require surgical repair using a
muscle or fasciocutaneous flap or skin graft. Such procedures
aim to restore skin integrity and its barrier function to prevent
infection, maintain normal functioning and to minimize
disfigurement.5 Complications post flap/graft procedure
are common with rates estimated to be around 18.6%.6 In asystematic review involving 1,184 patients, the most common
complications were wound dehiscence (9.7–11%), necrosis(5.1–9%) and infection (4.3–7.5%).6

The 2019 International Pressure Injury Guideline views
support surface technologies as an important component
in pressure injury prevention and treatment since they canhelp prevent the effects of damaging tissue deformation andprovide an environment that enhances perfusion of at risk
or injured tissues.3 The Guideline recommends choosing

1

WHITEPAPER

Post-operative management of flaps and grafts

Comparison between two of Arjo’s support
surfaces: the Citadel® C200 + Skin IQ® and
KinAir MedSurg Pulse

Individuals who have undergone flap or graft repair are ata higher risk for developing additional pressure injuries
due to reduced mobility and postoperative limitations for
positioning.7 Vigilant postoperative care including a specialty
support surface and a positioning regime is essential for
positive patient outcomes. According to the International
Pressure Injury Guideline1 support surface features toconsider for the postoperative care of flaps and grafts include
pressure redistribution properties, and the management offriction, shear forces and microclimate.

The KinAir MedSurg Pulse is a legacy Arjo integrated
support surface providing Low Air Loss and Pulsating Air
Suspension Therapy and is indicated for patients with burns
or postoperative flap or graft surgery as well as for theprevention and treatment of pressure injuries. The Citadel
Patient Therapy System C200 model is an integrated pressure
redistribution surface providing reactive and active surface
technology and pulsation therapy (Figure 2).

Citadel Patient Care System
A New Era of Performance

Since the 1980’s many surgeons have used air-fluidized
therapy (AFT) support surfaces in the immediate
The Citadel Patient Care System (Figure 1)
postoperative period for patients
who have undergone flap
provides the user with a choice of pressure redistributing
surgery. Over time, use of alternatingpressure
andwithlow
loss
support surfaces
integrated
theairCitadelBed Frame
System.
surfaces have become firmly establishedas viable alternatives
6in the postoperative managementof thispatient
The Citadel
Patient
Therapypopulation
System C100 is a ‘reactive’
supportsurface that optimisespressure redistribution using
and are listed as support surface
considerations
following
pre defined patient height/weight pre-sets1 which can bepressure injury surgery in the further
2019 customised
International
Guideline.
across four anatomical pressure zones.
The head and seat sections can be independently deflated
and a full-length ‘firm’ mode can also be used to assist nursing
The variation in support surface
utilization for postoperativeinterventions.
flap patients is clearly demonstrated in the results of an
The Citadel
Therapy
Systemof
C200 has similar features
online survey8 completed in 2019by a Patient
randomsampleto the C100 support surface, but also offers the option of
Figure 1
sixty-six Wound, Ostomy and multiple
Continence
Nurses (WOCNs)‘active’ therapeuticmodes: 1 in 2 alternation and 3
levelsof pulsation,
andwithinalso includes
currently treating postoperative
flap
patients
the a manual and automatic
Citadel Patient Therapy System C200
‘patient turn’ mode to assist with repositioning.
United States (Figure 1). The survey
also revealed practicediversity regarding positioning protocols for postoperative
flap patients. Most surveyed WOCNs reported postoperative
positioning on the flap/graft surgical site within 24 hours.
Key Points
Repositioning practices are influenced
by the surgeon’s• Exposure to prolonged or extreme pressure results in• The Citadel C100 support surface delivers a constantorders for bedrest or wound offloading
depending on thepressure injury; tissue damage can be rapid
low pressure environment that is equal to, or better
location of the surgical and donor• site.
Other considerations
than, comparator support surfaces
Physical immobility, or factors that affect a patients Reactive modein repositioning include the use of ability
wedges,pillows,
boots,
the to move, areto senseor respondto a stimulus
The Citadel C200 support surface delivers exceptionallyrecognised
critical risk
factors
degree of head of bed elevation, anduse ofasprone
positioning.
low tissue/surface interface pressures during active• Timely pressure
regulartherapy (lower for longer), while providing a semiAs the incision site heals, most facilities
have aredistribution
protocol throughinrepositioning is key to pressure ulcer prevention andimmersive environment over the heel: performance
place that allows for dangling and progressive
sitting,withmanagementthat captures the therapeutic benefit of an Active andpressure redistribution interventions
to eliminate
sustained
Reactive environment.
• Therapeutic
support surfaces
with effective pressure
redistribution
canandcomplement
repositioning regimenspressure. With an increase in sitting
tolerance
incision
healing, the patient is often transitioned from a powered to
Active (Alternating Pressure) modea non-powered support surface in readiness for discharge
home.

