Support Surfaces Laura E. Edsberg, Ph.D.

Overview Effects of Pressure on Tissue Support Surfaces Testing Support Surfaces

Effects of Pressure on Tissue Pressure Ulcer Any lesion caused by unrelieved pressure resulting in damage of underlying tissue. P=F/A

Variables Pressure Shear Friction Moisture

Tissue Interface Pressure TIP Minimal pressure to collapse capillary 32 mm Hg - Numerical “Standard” Landis Study Age Health Shear

Tissue Pressure Pressure on subcutaneous tissue may be 3-5x > than skin pressure Bony prominences

Effects of Pressure on Tissue In Vitro In Vivo

In Vivo Results Pressure ulcer tissue has significantly fewer fibers, but the fibers are significantly longer and wider What does this mean to the structure and support functions of the tissue ? How can this information be applied ?

Tissue Load

Pressure “The perpendicular load or force exerted on a unit of area” (Collier 1999)

Shear “The mechanical stress or load acting parallel to a plane of interest” (Collier 1999)

Strategies for Changing Pressure & Shear

Offloading Removes pressure from high risk areas or areas with ulcers Can be done with pillows, devices and/or beds

Elevate Heels There must be space between the heel and bed Use pillows to elevate heels off the bed surface Avoid hyper-extension of the knees Check for injury from splints when used for heel elevation

Repositioning Reposition bed-bound individuals (time should depend on patient (1-3 hours) Reposition chair-bound individuals every hour Reposition even while on special beds

Positioning Devices Teach individual to reposition using the trapeze Use lifting devices to move individuals who cannot assist Place pillows or wedges between knees and ankles

Head of Bed Elevation Limit amount of time head of bed is elevated to reduce friction and shear Maintain the lowest possible elevation Avoid more than 30° head-of-bed elevation unless medically needed

Side lying position Avoid positioning directly on the trochanters Use the 30° lateral inclined position

No Donuts Do NOT use plastic rings or donuts for pressure relief Can cause larger area of tissue injury because of intense pressure along the donut

Support Surfaces Most pressure reducing devices are more effective than standard hospital mattress Types –Overlays –Mattress replacements –Beds

Support Surface Criteria Low surface tension No/low recoil 6  of freedom/motion Low friction & shear Control moisture & heat Low TIP

Types of Support Surfaces Static Surfaces –Category 1 –No moving components –Overlays/foam and gel Dynamic Surfaces –Category 2 –Have motion –Alternating air Low Air Loss Beds / Mattresses Air Fluidized Therapy Mixed

Design and Technology of Support Surfaces Pressure Reduction –The reduction of interface pressure, not necessarily below capillary closing pressure (AHCPR 1992). Pressure Relief –The reduction of pressures below capillary closing pressures (AHCPR 1992).

Pressure Reducing Device A support surface that has a lower TIP than a standard hospital mattress TIP is greater than 32 mmHg Comfort

Pressure Relieving Devices Consistently reduce pressure below capillary closing pressure (32mmHg) Indicated: –Prevent skin breakdown in people who cannot be turned –Prevent further skin breakdown –Promote healing in patient who already has skin breakdown involving multiple surfaces

Three Physical forms Overlays Replacement mattresses Integrated bed systems

Pressure Reduction Systems Overlays Replacement Mattresses Static or Dynamic Systems

Overlays Sheepskin Pads Foam Water Gel Air

Constant Low Pressure Support Surface Devices

Static Systems No Moving Components –Overlay or mattress –Foams –Water –Gel

Constant Low Pressure Support Surface Devices

Constant Low Pressure Support Surfaces Maximize skin contact area to reduce peak interface pressures –Foam –Gel –Fiber –Low Air Loss –Air Fluidized

Constant Low Pressure Support Surfaces The redistribution of skin interface pressure over as large an area as possible.

