Understand tissue circulation supp surface testing through ... · Microsoft PowerPoint - Understand...

Living withEquipment in 2011:

“Understanding tissue circulation and support surface testing through PRI and PAI testing as a means of assessing patients for the selection of pressure redistribution and relieving mattresses and seating”

Phil Morrisey:

Pressure Injury:Pressure Injury:

AetiologyAetiology

International NPUAP-EPUAP Pressure Ulcer Definition

“A pressure ulcer is localized injury to the skin and/or underlying tissue usually over a bony prominence, as a result of pressure, or pressure in combination with shear. A number of contributing or confounding factors are also associated with pressure ulcers; the significance of these factors is yet to be elucidated.”October 2009.”

The microcirculationThe microcirculation

Artery

120mmHgArteriole32 mmHg

MetarteriolePrecapillary

Arterial capillary

20 mmHg

Venous capillary

Venule12 mmHg

Sensorynerve ending

Sebaceous gland

Hair follicle

Epidermis

Dermis

Subcutaneouslayer

Capillaries

Erector pilimuscle

Cross section of the skinCross section of the skin

Sweat duct

Muscle and bone

© ArjoHuntleigh

Wide individual variation

healthy subjects

Supine positionSupine position

Elbow

Occiput

Dorsal thoracic area Sacrum

Heel

Side lying positionSide lying position

AnklePerineum

Ear

Outer aspect of feet

Outer aspect of knee

Greater trochanter

Ribs

Shoulders

Prone positionProne position

Ear

Breasts (female)

Cheek

Genitalia (male)

Knees

Toes

Sitting in bed positionSitting in bed position

Heels

Ischial tuberosity

Sacrum

Spine

Back of head

Elbows

Seating positionSeating position

Shoulder blades

Sacrum

Ischials tuberosities

Heels

Foot

Posterior knee

Heels

Pressure ulcer formationPressure ulcer formation

External compression

Capillary closure

Tissue breakdown

Concept of tissue toleranceConcept of tissue tolerance

•Malnutrition•Age•Immobility

•Disease•Medication•Incontinence

The ability of both the skin and its supporting structures to endure the effects of pressure without adverse sequelae (Braden and Bergstrom, 1987).

Tissue tolerance factors include:

Intensity & duration of pressureIntensity & duration of pressure

Assessing pressure ulcer risk status

© ArjoHuntleigh

Ideal tool

•General medical condition

•Skin assessment

•Mobility

•Moisture / incontinence

•Nutrition

•Pain EPUAP 1998

Examples of pressure ulcer risk assessment tools

Immobility

• The primary cause of pressure ulceration:• Unrelieved pressure

Associated risk factors• Microclimate

• Moisture

• Incontinence

• Sweat

• Increased temperature

• Poor Nutrition

• Obesity or cachexia

• Co-morbidities

• Diabetes

• Peripheral vascular disease

• Drug therapy

The list is endless……..

Avoiding pressure ulcers

• Although co-morbidities and risk factors are important…..

the primary cause of

pressure Injury:

Immobility = Pressure

• No matter how many intrinsic and extrinsic risk factors people have they rarely get ulcers if they move

Normal spontaneous movement

• Humans move spontaneously several times each hour

• Subconscious response to pressure stimulus

• Occurs even when asleep

• Periods of pressure, followed by pressure relief, will encourage hyperaemic reperfusion of the tissue and is a:

• Reperfusion of the tissue

• Oxygenation

• Removal of toxic metabolites NOTE: Not to be confused with reperfusion injury

which is associated with prolonged ischaemia

(>1-2 hours) predominantly in major organs (heart, brain, kidney)

Active therapy: physiological benefit

Landis(1930)

Le (1984)

Williams (1988)

Kosiak (1991)

Schregel (1993)

Hunt/West (1995)

Gunther (2000)

Mayrovitz (2002)

Heath (2006)

Rithalia (2008)

Goossens (2008)

Tissue perfusion depends upon adequate off-loading: Active therapy can deliver a high-amplitude cycle

Dr Thomas Hunt:Used invasive blood flow studies to show normal reperfusion & reactive hyperaemia

33

“…alternating therapy systems provide a superior match between O2 supply and

demand which may be particularly relevant for healing patients with pressure injury….”

Skin temperature remained stable

Reactive hyperaemiaUsing contemporary Doppler fluxometry

Background perfusion

Black line: Pressure increase-decrease as cells inflate over timeBlue line: Tissue perfusion

Perfusion diminished during loading




Significant increase in blood flow seen immediately after the pressure is removed


© ArjoHuntl

Pressure ulcer avoidancePeriodic off-loading

• When movement is limited damage can be avoided

• Typical nursing interventions

• Basic preventative strategy – 4 hourly turns

• More vulnerable patient – 2 hourly turns

• Sickest patient – 1 hourly turns

• Or self-repositioning regimens 3-4 x per hour Assisted positioning: effective, but labour intensive, and with a risk of injury to the patient and carer.