Figure 2: Citadel C200 Patient Care System and example modes

Type of support surface used for postop
flap and graft patients (n=66)

The Citadel C200 is indicated for the prevention andtreatment of pressure injuries, although clinicians havereported use of the C200 with postoperative flap patients.
Within clinical practice, the Skin IQ Microclimate Manager(MCM), an adjunctive therapeutic mattress coverlet for
microclimate control, is used in conjunction with the C200
support surface. The Skin IQ MCM (Figure 3) is a fluid
resistant, vapor permeable, single patient or multiple patientuse coverlet that applies negative airflow technology to draw
moisture vapor and heat away from the skin surface interface
to help prevent excess moisture, humidity and heat buildup(Figure 4).

74%

Air Fluidized (AF)59%

Low Air Loss (LAL)
Alternating
Pressure (AP)

35%

Foam

6%

Constant
Low Pressure (CLP)

5%
0%

10%

20% 30% 40% 50% 60% 70% 80%

Figure 1: Results from a 2019 online survey of US based WOCNs

2

Citadel C200 support surface operating modeand therapy parameters
The Citadel C200 system has multiple therapy modes andfeature options to adjust or alter the air pressure within
this specialty support surface. Adjustments to the Citadel
C200 support surface allows for air pressure configurationaccording to the needs of a patient.9 The operating
adjustments described in Figure 5 (a–d) will have an impact
on the air pressure within the support surface and thepressure redistribution achieved. These properties can bemeasured through the resulting parameters of interfacepressure, immersion and envelopment.
Figure 3: Citadel C200 + Skin IQ MCM

Skin

Heat

Bacteria

Moisture

Moisture

Skin IQ® MCM top layer

Top layer

SpacerHeat
Moisture

Skin IQ® MCM middle layer
Skin IQ® MCM bottom layer

Figure 4: Skin IQ MCM Schematica) Altering the patient
weight/height preset range.

b) Changing theoperating mode fromthe default Reactivemode to Pulsation or
Alternating Pressuremode will result ina different level ofimmersion.10

Alternating
Pressure

Pulsation High

Pulsation Medium

Pulsation Low

Reactive Mode(default)c) For example,
selecting Alternating
Pressure mode
(Active Therapy)
provides periodic
offloading of tissue
and increases
immersion.

d) Using the manualadjustment tocustomize pressurelevels within specificregions of the mattresscan further reduce
the pressures at theanatomical area ofconcern.

Figure 5: Options for adjusting Citadel C200 Operating Mode and Therapy
3 Parameters2. Envelopment and immersion - hemisphericalindenter test - SS-1:2019 Section 6 11

Laboratory performance testing results
To understand the performance of the Citadel C200 + Skin IQ
MCM and how it compares to the performance of the legacy
KinAir MedSurg Pulse, assessment and testing was performed
to the US National Standard (SS-1:2019)11 using a combinationof external independent test laboratories and internalmeasurements. Since the microclimate performance of theC200 + Skin IQ demonstrated superior operation, the results
were compared with commonly used high performance
support surfaces in the US market.

The depth of immersion of a support surface is an importantcharacteristic. Increased immersion can lead to an increasein envelopment. The pressure redistribution provided by areactive surface can improve if the patient’s body is in contact
with a larger surface area.
Results: The average immersion level provided by the Citadel
C200 + Skin IQ for each operating mode was compared to the
KinAir MedSurg Pulse in its High Pulsation Mode (Figure 7).
Despite these two products significantly differing in heights,
construction and operation, it is possible to compare them interms of their immersion and envelopment.

1. Support surface horizontal stiffness (shear)test – SS-1:2019 Section 5 11
The purpose of this test is to measure the force necessary
to slide an anatomically representative part of a mannequin
across the support surface. This allows a comparative
measurement of the sliding forces (shear force) provided
by each surface and is an analogue to the expected forcesencountered when patient movement occurs on the surface.

Comparison of average immersion %by mode of operation
p KinAir Pulse Hi
p C200 AP
p C200 Pulse Highp C200 Pulse Low
p C200 Reactive

100

Results: Comparison tests were performed between the
C200 + Skin IQ MCM and an existing legacy product, KinAir
MedSurg Pulse which is indicated and widely used for Flapand Graft applications. Figure 6 shows the C200 + Skin IQ
MCM has a lower horizontal stiffness and so offers lessresistance to patient motion on the surface. This reduces theeffects of shear, which is critical for patients with sensitive
tissue areas.