Constant Low Pressure Support Surfaces Interface Pressure Measurement

Have Motion –Pressure relieving/reducing –Typically use electricity –Alters inflation and deflation (dynamic) –Examples: Alternating-air Dynamic Systems

Alternating Pressure Air Support Surface Removes pressure from a localized skin area Changes the interface pressure on the skin over time by periodically inflating and deflating air cells under the body Redistributes the pressure on soft tissue and encourages reperfusion of the previously supported areas

Alternating Pressure Air Support Surface Devices

Alternating Pressure Air Support Surfaces Made up of interconnected air cells that cyclically inflate and deflate to periodically remove pressure from soft tissue Alternating cells Head section

Alternating Systems Remove The Pressure Over Time Tissue Interface Pressure Measurement

Alternating Pressure Air Support Surface Removes pressure over time Promotes movement –Healthy adults move every five minutes –Alternating systems move for the body every five minutes Proven to reduce the incidence rate of pressure ulcers in high risk patients Mimics natural body movement Re-establishes blood flow

Clinical Practice Guidelines Dynamic Support Surface –If the patient can assume a variety of positions without bearing weight on a pressure ulcer, – if the patient fully compresses the static support surface, –or if the pressure ulcer does not show evidence of healing.

Pressure Relieving Systems Low Air-Loss Systems Air-Fluidized Systems

Low Air Loss Pressure relief Interconnected woven fabric air pillows that allow some air to escape through the support surface. Can adjust to level of pressure relief Potential for maceration –Excessive moisture

Air Fluidized Air Fluidized Pressure Relief High rate of air flow to fluidize fine particulate material (such as sand) to produce a support medium that has characteristics similar to a liquid.

Clinical Practice Guidelines Low Air Loss Bed or Air-Fluidized Bed –If a patient has large Stage III or Stage IV pressure ulcers on multiple turning surfaces

Lateral Rotation Lateral Rotation Potential for pneumonia –Pulmonary deficits of immobilized patients

Support Surfaces in Chair For individuals who spend majority of time in wheelchair: –Use pressure reducing cushion –Instruct to also relieve pressure with hand lifts if possible –Consider changing chair to tilt/recline for more pressure distribution

Assessing Performance of a Support Surface Bottoming out –Surface totally compressed often weight related –Use hand check, should not be able to feel person Memory in foam –Shape remains Bunching in gels Deflation in air filled

Monitor & Document Document interventions & outcomes Multidisciplinary approach Periodic re-evaluation

Pressure Ulcer Treatment Avoid ALL pressure on the ulcer Institute measures to prevent additional injury Prevent Pressure Injury

Evaluation of Support Surfaces

No government standards or rating systems exist to evaluate support surfaces Chosen primarily on manufacturer’s claims

Importance of Tissue Interface Pressure One of the major causes of pressure ulcers Pressure management Assist clinician in selecting the most appropriate support surface to meet patient’s needs

Support Surface Evaluation Healthy Subjects Body Sites Single Site Sensors Pressure Mapping

Body Sites Evaluated Scapula Elbow Trochanter Sacrum Heel

Copper Contact Strips Pressure Sensor Inflatable Capsule Tape Placed Here Wires Air Hose Connection Electrical Connection

Single Sensor Measurements Common testing procedure -10 subjects (convenient sample) -Trochanteric site -Three sets of three readings -Average highest reading for each set

Example of Gaymar Protocol Trochanter (mmHg) Set one Set two Set three mean

Single Readings/Different Method of Reporting Data - Trochanter (mmHg) Set one Set two Set three mean

XSensor System

Pressure Mapping Measurements Twin Cities testing procedure  Three subject (average frame)  Will report any site requested  Report average individual pressure (mmHg)  Report Maximum pressure (mmHg)

Pressure Mapping

Pressure Mapping (0-50mmHg) Key mmHg

Pressure Mapping (0-100mmHg) Key mmHg

Pressure Mapping (0-150mmHg) Key mmHg

Critical Analysis of Test Data Source of data Number of test subjects Test site reported Single/multiple readings Average of readings/maximum readings Key for pressure mapping

Clinical Significance of TIP Provides information on the performance of a support surface May help differentiate between products Standard criteria for evaluation of support surfaces currently Tool used by clinicians to determine which support will best meet patient’s needs

Support Surface Initiative NPUAP - National Pressure Ulcer Advisory Panel –Tissue Integrity –Lifespan –Terms and Definitions

Conclusions No magic number No standards in place Relieving vs. Reducing Critically evaluate testing