Bed-frame functionsInterventions

• Support Surfaces

• Mattresses, overlays, seat cushions

• Positioning• Frequency of re-positioning

• Manual handling aids

• Bed-frame and chair functions

• Education• Healthcare providers

• Patients, relatives, care-givers

Factors influencing equipment choice

Skin Integrity

Patient Health Factors

Case MixRisk Status

Evidence

Resources and finance

24 Hour Care

Patient Management Goals

Care Environment Specialist Requirements

Bed-frame Functions

Risk Management

Specialist support surfaces

Pressure reducing surfacesPressure reducing surfaces

Foam

Powered

Pressure Area Index (PAI)•A formula that measures the ability of a support surface to spread pressure across available contact area

•PAI Thresholds < 30 mmHg

•The higher the PAI %, the better the performance

Pressure Area Index

Measuring interface pressure in

Constant Low Pressure

support surfaces

Simple techniques

FOAM LOW AIR LOSS

AIR FLUIDISED

Full body mapping

• Constant low pressure surfaces

• Gel

• Foam

• Static air

• Air fluidised

• Multi sensor map

• Pressure reductionproperties

• ‘Hot spots’

Comparison Of Support Surfaces Using Pressure Area Index (Range 56 - 90 kg)

97

73

0

20

40

60

80

100

Breeze KFund Mattress

PAI <

30 m

mHg (%

)

© ArjoHuntleigh

Effect of Posture on Pressure distribution

0%

20%

40%

60%

80%

100%

1 2 3

Position

PA

I <

30

mm

Hg

© ArjoHuntleigh

Bed Frame Design:Standard profiling bed

Bed frame with regression platform

Specialist Seating Prescription

WheelchairWheelchair + Cushion © ArjoHuntleig

Pentaflex® Performance

Pressure Area Index (PAI)

• 86kg patient supine 89% < 30mmHg

• 145kg patient supine 87% < 30mmHg

Simple arbitrary thresholds

•Number (%) of sensors below

•30 mmHg•20 mmHg•10 mmHg

0

3 0

6 0

9 0

1 2 0

1 5 0

0 2 4 6 8 1 0

T im e (m in )

Inte

rfa

ce p

res

su

re (

mm

Hg

)

Pressure Area Index Pressure Relief Index

Pressure Relief IndexMeasuring interface pressure in

Alternating Pressure

support surfaces

Pressure relief is related to design

•Pressure = periodic removal, sufficient to restore blood flow

•Time = frequency and duration similar to ‘normal’spontaneous movement

Alternating cellsHeadHead

sectionsection

PRI Techniques•Simple to do…..easy to get wrong!

•Standardise test methods

•Sensor positioning•Bony prominence•Apex of the cell

•Sensor calibration………and much more…..

Alternating support surfaces

HeadHeadsectionsection

Alternating cellsAlternating cells

Made up of interconnected air cells that cyclically inflate and deflate to periodically

remove pressure from soft tissue

1 in 2 Cell 1 in 2 Cell CycleCycle

Alternating cellsHeadsection





50% Pressure Relief=50% Body Contact

66% Body Contact = 33% Pressure Relief

25% Pressure Relief=75% Body Contact

Alternating cell cycles

Interface pressure on heel of 69kg, 1.73m male subject

0

30

60

90

120

150

180

210

240

0 4 8 12 16

Nimbus 3

Note: This example represents test results from one individual only and different results may occur with different subjects. Only large scale tests can determine true performance differences.

Interface pressure on sacrum of 52kg, 1.61m female subject supine

0

10

20

30

40

50

60

0 2 4 6 8 10

Nimbus 3

Note: This example represents test results from one individual only and different results may occur with different subjects. Only large scale tests can determine true performance differences.

When movement is inappropriate or impossible…..Active therapy simulates turning SEVERAL times each hour!

Mimics spontaneous movement and reperfuses the tissue.

Highly effective even in the most vulnerable populations

Can be adapted for those with extreme risk e.g.

• Critical limb ischaemia

• Peripheral vascular disease

1 min

Watch the cells under the sacrum as indicated by the arrow

2 min

3 min

4 min

Background pressure ulcers

•Public are increasingly aware that pressure ulcers are preventable

•Viewed as evidence of a failure to provide a reasonable standard of care

•Patients and relatives complain and may sue for compensation

•Nursing records are crucial to the defence of the nurse Tragic, unnecessary, painful, expensiveTragic, unnecessary, painful, expensive……………… BUT (MOSTLY) PREVENTABLEBUT (MOSTLY) PREVENTABLE

Statue of a sleeping Maenad, lying on a panther skin spread on a rocky surface; the type in known as the reclining Hermaphrodite; http://commons.wikimedia.org/wiki/User:Marcus_Cyron

A rocky surface?

Or an early example of an active therapy surface!!

2,000 years ago…….maybe the Ancient Egyptians were on to something!

Questions?

Thank You

Understand tissue circulation supp surface testing through ... · Microsoft PowerPoint - Understand...

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