Percentage

80
60
40
20
0
KinAirPulse Hi

The initial point (at t=0) on the graph (Figure 6) shows thestatic force that prevents the movement of the mannequin(patient) which has to be overcome in order for movement
to occur. Once movement starts, the force is then known as
dynamic force. The dynamic force shown in the graph acts on
the mannequin during movement and is comparable to forces
during repositioning and in-bed movement. The lower initialstatic and dynamic forces measured with the C200 + Skin IQ
MCM can be expected to reduce the shear effect and tissue
strain on the patient when repositioned. The C200 + Skin IQ
MCM shows a considerable improvement to the horizontal
stiffness performance compared to the legacy product.

C200
AP

Comparison of average envelopment %by mode of operation
p KinAir Pulse Hi
p C200 AP
p C200 Pulse Highp C200 Pulse Low
p C200 Reactive

80

Percentage

Shear force (N)

C200
Reactive

The Citadel C200 in Alternating Pressure (AP) mode provides
a broadly equivalent percentage depth of immersion to the
KinAir MedSurg® Pulse as represented in Figure 7.

Shear force versus time
KinAir MedSurg Pulse
Citadel C200 w/Skin IQ

60

C200
Pulse Low

Figure 7. Immersion test data.13

100

70

C200
Pulse High

50
40

60
40
20

30
20

0
KinAirPulse Hi

10

C200
AP

C200
Pulse High

C200
Pulse Low

C200
Reactive

0
0

50

100

150

200

250

300

Time (s)Figure 8. Average Envelopment data comparing KinAir MedSurg Pulse(High Pulse mode) to Citadel C20013

Figure 6: Comparison of horizontal stiffness results for the KinAir
MedSurg Pulse compared to the C200 + Skin IQ.13
44. Standard protocol for measuring heat andwater vapor dissipation characteristics for fullbody support surfaces – body analog method –SS-1:2019 Section 3 11

The range of envelopment % of the KinAir MedSurg Pulse ishigher than the Citadel C200, however the performance canbe most closely matched through the use of Citadel C200 +Skin IQ in Pulsation High Mode (Figure 8).

Microclimate assessment used the RESNA SS:1 2019 Section
3 – The Body Analog Test Method. The test purpose is tomeasure heat and moisture dissipation properties of the
support surface by creating a comparable environment to thehuman body lying on a mattress11. The test also includes asimulated repositioning event (shown at time = 180 minutes)
demonstrating the ability of the surface to return to its
original state prior to surface loading. A Thermodynamic Rigid
Cushion Loading Indenter is used to generate, control andmeasure the environmental conditions of temperature andrelative humidity (% RH) at the patient interface.

3. Standard protocol for measuring heat andmoisture dissipation characteristics of full bodysupport surfaces – sweating guarded hot plate
method (SGHP) SS-1:2019 Section 4 11
Microclimate assessment used the RESNA SS-1:2019 Section
4 SGHP method. The purpose of this test is to identify theability of the support surface to remove heat and moisturefrom the patient interface. There is a growing appreciationof the role of microclimate management in helping to
improve tissue tolerance to aid in pressure injury prevention
and management, particularly in the presence of excessive
moisture and elevated temperature at the skin/surface
interface.12 Any surface that is in contact with the skin has
the potential to affect the microclimate. The overall effectis dependent on the nature of the support surface and thecover.12

Results: Within the test conditions, the % RH at the interfaceof the indenter to the surface was kept at a steady statedemonstrating that the C200 + Skin IQ was able to quickly
stabilize and remove a significant portion of the humidity
introduced from the test environment (Figure 10). The flat
nature of the curve shows that the C200 + Skin IQ is able tocontrol and limit the increase in moisture at the simulatedskin interface compared to a reference surface. The testing
occurred over a three-hour timeframe that simulates a typicalperiod of patient immobility. This demonstrates the beneficial
microclimate effect that could be present in a real life clinicalsituation. Humidity can have an adverse effect on tissue
viability and often results in moisture being condensed andtrapped under the patient’s body.

A heated, moist indenter measures the resistance to flow ofheat and humidity through a support surface simulating theskin in contact with the support surface.11 The evaporative
capacity reported by the test details the ability of the support
surface to dissipate moisture at the patient interface.
Results: The C200 + Skin IQ MCM was compared with
examples of other commonly used support surfaces readily
available in the US market and this is shown graphically in
Figure 9.

Average % Relative Humidity (RH)
Examples of evaporative capacity bysupport surface type90

Relative Humidity (%)

85

Evaporative capacity (g/m2/hr)

300
250
200
150

80
75
70
65
60
55
50

100

45

50

LAL-HI

LAL-LO

Alternating
Air

Unpowered
Gel

30

60

Reference
C200+SkinIQ
Average Ambient0
MCM
Coverlet0

UnpoweredHybrid

90

120

150

time (mins)

Figure 10: Test results using the Body Analog method13
Figure 9: Comparative test results using the SGHP method135180Conclusion
measurable parameters, the user can readily configure
the Citadel C200 system at the bedside to provide a
broadly comparable level of surface performance toaddress the clinical needs of the postoperative patient.
Based on these measurable parameters, the utilization of
the Citadel C200 could provide an acceptable alternative
to air fluidized therapy (AFT) or low air loss (LAL)
support surfaces for the postoperative patient.

Vigilance is required in the postoperative care of patientsrequiring flap or graft surgery for difficult to heal deep
tissue or full thickness pressure injuries. Care of thewound and prevention of further pressure injury involves
many factors including rigorous positioning protocols
often determined by the surgeon and use of a support
surface with low air loss/microclimate management,
alternating pressure or air fluidized technologies.
Many product features within the design, construction
and operation differ between the KinAir MedSurg Pulse
and the Citadel C200 + Skin IQ. However, in terms of key

References
1. European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory
Panel and Pan Pacific Pressure Injury Alliance. Prevention and Treatment ofPressure Ulcers/Injuries: Clinical Practice Guideline. The International
Guideline 2019. Emily Haesler (Ed.) EPUAP/NPIAP/PPIA. Page 16, 40.

6. Sameem M, Au M, Wood T, Farrokhyar F, Mahoney J (2012) A systematic
review of complication and recurrence rates of musculotaneous,fasciocutaneous and perforator-based flaps for treatment of pressure
sores. Plastic and Reconstructive Surgery, 2012;130(1):67e-77e

2. European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory
Panel and Pan Pacific Pressure Injury Alliance. Prevention and Treatment ofPressure Ulcers/Injuries: Clinical Practice Guideline. The International
Guideline 2019. Emily Haesler (Ed.) EPUAP/NPIAP/PPIA. Section 2: The
etiology of pressure injuries – contributors to cell damage & tissue necrosis
in pressure injuries. Pages 22-23

7. European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory
Panel and Pan Pacific Pressure Injury Alliance. Prevention and Treatment ofPressure Ulcers/Injuries: Clinical Practice Guideline. The International
Guideline 2019. Emily Haesler (Ed.) EPUAP/NPIAP/PPIA. Section 22:
Pressure Injury Surgery. Pages 300-314.

3. European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory
Panel and Pan Pacific Pressure Injury Alliance. Prevention and Treatment ofPressre Ulcers/Injuries: Clinical Practice Guideline. The International
Guideline 2019. Emily Haesler (Ed.) EPUAP/NPIAP/PPIA. Section 10:
Support Surface Recommendation 7.7. Alternating support surfaces.
Page 165
4. Clark M, Black J. Skin IQTM Microclimate Manager Made Easy. Wounds
International. 2011;2(2):s19-s24.
Available from http://www.woundsinternational.com
5. Woo K (2014) Support surfaces for skin grafts and flaps: A scoping review.
Kestrel Health Information Inc, 2014.

8. Arjo commissioned online survey 2019. Data on File
9. NPIAP 2020 Poster “Varying the Immersion Level of a Support Surface inUse”. D Newton, C Gillespie, S Tackson
10. Citadel Patient Therapy System IFU Arjo Ref 830238
11. RESNA SS-1:2019 Requirements and Test Methods For Full Body Support
Surface12. International Review. Pressure ulcer prevention, pressure, shear, friction
and microclimate in context. A consensus document. Wounds
International. 2010.1-25
13. Arjo Test Data on File

At Arjo, we believe that empowering movement within healthcare environments is essential to quality care. Our products and solutions aredesigned to promote a safe and dignified experience through patient handling, medical beds, personal hygiene, disinfection, diagnostics, and theprevention of pressure injuries and venous thromboembolism. With over 6000 people worldwide and 60 years caring for patients and healthcare
professionals, we are committed to driving healthier outcomes for people facing mobility challenges.
Arjo AB • Hans Michelsensgatan 10 • 211 20 Malmö • Sweden • +46 10 335 4500
www.arjo.com

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